Christmas Storm VI

[Itunis]

I hope so too lol. Hopefully we can get enough precip early enough to prevent much warming tomorrow. This is one of the rare times it looks to start early in the morning. If this started in the afternoon, we would warm up too much.

I agree. I'd be surprised if anyone gets 2 inches outside the mountains in north georgia. I think the best anyone can hope for is an inch. It probably will only occur in rather narrow/small areas with everyone else getting a dusting to half inch or less. Mainly because of marginal surface temps combined with the fact this is falling in the daytime so you have solar insolation keeping ground temps warm enough to melt a good portion of whatever falls. The gfs/nam don't show a lot falling after dark unfortunately.

Of course this is assuming the models are handling things right. Obviously if such scenarios robert and others have mentioned happened, we would be looking at something a lot more interesting.

Here is the current ground temps

Yeah, I'm more optimistic that we'll see at least a dusting but anything beyond that is up in the air for sure. Side note, some of those soil temps look off...if only the ground was 33 degrees here

[El Kabong]

I look forward to seeing some updated call maps later this afternoon. I don't believe there are many forum members in my immediate area (central Georgia - about 25 miles south of Macon), but I'm hopeful that we might be able to squeeze out a few flakes later tomorrow evening. FoothillsNC got a lot of us excited with the animated map from a couple of days ago. It was awesome seeing this part of Georgia in some of the "bright white" snow bands. Even though the extreme Euro solution is looking far less likely, maybe something in between would still give us a shot at a dusting to 1". The disco for this storm has been nothing short of amazing and I tip my cap to the pros who have been analyzing the data and translating it for the rest of us. Keep up the great work, guys!

[CandymanColumbusGA]

As a broadcast Met, who has to tell the population tonight about what they can anticipate for Christmas.... I must say, this is THE least confident I have ever been with a forecast. Usually I get a gut feeling about things, and right now my gut is like DOES NOT COMPUTE DOES NOT COMPUTE!

This is going to be the epitome of nowcasting... The shortwave toward North Dakota right now is going to be the main player in all of this. The convection occuring right now over Texas is a good sign as it will help get this thing to a more neutral tilt, but until that happens we are going to be up in the air forecast wise.

One very interesting thing for tonight though is when will the clouds roll in? If the clouds roll in early in the morning, then temperatures MIGHT be held low enough, that if we see heavy enough rain, we may be able to see snow here across West Central Georgia.... However, if we start seeing the sun tomorrow, it's going to warm up fairly quickly. I'm tending to think the clouds will get here after the sun is up for an hour or two and we will miss out on seeing flurries here. However, it is something to keep in mind is how the cloud cover will effect temperatures.

[NCSNOW]

Heres a good long loop of water vapor. Shows all players on field and is the best thing to be viewing now. Gonna be close phrase doesnt even do it justice. Off to start Christmas Eve with family. Done instructed brother -in-law to bring his blackberry.

http://www.nws.noaa.gov/sat_loop.php?image=wv&hours=24

[CaryWx]

Ugh...eyewall. That map is definitely not GFS centric is it?

[burgertime]

Ugh...eyewall. That map is definitely not GFS centric is it?

Based on the bad initialization it's probably a smart idea to stick with the NAM since the Euro and GFS at this point would be outliers. However I'm sure he would be perfectly fine with eating crow.

[CandymanColumbusGA]

Are you at WRBL? What do you think for Atlanta, with all the ignoramus mets we have in ATL, they have no idea. Kirk Mellish has been missing for weeks now,

Why, yes I am at WRBL. I am their new Morning Meteorologist. I cannot say I know any of the meteorologists in Atlanta... My last post though is going to determine whether a lot of people here in Alabama/Georgia are going to be able to see snow. I have a feeling that Atlanta will see a dusting or so of snow, but not until evening.

This is something I am getting used to. I am used to forecasting severe weather and tropical systems (I grew up in Florida...), but this phasing issues is something I have had to learn a lot about on here and read up on. Again, the strength of the storms in Texas is a good thing in my opion, but this shortwave in North Dakota will be moving into the south east and depending on the exact timing of this thing will depend on whether Alabama/Georgia will see a few flurries or just rain or a rain/snow mix off and on.

This will be a mostly rain event, with flurries possible for many locations through central georgia. Up to Atlanta is where there is a better 'chance' of seeing snow.

It's time to start looking out the window now... Clouds are going to play an important roll in whether we see a primarily rain event, or a rain/snow event....

[NEGa]

well gsp sounds as confused as most of us are lol

* * *

Near term /through Saturday/...

unfortunately...forecast confidence is not increasing with the

approach of the long-advertised storm system. This is not unusual

concerning the split flow regime...and anticipated phasing of the

two streams...always one of the major headaches in operational

forecasting. For the most part...the 12z models are much wetter than

their 00z/06z counterparts. The GFS phases the two streams sooner

than prior runs...resulting in Gulf/Atlantic cyclogenesis that is

more intense and closer to the coast. This results in a not-too-

shabby band of frontogenetically-forced precipitation developing along the

I-85 corridor Saturday morning. The NAM and Canadian Gem are also

trending wetter...although they are more muted than the GFS. To

complicate matters...HPC has essentially thrown out the 12z runs of

the NAM/GFS due to to initialization errors. What we have opted to

do is to feature essentially a 50/50 blend of the NAM and GFS. This

results in a very European model (ecmwf)-like forecast...which provides ME with some

assurance...since it has been by far the most consistent model over

the past few days.

In this scenario...the expansive shield of light/moderate snow

associated with the northern stream energy should weaken as it

approaches the southern Appalachians overnight...and become less of a

concern as the streams phase and the better deep layer forcing

shifts to the south. Nevertheless...this should be good for a 0.5 to

2 inch snowfall across the higher terrain through Sat morning. By late

morning...a band of light precipitation will likely develop in the

vicinity of the I-85 corridor as cyclogenesis gets underway over the

northern Gulf. This band is then expected to gradually shift east/

southeast...but pivot and intensify as the cyclone intensifies off

the southeast coast. This creates a dilemma as far as p-type... as

we should be getting off to a cold enough start...and thickness

values are cool enough...that accumulating snowfall is a definite

concern over the Piedmont...especially in the vicinity of I-85. Although

numerical guidance is very warm at the surface...model soundings are

not. Freezing levels are generally depicted at less than 1000 feet.

Therefore...wherever the band sets up during the morning...dynamic

cooling processes will likely result in mainly snow falling. As the

precipitation band shifts south and east during the afternoon...insolation

should be sufficient that it will likely begin to mix with or change

over to rain.

Needless to say...there are many ifs/ands/buts regarding this

forecast...but the window for opting to punt to the next shift is

rapidly closing. Considering the potential impact on the

Holiday...we are opting to issue a Winter Weather Advisory for

around an inch of snow...generally for areas along the I-85 corridor

from Charlotte west.

[phil882]

For Those Interested... here is what the 12z GFS is spitting out on BUFKIT using the max temp in profile. This is raw data but since it does take into account max temperatures in profile, if the boundary layer is too warm it won't show much snowfall accumulation.

Needless to say, BUFKIT is rather optimistic.

KFAY: 5.9"

KRDU: 8.8"

KCAE: 2.1"

KCLT: 5.5"

KHKY: 0.7"

KGSP: 5.5"

KATL: 1.8"

KATN: 1.1"

[eyewall]

Based on the bad initialization it's probably a smart idea to stick with the NAM since the Euro and GFS at this point would be outliers. However I'm sure he would be perfectly fine with eating crow.

You guys can read my discussion here:

http://www.sandhillswx.com/discussion.html

Anyway it is a blend and a low confidence call. As for eating crow it would taste sweet if this were a blockbuster storm in the end.

[BIG FROSTY]

Well checked inaccuweather and they are giving me 2-4 lol , Now that's was this afternoon forecast. BTW- JB likes ths JMA model he updated at 2pm said it was just like last night run, Which had most of NC Raleigh west in 1/4-1/2 qpf more to the east 1/2-3/4 and right along the coast 3/4-1 ? Now I think i'm reading this right, If not somebody correct me. So maybe it's on to something It looks like the 12z GFS

[strongwxnc]

Wish the that run would not have the HPC non-approval attached to it. That would be killer.

GSP had a great discussion and they want to throw out the 12Z run but.......

For Those Interested... here is what the 12z GFS is spitting out on BUFKIT using the max temp in profile. This is raw data but since it does take into account max temperatures in profile, if the boundary layer is too warm it won't show much snowfall accumulation.

Needless to say, BUFKIT is rather optimistic.

KFAY: 5.9"

KRDU: 8.8"

KCAE: 2.1"

KCLT: 5.5"

KHKY: 0.7"

KGSP: 5.5"

KATL: 1.8"

KATN: 1.1"

[burgertime]

well gsp sounds as confused as most of us are lol

In this scenario...the expansive shield of light/moderate snow

associated with the northern stream energy should weaken as it

approaches the southern Appalachians overnight...and become less of a

concern as the streams phase and the better deep layer forcing

shifts to the south. Nevertheless...this should be good for a 0.5 to

2 inch snowfall across the higher terrain through Sat morning. By late

morning...a band of light precipitation will likely develop in the

vicinity of the I-85 corridor as cyclogenesis gets underway over the

northern Gulf. This band is then expected to gradually shift east/

southeast...but pivot and intensify as the cyclone intensifies off

the southeast coast. This creates a dilemma as far as p-type... as

we should be getting off to a cold enough start...and thickness

values are cool enough...that accumulating snowfall is a definite

concern over the Piedmont...especially in the vicinity of I-85. Although

numerical guidance is very warm at the surface...model soundings are

not. Freezing levels are generally depicted at less than 1000 feet.

Therefore...wherever the band sets up during the morning...dynamic

cooling processes will likely result in mainly snow falling. As the

precipitation band shifts south and east during the afternoon...insolation

should be sufficient that it will likely begin to mix with or change

over to rain.

Needless to say...there are many ifs/ands/buts regarding this

forecast...but the window for opting to punt to the next shift is

rapidly closing. Considering the potential impact on the

Holiday...we are opting to issue a Winter Weather Advisory for

around an inch of snow...generally for areas along the I-85 corridor

from Charlotte west.

Man I don't like seeing that, like Rankin I wasn't even thinking about the temps being an issue here but obviously they might be. Any mets want to chime in? I take it, if it phases perfectly temps won't be a problem?

[dsaur]

As a broadcast Met, who has to tell the population tonight about what they can anticipate for Christmas.... I must say, this is THE least confident I have ever been with a forecast. Usually I get a gut feeling about things, and right now my gut is like DOES NOT COMPUTE DOES NOT COMPUTE!

This is going to be the epitome of nowcasting... The shortwave toward North Dakota right now is going to be the main player in all of this. The convection occuring right now over Texas is a good sign as it will help get this thing to a more neutral tilt, but until that happens we are going to be up in the air forecast wise.

One very interesting thing for tonight though is when will the clouds roll in? If the clouds roll in early in the morning, then temperatures MIGHT be held low enough, that if we see heavy enough rain, we may be able to see snow here across West Central Georgia.... However, if we start seeing the sun tomorrow, it's going to warm up fairly quickly. I'm tending to think the clouds will get here after the sun is up for an hour or two and we will miss out on seeing flurries here. However, it is something to keep in mind is how the cloud cover will effect temperatures.

Out of curiosity which products will you blend for your temp forecast? As you say, cloud cover, heavier precip....such difference makers down south. T

[NEGa]

Man I don't like seeing that, like Rankin I wasn't even thinking about the temps being an issue here but obviously they might be. Any mets want to chime in? I take it, if it phases perfectly temps won't be a problem?

i wasnt over overjoyed myself lol. i am hoping it comes in early enough and is heavy enough to bring down the cooler temps. it may be a case where if you are fortunately and under heavier precip its snow, otherwise its rain/drizzle YUCK

[eyewall]

Man I don't like seeing that, like Rankin I wasn't even thinking about the temps being an issue here but obviously they might be. Any mets want to chime in? I take it, if it phases perfectly temps won't be a problem?

I honestly think noboday has a damn clue at this point LOL. Everyone is taking their best shot at it. Warmer BL problems are more likely the less phased this thing is.

[Solak]

New RAH HWO...

252 PM EST FRI DEC 24 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL NORTH CAROLINA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

WINTER WEATHER ADVISORIES FOR LIGHT SNOW WILL LIKELY BE NEEDED

FOR A LARGE PART OF CENTRAL NORTH CAROLINA SATURDAY NIGHT INTO

SUNDAY.

AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS CENTRAL NORTH CAROLINA

ON SATURDAY SPREADING LIGHT SNOW OR A MIX OF RAIN AND SNOW INTO

THE AREA. LITTLE SNOW ACCUMULATION IS EXPECTED ACROSS CENTRAL

NORTH CAROLINA THROUGH LATE SATURDAY.

ON SATURDAY NIGHT AND SUNDAY...A DEVELOPING COASTAL STORM IS

EXPECTED TO SPREAD SNOW OVER NORTH CAROLINA. THE LATEST MODEL

TRENDS SUGGEST THE BULK OF THE PRECIPITATION...IN THE FORM OF

LIGHT SNOW...WILL OCCUR SATURDAY NIGHT THROUGH SUNDAY MORNING AND

NEAR AND EAST OF HIGHWAY ONE. AT THIS TIME...IT APPEARS THAT SNOW

AMOUNTS WILL VARY FROM LESS THAN AN INCH IN THE NORTHWEST PIEDMONT

TO A COUPLE OF INCHES NEAR AND EAST OF HIGHWAY ONE. A WINTER STORM

WATCH MAY BE NEEDED FOR SOME AREAS EAST OF INTERSTATE 95 FOR THIS

PERIOD.

RESIDENTS OF CENTRAL NORTH CAROLINA AND THOSE PLANNING TO TRAVEL

ON SATURDAY OR SUNDAY SHOULD MONITOR THE LATEST FORECASTS AND

STATEMENTS OVER THE NEXT COUPLE OF DAYS.

(bolded mine)

[Itunis]

NWS Huntsville has just put the NErnmost two counties of AL under a WWA. I expect FFC to at least put the top tier of counties under one, as moisture is more plentiful over the N GA mtns.

[beanskip]

18z NAM underway -- just at 6 hours, looks like the northern stream is stronger than 12 run at 12 hours. Looks like the second s/w is now digging due south rather than SSE on 12z run.

[Brick Tamland]

This is what WRAL is saying now. Of course, if this thing comes in more west and/or wetter, all bets are off. And from the recent model runs, that is a real possibility.

[eyewall]

RAH

THICKENING AND LOWERING CLOUDS TONIGHT WITH TIME WITH WINDS MORE

CALM THAN THURSDAY NIGHT. 1000 TO 850 MILLIBAR THICKNESSES RANGING

FROM 1295 NORTH TO 1305 SOUTH. MOST LOW TEMPERATURES IN THE UPPER

20S.

850 MILLIBAR TROUGH DEEPENS AND SHARPENS TONIGHT INTO SATURDAY IN

RESPONSE TO UPPER LEVEL SHORT WAVE CROSSING THE GREAT LAKES REGION.

DECENT SPEED CONVERGENCE IN MINI LOW LEVEL JET AHEAD OF THIS

SYSTEM... INITIALLY OVER THE WEST SATURDAY MORNING... SLIPPING TO

THE SOUTHEAST TOWARD SUNSET... TAKING ITS LIFT WITH IT. THE 12Z GFS

IS UNIQUE IN ITS DEGREE OF SPEED AND DIRECTIONAL CONVERGENCE

SATURDAY WITH THIS BEING NEW TO THE 12Z RUN AND MUCH MORE MUTED IN

OTHER MODELS. GFS MODEL PRECIPITATION AMOUNTS LIKELY OVERDONE.

PRECIPITATION WILL STILL HAVE THE DRY AIR MASS BELOW 6000 FEET TO

OVERCOME... AND ANYTHING MORE THAN FLURRIES MAY BE DELAYED IN THE

WEST UNTIL AFTER 10 AM.

THE GROUND WILL GET A HEALTHY DOSE OF WARMING WITH AMPLE SUNSHINE

TODAY AND AIR TEMPERATURES WELL INTO THE 40S. LATEST PROJECTIONS

INDICATE SNOW MIXED WITH RAIN IN THE FAYETTEVILLE GOLDSBORO AREA

SATURDAY... WITH ALL SNOW IN HEAVIER PRECIPITATION. ELSEWHERE IT

IS NOT IMPOSSIBLE TO SEE SOME RAIN MIXED WITH SNOW INITIALLY (ALL

SNOW TRIAD HOWEVER)... BUT THE OVERWHELMING CHARACTER OF THE

PRECIPITATION SHOULD BE SNOW.

WILL CONTINUE TO KEEP LIQUID AMOUNTS SMALL FOR SATURDAY. AMOUNTS

AROUND ONE TENTH INCH SOUTH... AND A FEW HUNDREDTHS ELSEWHERE.

WITH THE TROUGH STRENGTHENING AS IT MOVES EAST... PRECIPITATION IN

THE WEST MAY NOT BE HEAVY ENOUGH TO PRODUCE MORE THAN SPOTTY

ACCUMULATION IN GRASS AND MULCH. DURING THE AFTERNOON... SOME

SWEET SPOT WHERE TEMPERATURES AND MOISTURE ARE IDEAL... PERHAPS

NEAR AND SOUTH OF HIGHWAY 64 IN THE EAST... DOWN TO SANFORD...

MIGHT SEE MORE WIDESPREAD ACCUMULATION ON ALL SURFACES... BUT WELL

UNDER ONE INCH.

LOW TEMPERATURES IN THE UPPER 20S. AFTERNOON HIGH TEMPERATURES UPPER

30S WITH MID 40S EXTREME SOUTH.-- End Changed Discussion --

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...

-- Changed Discussion --AS OF 250 PM...

NO TIME TO PANIC. NO ADVISORIES OR WATCHES AT THIS TIME.

THE LATEST GFS RUN MUCH MORE AGGRESSIVE WITH PRECIPITATION. HOWEVER

HPC IS QUICK TO POINT OUT INITIALIZATION ERRORS IN THE MODEL...

ESPECIALLY WITH THE NORTHERN SHORT WAVE NEAR SOUTH DAKOTA. THIS

FEATURE WILL BE A SIGNIFICANT PLAYER IN THE WEATHER FOR NORTH

CAROLINA DURING THIS PERIOD. THIS SHIFT IN THE GFS IS A MAJOR ONE.

AT 850 MILLIBARS SUNDAY 8AM... WINDS OVER THE WESTERN PIEDMONT ARE 30

KNOTS... WITH 06Z GFS RUN AND OTHER MODELS 15 TO 20 KNOTS. LATEST

GFS DROPPING ITS 850 MILLIBAR HEIGHTS 70 METERS TO 1300 FROM ITS

PREVIOUS 06Z RUN FORECAST! OTHER MODELS ARE 1350 METERS OR HIGHER.

THIS IS SUCH A RADICAL SHIFT... AND WITHOUT SUPPORT... AS WELL AS

WITH INITIALIZATION PROBLEMS... THAT THE 12Z GFS WILL BE ONLY VERY

LIGHTLY CONSIDERED.

THE NEW 12Z ECMWF IS LITTLE CHANGED FROM ITS 00Z RUN DURING THIS

PERIOD. 12Z SUNDAY 850 MILLIBAR HEIGHT OF THE LOW IS AT 1360

METERS AND WINDS WITHIN REASON. LIQUID PRECIPITATION MAXIMIZING

NEAR THREE TENTHS VICINITY OF FAYETTEVILLE.

TEMPERATURES ALOFT ARE COLD ENOUGH FOR PRECIPITATION DURING THIS

TIME FRAME TO BE SNOW. HOWEVER MODEL SOUNDINGS ARE INDICATING

POSSIBLE LOSS OF SATURATION AT THE CRYSTALLIZATION LEVEL ABOVE MINUS

12 DEGREES CELSIUS AT TIMES DURING THE EVENT (POTENTIALLY EVEN IN

THE TRIAD EARLY IN THE EVENT). IN THE FAYETTEVILLE REGION THIS COULD

OCCUR DURING A SIGNIFICANT PORTION OF THE EVENT IN THE HOURS AROUND

MIDNIGHT... CUTTING INTO SNOW AMOUNTS ON THE GROUND DUE TO A COLD

RAIN... AND DUE TO COMPACTION OF SNOW ALREADY ON THE GROUND. SURFACE

TEMPERATURES WOULD SUGGEST ANY RAIN WOULD BE FREEZING RAIN EXCEPT

PERHAPS EXTREME SOUTHEAST. ANYTHING FREEZING WOULD BE NO MORE THAN A

THIN GLAZE. MODELS END ANY THREAT FOR ANYTHING OTHER THAN SNOW WELL

BEFORE SUNRISE SUNDAY AS THE AIR MASS COOLS. THERE IS NOT ENOUGH

CONFIDENCE TO INTRODUCE THIS INTO THE FORECAST AT THIS TIME... AS

EVEN A SLIGHT MOVE OF SATURATION VERTICALLY UPWARD WOULD ELIMINATE

THIS SCENARIO. STILL FORECASTING ANY SIGNIFICANT SNOW TO END IN

THE WEST BY EARLY AFTERNOON OR EARLIER... AND IN THE EAST BEFORE

DARK. SOME VERY MINOR ACCUMULATING SNOW POSSIBLE IN THE EAST INTO

EARLY SUNDAY NIGHT.

ACCUMULATION FORECAST WILL REMAIN LARGELY UNCHANGED. AROUND TWO

INCHES FAYETTEVILLE GOLDSBORO AND SOUTH WITH WARNING CRITERIA SNOW

(THREE PLUS) NOT IMPOSSIBLE. AMOUNTS FALLING TO ONE TO TWO INCHES

NEAR HIGHWAY ONE... AND LESSER AMOUNTS FURTHER WEST (WHICH WOULD

BE NON ADVISORY IF IT CAME TO PASS).

LOW TEMPERATURES UPPER 20S TO NEAR 30. AFTERNOON HIGH TEMPERATURES

IN THE MID 30S.-- End Changed Discussion --

[NEGa]

18z NAM underway -- just at 6 hours, looks like the northern stream is stronger than 12 run at 12 hours. Looks like the second s/w is now digging due south rather than SSE on 12z run.

thank goodness its started. today would have been a good day to be at work and busy. my family has really started whining about my time on the computer today so far. and its just beginning (hopefully)

[Isopycnic]

This is what WRAL is saying now. Of course, if this thing comes in more west and/or wetter, all bets are off. And from the recent model runs, that is a real possibility.

WRAL has had that graphic posted since 7am this morning.

[crossthread]

I had a long post W/info ,, but my computer crashed...

sry, NOT in IMBY post...

expected acculations of 1" too 1/1/2" in KILM, beteen Sat. night into sunday with "lingering" flurries into monday...

[beanskip]

LOL -- sounds like my house. "Honey, when are you going to spend time with US."

OK, back to 18z NAM -- at 12 hours, looks like some changes -- southern shortwave stronger and a touch more north. More digging from northern stream? Not sure ....

thank goodness its started. today would have been a good day to be at work and busy. my family has really started whining about my time on the computer today so far. and its just beginning (hopefully)

[strongwxnc]

Hr 18 the N is much stronger and further SW at the same time on the 12 run NAM...

18z NAM underway -- just at 6 hours, looks like the northern stream is stronger than 12 run at 12 hours. Looks like the second s/w is now digging due south rather than SSE on 12z run.

[oconeexman]

Anyone care to give pbp with the 19RUC? That's the one i'm watching as well.

[beanskip]

Oh my -- southern stream low has closed off again at 18 hours and is near Texas/La. border.

[NEGa]

LOL -- sounds like my house. "Honey, when are you going to spend time with US."

OK, back to 18z NAM -- at 12 hours, looks like some changes -- southern shortwave stronger and a touch more north. More digging from northern stream? Not sure ....

-what could have possibly changed in the last 5 minutes?

-what are you DOING?

-Are you really leaving to chase snow on Christmas eve?

i assume it will get worse. lol the problem is mby will probably be a much better location that the snow hole that is athens. i have learned a lot from the boards on how to read and interpret maps, but will admit that i am lost today since its such minute details that are making the difference. i am just not as used to digging that deep for info on a potential se storm

[HKY18]

at 300mb the jet is headed due south northern stream looks better on this run imho.