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Medium/Long Range Discussion Part 2


IWXwx

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I have been looking at the SSW maps posted here....

 

Can someone explain what that is?  All I see are warmer temps, and just want to understand what that is all about, and what it's potential implications are, for our winter weather.  More active? Warmer? Colder? More precip?  Just kind of confuses me, that's all.   Thanks. 

 

Warmer temperatures in the stratosphere. Not the troposphere. Warm air is getting into the stratosphere's polar vortex, which weakens it. A strong, single polar vortex over the pole locks up all the Arctic/Polar air over the Arctic regions and really doesn't allow much to "leak" out into lower latitudes. A SSW event is in the process of weakening the polar vortex, which will essentially break the dam holding all the cold air to the north. Once there is a high pressure cell over the north pole, the AO will crash and probably set off a -NAO. Not a guarantee for a -NAO, but possibly. Greenland blocking is very common when there is higher pressure of the polar regions. Cold air will be allowed to flow where it wants to then, which includes the lower 48.

 

This posting on this page, is a great read if you have time > http://theweathercentre.blogspot.de/

 

And there is a thread here on AmWx discussing this phenomenon: http://www.americanwx.com/bb/index.php/topic/38593-sudden-stratospheric-warming-begins-significant-cold-ahead-for-january-februarycross-polar-flow/

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Warmer temperatures in the stratosphere. Not the troposphere. Warm air is getting into the stratosphere's polar vortex, which weakens it. A strong, single polar vortex over the pole locks up all the Arctic/Polar air over the Arctic regions and really doesn't allow much to "leak" out into lower latitudes. A SSW event is in the process of weakening the polar vortex, which will essentially break the dam holding all the cold air to the north. Once there is a high pressure cell over the north pole, the AO will crash and probably set off a -NAO. Not a guarantee for a -NAO, but possibly. Greenland blocking is very common when there is higher pressure of the polar regions. Cold air will be allowed to flow where it wants to then, which includes the lower 48.

 

This posting on this page, is a great read if you have time > http://theweathercentre.blogspot.de/

 

And there is a thread here on AmWx discussing this phenomenon: http://www.americanwx.com/bb/index.php/topic/38593-sudden-stratospheric-warming-begins-significant-cold-ahead-for-january-februarycross-polar-flow/

 

Thanks, Geos..  Makes sense to me.  I will read the articles later when I have more time.  Thanks for taking the time to explain that.   :thumbsup: :thumbsup:

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Lol, 18z GFS even faster with the evolution of the system/trough, producing a strong Milwaukee cutter moving through at 132 hours.  Might be just enough cold air here to produce a rain to snow type event, but not sure.

 

That's an interesting solution! Looks like the bulk of the warm gets left further SE, so a mix to snow I could see for Milwaukee. and southern WI.

 

Definitely no cut off again on this run...

 

gfs_namer_132_850_temp_mslp_precip.gif

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I'm thinking it will be another Madison to Green Bay special, in which case I definitely will be roadtripping it.

 

200+ hrs out? lol

 

EDIT: Sorry, maybe you're talking about the midweek system. Still a little far out to be making that call, but good luck.

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The first storm that the GFS, GEM and UK have latched onto.  It may not even happen, but it's the first storm the GFS is showing 5 to 6 days out I was talking about.  One storm at a time.

 

Yeah, I just edited my post. Still a pretty bold call 5 days out.

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If everything goes as planned with the pattern shift late next week, then yeah - I can see the CFSv2 being right. Nice deep cold air for LES weekend after next!

The last frame of the Euro is a cold lover's wet dream.  Magnificent EPO ridge and look at that stuff in southern Canada with no place to go but south. 

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That's pretty chilly for the Canadian medium range!

 

MKX discussion on diverging solutions next week.

 

QUIET START TO THIS PERIOD WITH THE THREAT FOR UNSETTLED WEATHERRETURNING TO SOUTHERN WI LATER IN THE WEEK. DRY WEATHER RETURNING ONSUNDAY ASSOCIATED WITH SHORT WAVE RIDGING LINGERS THROUGH SUNDAYNIGHT. MEDIUM RANGE GUIDANCE BEGINS TO DIVERGE AFTER THAT WITH THEMORE CONSISTENT ECMWF SHOWING CONTINUED BRISK WESTERLIES CONTINUINGACROSS THE UPPER MIDWEST AND GTLAKES INTO TUESDAY...WITH SRN WIGETTING CLIPPED BY WEAK SHORT WAVE ON MONDAY BUT LOW TO MID LEVELSOF ATMOSPHERE REMAIN DRY.OVER THE UPCOMING WEEKEND NEXT SHORT WAVE TROUGH PUSHES INTO WESTCOAST FROM EASTERN PACIFIC...WITH CUTOFF LOW DEVELOPING OVERSOUTHWEST CONUS BY MONDAY. ALREADY UPSTREAM KICKER EXPECTED TO BEMOVING EWD THROUGH NRN PACIFIC...SO CUTOFF LOW LIKELY TO CONTINUEMOVING EAST. 06Z DETERMINISTIC GFS WAS OUTLIER...BUT 12ZDETERMINISTIC GFS ALSO SHOWING FASTER EWD MOVEMENT OF SHORT WAVEINTO THE UPPER MIDWEST TUESDAY NIGHT AND WED. 12Z GEM HAS ALSO COMEINTO BETTER AGREEMENT WITH FASTER GFS.MEANWHILE...ECMWF AND DGEX ABOUT A DAY SLOWER IN BRINGING SHORT WAVENORTHEAST INTO THE UPPER MIDWEST...MORE WEDNESDAY NIGHT ANDTHURSDAY. HOWEVER WHEN COMPARING LAST SEVERAL RUNS OF THE ECMWF...ITDEFINITELY HAS INCREASED THE EJECTION OF THE SHORT WAVE NORTHEASTACROSS THE CENTRAL PLAINS INTO THE UPPER MIDWEST.HENCE MOST LIKELY WE ARE SEEING THE LONG TERM GUIDANCE SHIFTINGSLOWLY TOWARD A COMMON SOLUTION...WHICH COULD VERY WELL AFFECT SRNWI MORE WED OR WED NGT. FOR NOW...DUE TO ALL THIS UNCERTAINTLY...WILL STICK WITH MORE CONSISTENT AND SLOWER ECMWF SOLUTION AND HAVEHIGHER CHANCE POPS ON THU AND THU NGT...HOWEVER WILL INTRODUCE SMALLPOPS IN SOUTH WED NGT. AT THIS TIME...ENOUGH OF A WARM AIR SURGEAHEAD OF THIS SYSTEM TO GO WITH A RAIN/SNOW MIXTURE. FUTURE SHIFTSMAY BE BUMPING UP POPS WED/WED NGT.

 

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We have had a snowcover here since Dec 21st, and a solid blanket with not a grass tip to be found since Dec 26th, and it should last at least another week. This longevity already blows anything in 2011-12 out of the water lol. While Im not happy to see it go next week (plenty of snowbanks and patches around if GFS is right, which is always a base for future snow...euro not so much). The warmspell appears to be short-lived however with cold signals lying ahead, and a clipper pattern would be wonderful (and the lakes may finally get going) which hopefully would replenish the snowcover. Im never happy to lose snowcover, but as long as the cold, active pattern after mid-Jan shapes up Im fine. 2010-11 winter-long snowcover is NOT the norm unfortunately.

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