WEATHERAmerica Newsletter, Saturday, January 7, 2017 (Longer Term Forecast)
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Larry Cosgrove
Jan 7, 2017, 7:43:38 PM1/7/17
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EXTENDED PERIOD FORECAST
(Between Day 11 And Day 15)
How Long Will The January Thaw Last? And What Will Follow?
NRL
NRL
NOAA/IMS (3)
NOAA/NCEP
NOAA/TAO
NOAA/CPC (2)
HPRCC/University Of Nebraska (2)
Environment Canada
TropicalTidbits.Com (Levi Cowan (5)
NOAA/ESRL (4)
From looking at the computer model and analog forecasts, it seems pretty certain that something approximating the "January Thaw" will be affecting most of the nation between January 13 and 22. But the question many forecasters have on their minds is, "Is winter over"? If you look at past history of the season so far, the volatile pattern swings back and forth between intense cold snaps and bizarre warm-up, with the tendency for the milder air to establish its presence over the southern and eastern tiers of the nation. This alignment has been repeated in the first week of January. So right off the bat we can say that any major surges of warmth have a tendency to be pushed out by portions of the vast cold air field across Canada, aided and abetted by the impressive snowpack that is touching the Gulf Coast at this time.
Keep in mind that I do not expect that snow cover to stay in the Deep South. The ice and snow field may actually recede into the far northern tier of the country to the right of the Continental Divide during the middle of the month. But here, climatology and the analogs point out that the southern branch wind field will work its magic, likely setting up a broad storm near Baja California by the end of the third week of the month. This is not a La Nina winter; rather, this is a negative/neutral ENSO signal that has sometimes displayed tendencies like an El Nino, with an impressive subtropical jet stream. If the ECMWF and GFS series are correct with energy from the northern jet stream digging through the Intermountain Region and phasing with the lower latitude wind maximum, the resultant cyclone will roll through Texas and into the lower Great Lakes around January 22 - 24. Such a track, of course, would pull the mean 500MB trough yet again into the Great Plains and Mississippi Valley. Cold air drainage into the western 2/3 of the nation would surely follow.
But a potentially new rub shows up in the weekly forecasts of the CFS and ECMWF platforms: strong -EPO/+PNA ridging from Alaska to California. The analog depiction seems a little fast with this development (January 22), but I am confident that a warm/dry West vs. cold/stormy Central East configuration is likely to occur shortly thereafter, and quite possibly last through February and the first half of March. The 1996 comparison has some value here, albeit with a colder outcome like 2014 or 2015. If dual blocking signatures emerge again along the entire Pacific shoreline and Greenland, the most recent Arctic intrusion will seem like just "part of the pattern" of the winter of 2016-2017.
With some more eastern U.S. snow and ice events thrown into the mix, just for fun.
Keep in mind that I do not expect that snow cover to stay in the Deep South. The ice and snow field may actually recede into the far northern tier of the country to the right of the Continental Divide during the middle of the month. But here, climatology and the analogs point out that the southern branch wind field will work its magic, likely setting up a broad storm near Baja California by the end of the third week of the month. This is not a La Nina winter; rather, this is a negative/neutral ENSO signal that has sometimes displayed tendencies like an El Nino, with an impressive subtropical jet stream. If the ECMWF and GFS series are correct with energy from the northern jet stream digging through the Intermountain Region and phasing with the lower latitude wind maximum, the resultant cyclone will roll through Texas and into the lower Great Lakes around January 22 - 24. Such a track, of course, would pull the mean 500MB trough yet again into the Great Plains and Mississippi Valley. Cold air drainage into the western 2/3 of the nation would surely follow.
But a potentially new rub shows up in the weekly forecasts of the CFS and ECMWF platforms: strong -EPO/+PNA ridging from Alaska to California. The analog depiction seems a little fast with this development (January 22), but I am confident that a warm/dry West vs. cold/stormy Central East configuration is likely to occur shortly thereafter, and quite possibly last through February and the first half of March. The 1996 comparison has some value here, albeit with a colder outcome like 2014 or 2015. If dual blocking signatures emerge again along the entire Pacific shoreline and Greenland, the most recent Arctic intrusion will seem like just "part of the pattern" of the winter of 2016-2017.
With some more eastern U.S. snow and ice events thrown into the mix, just for fun.
Prepared by Meteorologist LARRY COSGROVE on
Saturday, January 7, 2017 at 6:30 P.M. CT
Disclaimer:
The previous statements are my opinions only, and should not be construed as definitive fact. Links provided on this newsletter are not affiliated with WEATHERAmerica and the publisher is not responsible for content posted or associated with those sites.
Copyright 2017 by Larry Cosgrove
Saturday, January 7, 2017 at 6:30 P.M. CT
Disclaimer:
The previous statements are my opinions only, and should not be construed as definitive fact. Links provided on this newsletter are not affiliated with WEATHERAmerica and the publisher is not responsible for content posted or associated with those sites.
Copyright 2017 by Larry Cosgrove
All rights reserved.
This publication may not be reproduced or redistributed in whole or in part without the expressed written consent of the author.
This publication may not be reproduced or redistributed in whole or in part without the expressed written consent of the author.
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