The +PNA cometh !!!!
Looking at the data in the overnight hours and early this morning it appears that I have become a WEATHER GOD. OK.... OK..... I don't really mean that but what I am trying to drive home is the idea that the significant pattern change I have been banging on at the end of the month is real . I think its clear to all now that from looking at all the data that not only is this warm pattern about to come to an end but there is increasing amount of data that shows were moving into a +PNA.
To be sure when I first post to this idea back over Nov 15 - 16 it was greated with a lot of shall we say "Negative" comments and feedback at some of the weather forums where I occasionally post. Well I don't think those folks still hold the same view!!!!!... and if they do they probably should well get out of weather business and go sell some shoes.
There is of course debate as to how long the +PNA is going to last or If the +PNA is going to be a split flow... with the southern branch coming into say California and the northern branch showing the Ridging over western Canada. But again it's time to face reality... Winter is coming so enjoy this spectacular weather while you can.
the 0z Sunday GFS at 132 and 144 hrs showed one of the most impressive cold fronts I have seen a longtime. The 850 temps at 132 hrs -- the morning of 12/1-- RIC +13C DCA +12 NYC +11 BOS +10 ALB +9... yet 12 hours later RIC drops to -3c DCA-9c NYC -8c BOS -6c and ALB -9c
http://weather.unisys.com/gfsx/5e/gfsx_850_5e.html
http://weather.unisys.com/gfsx/6d/gfsx_850_6d.html
Bloody hell... now that's a cold front!!
The other issue of concern I have expressed many times here as well as some other places is that some sort will wave of Low pressure is going to develop on the front as the southern end of it comes slows down significantly DEC 1.
The 0z Euro show this wave developing over the TN valley and bringing a early-season snowstorm to portions of the Midwest and this is now supported by the 6z GFS. Recall the rule I mentioned in a previous posting here that whenever the 6z GFS and 0z Euro agree it is always a good sign that the 0z Euro run is correct. Of course such a wave of Low pressure would delay the Arctic front at least another 12 hours until it passes through the East Coast.
http://www.meteo.psu.edu/~gadomski/ECMWF_0z/f120.gif
http://www.meteo.psu.edu/~gadomski/ECMWF_0z/f144.gif
http://www.meteo.psu.edu/~gadomski/ECMWF_0z/f168.gif
6z GFS 500 MB
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/06/images/gfs_500_132m.gif
surface map
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/06/images/gfs_slp_132m.gif
Here is the mean pattern taken from the Penn State e-wall site for Day 8-10 at 500 MB... for the 0z operational ECMWF and the 0z GFS. Again we can see clear indications on a full power classic +PNA. Of course the 0Z GFS-- map on the right side -- is not THAT impressive because it closes off a Low at 500 MB over the southwest US but as I already stated the 6z GFS does not show this feature and is very close to the operational European..
http://www.meteo.psu.edu/~gadomski/ECMWF_0z/hgtcomp.html
In addition you can see this for yourself by taking a look at the ensembles runs of the 0z GFS. As you can see a few members to hang back a LITTLE piece of energy or bend in the Jet stream over the southwest states but NONE ( not one!!!) of the 11 members show closed off Low over the SW states. Therefore the data is overwhelming that idea of the closed 500 Low over the southwest US as depicted by the 0z GFS to be BS.
http://www.meteo.psu.edu/~gadomski/ENSHGT_0z/f240.html
We can also see that by taking a look at the 240 hr Canadian and GFS ensembles Mean maps. The map in the upper left corner shows the operational GFS and again note the closed 500 Low over the southwest. However the bottom left map which is the GFS ensembles mean at day 10 clearly shows a classic +PNA as does the 0z CMC ensembles mean ( bottom right).
http://www.meteo.psu.edu/~gadomski/NAEFSHGT_0z/f240.gif
Again let me emphasized that I am not forecasting the coldest air mass of all time or anything close to historic levels or even SIGNIFICANT cold oubreak (yet) . My point is that the pattern shifting and showing signs moving into a early December 1 run of the mill Winter pattern. To be sure there is no reason to start running specials on the god awful Weather Channel (one day I have have a post about TWC and what a wretched place that has become) just yet but in my opinion any time a Winter pattern develops in El Niño year is always a good sign since there been many El Niño Winters where thehre has never been a sustained Winter pattern that has locked in place. Of course I don't know if the new pattern is going to "lock in" or last seven days and then collapse.
A case can be made for either scenario at this point I just don't know but it's nice to see this pattern developed if you are Winter lover as opposed to what we have seen for much of NOV.
To be sure when I first post to this idea back over Nov 15 - 16 it was greated with a lot of shall we say "Negative" comments and feedback at some of the weather forums where I occasionally post. Well I don't think those folks still hold the same view!!!!!... and if they do they probably should well get out of weather business and go sell some shoes.
There is of course debate as to how long the +PNA is going to last or If the +PNA is going to be a split flow... with the southern branch coming into say California and the northern branch showing the Ridging over western Canada. But again it's time to face reality... Winter is coming so enjoy this spectacular weather while you can.
the 0z Sunday GFS at 132 and 144 hrs showed one of the most impressive cold fronts I have seen a longtime. The 850 temps at 132 hrs -- the morning of 12/1-- RIC +13C DCA +12 NYC +11 BOS +10 ALB +9... yet 12 hours later RIC drops to -3c DCA-9c NYC -8c BOS -6c and ALB -9c
http://weather.unisys.com/gfsx/5e/gfsx_850_5e.html
http://weather.unisys.com/gfsx/6d/gfsx_850_6d.html
Bloody hell... now that's a cold front!!
The other issue of concern I have expressed many times here as well as some other places is that some sort will wave of Low pressure is going to develop on the front as the southern end of it comes slows down significantly DEC 1.
The 0z Euro show this wave developing over the TN valley and bringing a early-season snowstorm to portions of the Midwest and this is now supported by the 6z GFS. Recall the rule I mentioned in a previous posting here that whenever the 6z GFS and 0z Euro agree it is always a good sign that the 0z Euro run is correct. Of course such a wave of Low pressure would delay the Arctic front at least another 12 hours until it passes through the East Coast.
http://www.meteo.psu.edu/~gadomski/ECMWF_0z/f120.gif
http://www.meteo.psu.edu/~gadomski/ECMWF_0z/f144.gif
http://www.meteo.psu.edu/~gadomski/ECMWF_0z/f168.gif
6z GFS 500 MB
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/06/images/gfs_500_132m.gif
surface map
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/06/images/gfs_slp_132m.gif
Here is the mean pattern taken from the Penn State e-wall site for Day 8-10 at 500 MB... for the 0z operational ECMWF and the 0z GFS. Again we can see clear indications on a full power classic +PNA. Of course the 0Z GFS-- map on the right side -- is not THAT impressive because it closes off a Low at 500 MB over the southwest US but as I already stated the 6z GFS does not show this feature and is very close to the operational European..
http://www.meteo.psu.edu/~gadomski/ECMWF_0z/hgtcomp.html
In addition you can see this for yourself by taking a look at the ensembles runs of the 0z GFS. As you can see a few members to hang back a LITTLE piece of energy or bend in the Jet stream over the southwest states but NONE ( not one!!!) of the 11 members show closed off Low over the SW states. Therefore the data is overwhelming that idea of the closed 500 Low over the southwest US as depicted by the 0z GFS to be BS.
http://www.meteo.psu.edu/~gadomski/ENSHGT_0z/f240.html
We can also see that by taking a look at the 240 hr Canadian and GFS ensembles Mean maps. The map in the upper left corner shows the operational GFS and again note the closed 500 Low over the southwest. However the bottom left map which is the GFS ensembles mean at day 10 clearly shows a classic +PNA as does the 0z CMC ensembles mean ( bottom right).
http://www.meteo.psu.edu/~gadomski/NAEFSHGT_0z/f240.gif
Again let me emphasized that I am not forecasting the coldest air mass of all time or anything close to historic levels or even SIGNIFICANT cold oubreak (yet) . My point is that the pattern shifting and showing signs moving into a early December 1 run of the mill Winter pattern. To be sure there is no reason to start running specials on the god awful Weather Channel (one day I have have a post about TWC and what a wretched place that has become) just yet but in my opinion any time a Winter pattern develops in El Niño year is always a good sign since there been many El Niño Winters where thehre has never been a sustained Winter pattern that has locked in place. Of course I don't know if the new pattern is going to "lock in" or last seven days and then collapse.
A case can be made for either scenario at this point I just don't know but it's nice to see this pattern developed if you are Winter lover as opposed to what we have seen for much of NOV.
posted by DT @ 11/26/2006 11:25:00 AM
14 Comments:
At 11:55 AM,
Anonymous said…
It appears that you are accurate with your PNA call, so kudos to you.
Any thoughts on specific weather during the next 10 days??
Thanks,
JD
At 1:40 PM,
Anonymous said…
DT great write up and congrats on being in the Phil Inquirer today.
At 1:54 PM,
Anonymous said…
good post. Over at eastern there are so many opinions about what is going to happen, its almost ridiculous. However one post this mrning was interesting in that it was a prediction of a low forming in the gulf and riding up inland to the lower part of md, va and then riding up the northeast coast. It was a forecast for some snow in the big cities. Are you forecasting something similar
At 3:20 PM,
Anonymous said…
RAY- The bad news is that the NAO/AO look just as positive as the PNA, but the good news is that the esembles' moduality of the polar indicies has been about as consistent as flipping a coin 10 times over.
At 3:54 PM,
DT said…
Yeah I saw that article over at Philly Inquirer. The reporter Tony Wood is BIG weather nut and found wwbb and eastern us thru MY web site... yes I know I had had nothing to do helping eastern us wx to grow... sure whatever
I dont see the Low that forms in he base of the through over the Great Basin / the Lower Plains and the surface Low as a East coast snow threat at all and Neither should you. Such a forecast is BS and mindless s weenie wishcasting. I sure hope no professional Met is forecasting that!... talk about jumping the Gun. Its clear the arctic front has to pass thru the East coast FIRST just to get the cold air in Place... synoptically that is NOT going to happen and the 12z Data is admant that this Low DEC 1 is Midwest Low track and NOT a East coast Low
At 5:14 PM,
Anonymous said…
Good write up DT. Could not agree with you more about the "weather channel". It is become the global warming channel; it was much more technical and in depth in its earlier days, and really spurred my interest in the weather growing up. Losing Kocin was a big loss.
At 5:18 PM,
Anonymous said…
DT,
Nice write up.
+PNA is good, but the freight train needs to slow down. Any secondary area of low pressure (if it forms) is going bye bye.
Pattern will still be a quick one until we can get the heights to rise over Greenland and Iceland. At this point a block is out of the question, but that Icelandic low has to go.
Anything is better than nothing at this point. People forget that it doesn't have to be brutally cold to snow.
Take care,
Eric
At 5:31 PM,
Anonymous said…
DT, good stuff as usual. From what I gather, you seem unsure if this pattern change is here to stay for "a while" or that it may be transient in nature. Seems like from other opinions I have been reading, this air mass is transient and that much of December looks to be normal to slightly above normal temp wise and the real change to be "locked in" will not come into play until lat Dec or early Jan. I know you came out with your winter outlook already, but could you please break it down a little and give us your forecast both temp and precip wise for the month of December. As always much appreciated.
At 8:17 PM,
Anonymous said…
DT, great reading for "us"(me)snow trackers for the upcoming snowmobile season. When you say Northern New England in your forecasts, are you talking about the Wht. Mountains area and north or say even MA line/souther NH and north?
At 10:36 PM,
Anonymous said…
Anon, Northern New England's area as per DT is found here: http://wxrisk.com/Meteorology/regions.jpg
Good stuff, Dave.
At 12:54 AM,
Anonymous said…
Great job with your blog or should I say your bully pulpit? Well done.
At 4:12 PM,
Anonymous said…
DT,
Kudos, but, you should commit. Lock in or no lock in? I say none until Jan. It should be another one month's worth of steady winter. The old fashioned ones are too much to expect in this era of changing climate
At 12:42 AM,
Anonymous said…
DT:
Your meteorology would come off so much more professional if you could stop the chest thumping and bragging....it is a bad mix. No shit dude. What is that anyway? Ego?...lose it
At 2:37 PM,
Mike Masco said…
Yeah what's with the cursing. You would be more respected if you would calm down a bit and acted a tad more professional. Trust me i would love to throw the F bomb here and there. Your a smart man who has taught me alot through the years
Post a Comment
<< Home