Christmas Storm VI

[BullCityWx]

I don't have time to be specific with qpf as I'm headed to bed but it seems .6 is a popular number statewide

[Wow]

Euro is a guaranteed half a foot here...maybe more

Most likely. The entire state is in the 0.5-1" shading but I'd disregard the euro qpf maps for this short range. DC actually gets screwed here!

[Shawn]

CAE: .67

ATL: .37

CLT: .56

CHS: .48

RDU: .61

Dont have maps but CHS doesn't make sense to me.

[burgertime]

Most likely. The entire state is in the 0.5-1" shading but I'd disregard the euro qpf maps for this short range. DC actually gets screwed here!

Yea that low just screams up to fast whips SNE and is outta here. Pretty fun to watch animating the maps.

[DopplerWx]

Did temps trend cooler or is it about that same?

[FoothillsNC]

Just looked at the Euro, I'm not surprised. We already knew this was coming back. So looks like it is true how it sniffs out the big ones, loses them, then brings it back. The strange thing about this storm is how far south the snow will probably get and how widespread it will be. Its a nice one. You may have to go back even past 1987, or even 88, maybe something like 1982 to get this cold and moisture combo down so far south. Hopefully the dreaded dryslot won't be an issue for too many. The best thing now is really the short range and nowcasting. I'm 34 (wsas 32) so clouds are coming in. Only thing now to do is wait for the fun to begin.

One other thing, most likely the Euro is too weak with its pressure. If the RUC is right on the northern scream, a real deepening is going to occur. The models are having some convective feedback issues on that. Thanks again on prayers and thoughts for mom.

[beanskip]

An interesting question when all is said and done is: "How did the Euro do on this storm." If it plays out like it appears, the Euro was ungodly good in the medium term and simply Godawful in the short term.

Euro is a guaranteed half a foot here...maybe more

[WeatherNC]

0z GFS ensemble track is almost a coastal hugger! Moves from Pensecola to just off Cape Hattaras

MODEL DIAGNOSTIC DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD

1233 AM EST SAT DEC 25 2010

VALID DEC 25/0000 UTC THRU DEC 28/1200 UTC

...SEE NOUS42 KWNO ADMNFD FOR THE STATUS OF THE UPPER AIR

INGEST...

00Z NAM/GFS/UKMET/CANADIAN EVALUATION INCLUDING MODEL

PREFERENCES...

MODEL INITIALIZATION ISSUES WHICH COULD BE RELEVANT LIE BELOW.

CONSOLIDATING UPPER LOW OVER THE EAST...

LOW PRESSURE FORMING UP THE EAST COAST...PREFERENCE FOR A 00Z

NAM/00Z UKMET/00Z CANADIAN/15Z SREF MEAN COMPROMISE

THERE ARE SMALL SCALE DETAILS THE NAM/GFS/ECWMF ARE SHOWING ISSUES

WITH WHICH MAY IMPACT ITS FORECAST LATER ON. THEIR SOUTHERN

STREAM SHORTWAVE IN TEXAS ARE 30-40 METERS TOO WEAK AT THE 500 HPA

LEVEL BASED ON RAOB REPORTS FROM TEXAS...MUCH CLOSER BUT STRONGER

THAN THE 00Z UKMET INITIALIZATION. THE NAM DOES NOT CAPTURE THE

ONGOING CONVECTION IN EASTERN TEXAS. THE 18Z AND 00Z GFS RUNS ARE

SHOWING SIGNS OF CONVECTIVE/GRIDSCALE FEEDBACK AS THE SYSTEM MOVES

ALONG THE GULF COAST WHICH COULD BE MAKING ITS SOLUTION AT THE

SURFACE AND ALOFT TOO STRONG. THERE ARE HINTS THAT THE RIDGE

INITIALLY ALONG THE EAST COAST IS MORE AMPLIFIED THAN THE

NAM...WHICH WOULD BE CLOSEST TO THE 00Z GFS/00Z UKMET/12Z ECMWF

DEPICTIONS. ANY OF THESE DETAILS COULD DEGRADE/NEGATIVELY AFFECT

THE SHORT RANGE FORECAST OF THIS COMPLICATED SYSTEM.

THE SHORTWAVE MOVING THROUGH THE MIDWEST THE DETERMINISTIC AND

ENSEMBLE SPREAD HAS SIGNIFICANT INCREASED SINCE THIS TIME

YESTERDAY...WITH THE 18Z AND 00Z GFS/18Z GEFS MEAN ON THE WEST

SIDE OF THE OVERALL SPREAD AND THE 12Z CANADIAN AND A SIGNIFICANT

PERCENTAGE OF ECMWF/CANADIAN ENSEMBLE MEMBERS ON THE EAST/QUICK

SIDE DUE TO GREATER INTERACTION WITH A VORTEX IN EASTERN CANADA.

THE NAM HAS TRENDED STRONGER ALOFT AND MORE WESTWARD AT THE

SURFACE OVER ITS PAST DAY OF RUNS...WHICH IS A TREND WHICH HAS

EXTENDED TO THE CANADIAN/UKMET SINCE THEIR 12Z RUNS. THE GFS AND

ECMWF HAVE TRENDED APART...WITH THE ECMWF SHOWING A EAST TO

SOUTHEAST TREND FOR THE PAST FEW DAYS AND THE GFS TRENDING WEST.

IN BOTH CASES...THE MODELS ARE SHOWING LONG TERM WAVERING...WITH

THE GFS RETURNING TOWARDS /IF NOT WEST OF/ ITS SOLUTIONS FROM

MONDAY THOUGH THE ECMWF IS MORE EAST THAN SEEN ON ITS PRIOR FIVE

DAYS OF RUNS. THE SREF MEMBERS HAVE SLOWED DOWN AND SHIFTED THE

LOW MORE WESTERLY WHILE THE CANADIAN AND ECMWF MEMBERS HAVE

TRENDED QUICKER AND MORE OFFSHORE. WITH MINIMAL OVERLAPPING

BETWEEN THE 21Z SREF MEMBERS AND THE 12Z GLOBAL ENSEMBLE MEMBERS

/ESPECIALLY WHEN COMPARED TO ITS 15Z RUN/...WILL NOT CONSIDER ITS

SOLUTION VIABLE. WHEN THE GFS SHOWS CONVECTIVE/GRIDSCALE

FEEDBACK...IT LOWERS OUR CONFIDENCE IN ITS FORECAST. THE GFS 850

HPA WINDS...BOTH THROUGH THE COASTAL PLAIN OF THE EAST AND WELL

OFFSHORE IN ITS WARM CONVEYOR BELT ARE DOUBLE THAT OF THE 00Z NAM

AND 12Z ECMWF. SINCE TRENDS ARE APART AND THE GFS AND ITS

ENSEMBLE MEAN ARE ON THE STRONG/WEST SIDE OF THE GUIDANCE...WHICH

IS UNUSUAL...AND A MODEL CONSENSUS IS RE-FORMING...WILL MINIMIZE

CHANGES TO CONTINUITY AND SPLIT THE GUIDANCE DOWN THE

MIDDLE...PREFERRING A 00Z NAM/00Z CANADIAN/00Z UKMET/12Z SREF MEAN

COMPROMISE.

...MODEL TREND GRAPHICS AT

WWW.HPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML...

...500MB FORECASTS AT WWW.HPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML...

ROTH

[Shawn]

Oh yeah, GSP: .59

[superjames1992]

Thanks for the Euro info, guys. I'm off to bed. I need my sleep for my probably all-nighter Saturday night with the flakes falling!

[jburns]

I don't have time to be specific with qpf as I'm headed to bed but it seems .6 is a popular number statewide

Looks to me as if its time for RAL to expand their WSW to their western counties.

[ncskywarn]

This came from the HPC model discussion page. Can someone please explain what kind of a difference the part that is highlighted could make?

THE SHORTWAVE MOVING THROUGH THE MIDWEST THE DETERMINISTIC AND

ENSEMBLE SPREAD HAS SIGNIFICANT INCREASED SINCE THIS TIME

YESTERDAY...WITH THE 18Z AND 00Z GFS/18Z GEFS MEAN ON THE WEST

SIDE OF THE OVERALL SPREAD AND THE 12Z CANADIAN AND A SIGNIFICANT

PERCENTAGE OF ECMWF/CANADIAN ENSEMBLE MEMBERS ON THE EAST/QUICK

SIDE DUE TO GREATER INTERACTION WITH A VORTEX IN EASTERN CANADA.

THE NAM HAS TRENDED STRONGER ALOFT AND MORE WESTWARD AT THE

SURFACE OVER ITS PAST DAY OF RUNS...WHICH IS A TREND WHICH HAS

EXTENDED TO THE CANADIAN/UKMET SINCE THEIR 12Z RUNS. THE GFS AND

ECMWF HAVE TRENDED APART...WITH THE ECMWF SHOWING A EAST TO

SOUTHEAST TREND FOR THE PAST FEW DAYS AND THE GFS TRENDING WEST.

IN BOTH CASES...THE MODELS ARE SHOWING LONG TERM WAVERING...WITH

THE GFS RETURNING TOWARDS /IF NOT WEST OF/ ITS SOLUTIONS FROM

MONDAY THOUGH THE ECMWF IS MORE EAST THAN SEEN ON ITS PRIOR FIVE

DAYS OF RUNS. THE SREF MEMBERS HAVE SLOWED DOWN AND SHIFTED THE

LOW MORE WESTERLY WHILE THE CANADIAN AND ECMWF MEMBERS HAVE

TRENDED QUICKER AND MORE OFFSHORE. WITH MINIMAL OVERLAPPING

BETWEEN THE 21Z SREF MEMBERS AND THE 12Z GLOBAL ENSEMBLE MEMBERS

/ESPECIALLY WHEN COMPARED TO ITS 15Z RUN/...WILL NOT CONSIDER ITS

SOLUTION VIABLE. WHEN THE GFS SHOWS CONVECTIVE/GRIDSCALE

FEEDBACK...IT LOWERS OUR CONFIDENCE IN ITS FORECAST. THE GFS 850

HPA WINDS...BOTH THROUGH THE COASTAL PLAIN OF THE EAST AND WELL

OFFSHORE IN ITS WARM CONVEYOR BELT ARE DOUBLE THAT OF THE 00Z NAM

AND 12Z ECMWF. SINCE TRENDS ARE APART AND THE GFS AND ITS

ENSEMBLE MEAN ARE ON THE STRONG/WEST SIDE OF THE GUIDANCE...WHICH

IS UNUSUAL...AND A MODEL CONSENSUS IS RE-FORMING...WILL MINIMIZE

CHANGES TO CONTINUITY AND SPLIT THE GUIDANCE DOWN THE

MIDDLE...PREFERRING A 00Z NAM/00Z CANADIAN/00Z UKMET/12Z SREF MEAN

COMPROMISE

[burgertime]

Makes you wonder what they will say about the Euro? The one thing is, that the event hasn't happened yet. Let's all hope this isn't a fail of epic proportions here when all is said and done.

[Shawn]

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE COLUMBIA SC

1243 AM EST SAT DEC 25 2010

SHORT TERM /SUNDAY/

UPDATE...LATEST MODEL RUNS RAISING QUESTIONS ON PRECIPITATION TYPE

FOR LATE SATURDAY NIGHT AND SUNDAY. EVALUATING NEW DATA CURRENTLY.

PREVIOUS DISCUSSION...UPPER TROUGH OVER THE GREAT LAKES REGION TO

DEEPEN AS IT MOVES EAST TROUGH SUNDAY. SHOULD REMAIN POSITIVELY

TILTED AS IT TRACKS ACROSS KENTUCKY/CAROLINAS THROUGH SUNDAY.

SHORT WAVE OVER TEXAS WILL CONTINUE TO TRACK SOUTHEAST ALONG THE

NORTHERN GULF OF MEXICO SATURDAY...AND TRIGGER WEAK SURFACE

CYCLOGENESIS. THE MODEL CONSENSUS SURFACE LOW PRESSURE TRACK IS

EAST-NORTHEAST ACROSS NORTHERN FLORIDA AND RAPIDLY NORTHEAST OF

THE CAROLINA COAST...TOO FAR NORTH AND FAST FOR SIGNIFICANT

SNOWFALL FOR THE MIDLANDS. THE MUCH STRONGER SURFACE CYCLOGENESIS

WILL OCCUR ALONG THE MID ATLANTIC COASTLINE LATER ON SUNDAY AS

SYSTEM PHASES WITH UPPER LEVEL TROUGH.

MODEL SOUNDINGS SUPPORT MORE RAIN THAN SNOW WITH IMMEDIATE

SURFACE LAYERS MAINLY ABOVE ZERO. PARTIAL THICKNESSES AND MODELS

SOUNDINGS SUPPORT HIGHER CHANCE SNOW NORTH AND WEST OF COLUMBIA

LATE SATURDAY AND SATURDAY NIGHT. STRONGEST SYNOPTIC LIFT SATURDAY

EVENING AS UPPER LEVEL DIVERGENCE INCREASES AHEAD OF APPROACHING

SHORT WAVE TROUGH IN WESTERN GEORGIA. AS 850MB LOW MOVES OFFSHORE

EARLY SUNDAY COLD ADVECTION DEVELOPS AND SOUNDINGS SUPPORT SNOW

FLURRIES/OR FREEZING DRIZZLE ACROSS THE REGION AS MOISTURE BECOMES MORE

SHALLOW DURING THE DAY SUNDAY. ANY SNOW ACCUMULATION WILL REMAIN ACROSS

THE NORTH MIDLANDS/PEE DEE AND WILL LIKELY BE QUITE LIGHT. LITTLE

OR NO ACCUMULATION EXPECTED FROM THE CENTRAL MIDLANDS TO THE

CENTRAL SAVANNAH RIVER AREA. HIGH TEMPERATURES SATURDAY RANGING

FROM THE UPPER 30S NORTH TO AROUND 50 SOUTH. LOW SATURDAY NIGHT

CLOSE TO CONSENSUS IN THE UPPER 20S TO MID 30S. HIGHS SUNDAY ONLY

IN THE UPPER 30S TO LOWER 40S.

After this .67 for CAE off the Euro and the GFS ensemble mean etc, CAE better go ahead and issue at least a watch. Seriously. Also, although these models say the surface is too warm.. i do not buy it because with these totals... the precip is going to overcome it.

[Tyler Penland]

Haven't posted during this storm but I am getting VERY excited.

Foothills, loved that writeup. Absolutley despise asking IMBY questions but in this case I was just wondering about how much you would expect in the NE GA mountains?

[phil882]

This came from the HPC model discussion page. Can someone please explain what kind of a difference the part that is highlighted could make?

I think the important part to now is how the ensembles are "west" of the Op run.... this is a sign that the gfs is still not showing a solution that is phased enough and we might see subsequent runs go even further west.

[weatherheels]

Damn, those ensemble mean images are impressive, looks like something we usually see on the gfs about 384 out. Aren't the ensemble means usually bullish on qpf compared to the op, or do I have it backwards?

[WeatherNC]

Makes you wonder what they will say about the Euro? The one thing is, that the event hasn't happened yet. Let's all hope this isn't a fail of epic proportions here when all is said and done.

The Sh!t is about to hit the fan, watch! WFO's will upgrade quickly overnight, based on coordination from surrounding offices, and mother ship HPC. This is going to be special, with the EC leading the way, except for falling off in the dead-zone (latest pickup in the red-zone I have ever seen btw), only to have the Americans recover the funble and score a touchdown .

check your pm

[HKY_WX]

http://www.examiner....torm-on-the-way

posting this one more time just in case anyone missed it. forecast map for the storm.

[SnowDeac]

There hasn't been much talk about dryslotting yet. Is it possible to predict where this could potentially be an issue, and could it cause problems for parts of the Central Carolinas? I vividly remember one event (I think December of 2002?) where RDU was projected to get a foot and ended up with flurries, while E NC got pounded, and W NC had a decent snowfall as well. Thanks.

[brettjrob]

If the RUC and HRRR have anything to say about it, a big chunk of the Mid South needs a WWA hoisted now (namely N MS, W TN, and NW AL), and some areas currently under a WWA may need a WSW.

[Lookout]

fwiw, here is the 0z hires 48 hour total . What is interesting about it though is the deformation zone precip it has and lingers it through the entire period..still light snow here at 48 hours with high 700mb rh. It makes me wonder if it's underdone. Also keep in mind that 850mb temps plummet to -7/8cc and colder by 12z sunday over ga/western carolinas, and even -10c by hour 48 over the western carolinas/north ga as well..with -9c dipping into central/eastern north carolina...so some really good ratios if any is falling at that time. Pretty remarkable storm if you look at the 500 and 700mb maps and you have to wonder if the models still are trying to catch and there will be even more improvements.

39 hour 700mb rh and omega

simulated radar at hour 39

Still snow in the air in the world of the hires at hour 48 for most of the carolinas/far eastern ga

48 hour 850mb temps

[keithinala]

Explosion over north Alabama in the morning

[SnowDeac]

fwiw, here is the hires 0z 48 hour total. What is interesting about it though is the deformation zone precip it has and lingers it through the entire period..still light snow here at 48 hours with high 700mb rh. It makes me wonder if it's underdone. Also keep in mind that 850mb temps plummet to -7/8cc and colder by 12z sunday over ga/western carolinas, and even -10c by hour 48 over the western carolinas/north ga as well..with -9c dipping into central/eastern north carolina...so some really good ratios if any is falling at that time. Pretty remarkable storm if you look at the 500 and 700mb maps and you have to wonder if the models still are trying to catch and there will be even more improvements.

Interesting that there seems to be some dryslotting modeled in Central NC, and naturally right after I posted. Is anyone else concerned about this issue?

[packbacker]

Interesting that there seems to be some dryslotting modeled in Central NC, and naturally right after I posted. Is anyone else concerned about this issue?

Not sure that is dryslot, but yes, someone will get dry slotted.

[KO0588]

Not sure that is dryslot, but yes, someone will get dry slotted.

Match it up with the precipitation and it appears after the majority of its gone so it might just be the system leaving, but a meteorologistcould answer it better.

[WeatherNC]

Interesting that there seems to be some dryslotting modeled in Central NC, and naturally right after I posted. Is anyone else concerned about this issue?

Please do not quote these large images, remove the link when replying in text. Huge shift west tonight, wife is packing two sets of clothes and some hygiene gear for her 13 hour shift at the hospital tomorrow, with the likelihood she will have to stay for 24 plus. Also talked to one of our TV Chief Mets here in the east tonight, after his 11 pm air. He is bringing two sets also, thinking he will not be going home for at-least 24 hours. It is a Christmas Miracle Charlie Brown!

The one issue he raised with me, and that from some of the on air mets in the Myrtle Beach and Wilmington markets, is that there is a disconnect between the 0z american guidance, NAM keeps it south, and GFS takes it north. That may be do to feedback issues with both models, GFS in the short term (<48hrs), and NAM in the long term (>48hrs).

MODEL DIAGNOSTIC DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD

134 AM EST SAT DEC 25 2010

THE DETERMINISTIC GUIDANCE SPREAD HAS SIGNIFICANTLY NARROWED WITH

THE 00Z GUIDANCE. THE NAM HAS TRENDED STRONGER ALOFT AND MORE

WESTWARD AT THE SURFACE OVER ITS PAST DAY OF RUNS...WHICH IS A

TREND WHICH HAS EXTENDED TO THE CANADIAN/UKMET SINCE THEIR 12Z

RUNS THOUGH MORE EXTREME IN THE CASES OF THE CANADIAN AND UKMET.

THE GFS AND ECMWF HAVE TRENDED APART...WITH THE ECMWF SHIFTING

SHARPLY WESTWARD AFTER ITS 2-3 DAY TREND TO THE EAST TO

SOUTHEAST... AND THE GFS TRENDING WEST. IN BOTH CASES...THE

MODELS ARE SHOWING LONG TERM WAVERING...WITH THE GFS RETURNING

TOWARDS /IF NOT WEST OF/ ITS SOLUTIONS FROM MONDAY. THE ECMWFS

DRASTIC CHANGE MAKES THE CONFIDENCE IN ITS CURRENT SOLUTION LOW.

THE SREF MEMBERS HAVE SLOWED DOWN AND SHIFTED THE LOW MORE

WESTERLY WHILE THE CANADIAN AND ECMWF MEMBERS HAVE TRENDED QUICKER

AND MORE OFFSHORE. THE 21Z SREF MEAN IS SLOWER THAN THE

DETERMINISTIC GUIDANCE...BUT SHOWS A SIMILAR TRACK. WHEN THE GFS

SHOWS CONVECTIVE/GRIDSCALE FEEDBACK...IT LOWERS OUR CONFIDENCE IN

ITS FORECAST. THE GFS 850 HPA WINDS...BOTH THROUGH THE COASTAL

PLAIN OF THE EAST AND WELL OFFSHORE IN ITS WARM CONVEYOR BELT ARE

DOUBLE THAT OF THE 00Z NAM. SINCE THE CANADIAN AND ECMWF MODELS

HAVE SHIFTED SIGNIFICANTLY WESTWARD FROM THEIR 12Z RUNS...LITTLE

WEIGHT CAN BE PLACED ON THEIR ENSEMBLE MEAN SOLUTIONS AND ADDS

CONFIDENCE IN THE 00Z GEFS MEAN. THIS LEAVES US WITH A PREFERENCE

LYING BETWEEN THE MORE WESTERN 00Z GFS/00Z ECMWF AND THE MORE

EASTERN 00Z NAM/00Z UKMET/00Z CANADIAN...A SOLUTION SIX HOURS

SLOWER AND WEST OF THE PREFERENCE FROM THIS TIME YESTERDAY.

CONFIDENCE REMAINS LOW IN THIS FORECAST UNTIL THE MULTIPLE

SHORTWAVES WHICH MAKE UP THE PARENT SYSTEM MERGE...AND WINTER

RECONNAISSANCE FLIGHTS CAN BEGIN IN THE GULF OF MEXICO/WESTERN

ATLANTIC LATER TODAY. SEE QPF AND WINTER WEATHER DISCUSSIONS FOR

THIS SYSTEMS PRECIPITATION IMPACT.

Link: http://www.hpc.ncep.noaa.gov/wwd/impactgraphics/

[Pyro4Life]

Check out this WV loop. Look at the interaction of our southern storm and the energy that's pushing down from the north. Notice the ripple effect, almost looks like waves crashing ashore.

http://www.rap.ucar.edu/weather/satellite/displaySat.php?region=CLT&itype=wv&size=small&endDate=20101001&endTime=-1&duration=12

[phil882]

I hope this was a great example in how small changes in a phasing solution can make huge differences in the modeling.

Take a peak at the comparison between the 06z of the nam and the 00z tonight.

Does look so bad at the beginning

But can turn into something completely different.

In the end the biggest game changers were the amplified Pacific Ridge... and the extra piece of energy left behind from the main northern stream s/w. The stronger southern stream s/w was just icing on the cake.

[FoothillsNC]

Guess its bed time now, but can't sleep. Ugg what a week this has been. Just checked out the latest RUC and if you want to see the very definition of what historic is, check it out. The northern stream goes from north of Hudsons Bay to the Gulf of Mexico. Don't think we've ever seen that in the Winter time here, so this is going to be one interesting storm system for the Southeast. If I wasn't so tired, I'd update the maps, but its too late. Paint a foot from northern and eastern GA , the western Carolinas and then probably a good chunk of the eastern or piedmont of the Carolinas. If the RUC is right, we're in for a storm most of us will remember the rest of our lives.