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 .

http://wxrisk.com/MODELFOLDERS/today/jan18/12gfs_500_120s.gif
http://wxrisk.com/MODELFOLDERS/today/jan18/12gfs_500_144s.gif

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 .
http://wxrisk.com/MODELFOLDERS/today/jan18/12gfs_500_168s.gif

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
http://wxrisk.com/MODELFOLDERS/today/jan18/gfs_slp_144s.gif
http://wxrisk.com/MODELFOLDERS/today/jan18/gfs_slp_168s.gif

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 .
http://wxrisk.com/MODELFOLDERS/today/jan19/f132.gif

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.
http://wxrisk.com/MODELFOLDERS/today/jan19/f144.gif

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.