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Pattern Dazzling December

Loganelliott99 said:
The 12z GFS didn’t look too great. I trust the GEFS much more though
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Loganelliott99 said:
12Z CMC took a step in the wrong direction as well.
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Agree. I kind of like living and dying by each model run, including the Op runs....I see no problem with that, lol. Anyway, the 12z GFS and CMC Ens were back to throwing low pressure up into AK. The GFS run in the extended was the nightmare scenario with heavy low pressure from Fairbanks to Los Angeles. The GEFS looked fine. Let's see what the daddy shows
 
ILMRoss said:
and that's fine. i generally don't think your airmasses need to be that cold to generate decent southern snowfall chances. obviously they still need to be supportive of snow but i don't think they need to be record-breaking per se. i think what you're purchasing with NAO blocking is a drunken storm track that gets easy to amplify, and by virtue of where that storm track ends up, it's easier to push colder air in as well.

the example i'll cite is the feb 12 2010 storm, which is, to this day, the most classic, no stress, southern slider i've ever seen. it happened on a friday night- that friday was cloudy with a high in the upper 30s in wilmington, cold for sure but nothing frigid. we got 4 inches of snow that night, arguably should of been more given the synoptics (jacksonville got 8). I think the night after radiational cooling brought it down to, say, 25? 23? Point is that one of the most slam dunk snow events that was working with a -nao i can remember was going into an airmass that was nothing to write home about. just my take.
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For those of us that like pictures. :p Courtesy to Mr Webb

february_12-13_2010_nc_snowmap.gif
 
Mountain torque getting driven into the ground by E Asia & N America to a lesser extent. This should force a huge retraction of the Pacific jet (-PNA) and allow our Greenland block to retrograde over the top (because the background westerly flow is being slowed down). Has the feel of the kind of pattern where more climo favored areas of the mountains, west, and NW piedmont of NC can score, gonna take a little more to get everyone else involved between now & about Dec 15-20 ish. Still plenty of time for a renewed bout of west pacific tropical forcing to set in and force a -EPO.

gltaum.90day.gif
 
Webberweather53 said:
Mountain torque getting driven into the ground by E Asia & N America to a lesser extent. This should force a huge retraction of the Pacific jet (-PNA) and allow our Greenland block to retrograde over the top (because the background westerly flow is being slowed down). Has the feel of the kind of pattern where more climo favored areas of the mountains, west, and NW piedmont of NC can score, gonna take a little more to get everyone else involved between now & about Dec 15-20 ish. Still plenty of time for a renewed bout of west pacific tropical forcing to set in and force a -EPO.

View attachment 124405
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Agreed… I think the biggest thing right now is that we’re going into a pattern that promotes sustained below average temperatures which will give more areas a chance as we get deeper into the month. With any luck, maybe we’ll have a storm to track close to Christmas
 
Myfrotho704_ said:
Some legit cold this run as well View attachment 124409
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Euro Suite is taking baby steps toward the GFS Suite with respect to it wanting to send more of that low pressure from NE Siberia toward Alaska. On the flip side, this was a hardcore west-based Greenland block and east coast trough couplet on this run of the EPS....very nice.

Anecdotally / Historically, I tend to view the GFS Ensemble as being a little better performer on the Pacific side, and with how it depicts the associated downstream pattern over the U.S., while I tend to view the Euro Ensemble a better performer on the Atlantic side. A retrograding Greenland Block like this should be taylor-made for the Euro Ens
 
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