Winter 2013-14 Pattern Discussion II

[Wow]

Things have changed with model accuracy since then but this is the storm that crowned the Euro as king to many folks here. It was the first to latch on to a huge storm at least 5 days out. GFS didn't catch it until a couple days out.

[Wow]

12z GFS continues the trend of a weaker SE ridge thru 144.

 

BTW.. here's a blast from the past on the 96 storm: http://wow.americanwx.com/gg/

[Wow]

Snow breaking out over W NC/SC by 156 hrs.  HP sliding out too quickly to hold the cold in after that.. it over amplifies the phase a bit.  Needs to cutoff earlier.  But it is a step toward the 0z Euro solution of progressing it farther east and weakening the SE ridge.

[Marion_NC_WX]

Snow breaking out over W NC/SC by 156 hrs.  HP sliding out too quickly to hold the cold in after that.. it over amplifies the phase a bit.  Needs to cutoff earlier.  But it is a step toward the 0z Euro solution of progressing it farther east and weakening the SE ridge.

 

 

Yeah, looks like a snow to ice event for Western half of North Carolina...but could use some improvement in the placement of the CAD.

[GaWx]

The 12z GFS gives virtually no wintry precip. to the bulk of N GA in advance of this storm per my provider's sfc maps. The same could be said for the prior 2 runs though the 18z did give some ZR to some.

[Ang]

I just wanted to take a minute to thank you all for your weather predictions. I began following your thread a couple days before the snow hit in Georgia. While most everything I read on here was wayyyyy over my head, I was able to pick up a few words I was familiar with!

 

Our local news meteorologists admitted the models weren't lining up, but to me, it seems like they will choose the model that doesn't send Georgians into a bread and milk frenzy. 

 

I will forever follow you folks on here when these weather systems come our way.

 

Thanks again!

[Marion_NC_WX]

I will add this...better hope the temps are correct under this current synoptic setup because after 168 there is plenty of moisture left that would slow the favored areas of the Southeast down to a craw...

[Lookout]

The 12z GFS gives virtually no wintry precip. to the bulk of N GA in advance of this storm per my provider's sfc maps. The same could be said for the prior 2 runs though the 18z did give some ZR to some.

There is a discrepancy between the surface maps (temp and wetbulb) from COD and air resources laboratory/twister. The actual temps look ok but COD shows wetbulbs as low as 26 to 28 right before and while precip is ongoing across north ga air resource laboratory/twister has wetbulbs right at or slightly above freezing.

 

if the cod maps were right, we would most likely be looking at a lot of ice over much of north ga while if if the two are it would be the dreaded and worst 32.5 and rain over north ga. But ready/twister soundings do indicate sub freezing temps over the upstate/nc.  Not sure why there is a difference between them

 

Here is the wetbulb temp from cod. Although cod only shows freezing temps into the upstate, With temps just barely above freezing over north, a lot of precip, and with wetbulbs that low...temps would likely get to below freezing. Gfs shows subfreezing wetbulbs until hour 174 to 180. By that time a huge amount of precip has fell.

 

 

 

[burgertime]

@138 CMC is a lot more progressive with the southern energy but looks a lot better. My maps are stuck there, haven't looked at the b&w images. 

[franklin NCwx]

Cmc is very weak and colder. Flurries/snow showers at best for north ga and upstate sc.

[BullCityWx]

well thats a definite change.

[franklin NCwx]

well thats a definite change.

from inches of qpf to nothing in one run. Hopefully the euro is a blend of the two.

[tarheelwx]

12z GFS is quite a winter storm for the triad from Friday evening to almost noon on Saturday.  Then it all gets melted and washed away.  By around 1 am Saturday morning about .24 has fallen at GSO as frozen.  Then over the next 9 hours, about .67 falls as zr.  Another .75 or so of cold rain falls after that.  This all comes from Meteostar. 

TW

[mackerel_sky]

from inches of qpf to nothing in one run. Hopefully the euro is a blend of the two.

Weaker and colder is a good thing, right? I think wow said it could trend torwards a miller A. Cold first and then worry about precip later. The Euro should be fun.

[Wow]

Weaker and colder is a good thing, right? I think wow said it could trend torwards a miller A. Cold first and then worry about precip later. The Euro should be fun.

 

The polar trough needs to cutoff while digging SE and not phase too much energy from the primary jet during that time.  If it does cutoff, confluence will rapidly build and a banana high will develop.  Meanwhile, jet divergence will develop along the gulf coast and begin to bring up gulf moisture as the ULL travels down.  I'm essentially explaining how Jan 96 came to be.  That's your ideal (or near ideal for some places) setup.

 

If the Euro latches on to this scenario for a couple of runs, I'm going all in. 

[GaWx]

Lookout,

Which one goes into MeteoStar? Usually, MS and my provider agree well. But I 'm now noticing discrepancies in some runs. For the 12z, MS is a bit colder and does have some IP and ZR even over to much of ATL fri to early sat before warming with ~32 for the coldest with a very impressive wedge causing 925's to be 3-7 colder than 850's! Hmmm. For gvl and mge, it gets. 935's as low as -3 C! So, 27 at 2,500 feet asl or 1,500 above the ground. IF that were to really happen, I don't see how there wouldn't be IP on the ground. Also, I do see the high 20 wet bulbs. Then again, don't forget about the GFS cold bias, especially toward the ground with both temp and td. This turns out to be the case quite often. I definitely don 't trust low td's on the GFS. So , those wet bulbs could easily be too cold. I imagine the 925 temp could also be too cold. So, maybe twister is somehow taking cold bias into account somehow and could be more accurate.

[LovingGulfLows]

The polar trough needs to cutoff while digging SE and not phase too much energy from the primary jet during that time.  If it does cutoff, confluence will rapidly build and a banana high will develop.  Meanwhile, jet divergence will develop along the gulf coast and begin to bring up gulf moisture as the ULL travels down.  I'm essentially explaining how Jan 96 came to be.  That's your ideal (or near ideal for some places) setup.

 

If the Euro latches on to this scenario for a couple of runs, I'm going all in. 

 

 

1996 didn't seem to do much for the ATL area...it crushed NC northward though, especially western. The low seem to have tracked too far west. If it tracked more East, I think Atlanta's totals would have increased by a lot.

[HKY_WX]

still like the odds for something. need to see some continuity before jumping to a certain conclusion, although the pattern favors a mixed bag versus any kinda pure snow event, for sure.

[Wow]

1996 didn't seem to do much for the ATL area...it crushed NC northward though, especially western. The low seem to have tracked too far west. If it tracked more East, I think Atlanta's totals would have increased by a lot.

 

Yes, possibly so.  The foothills and mountains received the most snow.  I remember it turning to sleet at the end here in the western piedmont as the low bombed off the SE coast.

[Wow]

Euro does not allow the arctic front to pass through ahead and build in confluence over the NE, rather wait to phase into with the storm... result is a warm surge ahead of it.  Looks more like severe wx instead of snow.

 

Actually this run looks more like the Jan 2-3 1996 event which led up to the blizzard.

[packbacker]

Euro does not allow the arctic front to pass through ahead and build in confluence over the NE, rather wait to phase into with the storm... result is a warm surge ahead of it. Looks more like severe wx instead of snow.

The Euro is a snow parade for Boston for the next 8 days, 4 systems give it snow with 3 big ones.

[GaWx]

1996 didn't seem to do much for the ATL area...it crushed NC northward though, especially western. The low seem to have tracked too far west. If it tracked more East, I think Atlanta's totals would have increased by a lot.

 

 Agreed as ATL had rain and low 40's on the frontside although ATL's 1.4" and AHN's 0.8" on the backside are notable for our areas. The ATL 1.4" was the heaviest since 12/93 and wasn't to be exceeded til 12/00. ATL had only 4.1" total S/IP during that six winter stretch, highlighted by this 1.4" and 1.3" in 12/96. ATL has been spoiled since 3/09 with a whopping 19.6" vs. a normal of ~12"!

[tarheelwx]

The Euro is a snow parade for Boston for the next 8 days, 4 systems give it snow with 3 big ones.

got details? I fly into Logan Tuesday afternoon and back out Thursday afternoon.

TW

[Shawn]

Can't say I'm upset about the Euro being much warmer at the surface for almost all of SC/GA.  With that said; I still have an odd feeling.

 

I read a post from lookout about the wetbulb temps and soundings not matching up with various sources; and I'm not sure why the surface maps on Dupage are showing 32 or lower wet bulbs all the way through KCAE; but the soundings are much different and warmer.

 

Granted, during the heavy precip we get down to 34 or so here in CAE.. but something seems off on dupage and twisterdata sites.  Definitely thinking the icing threat is very real furth into GA/SC per GFS runs.

[packbacker]

got details? I fly into Logan Tuesday afternoon and back out Thursday afternoon.

TW

They are looking at 6-8" for Wed.

[Cheeznado]

Through all of this the GFS ensemble mean has been very consistent in showing a CAD precip event. Here are the various members for 6Z Saturday, and while details differ, most show a colder CAD setup than what the Euro has. For now I an sticking with an ice event for someone in the Piedmonts of GA/SC/NC, exact details far from being worked out of course.

[I85Greenville]

Hmmm... (GSP Disco)

 

LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/  
 
AS OF 225 PM EST SAT...GOOD MODEL AGREEMENT IS HAD IN THE FIRST  
PORTION OF THE FCST. THE NW FLOW SN SHOULD BE TAPERING OFF RATHER  
QUICKLY WED NIGHT AS DRYING OCCURS IN THE H92/H85 LAYER ON THE FRONT  
END OF A DRY AND COLD ARCTIC AIRMASS. THERE SHOULDN/T BE TOO MUCH OF  
A SE/RN PUSH WITH THE ARCTIC FRONT OUTSIDE THE MTNS THU AS THE MEAN  
MLVL FLOW REMAINS SW/LY. THIS SHOULD CREATE A DISPARATE MAX  
TEMPERATURE REGIME ACROSS THE FA WITH THE MTN VALLEYS WARMING ABOUT  
5-8 DEGREES LESS THAN THE NON/MTNS. OVERALL...MAX TEMPS SHOULD BE  
HELD ABOUT 8-12 DEGREES BELOW NORMAL IN GOOD INSOLATION YET COLD  
N/LY SFC FLOW.  
 
UNCERTAINTY INCREASES IN THE FCST BEGINNING THU EVENING THROUGH THE  
PERIOD. THE 00Z GFS IS STILL A COLDER AND MORE DYNAMIC OUTLIER THAN  
THE CWM/ECMWF SOLNS AND THE MODEL HAS A VERY DIFFERENT ULVL  
CONFLUENT PATTERN OVER THE NE CONUS. THE GFS IS PRODUCING A MUCH  
STRONGER AND COLDER SFC HIGH THAN THE OTHER OP MODELS AS IT/S  
UPPER PATTERN INCLUDES AN UPSTREAM RIDGE BEHIND THE CONFLUENT ZONE.  
THE OTHER MODELS HAVE CYCLONIC FLOW IN THIS AREA...THUS THE GFS IS  
ABLE TO SUSTAIN STRONGER LLVL SUPPORT.  
 
A QUICK LOOK AT THE INCOMING 12Z ECMWF SHOWS THIS MODEL IS TRENDING  
TOWARD THE UPPER PATTERN OF THE GFS...BUT IT STILL HAS A WEAKER SFC  
LOW...ALBEIT IN A BETTER CAD POSITION BY 12Z FRI. SOUNDINGS ON THE  
GFS ARE SO COLD WITH THE CAD ONSET THAT THEY SHOW ALL SNOW FOR THE  
FIRST PART OF FRI CHANGING OVER THE -FZRA IN THE AFTERNOON ACROSS  
THE NRN ZONES. THE OLD ECMWF HAD ALL RAIN...WHILE THE NEW ECMWF  
SOUNDINGS ARE MUCH COLDER THROUGH H7. WITH SO MUCH CHANGE OCCURRING  
IN THE MODELS AND VARYING AVAILABLE MOISTURE DIFFERENCES ASSOCIATED  
WITH SFC CYCLOGENESIS...POPS HAVE BEEN LEFT IN THE CHANCE RANGE  
WITH A PUSH TOWARD THE HIGHER END. WILL STILL COUNT ON A STRONG WARM  
NOSE BUILDING IN FRI AND MAKING THE CASE FOR -FZRA AS THE STRONGER  
CAD SCENARIO LOOKS TO BE FAVORED ATTM. IT/S TOO EARLY TO SPECULATE ON  
QPF/ICE AMOUNTS AS THE LLVL MASS FIELDS/FLUXES HAVE LOW CONFIDENCE  
AND NEED TO BE FIGURED OUT...BUT THIS WILL BE A SYSTEM TO KEEP AN  
EYE ON FRI INTO SAT. 

[JoshM]

VERY complicated long range... as usual. Going to be a very tight gradient between ice with temps in the upper 20s to thunderstorms and 60s. How far the warm nose goes north is anyone's guess ATM

 

If I'm not mistaken wasn't Dec '02 a Miller B setup that transitioned from snow to sleet to ZR? Need to go back to the case study and see if these setups have anything in common.

[EmersonGA]

 Agreed as ATL had rain and low 40's on the frontside although ATL's 1.4" and AHN's 0.8" on the backside are notable for our areas. The ATL 1.4" was the heaviest since 12/93 and wasn't to be exceeded til 12/00. ATL had only 4.1" total S/IP during that six winter stretch, highlighted by this 1.4" and 1.3" in 12/96. ATL has been spoiled since 3/09 with a whopping 19.6" vs. a normal of ~12"!

I think I had 2-3" from it in the NW burbs.  What I do remember is having flurries/snowshowers for days it seemed like.

[BullCityWx]

There's a NEW ecmwf?