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Winter 2015-16 Medium-Long Range Discussion


OHweather

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Probably going to need to start a thread for this soon, perhaps on the main board, since multiple sub-forums may be involved. The 00z Euro run was almost certainly showing a significant and widespread severe weather event on the 23rd into Christmas Eve.

NAM, too. But it's the hour 84 NAM... while it's very impressive, I don't put much stock into it at this point.

 

Dr. Forbes has a TORCON of 4 for Wednesday... mostly around the mid-Mississippi valley.

 

NWS Birmingham has a really alarming AFD

 

NOW ON TO THE POSSIBLE HIGH IMPACT PART OF THE FORECAST...

MODELS ARE IN SIGNIFICANTLY BETTER AGREEMENT TODAY REGARDING THE

EVOLUTION OF THE UPPER-AIR PATTERN FOR WEDNESDAY...AND IT IS NOT

GOOD NEWS. SEVERAL HISTORIC COOL-SEASON SEVERE WEATHER ANALOGS ARE

SHOWING UP BASED ON THE FORECAST UPPER-AIR PATTERN. MODELS HAVE

TRENDED TOWARD THE ECMWF SOLUTION WITH MORE VORTICITY IN THE BASE

OF THE TROUGH ACROSS THE SOUTHERN PLAINS. THIS WILL CAUSE STRONG

SURFACE CYCLOGENESIS TO OCCUR TO OUR NORTHWEST AND SUBSTANTIAL

PRESSURE FALLS FARTHER SOUTH ACROSS INTO OUR AREA...LEADING TO

STRENGTHENING WIND FIELDS ACROSS A LARGE AREA. THE CONVECTIVE

EVOLUTION WITH THIS SYSTEM REMAINS A BIT UNCLEAR...BUT IT APPEARS

LESS LIKELY THAT COASTAL CONVECTION WILL BE A SIGNIFICANT

INHIBITING FACTOR IN POLEWARD MOISTURE ADVECTION. ONE POSSIBLE

SCENARIO IS THAT RAIN DEPARTS TO THE EAST DURING THE MORNING ON

WEDNESDAY...ALLOWING UNUSUALLY RICH GULF MOISTURE TO MOVE INLAND

FROM THE NORTHWESTERN GULF OF MEXICO. IF THIS OCCURS...CONDITIONS

COULD BECOME RIPE FOR A TORNADO OUTBREAK FROM THE LOWER MS VALLEY

EASTWARD INTO PARTS OF CENTRAL ALABAMA. FORECAST SOUNDINGS...

PARTICULARLY ACROSS THE NORTHERN AND WESTERN PARTS OF OUR AREA...

SHOW ABUNDANT LOW-LEVEL MOISTURE BENEATH STEEP MID-LEVEL LAPSE

RATES AND NEARLY TEXTBOOK WIND SHEAR PROFILES. IF THIS OCCURS...

SUPERCELLS WITH TORNADOES...DAMAGING WINDS...AND LARGE HAIL WOULD

BE POSSIBLE WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT. IT IS

IMPOSSIBLE TO KNOW EXACTLY HOW MUCH GULF COAST CONVECTION WILL BE

PRESENT ON WEDNESDAY...AND IT MAY MAKE OR BREAK THIS FORECAST.

 

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The slow process of a change perhaps. Many in the NE forum think so (talking the trusted ones, not the weenies).

 

The Scandinavian ridge is a known precursor to PV weakening, so it is important that it come to fruition as previously modeled.  Powerful/deep GOA low further west/near the dateline by D10 on the EC as well.  That is also a recognized precursor.  Together, they could do some damage to the PV.  I'm not holding my breath...yet.

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Yep, for the most part the GFS is a disaster. Getting into Jan now and it's abysmal.

At least run-to-run, the GFS has been indicating normal to slightly above normal temperatures in the eastern third of the country post-truncation. You can get snow with above normal temperatures-- it's just a bit harder to.

 

I'm not saying January is going to be great, but it doesn't look as terrible as December-- which isn't saying much. The Euro isn't quite on board, but there's a fair amount of cold air to be had out west. The Texas panhandle looks to majorly cash in on the Christmas system, so the cold air is there. We just need to stay patient and let the PV run its course. It's a driving meteorological feature-- it won't be overnight. But it'll happen eventually.

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At least run-to-run, the GFS has been indicating normal to slightly above normal temperatures in the eastern third of the country post-truncation. You can get snow with above normal temperatures-- it's just a bit harder to.

I'm not saying January is going to be great, but it doesn't look as terrible as December-- which isn't saying much. The Euro isn't quite on board, but there's a fair amount of cold air to be had out west. The Texas panhandle looks to majorly cash in on the Christmas system, so the cold air is there. We just need to stay patient and let the PV run its course. It's a driving meteorological feature-- it won't be overnight. But it'll happen eventually.

The GFS shunts everything to the FAR northeast and leaves the midwest in a SW flow. It's 2011-2012 on steroids.

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The new Euro shows a potential light snow event Christmas Eve from parts of MO/IA through northern IL into central-lower MO.  The GFS has this as well, although it craps out sooner and dries up near the MS river.  Would probably be more mood flakes than anything, but given the fact that it would happen on xmas eve would be pretty cool.  Especially after the recent warmth.  

 

The Euro has been showing this little wave in previous runs, but this is the most robust it's been with it so far.  

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The new Euro shows a potential light snow event Christmas Eve from parts of MO/IA through northern IL into central-lower MO. The GFS has this as well, although it craps out sooner and dries up near the MS river. Would probably be more mood flakes than anything, but given the fact that it would happen on xmas eve would be pretty cool. Especially after the recent warmth.

The Euro has been showing this little wave in previous runs, but this is the most robust it's been with it so far.

It's too warm for snow verbatim with surface temps in the 40s for much of the area.

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