Christmas Storm V

[MotoWeatherman]

Gainesville GA 7am Saturday sounding....supports snow as Precip type.

Date: 36 hour GFS valid 12Z SAT 25 DEC 10
Station: Kgvl
Latitude:   34.32
Longitude: -83.83
-------------------------------------------------------------------------------
LEV PRES  HGHT  TEMP  DEWP  RH  DD   WETB DIR SPD THETA THE-V THE-W THE-E   W
    mb     m     C     C    %   C     C  deg knt   K     K     K     K    g/kg
-------------------------------------------------------------------------------
 0 1000   145                                                                 
SFC  971   381   1.8  -1.6  78  3.3   0.4 284   5 277.2 277.8 275.0 286.9  3.51
 2  950   560   2.0  -3.5  67  5.5  -0.2 288   9 279.2 279.8 275.6 287.9  3.11
 3  850  1449  -0.2  -3.9  76  3.7  -1.7 268  26 285.9 286.5 279.4 295.6  3.37
 4  800  1936  -0.0  -1.9  87  1.9  -0.9 268  31 291.1 291.9 282.7 303.2  4.16
 5  750  2452  -1.3  -1.5  98  0.2  -1.4 270  35 295.1 296.0 284.8 308.6  4.56
 6  700  3001  -3.4  -3.6  99  0.2  -3.5 267  41 298.7 299.4 285.8 311.2  4.19
 7  650  3584  -6.6  -6.7  99  0.1  -6.6 264  46 301.5 302.2 286.2 312.4  3.57
 8  600  4205 -10.5 -10.7  99  0.2 -10.6 262  50 304.0 304.5 286.3 312.8  2.83
 9  550  4870 -14.5 -14.7  99  0.1 -14.6 262  56 306.8 307.3 286.7 313.9  2.23
10  500  5585 -19.3 -19.7  97  0.3 -19.4 264  58 309.5 309.8 287.0 314.7  1.60
11  450  6360 -24.9 -26.0  90  1.2 -25.1 262  59 312.0 312.2 287.2 315.4  1.02
12  400  7206 -30.8 -31.1  97  0.4 -30.8 257  65 315.0 315.1 287.9 317.5  0.71
13  300  9179 -47.9 -48.0  99  0.1 -47.9 260  78 317.8 317.8 288.2 318.4  0.16
14  250 10358 -53.9 -57.7  63  3.8 -54.0 261  86 326.0 326.0 290.6 326.2  0.06

[Rankin5150]

if the 60 hour is right, we're not done. I'd say somethng is ripe for part of Georgia and Carolinas. The flow backs enough west in time to allow the southern stream to develop near the Fl. panhandle. I don't think its handling this exactly right, so theres room either way, but if the southern vort is in tact at all at 48 to 60 hours down there, then this could be a HUGE suprise for somebody

Robert,

Is this the Deformation NWS-GSP mentioned early today?

[strongwxnc]

This runs is most def wetter than the 00 Nam.

[MotoWeatherman]

Atlanta GA sounding at 1pm Saturday...boundary issues perhaps. I think this will trend colder.

Date: 42 hour GFS valid 18Z SAT 25 DEC 10
Station: Katl
Latitude:   33.65
Longitude: -84.42
-------------------------------------------------------------------------------
LEV PRES  HGHT  TEMP  DEWP  RH  DD   WETB DIR SPD THETA THE-V THE-W THE-E   W
    mb     m     C     C    %   C     C  deg knt   K     K     K     K    g/kg
-------------------------------------------------------------------------------
 0 1000   137                                                                 
SFC  984   270   3.3   1.7  89  1.6   2.6 269   6 277.7 278.5 276.5 289.8  4.39
 2  950   552   1.1  -0.6  88  1.8   0.4 273  11 278.3 279.0 276.1 288.9  3.83
 3  850  1444   0.2  -0.9  93  1.0  -0.3 271  20 286.3 287.0 280.6 298.3  4.22
 4  800  1929  -0.7  -1.0  98  0.3  -0.8 269  25 290.4 291.2 282.7 303.3  4.46
 5  750  2444  -2.1  -2.3  99  0.2  -2.2 264  32 294.3 295.1 284.2 307.0  4.31
 6  700  2991  -4.3  -4.5  98  0.2  -4.4 260  37 297.7 298.4 285.1 309.4  3.91
 7  650  3573  -6.9  -7.3  97  0.4  -7.1 259  42 301.1 301.8 285.8 311.5  3.39
 8  600  4193 -10.5 -11.5  92  1.1 -10.9 260  45 304.0 304.5 286.1 312.2  2.63
 9  550  4858 -14.6 -15.9  90  1.3 -15.0 259  46 306.7 307.1 286.4 313.1  2.00
10  500  5573 -19.2 -19.8  95  0.6 -19.4 254  48 309.6 309.9 287.0 314.8  1.59
11  450  6350 -24.2 -24.3  99  0.1 -24.2 248  57 312.8 313.1 287.7 316.8  1.19
12  400  7198 -30.4 -30.4 100  0.0 -30.4 245  68 315.5 315.6 288.1 318.1  0.76

[kvegas-wx]

What's up with the 2.5" of rainfall in the DFW area? Seems kind of odd.

More important, what is that "thing" that is about to eat the entire west coast?? New Years storm?

[Wow]

man, this is the closest since the euro dropped it. goodness gracious.

[NCSNOW]

The way the GFS shows the northern stream coming from behind the southern vort is VERY good. IF they phase earlier in AL, BOOOOOOM!!!!! Perhaps the GFS isn't handling the phase properly.

hour 36 is the whole key here, we finally get a clean piece to break off/out of the convuleted Northern stream and seperate enough where it can drop/dig.

[DaculaWeather]

And this from FFC:

FXUS62 KFFC 240351AFDFFC

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE PEACHTREE CITY GA

1051 PM EST THU DEC 23 2010

.UPDATE...

SOME CONCERN ON THIS UPDATE THAT POTENTIAL FOR SNOW ACCUMULATION

IS LESSENING. RECENT MODELS STILL SHOW TWO SHORT WAVES MOVING

TOWARD THE STATE. THE NORTHERN WAVE IS CURRENTLY OVER THE NORTHERN

PLAINS AND THE SOUTHERN WAVE OVER THE SRN ROCKIES. MODELS HAVE

BEEN IN SOME DISAGREEMENT ON THE EXACT TIMING AND LOCATION OF

THE PHASING OF THESE TWO WAVES OVER THE SOUTHEAST US.

THE 18Z GFS KEEPS THE SOUTHERN WAVE SOMEWHAT INTENSE BUT ON A

MORE SOUTHERN TRACK ALONG THE GULF COAST AND A LITTLE WEAKER THAN

EARLIER RUNS. THE 12Z ECMWF DAMPS THE SOUTHERN WAVE MORE QUICKLY

THAN THE GFS AND HAS A STRONGER NORTHERN WAVE WHICH COULD PRODUCE

SOME LIGHT SNOW IN FAR NORTH GA. THE NEW 00Z NAM HAS A MUCH WEAKER

SOUTHERN WAVE THAN PREVIOUS RUNS A WEAK/BROAD NORTHERN WAVE. VERY

LITTLE IN THE WAY OF NET UVV AND QPF OVER CWA. MAYBE 0.10 OR 0.20

LIQUID OVER NORTH GA ON SATURDAY WHICH OCCURS BEFORE THE CRITICAL

SNOW THICKNESSES FULLY MET SATURDAY NIGHT. PUT ANOTHER WAY...18Z

NAM HAD TOTAL SNOWFALL OF 1-3 INCHES OVER NE GA...NOW THERE IS

NARY A DUSTING. THE 18Z GFS MAY BE SHOWING A SIMILAR TREND BUT TOO

SOON TO TELL. AS FOR ANY WRAPAROUND PRECIP SUNDAY...12Z ECMWF MOST

AGGRESSIVE WITH MORE SOUTHERN AND DEEPER/INTENSE UPPER LOW. COULD

SEE SOME FLURRIES OR LIGHT ACCUMULATIONS IN THE NE MOUNTAINS IN

THAT PATTERN SUNDAY.

ALL SAID...IF LATEST MODELS VERIFY...MAY ONLY SEE UP TO AN INCH

OVER MOST OF NORTH AND CENTRAL GA. WILL NOT UPDATE SPS OR MAKE

MAJOR CHANGES TO THE WX/POP/SNOW GRIDS. TWEAKED SOME OF THESE

GRIDS EARLIER...BUT NOT ENOUGH TO WARRANT UPDATED TEXT PRODUCTS.

[DopplerWx]

GFS is even better than 18z, the trends are obvious. If the euro comes in with the northern stream behind the s/w it'd be a real cause for excitement. And if it phases it at 00z......BOOOM....the board may crash and we wont get much sleep. Im more than excited right now with these trends.

[bingcrosbyb]

Yes, the GFS does remind me of the Euro before it went into the gutter. Just when I think I'm out, they pull me back in.

[RaleighWx]

Northern s/w keeps digging a little more south and west with each GFS run. That is what is driving the storm for sure. This is a nice 2-4 inch type snow across the Triangle if literally true, with 3-6 and locally more juts south of the Triangle between RDU and ILM.

[Stormsfury]

I say expect the 00z EURO to trend back towards a bigger storm idea with the northern stream s/w in question getting into the data network.

Won't be the 3 days in a row modeled historic monster that was shown but I think we're getting out of the "model loses storm" phase now.

[CAD_Wedge_NC]

GFS is even better than 18z, the trends are obvious. If the euro comes in with the northern stream behind the s/w it'd be a real cause for excitement. And if it phases it at 00z......BOOOM....the board may crash and we wont get much sleep. Im more than excited right now with these trends.

This is the trend I was looking for. Not a winner yet, but getting closer by the run......The NAM is not in it's deadly range yet. So, it is not cause for alarm. Looks like a lot of us will be up for the Euro.

[FoothillsNC]

The overall setup looks better on the 0z GFS run! I am staying up for the Euro. This one is not written off yet IMO...

I'll probably punish myself a couple more hours too. If the GFS is right at 5H or close, then there is definite big potential here. At 42 hours and beyond it has a screaming set of northern energy with one big vort that can catch the system in the western Gulf and then explode it up the coast. Its probably still a long shot esp for folks well inland like me, but you guys in the Piedmont around CLT, CAE and RDU and of course the eastern half definitely can't say its over yet. Its not quite the real big dog, but if you were to change a couple features location just a few miles, or any subtle nuances , minor changes , I mean really extremely tiny changes, then a much bigger storm would erupt quickly. I'll say good luck to the eastern halves and central and eastern Ga, I know my area would be on the western shield if it even did occur, but I'd hate to lose such a potentially good setup totally and would love to see somebody get dumped on.

[eyewall]

Well I think this is going to come down to nowcasting the main players as the day wears on tomorrow. I will be looking for of course the southern stream s/w and if it begins to get sheared by the northern stream tomorrow night. I will also be looking for the northern stream energy and if that ULL in IA and eventually MO is really going to throw a wrench in. Finally of course the speed and position of it all. We are still threading a needle here with the NAM on the low end of the scale right now. I am going to write a quick evening update (but it will be prior to the Euro as I have to wake up relatively early). I am waiting to see some QPF numbers etc. on Allen's site.

[MotoWeatherman]

Per this GFS run...not a forecast but just translating what the GFS is showing by my opinion.

BHM looks close to being snow but boundary layer is a bit warm. Need to watch for cooling trends there.

ATL looks to start as snow/sleet due to the dry air and does have boundary layer issues thru the first half of the day.

CAE - shows rain changing to snow overnight Sunday.

RDU - might be all snow. If it does rain on the front end it should change over before too long.

[DaculaWeather]

I'm a little surprised to see precip breaking out in OK and KS http://www.daculaweather.com/ridge_oklahoma_master.php

[strongwxnc]

I agree. Sitting out West, we need the system to look like the Euro was showing before 00 runs last night. Or at least close to it.

Going to get a few zzz before the Euro.

This is the trend I was looking for. Not a winner yet, but getting closer by the run......The NAM is not in it's deadly range yet. So, it is not cause for alarm. Looks like a lot of us will be up for the Euro.

[packbacker]

This seemed to be a big improvement over 18z GFS but the precip shield didn't improve that much, atleast in NC. I was expecting a bigger shift, guess I am getting greedy.

[Itunis]

And this from FFC:

Up to an inch rather than 1-2" is completely reasonable, even considering the 0Z GFS (which looks like it drops an inch or two over parts of N GA).

[NEGa]

ThIs certainly makes me feel a bit better (gfs amounts) after the nam disaster. Most of the southern 3/4 of Georgia gets .25

[Wild Weather Monger]

Another important change this run. The northern branch dives almost due south through the plains. Looks to me, that is how our southern VM is able to get out ahead of the northern jet.

Man this thing is close.

[lilj4425]

Anybody got the 00z RGEM? The good luck charm avatar is here.

[burrel2]

Look how far the RGEM has dug our northern stream s/w!! Well, looks like i'll be sucked into staying up for another dose of Dr. No's medicine

[eyewall]

Taking the GFS verbatim I would be in line for .50 QPF or so but obviously it is a model only and not something to take to the bank by any means.

[FoothillsNC]

What will probably happen the next 24 hours of runs, is as the northern systems are better sampled in our network, there may continue to be changes, they could be better or worse, but seeing this trend I'm actually inclined to think more west. I do believe the southern system is being handled pretty well through the next 24 to 36 hours, it seems similar from run to run , but the big unknown is the speed and trajectory and strength of any northern shortwaves, and that makes all the difference in the world right now. If you take that vort in the mid. Miss. Valley at 36 hours a little more west or a little more south, or make it faster it will most likely pick up the (still very healthy) vort in the western Gulf and suddenly a powerful gulf low will begin backing moisture right over Alabama, Georgia and the Carolinas extremely quickly.

And then most likely as the gulf system crosses Florida and into the Ga Coast, the remaining northern stream energy that is most likely backing and closing offa 5H low in the Ohio valley would really help the Southeast coastal. Its a HUGE potential. I'm afraid though with our luck, the likely thing is this whole process could take place just offshore by a fraction.

[phil882]

I'm glad I took a nice break from watching the models since 00z yesterday. Overall I think the last few model runs have highlighted the problem of needing a perfect phase for a major deepening low pressure system. The euro was able to phase all three pieces of energy back before 00z last night because the southern stream s/w was depicted stronger than in actuality. Unfortunately, that is a common model problem in a La Nina regimes, since the subtropical jet is weaker than expected and was not able to support a stronger shortwave with more vorticity. Thus we are reliant on the northern stream not suppressing the energy too much. You can see how this is prevented since the next pacific shortwave is knocking on the door step of the strong Western North America ridge, weakening it just in time to prevent a deeper and further west solution.

Basically what I am trying to say is that its much easier to get the northern stream to cooperate and produce a more amplified solution if the southern stream shortwave was stronger in the first place. I think that is what in large part the euro was doing that allowed for a strongly phasing solution that produced quite a large and powerful winter storm. Now that we have better sampling that shows that the shortwave is weaker than expected, the solution is much harder to come by since the upper ridge is being forced westward too early by the strengthening pacific jet near the West Coast. Its not impossible to get the right phase... it just has to be perfect. More times than not, thats not going to happen.

That doesn't mean there won't be snow... in fact 2-4" still looks like a safe bet for a lot of folks in eastern NC. Just don't expect the fantasy that the Euro had for so many runs.

[Wild Weather Monger]

Look how far the RGEM has dug our northern stream s/w!! Well, looks like i'll be sucked into staying up for another dose of Dr. No's medicine

Can you tell from the earlier panels, is that maximum over SE Louisiana part of the southern energy, or is it all northern stream having dug that far south?

[Carvers Gap]

I am hearing the UKMET is west...but still east of the 0z GFS. Does anyone have an image they can post?

[burrel2]

Can you tell from the earlier panels, is that maximum over SE Louisiana part of the southern energy, or is it all northern stream having dug that far south?

I think it's basically all northern stream energy... It's hard to say though since the panel size cuts off the view of southern shortwave...

Also, I think the rgem at 36hrs is a good bit farther south with the southern s/w, imagine if we could get the northern branch to dig that far west and south, but have the southern s/w placement of the american models! It's probably too late for me regardless, but I would be getting my hopes up yet again if lived in eastern SC/NC.