Winter 2013-14 Pattern Discussion III

[packbacker]

With that high in place and the track of the low, it seems like we'd get zr or ip, right?

In Jan/Feb, yes it's ice at worst, in March we are at the mercy of the ULL track with a retreating HP.

[GaWx]

Larry, do you think that we are in the time period, similar to the last storm, where the models will trend colder over the next few days?  Assuming that the major features don't wobble too much, that is some serious cold from the PV and arctic high.  Another super CAD may be on tap?

 

The Euro and GFS two meter maps will trend colder most likely assuming similar storm/CAD high setup. But with it as it is now, it has an amazing amount of wintry qpf (1.2-1.8" for a large area)!!

[superjames1992]

If you take it verbatim, we all change over to rain at the end.  Not sure if I buy that, but still.  Still, that's like 8-9" of snow before the changeover to a wintry mix and then rain for GSO and more in some other areas.  Very interesting.

 

I'm a weenie, but I'm not sure about that ULL producing rain at the end.  If you guys remember, many models were spitting out the ULL precip on 2/13 as rain, too, yet that was pretty much all heavy wet snow provided you had rates.

 

We torch after the storm, but I don't care.  It's March and it's going to melt like crazy even if it's cold with the freaking sun angle (like happened in March 2009).

[burgertime]

March 2009 redux. Marginal air mass with big cutoff I believe? Grit correct me if I am wrong?

 

March 2009 was a bit bowling ball cutoff trekking across the south. This is pretty different with the Miller A before it but outcome is about the same. If the ULL stays it's gonna be one hell of a roller coaster ride with cliff jumping from run to run. 

[griteater]

March 2009 redux. Marginal air mass with big cutoff I believe? Grit correct me if I am wrong?

March 2009 was a bit bowling ball cutoff trekking across the south. This is pretty different with the Miller A before it but outcome is about the same. If the ULL stays it's gonna be one hell of a roller coaster ride with cliff jumping from run to run. 

 

The slow moving, closed 500mb low would compare, but the Euro run had northern and southern stream phasing, a gulf to atlantic sfc low, and a strong damming high out front...all not present with March 2009.

[deltadog03]

 12Z Euro clown has a whopping 1.2-1.5" of wintry QPF MCN/ATL NE to CAE/CLT/HKY with jackpot of 1.8" at GSP!!!! Storm of the new century?

I was gonna say, by 18z THUR it has MCN down to like 33-34 and yall would be at freezing (verbatim this run) with very heavy qpf coming in.  Then we are at freezing (verbatim) until its over.  This would be nuts, the SFC hi looked like 1040mb ish??

[superjames1992]

How does RDU get screwed no matter what the scenario or orientation of features?

 

RDU gets a significant pop of snow from the front-end, similar to the 2/13-2/13 storm.  Even Greenville gets a few inches on the front-end, it appears.

[Brick Tamland]

Benchmark track and it's only going to get colder on future runs! All models are coming in colder today!

 

 

OMG, GSP almost 20". RDU gets screwed, knew that was coming, but historic event for 85 and points west.

 

 

What RDU said above, 2m line sets up just west of us. We need the track off the coast, not on the coast. The storm hits a brick wall and barely moves for 36 hours, crawls up the coast, why GSP gets 20".

 

 

In a weird way this looks more realistic to me. ULL's are our friends and seem to be more likely in March. Perfect end to winter with everyone cashing in. I would have hard time buying that RDU gets screwed in this setup. 

 

 

RDU gets a significant pop of snow from the front-end, similar to the 2/13-2/13 storm.  Even Greenville gets a few inches on the front-end, it appears.

 

 

From reading everything, I think this will be a good one for RDU, too. I think things will trend colder, and like superjames said, even this run has some snow from the front-end.

[Cold Rain]

From reading everything, I think this will be a good one for RDU, too. I think things will trend colder, and like superjames said, even this run has some snow from the front-end.

 

It's on now!

[POWERSTROKE]

How long before JB and DT say it's coming north....3, 2, 1

JB saying snow  south next week

[deltadog03]

There isn't much doubt in my mind the 12z gfs is screaming major ice storm for north ga/a lot of sc and of course nc.  At hour 120, dewpoints are in the low to mid teens with temps in the upper 20s to lower 30s with precip knocking on the door. Wetbulb temps at 12z range from mid 20s in atlanta, low to mid 20s in northeast ga, low 20s in the upstate and possibly as low as the upper teens in nc. Yet somehow the gfs warms temps into the mid and upper 30s with rain falling by mid to late morning. That warming simply would not happen...especially so if the rain moves in just a couple of hours sooner.

 

But just taken at face value, the wedge is sufficiently deep, through 925mb, and sufficiently cold with freezing temps extending above 950mb. However the 925mb temps could be too warm as the gfs shows winds turning more to the northeast with time and you end up with a northeasterly flow from the surface all the way to 900mb by hour 138 to 144. That is something that tells me the wedge would not erode very fast. And to top it off, we have 850mb temps that are hardly very warm.

 

But if precip does in fact start shortly after sunrise, or before, watch out because there is no doubt we would stay subfreezing through a significant portion of the storm and the damage would have already been done by the time we get above freezing, if we do at all.

 

With such a strong high, and it's not very progressive as it's in damming position for quite a while, and the conditions of the boundary layer, the gfs would be quite something if it verified. I'm a little surprised to be quite honest the gfs isn't much colder. With Previous systems, one could argue that the models might not be too far off since evaporational cooling was not a big factor but with this one I think the gfs is way too warm and it's missing that initial cooling..which of course throws the entire temperature profile out the window if it is. 

 

This would be quite the ice storm if that much precip falls and it's hard to believe though we could have a major ice storm in early march. We are getting into the time of year though that sun angle does play a larger and larger role. So if conditions are only marginal and not nearly this cold/dry, it's something to consider that temps might in fact warm quicker than usual given the setup. But If conditions are so cold and dry initially and we get the timing right, it won't matter at all.  This system certainly has my attention.

I think this is going to be more classical CAD, as you mentioned, the Td will be advecting will be much lower this time.  down in mid 20's from what I saw.  Also euro 850's are at or below 0c by the THur eve for yall and by 6z fri am for me. and just lay a nice deform band.  Euro shows yall about 32-33 at 2m to start, and me about 35-36 to start but we all quickly cool to freezing then a little bit below.

[Disco-lemonade]

From reading everything, I think this will be a good one for RDU, too. I think things will trend colder, and like superjames said, even this run has some snow from the front-end.

 

If the ens shows relatively the same thing and has the low a little more east, ill be pretty confident for snow in central nc.

 

 

Haha if not all in 

[Shawn]

12z Euro has a major Ice storm chance for KCAE.  Might be a bit warm and latent heat could wreck it

[FLweather]

12z Euro has a major Ice storm chance for KCAE.  Might be a bit warm and latent heat could wreck it

 

You might get some front end ice and snow. But if the euro is right then should be a mean dry slot running up 95 parreling the coast. Which maybe the saving grace like last time from a complete horrible crippling ice.

 

But hopefully the trends continue. Euro is almost picture prefect for a big snowtorm.

[Shawn]

You might get some front end ice and snow. But if the euro is right then should be a mean dry slot running up 95 parreling the coast. Which maybe the saving grace like last time from a complete horrible crippling ice.

 

But hopefully the trends continue. Euro is almost picture prefect for a big snowtorm.

 

I did notice 2.2 inches of liquid equiv.. but temps were bouncing back and forth.

[Cold Rain]

Well, RAH is less than impressed for next week...even with the Euro solution.  They're not even leaving the door open for any wintry possibility, which is unusual (normally, they at least admit the possibility).  Either they have no idea what they're doing or we're all out to lunch on this side.
 
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 230 PM FRIDAY...

ARCTIC HIGH PRESSURE WILL BUILD ACROSS THE GREAT LAKES RIDGE SOUTH
IN CLASSICAL DRY CAD FASHION. THIS WILL RESULT IN A COOL NORTHEAST FLOW
DOWN THE ATLANTIC SEABOARD ON TUESDAY AND WEDNESDAY WITH HIGHS BOTH
DAYS IN THE MID TO UPPER 40S. MORNING LOWS WILL BE IN THE 25 TO 30 RANGE.

LOTS OF MODEL DISAGREEMENT AS TO EVOLUTION AND PROGRESSION OF A SOUTHERN
STREAM SYSTEM DURING THE LATE WEEK PERIOD. BASICALLY...THE GFS SOLUTION
HINGES ON STRONGER DEVELOPMENT OF A COASTAL TROF AND COASTAL LOW...WHICH
WOULD INDUCE ISENTROPIC LIFT EARLY IN THE GAME...WITH RAIN MAINLY THURSDAY
AND THURSDAY NIGHT. MEANWHILE...THE ECMWF FEATURES A MORE SOUTHERLY
SUPPRESSED LOW PRESSURE AREA WHICH IS ENHANCED ALOFT BY A CUTOFF LOW AT
H5 THURSDAY NIGHT. THIS WOULD PRODUCE A COASTAL LOW FRIDAY WITH RAIN
LINGERING INTO FRIDAY NIGHT. FORTUNATELY...THE THERMAL PROFILES SUPPORT
ALL RAIN EVEN IN THE LINGERING WRAP AROUND AS THE SYSTEM LIFTS OUT.
GIVEN THIS HIGH DEGREE OF UNCERTAINTY...WILL MAINTAIN CHANCE POPS ON
THURSDAY AND STRETCH THESE THROUGH FRIDAY. HIGHS BOTH DAYS WILL BE IN
THE 40S.

 

[Blue_Ridge_Escarpment]

Good disco by GSP this afternoon as they tend to favor a Euro-like solution as the GFS and its ensembles have trended toward the Euro....

 

 

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 255 PM FRIDAY...GUIDANCE IS BEGINNING TO COALESCE ON A
SOLUTION FOR THE END OF THE PERIOD WEATHER SYSTEM. HOWEVER...SOME
DIFFERENCES IN TIMING...TEMPS AND RESULTANT P-TYPES REMAIN. GOOD
AGREEMENT THAT THE COLD FRONT DURING THE SHORT TERM QUICKLY MOVES
EAST OF THE AREA WITH DRY HIGH PRESSURE BUILDING IN FOR TUE AND WED.
THERE MAY BE SOME LINGERING NW FLOW ACROSS THE MTNS MON EVENING
WHICH WOULD END AS SNOW. HOWEVER...THE SNOW DURATION WOULD BE VERY
BRIEF WITH NO ACCUMS EXPECTED. BREEZY CONDITIONS WILL CONTINUE MON
NITE INTO TUE AS WELL BEFORE THE HIGH FULLY BUILDS IN. HIGHS AND
LOWS WILL BE 5 TO 10 DEGREES BELOW NORMAL.

THE PATTERN CHANGES THU AND FRI AS A SHORT WAVE DIGS INTO THE SRN
PLAINS THU AND MOVES TO THE ATLANTIC COAST BY THE END OF THE DAY
FRI. THE 12Z ECMWF REMAINS DEEPER AND STRONGER WITH THE WAVE CLOSING
OFF AN UPPER LOW AS IT MOVES ALONG THE GULF COAST. THE GFS KEEPS THE
WAVE OPEN AND SLIGHTLY FASTER. HOWEVER...THE GFS HAS TRENDED TOWARD
THE ECMWF SOLUTION...LENDING CREDENCE TO THAT SCENARIO. AT THE
SFC...THE WAVE/UPPER LOW SPINS UP A GULF LOW WHICH MOVES ACROSS FL
THU THEN UP THE SERN COAST FRI. SINCE THE GFS IS FASTER AND
WEAKER...IT KEEPS THE SFC LOW WEAKER AND FARTHER SOUTH...BUT SPREADS
PRECIP IN SOONER AND MOVES PRECIP OUT FASTER. THE ECMWF HAS A
STRONGER SFC LOW KEEPING IT CLOSER TO THE GULF COAST INITIALLY AND
THE SERN US COAST ON FRI. THE GEFS ENSEMBLE MEAN HAS TRENDED TOWARD
THE ECMWF SOLUTION AS WELL. WPC ALSO FOLLOWING THIS TREND AS THE
ECMWF HAS BEEN MUCH MORE CONSISTENT THAN THE GFS. THEREFORE...HAVE
GONE THIS DIRECTION AS WELL WITH CHC POP SPREADING IN THU AND
CONTINUING THRU FRI. TEMPS WILL REMAIN BELOW NORMAL THU THEN RISING
TO NEAR OR JUST BELOW NORMAL FRI. H85 TEMPS ARE INITIALLY COLD THEN
RISE THRU THE PERIOD AS WAA KICKS IN. THEREFORE...LOOKS LIKE A
WINTRY MIX MAY DEVELOP AS PRECIP MOVES IN EARLY THU...THEN CHANGING
TO RAIN. STILL UNCERTAIN HOW THE P-TYPE WILL DEVELOP THU NITE...BUT
WITH COLD SFC TEMPS REDEVELOPING AND WARMING H85 TEMPS...FREEZING
RAIN WILL BE POSSIBLE ACROSS THE NC MTNS AND I-40 CORRIDOR BEFORE
CHANGING BACK TO RAIN ON FRI. IT IS WAY TOO EARLY AND HIGHLY
UNCERTAIN TO SUGGEST WHETHER ANY WINTRY ACCUMS WILL DEVELOP...SO
STAY TUNED FOR THE LATEST UPDATES.

[packbacker]

Well, RAH is less than impressed for next week...even with the Euro solution.  They're not even leaving the door open for any wintry possibility, which is unusual (normally, they at least admit the possibility).  Either they have no idea what they're doing or we're all out to lunch on this side.

 

Smart by them, will be a miracle to get an impact winter storm here. Euro ENS mean warmer then the Op, warmer than 0z ENS run. Keeps 850 far NW NC and VA.

[GaWx]

Smart by them, will be a miracle to get an impact winter storm here. Euro ENS mean warmer then the Op, warmer than 0z ENS run. Keeps 850 far NW NC and VA.

 

 

 Remember that you don't need 0C 850's for major IP/ZR. Realistically, +5 to +6C can allow for major ZR and +2-3C for IP.

[packbacker]

 

 Remember that you don't need 0C 850's for major IP/ZR. Realistically, +5 to +6C can allow for major ZR and +2-3C for IP.

 

 

Good point, 2m's are warm on the Ens mean too, but don't put to much faith in that, but the sliding HP can't be denied, hopefully it can hang on a little longer.

[burgertime]

12z Euro has a major Ice storm chance for KCAE.  Might be a bit warm and latent heat could wreck it

 

If the ULL is the correct solution and it moved how the Euro is showing CAE would get a big dump of snow as it passes. 

[deltadog03]

I am still torn on this one...I do think there is going to be a storm, and it appears that there will be better CAD.  The CAD looks pretty darn good, and trending better.  EURO ENS Mean may be warmer, but I do think the MAJOR wild card is now the ULL.  The euro is very impressive.  We have to keep watching the trends on this one.  So far, they are stronger CAD *that doesn't really dislodge*  Colder 2m temps and colder 850's.   

[superjames1992]

Yeah, the Euro ENS mean is a little further NE with the high, but it's only probably ~50 miles, so I wouldn't make too much of it, to be honest.  For all intents and purposes, it basically supports the 12z operational Euro.

 

I'm not sure how great lower-resolution ensembles handle CAD, either?  Maybe that's why 850s are a little warmer (though not torching)?  Just spit-balling...

[WXinCanton]

Smart by them, will be a miracle to get an impact winter storm here. Euro ENS mean warmer then the Op, warmer than 0z ENS run. Keeps 850 far NW NC and VA.

  

how does the mean compare to the 0z mean temp wise?

[packbacker]

how does the mean compare to the 0z mean temp wise?

 A little warmer, but like SuperJames said, noise at this range. 

 

The CMC Ens mean still looks very nice...

 

[griteater]

I think the northern & southern stream phasing is key.  You can still have a closed 500mb low without phasing, but the phasing creates a stronger upper level system, and injects more cold air aloft.  Then you have the damming high out front...want to see the PV feature over SE Canada hang on, and not shift off to the NE too fast...positive trends on both of these fronts today.  Temperatures are obviously marginal, so a quicker high exit and/or non-phasing changes everything.

 

The Canadian, Euro, and UKMet all had the shortwave phasing in their 12z runs. 

 

UKMet at 144 has phasing upper waves in Miss River Valley on the backside, with 1042mb damming sfc high out front...precip is probably into northern GA on this image.

 

[superjames1992]

There's been amazing consistency from the GGEM ensemble mean.  It's pretty much looked the same for the past few days.  It might be consistently wrong, but nevertheless...

[FLweather]

Knock on wood and hopefully I won't jinx myself by saying this.

 

But the models have sucked with this current system. Too dry recently and currently more impressive than it has been shown.

 

http://radar.weather.gov/ridge/Conus/southmissvly.php

 

I'm sure the dry air limit the qpf. But the models have been showing this system as a dud pretty much the last couple of days. But some of the early Nam solutions that have been showing snow tomorrow morning maybe true. Remember it showed a band of snow in the mountains/foothills. FWIW the nam came in colder for tomorrow morning temps aloft supportive of snow roughly I95 to the mountains in NC. But one thing is common practically no moisture being shown.

 

But hopefully this system holds together. Should offer potential for snow>ip>zr instead of just plain zr in the morning.

[packbacker]

This is as good a CIP's analogs I have ever seen at 5 days.  Huge hits for 85 and points west in NC on over half the analogs.

 

http://www.eas.slu.edu/CIPS/ANALOG/stats.php?reg=SE&model=GFS212&fhr=F120&flg=

[burrel2]

The ukmet looks awesome for for the front end of the storm.  I’ve never seen a CAD setup that perfect before.  I think we’d be talking freezing rain all the way into alabama with that setup.