Thursday, January 25, 2007



As I go about explaining why I am about to bark I have set up key premises. Yesterday I made the following statement in the blog.... and it is really important you read it so you understand how the pattern is going to change at the end the month in such a manner so that there is likely be a significant winter storm over the East Coast of the US. Please read this statement carefully

from yesterday
You see the main problem have right now is that all the shortwave activity coming out of STJ / southern branch is over northern portions of Mexico and S Texas. In the current flow... and in the pattern over the next 7 days... these S/Ws cannot Gain enough Latitude so any surface development is over the Northern Gulf and the Lows end up sliding off the SC and GA in ENE direction.

However if we do enter the process undercutting the Ridge in the last few days in January and early FEB this will (as I said) establish a Split flow pattern. And more importantly the S/ws coming in across the Southwest will have enough time and distance to gain latitude as they head E or ENE . In other words IF you have a shortwave over the SE Texas that tracks in a 060 direction (ENE) it's going to slide out to sea as will the surface Low. The same track however with a shortwave which is starting back over the Southwest... well now you are in a different ball game.

Recall the weak Low that moved off the NC coast this past weekend ? Originally that Low was played up as 1st decent moderate snow for Middle Atlantic... yes several days out I did that as well. The reason? Most forecasters could NOT believe the pattern which has featured the prominent and very strong Southeast Ridge for the past 75 days would suddnely give up so quickly. But that is exactly what has happened.

That is why the shortwave which came through with the Northeast states on the Arctic front today is going to form a big Low so far out to sea because ....there is no Southeast Ridge to keep the Low closer to the coast.... That is why the area of Low pressure develops the Northeast Gulf in 60 hrs and moves off the GA SC coast in 72 hours is NOT going to climb further up the coast.... because there is NO Southeast Ridge.

The pattern change over the past 5 days has been so complete so massive and the PJ has become so dominant that any sort of Low that develops in Eastern Texas the Delta or along the Gulf Coast is quickly whisked out to sea....because we have no Southeast Ridge !!! and because we have no sustained negative phase of the NAO.


This pattern is NOT going to change unless something makes it change. We also have to keep in mind that we have no hint at all on a -NAO on any of the models. The PNA ridge is so massive and strongly positive and the flow is simply too fast to allow any sort of buckling in the jet stream over the North Atlantic to support a -NAO.

This leads to two important problem with respect to getting snowstorms for the East Coast. Right now in this pattern all the Arctic High-pressure systems are dropping down from western Canada into the lower Plains. At that point the Polar Jet tuns ENE so the HIGHs scoot across the Deep South then move off the Southeast coast. This of course shuts down the Gulf of Mexico as well as force the fronts deep into the Gulf. Low pressure areas are NOT forming over AL or TN but over or near New Orleans or in the North Central Gulf.... and in this flow that means Out to sea!!

As I stated yesterday there are only TWO ways to get out of this trap.
One way is to to have the S/Ws in the southern stream start out further WEST --- such as the Southwest states or perhaps even the Central Plains so that the same ENE flow of the PJ ....-whch has been taking these Gulf Lows off the SC coast and out to sea ... is now taking these Lows into TN and NC / VA. In this possible solution to the snowless trap for the Eastern US the overall pattern has not really changed .... what happens is st that the hypothetical shortwave which triggers the surface development is starting out further to the North and the West so it simply has more time to gain latitude.

TWO the Other solutioin is to have more and more energy coming over the top Ridge in western Canada plunging into the Plains states which forces the trough to become very deep and very powerful.... taking on more of a V shape then the broad U shape than what the trough is now in.

We can see many of the medium-range models are beginning to develop the second solution quite nicely. Here is the0z Thursday GFS at day 9 at 500 MB... and what has happened is a whole new surge of energy has dropped in from over thetop the Ridge on the West Coast of North America and has forced the trough into a large EGG shape.... with the bottom or rounded point of the EGG reaching into the central and Lower Mississippi Valley. This of course generates some sort of Llow pressure area developing over the Mississippi Valley or perhaps Tennessee Valley... but because it starts out at a further north latitude the whole system gets to track further to the North which brings the threat of significant winter to much of the eastern US.


At first glance one might argue that this pattern amplification could be an over reaction from the op GFS since it occurs after the model truncate at 180 hours and often that is when the model comes up with some thing that is goofy. However the 12z Thursday op GFS closely matches the European from Wednesday as well as the European runs from today...
many of the 0z GFS ensembles strongly supports the operational run ... pay attention to the particular members.
p01 p01 p05 p06 p07 p08 p09

The 12z op GFS continues this trend; you see what is happening here that this huge surge of energy coming over-the-top the Ridge in western North America is forcing the PV --polar vortex -- to drop dangerously far to the south by D10. Again this is NOT a recent model development but a trend I have been seeing since Since 0z WED and even some hints before that. Take a look at the three maps below -- at 500 MB -- from the Midday Thursday 12z GFS and notice how the vortex is being dragged into Manitoba.

What this does is
1) bring in even More Arctic air to dominate most of the nation especially east of the Rockies... 2) establishes the mean trough over the Mississippi Valley.... which is WEST of where it is now.

Because you have the mean a trough position over the Mississippi Valley you must also have a downstream Ridge developing which in this case is over the Southeast and Middle Atlantic states. Thus any sort of Low pressure area which develops in the Delta is forced to take more of NE track as opposed to E or ENE.
This is exactly what happens here at 192 and 204 hrs on the midday Thursday Op GFS as well as many of the other medium-range models.

More significantly the European runs are very consistent over the few cycles... and closely matches the0z and 12z operational GFS . Day 6 and Day 7 --- again notice how the overall trough and Day 7 sharpens up dramatically http://www.meteo.psu.edu/~gadomski/ECMWF_12z/f144.gif

I have seen the operational European past Day 7 and the model develops a significant TRIPLE point Low area over the Tennessee Valley that moves ENE off the coast of VA or Northeast NC at day 8.5 or 9. I think that is a little too far to the south but it's the general idea in the overall sense.

The midday GFS ensembles are very supportive of the operational solution as well.... with many members showing a significant system tracking east Northeast off the VA or NC coast... some of the members have a more Northeast track.

The critical issue is going to be what shaped as the trough move into after Day 6? According to most of the medium-range models the broad U-shaped trough is going to change into a much sharper and elongated elliptical trough . If that happens then when Low pressure forms over the Delta it will be able to track further up the coast than the last several systems and there will be a significant snowstorm for much of the East Coast.


that being said to me also emphasize again that is a very fine line we are going to have to walk with the system along the East Coast. Take a look at the 12z Day 8-10 op Ecmwf and op GFS maps... they both show a huge amplified trough whopse center or axis is over or along the Mississippi vally.

Because we are not going to have a large cold HIGH to the North and we do NOT have a -NAO temperatures are going to be very critical and very sensitive along many of the I-95 cities in this event FEB 3.... ASSUMING of course it does develop. If we end up getting too much of Ridge over the Southeast the Low will track further north so iot will be more of a snow to ice to rain set up for the big cities of I-95.. On the other hand If we don't get enough of a Ridge the Low stay south and much of the snow and/or ice will fall across places such as TN NC and VA .

Lastly as a move in February the solution offered by the midday operational GFS at day 10 seems very reasonable to me and it is supproted by the 12z GFS ensembles

Wednesday, January 24, 2007

Hey Baby it do what it do

The great philosopher and musician Ray Charles was once asked in interview how his music appealed to so many different groups of people... ethnically economically racially... and he said "Hey baby it do what it do..."

Which is really when I think about it sort of a variant on the philosophical underpinnings of Aristotle Marcus Aurelius and Dr. Hannibal Lecter. Of each thing we muts what does it do? what is its nature? What is its significance?... How does this exactly relate to the current pattern we have have over North Ameica? Well it's kind of entertaining watching the various forecasting services and a few individual forecasters continually try to assert that the new cold pattern is not really going to be all that cold... which is what they were saying last week or that it isnt going to last all that long.... then in the very next sentence forecast the cold pattern is now going to last into Midle of February ...but THEN it breaks down...

"Hey baby it do what it do..."

I think it's a little harsh to assert that such a warm biased forecast for second half of FEB and March is delusional but for life for me I cannot understand what the REASONING is behind that sort of call. The El Niño continues to weaken at a dramatic pace and surely even the most hard-nosed stubborn warm biased forecasters have to see the significant difference between the pattern of November and early December and the current pattern and what we will likly see in early FEB. Just like the data is strongly correlates that when you have moderate / strong El Nino you have a mild winter pattern in North America... it is equally strong that when you have weak El Niño conditions you end up with a colder to much colder than Normal over the central and eastern CONUS.

We'll start by taking a look at the operational GFS at 1am WED... as you can see there a pretty strong shortwave which is crashing underneath the Big west coast Ridge. This is a process known as undercutting and allows the Ridge over the West coast of Canada to become a OMEGA RIDGE or a REX BLOCK.

Note the 2 S/Ws... one coming into N Calif and Oregon and the other dropping south from western Canada about to enter eastern MT.

This process is called undercutting and IF it does in fact occur then we are going to significantly increase the chances for much of the central and eastern US seeing a snowy pattern as a month comes to an end and we move into February. But first the Undecutting has to occur. Seeing it a model is NOT the same thing as reality.

It do what it do ...

The undercutting process will SPLIT the flow which would significant increase the activity in the STJ/ southern branch which of course leads to increased chance of seeing systems develop either in the lower Plains and Deep South and NOT the Gulf Coast.

You see the main problem have right now is that all the shortwave activity coming out of STJ / southern branch is over northern portions of Mexico and S Texas. In the current flow... and in the pattern over the next 7 days... these S/Ws cannot Gain enough Latitude so any surface development is over the Northern Gulf and the Lows end up sliding off the SC and GA in ENE direction.

However if we do enter the process undercutting the Ridge in the last few days in January and early FEB this will (as I said) establish a Split flow pattern. And more importantly the S/ws coming in across the Southwest will have enough time and distance to gain latitude as they head E or ENE . In other words IF you have a shortwave over the SE Texas that tracks in a 060 direction (ENE) it's going to slide out to sea as will the surface Low. The same track however with a shortwave which is starting back over the Southwest... well now you are in a different ball game.

By day 8 on the 0z op GFS ... the two s/w... are GONE because the op GFS past day 8 suffers from Model resolution truncation ... which is a fancy way of saying the model past day 8 blows Chunks .

The 0z day 9 and day 10 ECMWF with its vastly superior model resolution has NOT lost these two S/Ws and this results in a pretty good over running pattern by Day 10.

The midday WED 12z GFS has caught on to this trend and is now showing these two S/Ws in a much better depiction. The shortwave which undercuts the Ridge near Oregon / N California is much stronger at D6 but of course the model resolution is still pretty good. At 192 hrs... when the model resolution is truncated we can see that the midday operational GFS has two fairly strong shortwaves but the southern S/W appears to be getting stuck over the southern Calif/Vegas area. Not surprisingly given the bias of the operational GFS the model put all its emphasis on the shortwave that stopping into the coat is at 192 hrs ... and it is this feature which develops a system for D9.

The midday ECMWF at day 7 again is showing significant activity over the western CONUS with two very distinct and powerful S/Ws. The Midday at day 9 does show some sort of triple point surface Low that brings a pretty decent amount of snow to the Tennessee Valley & Middle Atlantic states... followed by a bitter Arctic out break at D10

this idea is supported by the 12z Op GFS as well .

One last note... the 0z op GFS at 312 hrs was trying once again to knock down the Ridge over old western North America trough and develop a flat Ridge over the Southeast which of course end the cold pattern east of the Mississippi River.

But we can see from this link most of the ensembles 0z data does not support that idea at all

nor does the 312 hr 12z ensembles mean. As we can see the white lines are showing the operational run and the trough trying to reform at West while the fMost of the members show the trough staying strongly over the eastern North America

hey Baby it do what it do

Monday, January 22, 2007

COLD then NOT cold... COLD then NOT cold

how will start off with a review of the weekly ESNO data. There are two primary sources that most forecasters use in terms of getting the weekly data from the various ENSO regions. The first one is from CPC.. and there ENSO weekly SSTA numbers comes out every Monday. The cycle runs from Thursday to Wednesday but for some reason it takes five days for the CPC to get the data published to the web site but you can see here.


the other primary source for ENSO data is Australian Bureau of meteorology which also issues weekly reports on the variouis ENSO regions.

However the AUSSIE data cycle for the enso regions runs from SUNDAY to SATURDAY but they manage to get their data on to their wenb site in TWO days.... not Five. WHY this is the case I dont know.It is NOT my fault. The point is that since the Aussies data cycle goes much later in the week I think that it's data is more liable and a more accurate.

In other words suppose you has two models to consdier.. one from last night and then the latest run. Which one would you prefer to put more emphasis or reliability on (assuming the data in both models was the same?) Clearly you would prefer to or favor of the most recent model as opposed the one from yesterday with a day before.

Last week showed CPC has ENSO 3.4 region SSTAs were holding at +1.0C but the e Aussies showed a drop from +0.92 to +0.83 ( about -0.1 degree C). It's probable that the reason that CPC did NOT show that 0.1 drop.... is because the drop occurred in the THURSDAY FRIDAY SATURDAY period which would be after the cutoff time for the CPC data cycle.

As of today the Aussies weekly ENSO 3.4 dropped again from +0.83 to +0.67. Hhowever... if you look at the first link above you'll notice that as of JAN 20 CPC shows a drop IN ENSO 3.4 from +1.0 to +0.6... which is huge WEEKLY drop.

One of the claims that some forecasters were arguing back and forth during the months of November and December was that there was a difference a quality between the data from the climate prediction Center and the Aussies. But as I have explained part of the discrepancy is because the data cycle. And this case we did not really see a drop of -0.4c in 1 week in ENSO 3.4. Instead the data at CPC is playing "catch up" to what Aussie data.

The reason why I mention all of this is because I think any reasonable person can now conclude that there is no significant difference between the data onENSO SSTA between the Australians and CPC.

I will briefly touched on the former snowstorm threat for FRIDAY January 26. There really isn't much more to say. The operational GFS and the GFS ensembles were wrong and the other medium-range models and their ensembles were correct. As a general rule there are very few times when you have a case where one particular set of models ( such as the GFS and the GFS ensembles or say the CMC or CMC ensembles) show one particular event while the other models have no hint of it... only to see the GFS turn out ot be correct.

The reason for this is that the models especially in the MR and LR are now so good that when you have MODEL... lets call it MODEL XYZ is showing an event which is not supported by Models B C D and E even though the potential threat is getting closer... that should be a warning bell to you that something is wrong. Typically what happens is that when MODEL XYZ is showing an event at day 4 5 6 or 7 ... suaully within a run or two SOME of the various other Models will begin to shift IF MODEL XYZ was correct to begin with!!!

Typically the artgument then becomes WHERE the Low is going to form OR how far north as going to track OR where the ridge is going to set up.... etc etc. But over the past several days the problem was the operational GFS and many of the GFS ensembles is that they were the ONLY models that showed the JNa 25 storm tracking that close to the coast . None of the other models had even a hint of the major storm for East Coast. That's a totally different kettle of fish.

One of the problems we have with the current pattern --as I talked about on the Saturday evening update -- is that if you look at the upper air at say 500 MB you will see some important features as to WHY the system on Thuirsday develops off the coast on Friday.

  1. The first is that the Ridge which we typically want see on the West Coast is not really there but well inland over the Rockies... which is kind of Far East.
  2. This means that the PV position in eastern Canada is also to be East. Thus any sort of wave which is moving into the trough position aong the East coast is going to develop EAST of the coast. If the trough position was say back by 80° west longitude THEN we would have a much bigger snowstorm threat for the Northeast. But again because of the Ridge on the West Coast is now over the Rockies everything shifted to the east... and hence the development well off shore.

Let this be a lesson to you. It is not simply a matter of getting the right overall pattern at say 500 MB or 700 mb or 840 mb... but the system also has to develop in a fairly narrow area to bring significant or heavy snow to the mid-Atlantic and the New England region.

Once the system is off the NE coast on Friday Arctic air mass will plunge into the Midwest and Northeast US with strong N winds. As long as we keep that strong West coast Ridge then ther wwill be a series of srong cold Arctic HIGHs that will drop down into the central lower Plains then going east across the Deep South. This does two things... first shuts off the Gulf of Mexico as any moisture sources along the Gulf coast. Second er once these Highs reached the South East Coast and move off ... winds will turn around to Wes direction for bringing a day of mild temperatures over the Plains and Midwest and the Northeast before the next Arctic blast passes through. Essentially over the next 10 days we are looking at least three arctic cold fronts will into the Midwest and the Northeast.

The last point I want to bring up is the the last couple runs of the operational GFS. I think it should be obvious at this point that any attempt to break down the cold pattern and the monster Ridge over the west North America is ludicrous and most skilled forecasters should be all to detect bullshit when they see it on a model.

Here is the 0z GFS at 312 hrs and as you can see ... the strong West Coast Ridge is either been destroyed or cut in half by the powerful Pacific Jet. And if this work to turn out to be correct it might have implications for the entire pattern with some sort ridging developing over the Southeast.

We see the same sort of pattern at 6z and again at 12z Monday in the week 2 time frame.

However even a cursory glance of the ensembles shows how obsolete ludicrous this idea is as the overwhelming amount of model data from the 0z 6z and 12z GFS ensembles show the Rudge on the West Coast holding.

For example this link from the 0z run compares the white lines which represents the operational run of the GFS to all the other ensemble members. As you can see from the various blue red and green lines there's no support for the operational GFS trying to develop the trough over the West Coast and knocked out of Ridge.

Likewise we can see the same thing at the 6z GFS--- again note how the white lines are a huge model outlier when compared to what most of the model members are showing.

And this continues at 12 see on the operational GFS as well.

Saturday, January 20, 2007

SATURDAY NIGHT SPECIAL -- bang bang or woof woof ?

This is a special Saturday early evening report and I'm going to be talking mainly about the potential for a SECS / MECS event that has a lot of people all of buzz for Jan 25- 26.

Just remind y'all a S.E.C.S. event = Significant East Coast Snowstorm is something like a typical 4 to 12 " snowstorm...
a MECS = major East Coast Snowstorm such as widespread 8 to 16 inch snowstorm and a HECS which is a Historic East Coast snowstorm is something like a widespread Snowstorm that has 10 to 20 inches of snow with areas > 20 inches in the I-95 Metropolitan corridor.

I know that JB's been banging the drum here for several days as have I and several other well-known forecasters with regard to January 25... certainly the potential is there for a SECS or MECS event but I for one am NOT yet convinced that this event as shown by the last several runs of the operational GFS and the GFS ensembles is going to take place as those particular models are showing.

In other words in dealing with the time frame we are-- the event is still five to six days away-- we could end up with a large intense LOW off the East Coast but not close enough to produce any sort of significant or heavy snow except for perhaps far eastern New England... and yet because we are still dealing with five to six days in time at that medium-range it would STILL count as a "HIT" or a "good" forecast by the medium-range models.

Of course if you are all excited -- like I am -- about this possible event and you think that the GFS is going to verify correctly and you a may be salivating at the propsect of 12 inches of snow at your house.... well thats great. BUT suppose the other MR are correct... and we get a Big Low off the East coast but say 200 or 250 miles further to the east... well you are going to hear alot of bitching and complaining no end from the general public as well as weather hobbyists and weenies.

You see this is the risk that one pays by banging the drum so convincingly and so loudly. Moreover I can tell you that this is a source of considerable frustration with a lot of meteorologists... and if you are a weather hobbyists or member of the general public I don't think you fully understand the frustration that many of us feel the private sector. Just because one forecast or well known private forecaster Company happened to be on the Cable news a lot doesn't mean that I have to take the blame if your forecast goes wrong.

IF these other medium-range models turn out to be correct and those banging the drum for the big snow in the NE (like the GFS and GFS ensembles are showing) turn out to be wrong those forecasters like me who will have urged caution will be ignored even though we turned out to be correct.

The only thing that the public as well as weather weenies are going to remember if this event does NOT happen is that JB and a few other forecasters have been letting the BIG dog bark. And suddenly every single meteorologist will be viewed as have made the same forecast. The distinction between those who are making the big snow forecast and those who were not will be lost.

Interestingly when I used to post on some of the weather forums on this very point .. that there is reason why sometimes there is a little animosity between the various private forecasting companies and individuals... a lot of the more ignorant and slopeaded folks out there have the viewed this argument as nothing but jealousy or sour grapes.

But it does not matter whether we are talking about weather forecasting or taxes or medicine or stock trading... when you end up getting blamed for somebody else's mistake while at the same time u work tirelessly to show that you didn't agree... well that can really piss you off.

In taking a look at the 12z SAT op-GFS... this 500 MB map has a lot of features to talk about. And one of the main points I want to make is that even when you have all the pieces or almost all the pieces you need to get a snowstorm (with regard to the Upper Levels of the atmosphere) ... things can STILL go wrong. That's why is so difficult to get the "big dog" off the leash.

This map shows several features...
yes we do have a 50-50 low in position. It's not the greatest 50-50 low full-time but it's definitely there. We have a nicely situated PV ... a fairly strong Ridge on the West Coast/ Rockies... and we appear to have phasing occurring between the strong system dropping in on the northern branch and the remains of the system coming out of Southwest. In addition the phasing was occurring over the Mississippi Valley which is ideal and the trough alignment or axis is NEUTRAL....

So what seems to be the problem? And why aren't the other models picking up on the op GFS and GFS ensembles?

Well this is one reasons why I am not a big fan of using the operational GFS for forecasting East Coast snowstorms. In the early outlooks ... say Day 7 thru day day 10 the model often ends up crushing systems in the STJ/ southern stream which is what the Op GFS and many of the GFS ensembles were doing just a few days ago. Now that we are within the Day 7 time frame the cold bias of the model and the ensembles manifest itself in a different manner.

Now we see the same tendency in the current runs of the model and again this applies to the GFS ensembles just as much as it does the operational run... to over phase and / or over develop systems. So while we can use the GFS ensembles in some ways... all of them have the same problem that the operational run does. So when you look at the 12z Saturday GFS ensembles and you see eight of the 11 members strongly supporting the idea of a major Low off of the Delmarva or New Jersey or off the Southeast New England coast Jan 25... they all may be showing the same problem/ affect if the cold bias.

The midday as well as the 0z SAT op ecmwf does not show the northern branch dropping in phasing with the southern system.

WHY? The Europeans hang in the southern system back too far and as a result there is no phase and the primary Low develops only from the northern stream shortwave so what we get is the ocean Low off Cape Cod or the Gulf of Maine.

This is what the 0z and 12z Ukmet is showing as well as the last few runs of the operational CMC.

As a general rule I like using the European model over the operational GFS because of these various bias problems that the model has. However over the last two years the advantage that the European models has shown historically has now disappear in the 24 to 168 hr time frame. And the best-known case of this has to do with the HECS event from ast year for the Northeast and specifically New York City. If you recall the European model DID show the Low nut had the Low further south.... while the GFS was correct once we got within 72 hours showing the Low further now along with the stalled comma head snow band. That being said I must also point out that the operational European at least did have the Low. We did not see this sort of huge model disparity that we seeing Now.

There is no reason one way or the other to be particularly optimistic or pessimistic at this point. This evening is another run and tomorrow is another day.

Friday, January 19, 2007

NE USA winter storm threat for Next week JAN 25???

In dealing with the next 2 POSSIBLE winter events for the Northeast we have to keep a few things in mind.

The system that's coming out of the Southwest today in this weekend is come in providing major snowstorm for places that don't normally see at such as Northeast New Mexico Northern Central Texas Oklahoma and even significant snow into places such as northwestern Arkansas and Missouri.

The big issue with this first system is how fast does the upper level support --also known as a shortwave --weaeken as it comes east over the top of the flat Ridge over the southeast states.
Take a look at the short-range models humidity or the Rh fields and you'll see what happens.

The precipitation breaks out into the central Plains over places such as Missouri Illinois and Indiana while the is precipitation along the final S end of the front gets hung up over the Tennessee Valley. The northern edge of the precipitation kicks out of rapidly thru the the Middle Atlantic in a 6 -10 hr period .. while the Southern end of the front gets stuck over the SE states and there it will be mainly rain (or Ice over NC).

There is is some slight northward movement with the main surface low on some of the short-range models and that North Trend may continue. But unless the entire system is shifted North over the next few model runs that we're not looking at a significant snow over Northern Virginia Maryland Pennsylvania Delaware and New Jersey.

With regard to the bigger threat for next week. I know that one of the more popular forecasters in central Pennsylvania appears to be banging the snow drum pretty hard with regard to the event for January 24 --25. That may be correct but there's a lot of problems here which we have to work out and I'm not get one to go that far out on a limb given deal hall problems for having with this pattern.

There certainly is a good possibility that there IS going to be a major LOW pressure area somewhere along the East Coast but the whole system may also form too far off shore for many areas in the NE to see good snows. It is also possible the system may form along the NC coast and affect a much larger region of an Atlantic. So rather than be the first and the loudest and most extreme I'd rather the second or third and get it right and have the reputation that if I think its coming... there is a pretty good probability it is.

I'm presenting a couple maps here to drive home the complication we have what he system for January 25. Hhere is the bottom line: If the system in the Southern Stream or the STJ / subtropical jet holds together when it comes out early next week I'll cost Texas in the Delta... then the event that develop some East Coast as a very good chance of being a MECS or HECS.

If on the other hand the Southern system is crushed or ripepd apart then when the Northern shortwave drops into the Midwest on the PJ/ polar jet and middle of next week... we will end up with no facing off the two streams and bull had is a significant storm for New England... aka known as a MILLER B... and places such as Philly DC MD VA central PA and lower NJ would see nothing significant.

This first series a maps shows the problem very nicely... from the 12Z the run on Thursday. You can see clearly the shortwave looks very strong in the Southern branch over New Mexico and Western Texas AT 120 HRS .


By Day7 we can clearly see what has happened. The Southern shortwave gets ripped apart completely and there is nothing really left to develop at the surface .

Since the upper level feature and the shortwave has been ripped apart the only development we see is a weak area of Low pressure that forms along the Florida Panhandle or Southern Georgia which quickly scoots out to sea

As I stated d yesterday the key point here is the cold bias of the GFS and whether or not in this synoptic pattern the bias is kicking in and to what degree . As I explained in this synoptic pattern the cold bias is very evident and is likely be a major problem. We can see is by looking at the 12z THURS GFS ensembles.

This first link of course it is the 500 MB maps... as you can see many members to showing much stronger system over Texas and/or the Delta but some members also keep the South West shortwave hanging back with no phasing at all .

The surface Maps all showing much stronger system over the Gulf Coast area with a lot more significant precipitation. Some of the solutions to show significant phase some of them did not. In short data is inconclusive but there is reason to believe that the midday Thursday op GFS is mishandling the Southern system significantly.

The midday European of course shown a much bigger more organized East Coast low pressure area at a Day 6-7. And again the reasoning here has not changed from the Thursday Blog entry; as a general rule European model does very well with strong shortwaves moving through the Southern branch / STJ. And since there is more energy in the Southern branch you have more potential for storm on the East Coast January 24 --25. It's just that simple.

Interestingly the 18z GFS from Thursday showed how dramatically the op GFS can change in just one run. As I stated many times I do not like the 18z op GFS as statisticallu the data has proven conclusively (but for some unexplained reason) that the 18z op GFS is the least accurate of all for all the operational GFS runs. However in this case I'm referring to the 18z GFS to show that the European solution from yesterday as a some validity and also to show the impact of what could happened if the system coming out of the Southwest does not get sheared apart.
I have seen the FRIDAY 12z operational GFS; of course it rips up the system in the southern branch so there's nothing left to phase when the northern shortwave drops down at 120 HRS over the Midwest. This results in essentially a classic Miller B or secondary redevelopment type of MECS / HECS event for New England. The system according to the model actually closes off on very close to Cape Cod for almost 24 hours pounding much of New England with heavy snow... in a manner very similar to February 1978.

And as is the case with 90% of all Miller B SECS / HECS / MECS areas such as Baltimore DCA MD VA DE and possibly Philly and Southern New Jersey misses out on the best or heaviest snow.

Again let me emphasized that if the Southern Energy comes out as an intact feature then the 2 short waves are likely to phase and instead we could see a closed off Low over eastern NC or just off eastern NC.

Of course you have to check the midday GFS ensembles and also you could keep in mind that is not a good thing as a general rule to be in the bull's-eye D6- D8 out. The event on January 25 if it occurs would be on the weekend ... and this event would affect the synoptic pattern in keeping the deep rough over the eastern US right to the end of the month.

In fact the 0z European ensembles are very impressive with the Ridge over the West coast holding to D15 ... and the long-range European weekly ensembles continue to show the trough over yeast in US right to the middle of February.

Thursday, January 18, 2007

box of Biscuits a Box of Mixed Biscuits and a Biscuit mixer

the 1st issue to deal with is the s/w coming out of the sw states into the Lower Plains and Midwest this weekend and what it means for East coast with regard to Sunday and Monday.
There are some important changes in the midday models very early in the medium-range period -- Sunday night and Monday. The first major change is that the arctic HIGH which comes down after this cold front on Friday and Saturday does NOT drop y into the Lower Plains and instead it stays across the central Plains then heads into the Great Lakes and New England. This means that the cold air is going to be further north and the threat for significant snow and ice over Central and the lower portions of Texas as well as the upper Delta is greatly diminished. NM OK and north TX as well as MO look to see a good snow.

In addition most of the short-range models now show that the shortwave comes out of the Southwest further north. Yesterday that was taken a system to Missouri now it takes that of the northern Missouri Southern Iowa and very close to Chicago.

The primary reason for this shift has to do with the southeast ridge and eight another stronger shortwave which drops down from Weston Canada along the Rockies into Arizona and New Mexico this weekend in early next week.

Because you have one piece of energy dropping from north to south ...that is to say from the northern Rockies into the Southwest states you HAVE to get a corresponding reaction to the flat Ridge over the Gulf coast of Florida and that reaction will be to see the southeast Ridge expand a little to the north.

As a result the threat of winter precipitation with a system for the Tennessee Valley and lower portions of both NC and northwestern SC is greatly diminished in my opinion. Oh there maybe some BUT it does not look like a big deal at this point.

the model trend is clear to me... the strong s/w that comes out of the sw state that then gets crushed once it reaches Mississippi roiver is going to develop NOT a east coast Low per se... but it is an over running.

It is time for Me and others to make clear that this Sunday night Monday is NOT a coastal Low or major snow ... The only reason this event is going to be SIGNIFICANT is that its the 1st one of the season...

Not surprisingly the mid day Thursday GFS of courses screws this up since the cold air bias makes the model essentially useless this far out in time. Even though we can clearly see that the shortwave is now further north than what the model was showing yesterday and the Ridge over the southeast a little stronger somehow or another the model still takes the surface reflection of low well south of Cape Hatteras which of course makes no sense in all.

Actually I think the midday Canadian is probably the best are most reasonable with this solution regarding Sunday night and Monday

The next major problem have to deal with is that big shortwave I talked about above dropping into the Southwest states late this weekend and early next week. It certainly has the potential to bring another significant snowstorm to the central Rockies as well as a Denver area But the issue is that the MR models are having real trouble figuring out what to do with the shortwave.

For example the midday GFS has another piece of energy coming in on the northern branch which ends up crushing the shortwave in the southern branch and we end up with a sheer ZONE axis ... in a SW to NE direction tracking through the Deep South and Tennessee Valley. This means that the only wave / LOW development can occur over the Florida Panhandle or perhaps far southern Georgia and the low scoots out to sea by the end of Next week

as you can clearly see from this map at 144 hours... IF the southern s/w were to come out intact and NOT get sheared apart AND we do in fact have that next strong shortwave in coming down from Central Canada in the northern branch... the potential exists for significant winter storm on East Coast. I am confident that the operational GFS is ripping up the southern system too rapidly and therefore I reject the solution as shown on the Thursday midday operational GFS.

In addition most of the GFS ensembles which also still have the cold bias are mishandling this southern shortwave so most of their solutions are not viable in my opinion.

However the midday European does not have this problem and since it handles systems on the southern stream far better than he GFS we end up with a phased development.
The European keeps the coastal ffront which develops from the Monday system along the Southeast and middle Atlantic coast . Because the model handles the southern system differently we end up getting a significant coastal Low that forms late next week. Of course the issue is how close to the coast will this Low form and will there be enough cold air in place? None of those questions can be answered at this time but because we do have a split flow pattern and we are going to have a significant shortwave hanging back in the Southwest that will come out in SOME form or another the next several days has to be watched very carefully for the potential for winter storm on the NE Coast.

It is also possible that the system in the southern stream might get ripped apart and if that is the case we will end up with a Clipper system moving thru with a reinforcing arctic cold front
the other aspect to the potential for the storm on East Coast late next week is that this Low has major implications for the overall pattern in the last week of January and into early February.... and in particular which model is correct in terms of the Arctic blast after the 25th January.
As you know the last few runs of the operational European as shown a severe arctic outbreak developing after January 25 with the Arctic Airport in all liens isn't the Deep South and 850 temperatures as low as minus for driving into Central Florida.

The European model is doing this because the development of major Low the East Coast that moves into southeastern Canada LOCKs the Eastern trough positioned in place over the eastern half of the CONUS which results in a much colder pattern. That's the next strong arctic high that develops a Weston Canada does not plunge down East southern Rockies but hates into the Midwest and East Coast. The midday European model continues the trend from the last couple of days and develops a bitter cold Arctic air mass that plunges deep into the central and eastern CONUS... with below freezing temperatures plunging into Central Florida by Day 9-10!!!

On the other hand the midday Thursday op GFS does NOT develop a significant NE Low late next week... so the trough over the East Coast is able to slide further off the coast and the pattern is able to relax a little bit in terms of the cold air eastern Mississippi River.

In the week 2 time frame the midday American model Has a couple all the transient troughs that swing through the eastern US with some cold air on Day 10-11 then relaxes the trough of bit only to rebuilds the trough day 14-15 with a severe arctic blast over the eastern conus.
Which one do I think is going to be correct? At this point I don't know although I am far more likely to lean towards the European because as a general rule the European does better with Storms on East Coast and because the GFS solution which is to crush the shortwave in a Southwest when it comes East is most likely not the correct one. It's possible we may getting a big Low in the west of Atlantic similar to what the European are showing ... just a little further to the east. This would still lock the trough in place over the East Coast provided the ocean low would move up into southeastern Canada Labrador.

Wednesday, January 17, 2007

3 Winter "events" in next 8 days for the NE CONUS?

I am not going to issue a 1st GUESS or 1st Call forecast for the system Thursday PM into early Friday morning.... primarily because the data at 0z 6a and 12z as well as most of the SREF ensembles show some serious problems. The Low develops on the TRIPLE that forms on the new Arctic front that races east across s the Midwest Thursday. The cold HIGH which EARLY Thursday morning is Over New England is sliding east off the coast...fast. Thus while we do have some WEDGE it is NOT a CAD event.
Anyone who tells you different does know their ass from a Dick Cheney

The cold air ill be a adequate for many locations in the Interior Middle Atlantic to start as snow BUT by Thursday 7pm EST the HIGH is off the coast and we have strong S winds over the Immediate East coast and over MOST of New England http://www.meteo.psu.edu/~gadomski/WRFEAST_12z/f30.gif

Inland -- say ROA CHO IAD HGR LNS ABE the low and mid level S winds will NOT be strong enough to force the warming into those areas BUT those locations will also be too far to the WEST to get any significant snow.

Key word is SIGNIFICANT snow....

In the areas that do see the heavy precip b/c of the Low's explosive development-- eastern new England --the S winds at Low and Mid levels destroy the chances of the precip falling PRIMARILY as snow. The places that see the best chance of seeing SIGNIFICANT SNOW will be CEF CON EEN and much of western ME. Once this system 35N lat by Friday morning it will go BOOM with its MSLP dropping from 1000mb to 972 MB 12 hrs later... 28 MB in 12 hrs so this is not just a boom but a BOOOOOOOOOOM!!

As I stated yesterday the really important aspect to the storm is how it sets up the conditions for the next event which will be on the the 21st into the 22nd. I am very confident now that this Triple point LOW on Friday will in fact undergo explosive development and become a huge 50/ 50 LOW over southeastern Canada this weekend and into early next week. You really have to take a look at the pressure gradient that develops on all the models Friday and Friday night ight over the eastern third of the CONUS. This is some serious CAA action being shoved into the eastern CONUS.

But also leads to problems with how the models are handling the system that comes out of Southwest. If there are 2 immutable laws about weather forecasting point is that the GFS has a serious cold bias which becomes very pronounced when you have cold air outbreaks and some sort of surface Low pressure area that tries to form on the front. The second law is that Hillary Clinton is probably a Dyke. (Okay that really does NOT have anything to do with weather forecasting but it had things to be true)... The last few runs of the OP GFS have been showing the suppressed track which we typically see in Winter systems along the East coast.

You can see from these maps the 500 MB map from the 12z WED at 96 and 108 hrs as the main short wave passing through sent Missouri then tracks over the top of the flat SE conus Ridge thru Lower OHIO...

and the 850 Low forms over the lower Midwest near or just the north of the OHIO river and tracks due East across West Virginia and then across central Virginia.

This should show a surface LOW which is significantly for the north then what the operational 12z WED GFS is showing.
Of course the model is not going to show that at this time range because if ever there was a pattern which would trigger the GFS cold bias to manifest itself well this is a pattern that's going to show it. In fact I would of been shocked IF the GFS had NOT showed a more suppressed flat track off the North Carolina coast at this time range. We can also see from this next map that the position of the Southern low at 108 and 114 hours is significantly too far to the South and east almost over the far sw corner of GA... which makes no sense given the overall synoptic pattern.

Even so from that point the model takes the system ENE then once the Low reaches the latitude 34N it turns it sharply to the east. Thus one of the things that the operational GFS might be missing here is the flat Ridge over the Southeast. Behind this system comes more very cold air... and the potential for a more significant winter storm sometime around January 25 --26.

The 0z run of the European you can see here takes and other strong /w which drops down over the top the Ridge into New Mexico and far southwestern Texas and phases it with the next strong Arctic shortwave dropping in on the PJ across the Great Lakes. This results in a major storming off the Southeast coast and threatening the Mid Atlantic and New England areas while with a major snowstorm. The 12z GFS does not show this because it takes the s/w that drops in over western Texas and close it off over the Southwest with the operational run showing the 500 Low RETROGRADING off the Southern California coast at 168 -192 hrs. Thus the operational 12z GFS only has the strong northern shortwave and the cold front --- Manitoba Mauler type Clipper diving across the Great Lakes with note the Southern system to face with.

The Midday 12z WED euro is fairly consistent with the 0z run but because it hangs back the energy over the Southwest states a little longer -- again a common bias of the European model-- the phases is not as direct as what we saw on the 0z run and as a result the system takes already organizing makes a wide turn off the Southeast coast at 204 hrs . It's still a significant threat and one should not overreact to the what the 12z WED European model is showing is at 8.5 days out in time. There is very little support from the 12 see GFS ensembles for the European big storm scenario per se but on the other hand only 2 of the 11 members of the 12z GFS ensembles shows a closed 500 low retrograding back into California.

Lastly12z 8-10 day 500 mean shows that BOTH s the operational European and it now the operational GFS a -NAO REX block developing in the area between southeastern Greenland and Ireland. This is assuming that the models are correct would indeed count as a strong - NAO Block.


more later

Tuesday, January 16, 2007


Ever have one of those days where you have so many problems because of your owns success that you just fall behind the matter how hard you try and a stick the schedule?
I still have not made it to the gym and I still No inner yet and this is already 90 minutes late.

If you recall a couple blog entries from way back last week

Saturday, Jan 06 the COMING STUNNING pattern flip
JAN 8 -- The trend is MY friend

In those entries I made two very important points. The first one was that by any definition of terms one wanted to use the pattern was going to flip provided of course if you had a correct understanding what was driving the atmosphere. Over the weekend a well-known meteorologist came out with some specious assertions about what constitutes a pattern change ... and used a certain criteria which nobody ever knew about until he asserted it.

The other important point I made is that it's imperative that one simply does NOT focus on ones own backyard as to whether not there is a pattern change. For example it is of course easily possible for a significant pattern change to occur over North America but at your particular location say the East Coast or perhaps the West Coast the overall pattern in terms of actual weather conditions might not be significantly different. If one were to base their assessment on whether the pattern change simply on own backyard then you got nothing because the criteria is so subjective and professional meteorologists outa to be able to look at things in totality rather than their own backyard.

To drive home the point about how fundamentally different the overall pattern has been and what's it going to be I posted the East to images at another form or I occasionally make an obnoxious comment.... and as you can see these images really speak themselves about how totally different pattern has become.



JAN 19

The first issue to deal with is the triple point low-pressure area develops on the next Arctic front that sweeps thru Jan 118 over the Plains & Midwest and into the Northeast Jan 19. The NAM / WRF seems to be the most of aggressive with the development of the triple point low close enough to the coast so that it produces the first snow the season along the coastal areas all the Midlantic. Then as the feature movies off the coast and rapidly develops into a major system off the SE New England coast... and much better chance exists for the first significant snow for much of central and eastern New England late on the 19th.

Because we did not yet had any high latitude blocking or a 50-50 low over one-year Newfoundland Canada the surface low that forms on the triple point develops very rapidly and there's nothing to slow it down. In addition of the other problem for the coastal areas of the middle Atlantic is that the boundary level temperatures may be too warm to support all snow.
However what's really important out this feature is what it does as Nows off the coast. First the potential exists for a significant snow storm for New England as this low goes BOOM nar 40 and 70 and points to the north.

But more importantly is that this system plays a critical role in what happens to the NEXT and and potentially much bigger winter storm for the East Coast on January 21 --22.

JAN 21-22

Here is the 1st important rule than or first obstacle that must be overcome as the talk about the next system and its potential to be the first significant what do storm of the East Coast Jan 21-22. IF the Low that is suppose to BOMB out off the New England coast January 19 does NOT do so... the next event JAN 21-22 will NOT be a significant winter storm for the I-95 big cities of the Northeast and the precipitation fall primarily as RAIN.

This map from the midday European shows exactly why this is the case. The first map is the 120 hour European which shows the system from January 19 has now bombed out off th New England coast and we have a deep close cut off 500 Low over southeastern Canada - a classic 50/50 Low.

That Low feature does TWO things. After the cold front comes through in the 19th in the new Arctic High slides into the eastern US the 50-50 low blocks the cold High for moving rapidly off the coast and more importantly establishes a strong PJ in a CONFULENT flow across the Great Lakes and far northern New England. This becomes the cold air source for the Arctic high over northern New England Jan 20-21.

It is for these two very important reasons that the next system and its potential for Bringing a significant winter storm toi the NE is heavily dependent upon the first Low of the New England coast on January 20 bombing out.

Parenthetically at 72 hours the midday Euro does not have a significant system forming on the triple point over the Middle Atlantic states... and the low does not develop until it passes through 40/70..

The next important aspect to the potential for the event on January 21-22 is the strong shortwave over the Southwest. The midday European shows this feature the best.

12 z Tuesday Ukmet concurs

That shortwave is going to develop a significant amount of overrunning precip over southern & central TX and given the fact that the Arctic HIGH will be fairly South the potential exists for significant snow and ice event over places such as San Antonio Dallas into the upper Delta and the the Tennessee Valley Jan 19-20.

The midday op GFS solution as well as the gfs 12z ensembles showed a reasonable solution at this time ... with the primary Low & the secondary Low at almost equal strength with some sort precipitation passing over the Northeast but not as an impressive system.

However most of the medium-range models are just now focusing on the developing - NAO that is forming over southern Greenland. Again once his feature IS in place AND we have that deep low over southeastern Canada -- the 50/50 Low -- when the main shortwave energy in the subtropical jet that comes out of lower TX it wil be forced to stay to the south as will the primary Low.

If we were taken made a European verbatim we would see a significant ice storm over the Southeast states and then snow over the I-95 cities that turned over to rain because the cold High slides out to sea... while inland some places could see a significant snow. And in this sort of set up my new location up here near Leesburg VA could benefit from the that kind of set up.
Behind that feature we had yet another plunge of Arctic air into the central and eastern CONUS.
Taking a look at the hemispheric depiction of the mean 8-10 day 500 MB heights we can see that the operationally European which yesterday was showing a fierce REX block developing over Greenland-- and hence a very strong negative NAO -- is now no longer showing that feature!

On the other hand the operational Tuesday 12z GFS which yesterday was showing a 500 MB ridge extending NOT into Greenland but east of it into Ireland... is now showing a severe negative NAO because the model is showing strong Omega block configuration developing there as well.

The 240 hour GFS ensembles and midday are amazingly cold and show a lot of consistency.

The operational run shows a strong Arctic front already moving through with the Deep trough right along the East Coast... with several members showing equally strong troughs and some of them further to the WEST -- p04 p05 p06 p07 p08 p09

lastly have to mention the appearance on the operational GFS again of a severe Arctic outbreak developing sometime around the 26 427 the January. This first Started showing up late last week on some of the operational runs but of course we all know about the GFS famous cold bias.
Again however if we look at the GFS ensembles we see some support for the severe Arctic outbreak the operational model showing at midday.

the top row furthest LEFT represents the operational run... with the following mebers supporting the idea of a major arctic outbreak occurring at this time frame or about to occur P09 p07 p06 p05 p01

Sunday, January 14, 2007


I was going to issue a final call with regard to be developing system moving through the Midwest and southern New England but after looking over the latest data and Seeing that the main event is still 24 plus hours away I'll think all hold off until early this evening.
I've noticed looking at some of the weather boards is quite of the dismay and concern and disbelief that the warm air is going to surge as far north into New York State and southern new england as the models are showing. However the problem here is not whether one wants to arse kiss the NAM/WRF or the op GFS or even the SREF for that matter.

The problem is that synoptically there is Not a lot of support for the idea of keeping the Low level cold air in place over lower New England . There is little if any Eastern neck or extension of the Arctic HIGH now over the Upper Plains on the short range models and this makes sense synoptically.

As a result even as the LOW begins to develop the Ageostrophic circulation over Lower New England there is NOT a lot of cold air to pull south. Moreover when the 850 low is tracking too far to the north NOT to erode the cold air. When your 850 Low tracks that far to the north -- N of Cleveland and over or North of BUF and BGM you are going to have real problems keeping the cold air which is only marginal to begin with in place over Low New England.
Of course the cold air does not get into the East coast until after the Low passes off the New England coast on Monday.

I'm sure that the last few runs out some of theMR odels have caused quite a bit of consternation for those who want to see when to return to the eastern US. I was going to post on its Saturday but I want to see how things were going to play out before overreacting to what appeared to be a series of significant is handling so the features on some of the MR models.

Obviously the cold air is in place across the eastern US from the 16th into the 19th. The problem is that some of the models have been taking the next piece of energy coming in on the Pacific Jet from the far northeastern Pacific / western Canada and dropping it into the western US. This causes the Southeast Ridge to re assert itself and keeps the eastern US not nearly as cold as it might be of the otherwise. http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/00/images/gfs_500_120s.gif
However there is big difference SYNOPITCALLY this time around. Over the last several weeks we have had a strong Ridge over the Southeast or just off the Southeast coast there is been no vortex over Northern were eastern Canada to counter the power of the Ridge. As result the warm air gets to run across the eastern half of the US with no check or balancing factors. This time around even IF the operational GFS is correct we do have a large vortex sitting over eastern Canada which does keep the Southeast Ridge somewhat suppressed at least allow temperatures to remain close to seasonal normals over the eastern third of the US. That its you "BUY" the last few runs of the Op GFS.

which I dont.

Most of the other Medium range models are taking this energy that's dropping into the western US and closing off a 500 low over California and then retrogrades out into the immediate Pacific off the California coast. This results in a rex block configuration.... the 500 closed cutoff Low off the s california coast and the RIDGE over Alaska. The 0z euro shwos this nicely

And because you have a rex configuration here the Ridge is forced North which in turn forceds the trough over the eastern US deeper as well as a deeper PV... and drops a lot more Arctic air in the the eastern US .. and of course in this pattern there is no hint of a Southeast Ridge whatsoever.

OK... now that we have analyzed the Synoptic problem lets try and figure out which of these of these two solutions/ or possible scenarios is correct one.???

Here is the 0z GFS Jan 14 ensembles. As you can see the top row far left mao is the OP - GFS... and of course you can see that it has the Ridge over the Southeast and no close cutoff low over the Southwest. But as you can see about half the models in fact you have a 500 MB configuration that is much closer to the operational European.

The latest runs out the UKMET also strongly support the operational European with the closed 500 low off the California coast and rex block setting up which drives the Ridge over Alaska actually eastward into western Canada. And we can also see us on the latest run all the0z op


As we go further out in time we can see other problems develop with the operational GFS not only against the other medium range models but versus its own ensembles. Because the model screws things up at D6 and D7... the d9 and D10 solutions also model outliers and by considerable margin. Notice we can see the operational GFS here at day 10 is vastly different that what almost all the members are showing which is a huge trough over eastern US and a lot of very cold and place along with the potential for some sort significant storminess in around January 23 --24

Here's a comparison between the operational European day 8-10 500 MB mean heights on the LEFT vs the OP GFS day 8-10 on the right ... and you can see vast differences between the two. One of the reasons why the European weekly ensembles are showing such a cold blast coming into the eastern third of the US especially the Northeast in the last week of January & the first week of February is because the Ridge which is now over the Gulf Alaska is not really a +PNA configuration at all. But the development of the 500 Low off the California coast that retrogrades into the eastern Pacific and sets of the rex block results in the Ridge from the Gulf of Alaska being forced into western Canada and that DOES set up a +PNA which also finally gets rid of the Southeast Ridge once and for all.

Moreover the operational European is really developing the Ridge in the Central Atlantic Ocean and trying to drive it towards Greenland... which would be a significant development if the model is correct. The operational GFS just shows the strong Southeast Ridge now displaced a little bit into the Southwest Atlantic Ocean but it has no hint of any sort of ridging in the North Atlantic trying to drive towards Greenland Iceland.

In addition the operational GFS to showing a much weaker vortex and a much weaker northern branch....

As you can see the top row far left mao is the OP - GFS... and all you have to do is quickly scan through the different members to see a much deeper cloth over the eastern US.

You can also compare the operational run of the GFS to the other members on this link and see that the white lines which represent the operational run are not nearly as deep as the vast majority of the GFS ensembles

Therefore based upon all that I have seen so far it's pretty clear that the operational European at D10 is running far superior to the operational GFS. It should be noted that a D10 the operational Canadian has a significant snowstorm for the East coast and European is also showing some sort system coming out of the Southwest low and thee is t least some cold air in place over the Northeast that results in a possible winter threat as well but not nearly as impressive as what the operational Canadian showing. Even in the operational GFS does eventually get out to showing a couple threats and these are showing up on both the operational 0z and 6z runs... at around 240 and 300 hrs.

JAN24 6Z
6Z and 0z at 300 hrs

Friday, January 12, 2007


-45 this morning in Yellowstone Natl park in far northwest WY this morning.
LEFT MAP is MIN temps RIGHT MAP show the MAX temps

note the change in max and MIN temps over in western Canada
JAN 11 http://www.meteo.psu.edu/~gadomski/MAXMIN_NA/t0.gif

One of the characteristics of the El Niño winter is an enhanced or stronger than normal STJ- or subtropical jet. This can have a significant impact and manifests itself with forecasting problems in several different ways.

When you have a moderate or strong El Niño he subtropical jet becomes so strong that it into overpowering the PJ (polar jet) and as a result you can often get a zonal or west to east flow across the CONUS with all the Arctic air bottled up north of US Canada border. This will we saw in much of November and Decmber and when you had a four taxes situated over the Bering Sea... this sort of synoptic pattern in the general sense is more likely to be dominant and not.
Another characteristic of course it is that any sort of cold air outbreaks ends up coming in weaker than forecasted and / or does NOT lock in. I can this will we saw in the first week of December when the El Nino was moderate. This is NOT however a problem in weak El Ninos events.

Still another SEASONAL and common characteristic of Moderate El Niño winters featiures systems which are supposed to be fairly strong and take northerly tracts end up getting suppressed or shunted Eastern Northeast because of the progressive and stronger than normal subtropical jet.

Sometimes you will see in a El Niño winter where systems coming out of the Gulf of Mexico are depicted by the medium-range Models as developing into a major winter storm for the Midwest or the East Coast. Then as the possible event gets closer and closer the tracks end of shifting further to the south and east. Sometimes this can work for the benefit of those wanting snow and ice in the big cities of Northeast or Midwest. A classic case of this would be a track shown several days outgoing up the Appalachian Mountains and then as we get closer and closer to the possible event the track is shifted to the south and east so that a time event actually occurs the system is tracking through southeastern Virginia.

But on the other hand this can also work against you . When you have a very strong Arctic outbreak like we are currently experiencing and will be over the next several days the cold air plunges deep into the Plains and the eastern half the US. But without that any high latitude Blocking over eastern Canada / Greenland sometimes the cold Arctic HIGHs will drop all the way into Texas and Oklahoma and then track east across the Tennessee Valley. ( liek we are going to see over the next 4-5 days).

Because the flow is so progressive the enhanced STJ any sort of Low pressure development activity stays flat along the Gulf Coast and its tracks E or ENE tracking off the southeast coast of US... which can often result in winter weather lovers in the Midwest and Northeast nashing their teeth in frustration saying how the hell is Alabama getting more snow then Pennsylvania?

The morning weather map shows the Arctic front has driven into northern Texas and east and Oklahoma but it has NOT yet reached the Midwest b/c of the power of the the Southeast Ridge. Earlier there was some speculation that the significant shortwave coming out of the Southwest would become a Plains a snowstorm with heavy snows developing from Denver towards Minneapolis or maybe northern Wisconsin. However I argued several days ago here and in some other forums that such a forecast was bogus because of the seasonal trend one must taken consideration when you're dealing with weak and moderate El Niño winters.

In addition the model data has been very clear that the shortwave coming out of the Southwest US is going to be "suppressed " or crushed d by the strong Polar Jet dropping out of Canada. It is a GOLDEN RULE OF SYNOPTIC FORECASTNG and one that should be well-known ....when you have a s/w which is getting crushed or weakened it is very hard for the system to track to the NE or NNE. I will be issuing a FIRST GUESS for the Midwest and New England event shortly -- it's hard to believe that this point in the winter we have had so little activity in eastern half the US that this is the first one of the season I am doing here on January 12.
From what appears to me right now it looks like locations such as Des Moines Iowa Rockford or knowing at Chicago will see the best nose probably over to Detroit and then across Buffalo Syracuse perhaps Albany and then north New England. The tricky as portion of this is going to be eastern New England. No doubt that the initial precipitation over Boston will be generally rain at the start but once the 850 Low tracks closer it may shift to the south and the thermal gradient associated with this 850 Low is going to be very impressive. Additionally once the system was off the New England coast to may be some wraparound snows b/c of the comma head moisture into east New England which could produce some decent snows as the system is pulling away.

I also want to announce that I now have access to the European weekly forecasts that run out to 30 days or four weeks. These come out every Thursday evening or early Friday morning. And the latest information on these models are showing very cold temperatures the last week of January the first week of February over the entire Northeast quadrant of the country which means not only New England and Atlantic also the how Valley in eastern Great Lakes as well. That being said there is No support for the idea that Jan 15-Feb 15 are going to place in the top 10 coldest 30 days period in the last 50 years.

I am concerned that the potential exists for some sort of wave or Low pressure to develop over the Gulf/ Delta because the fairly s/w that develops a negative tils over the Mississippi Valley around January 20 --21. This is an showing up on some of the European and GFS ensembles over last few days so I think thee is enough support in ensembles that it registers as a RISK for the first POSSIBLE winter storm for the East Coast of the season. Right now it appears that the cold air is going to be around at the start but the Polar Let configurations dont look good. The lack of blocking over Northeastern Canada and Greenland is going to be a problem. You see if the Arctic high pressure systems continued to drop Deep into the Plains states then track across the TN VALLEY then off the SE coast then thigns are goping to have to occur JUST right to keep the cold air in place over the NE CONUS. We could end up seeing an event where the first cold High slides off the East Coast.... the Low develops between this high and the next Arctic HIGH that dropa out of central Canada and as result we end up going from snow to rain over the big cities of the Northeast. If we only had some high Latitude blocking to keep the cold air in place -- such as a Grenland Block OR a 50/50 Low then things would look a lot more promising and that may yet develop.