12Z TUE EC: ice/sleet storm ALL of north GA

[LarryWx]

The threat of a SE US ice storm continues to grow and not just for the Carolina's.

The 12Z TUE ECMWF is clearly showing a sleet and/or ice storm for many areas from as far west as NE AL through ALL of north GA (NOT just NE GA by any means) and to much of the Carolina's (not just western) with snow for some areas of far northern SC into NC especially early in the event. As depicted by this model, this is NOT anywhere close to just a Carolina's threat. It is every bit as much of a north GA threat per this model including Atlanta.

For Atlanta specifically, here is what it shows:

Precip. starts late in the afternoon on FRI when the surface pressure is near a very high 30.50" (~1033 mb), continues overnight with pressure still a high 30.42" (~1030 mb) as of 7 AM SAT and ~.35" of liquid equiv. precip. having fallen as of then, and ends early afternoon on SAT with the pressure still near a plenty high ~30.36" (~1028 mb) and a total of ~.65" of precip. having fallen for the entire event. This timing is significant as it is a pretty early onset of the precip. (vs. other model runs), when it would be colder. These pressures, although slightly lower than the prior run, are still more than sufficient imo to provide enough cold/dry advection to sustain a strong and cold enough wedge throughout this period to sustain wintry precip.

The 850's for ATL are as follows: ~+2C near onset of precip. late FRI afternoon, ~+3C at 7AM SAT in the midst of the event, and ~+5C at the end early SAT afternoon.

My studies of prior ATL ice storms tell me that the +2.5C to +5C is the ideal range for freezing rain with +1C to +2.5C for sleet. This tells me that the ECMWF is saying it would start as sleet but pretty quickly go over to freezing rain and then stay that way for the duration of the event.

Assuming the ~.65" of precip. suggested by the EC, it would be in the moderate ice storm category. This would be pretty similar to the second of the two Atlanta ice storms of 1/00 (1/28-30) in amount of liquid precip. During that storm, the pressures were ~1030 mb at the start in ATL and then fell slowly into the 1020's, i.e, a little lower than what the EC is showing for this weekend.

[QCWx]

There's an old weather proverb up here...if it's snowing in Atlanta you better expect it to be snowing here in short fashion. I am pulling for y'all.

[Wnghs2007]

Thanks for the info Larry. Wonder is my location helps...40 miles ENE of Atlanta.

Map Below of my home location.

[JenyEliza]

I wonder who'll be right on this? Don't have tremendous faith in NWS PTC (after years of misses and busts)....

AFD from Peachtree City as of 3:15 pm today:

000
FXUS62 KFFC 252013
AFDFFC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
315 PM EST TUE JAN 25 2005

.SHORT TERM...
WEAK UPPER LEVEL SHORT WAVE WILL MOVE ACROSS NORTH GEORGIA TONIGHT. VERY SHALLOW MOISTURE ASSOCIATED WITH THIS FEATURE AND MAIN IMPACT WILL BE AN INCREASE IN CLOUDS. OVERNIGHT LOWS WILL BE WARMER THAN THE PAST FEW NIGHTS WITH TEMPERATURES REBOUNDING TOMORROW. ASSOCIATED WEAK SURFACE FRONT WILL MOVE SLOWLY SOUTH ACROSS FORECAST AREA
TOMORROW AND EARLY THURSDAY...AGAIN THIS WILL BE A DRY FRONTAL PASSAGE. BROAD SURFACE HIGH PRESSURE MOVES ACROSS THE OHIO VALLEY THURSDAY.

.LONG TERM...
EASTERLY WINDS WILL PREVAIL ACROSS FORECAST AREA AS WEDGE SETS UP OVER FORECAST AREA THROUGH THE EARLY PART OF THE WEEKEND. LIMITED MOISTURE AVAILABLE FRIDAY NIGHT AND EARLY SATURDAY AND UPPER LOW NOW TRACKING FURTHER NORTH THAN PREVIOUS RUNS. WILL CONTINUE A SLIGHT CHANCE OF FREEZING RAIN MIXED WITH RAIN OVER PORTIONS OF NORTHEAST GEORGIA. CONFIDENCE CONTINUES TO BE LOW AS EVENT DEPENDS ON THE ARRIVAL OF MOISTURE AND HOW STRONG THE WEDGE SETS UP.
&&

[LarryWx]

QCWX, Thanks.

Wnghs, the 12Z ECMWF says you'd be getting it similarly to Atlanta proper.

Jeny, I'm not predicting this yet. I'm just showing what the model is suggesting to me. I wouldn't be surprised if they have still not yet seen this 12Z ECMWF run by the way. Maybe they won't see it until the good graphics are released. Then again, they may not care much about the EC.

[Stormsfury]

QCWX, Thanks.

Wnghs, the 12Z ECMWF says you'd be getting it similarly to Atlanta proper.

Jeny, I'm not predicting this yet. I'm just showing what the model is suggesting to me. I wouldn't be surprised if they have still not yet seen this 12Z ECMWF run by the way. Maybe they won't see it until the good graphics are released. Then again, they may not care much about the EC.

Good assessment of the EC model as usual, Larry ... FWIW, the 850mb temperatures at the height of the CAD event continue to trend ever so slightly colder with the 0ºC line reaching the GA/SC to south of ATL on Day 3, and aggressive moisture over the top of the cold dome would only serve to enhance the CAD effects, as you already well know ...

one of the things I keep noticing is that the EC continues to trend ever so slightly stronger with the 1st HIGH (now at 1043mb, and ONLY weakening to 1036mb (up from the 1032mb on the 0z run)) ... the 18z ETA (or should I now say the NAM model) is showing the clipper system becoming a 978mb low east of NF, and is really trending colder as well on this run. Again, the GFS scours out the wedge too quick and then goes berzerk with waves of northern stream snows down into the SE after the model truncates.

The BIG BIG KEY is the watch the DEWPOINTS as the parent high builds in ... we know the temperatures are going to trend colder, but IMHO, places that have wet bulbs at the SFC below 18ºF and a temperature of 38º or less have the BEST shot of prolonged FRZ ...

SF

[SouthernWx]

I agree....and tonight's 00z ETA (NAM) looks ominous for metro Atlanta and most of northern Georgia. Dewpoints progged <10° at precip onset Friday night, and surface temp of 27-28° in metro Atlanta on Sat a.m. with sleet/ z rain falling....experience tells me with strong high pressure ridging in from the NE, it will take a very long time for this area to reach freezing; I doubt it happening Saturday or Saturday night.

Maybe we'll lucky and not see a repeat of January 2000 or 1973.....but I don't know. If that wedge holds through Sunday night and we get 1.50-2.00" or more of liquid precip below freezing before it scours, it will be awful (and I'll be in the dark

One thing is certain.....if the 00z ETA verifies, Saturday will be a very difficult day for travel across northern and possibly central Georgia (to LaGrange, Macon, and south of Augusta).

PW

[jshetley]

The 0Z Euro model has lost the storm. No precip shown on it until next week.

[Stormsfury]

The 0Z Euro model has lost the storm. No precip shown on it until next week.

The 0z EC's bias again, showing hanging back the SW low and retrograding it, to create a REX BLOCK signature. temperatures are still within reason at the 850mb level WRT to cold air damming for ice with 850mb RH's climbing across the SE (and there still is plenty of overrunning moisture w/out the appearance of a SFC cyclone). b/c of the lack of a SFC cyclone, 850mb do NOT appreciably warm further south in Southern GA/Southern SC through the period ... (the 0z EC is 4ºC COLDER at the 850mb level after the peak of the CAD across Coastal South Carolina.)

[JenyEliza]

I agree....and tonight's 00z ETA (NAM) looks ominous for metro Atlanta and most of northern Georgia. Dewpoints progged <10° at precip onset Friday night, and surface temp of 27-28° in metro Atlanta on Sat a.m. with sleet/ z rain falling....experience tells me with strong high pressure ridging in from the NE, it will take a very long time for this area to reach freezing; I doubt it happening Saturday or Saturday night.

Maybe we'll lucky and not see a repeat of January 2000 or 1973.....but I don't know. If that wedge holds through Sunday night and we get 1.50-2.00" or more of liquid precip below freezing before it scours, it will be awful (and I'll be in the dark

One thing is certain.....if the 00z ETA verifies, Saturday will be a very difficult day for travel across northern and possibly central Georgia (to LaGrange, Macon, and south of Augusta).

PW

You said 1973. I grew up in Cobb. I was only 10 then...but I remember THAT ice storm. OMG....I hope not.

[RevDodd]

73? I reckon that's one older folks around Charleston remember...

We lived in Mount Pleasant and had the power go out during the Moultrie-Middleton basketball game (which was pretty dang big back then!) Ended up having to house Razorback fans and players on our side of the rive, since no one was fool enough to drive over the Cooper River Bridge in an ice storm.

Woke up to 10 inches of snow on top of ice. For a kid it was a wonderland...as long as thepower stayed on.

[DLI2k5]

I sure hope we can get some sort of transitioning going on. From freezing rain/sleet to snow or vice versa, whatever needs to happen for us to get any snow at all, i'm for it! The local mets here, are still saying nothing more than a rain event, with a slight possibility of freezing rain, maybe. So, what aren't they catching onto and are they just trying to cover there butts.

[Stormsfury]

I sure hope we can get some sort of transitioning going on. From freezing rain/sleet to snow or vice versa, whatever needs to happen for us to get any snow at all, i'm for it! The local mets here, are still saying nothing more than a rain event, with a slight possibility of freezing rain, maybe. So, what aren't they catching onto and are they just trying to cover there butts.

Predominantly just IP/ZR ... in the CAE area, right now, if anything, ZR ... transitioning to rain ... but it's still early yet, and more details need to be hashed out ...

SF

[NCGal]

all rain for me this weekend. They seem to be changing the forecast everytime I watch it. I wonder if they really have a clue as to what it's going to do this weekend?

[DLI2k5]

I wish something could happen to prevent this from being such an ice event and turn the ice into snow. That ice is a pain in the butt, way too may problems, causes too much damage! And, the local mets can't get a handle on what the heck is going on! They are basically calling for rain, nothing more , nothing less. The winter wx this winter is basically over for the SE, i truly think that! Unless we get something before Feb. 20th, we can kiss it goodbye!

[JenyEliza]

000
FXUS62 KFFC 262225
AFDFFC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
525 PM EST WED JAN 26 2005

.SHORT TERM...
UPPER LEVEL SHORT WAVE MOVES OFF THE SOUTHEAST COAST AS WEAK SURFACE BOUNDARY MOVES ACROSS FORECAST AREA...VERY LITTLE MOISTURE ASSOCIATED WITH BOUNDARY. LARGE SURFACE HIGH PRESSURE WILL MOVE ACROSS THE NORTHEAST...SETTING UP EASTERLY SURFACE FLOW AND A WEDGE BUILDING INTO THE AREA LATE THURSDAY INTO FRIDAY. UPPER LEVEL SHORT WAVE APPROACHES FROM THE WEST ON FRIDAY AS GULF MOISTURE SPREADS
NORTHWARD ON FRIDAY. MAX/MIN TEMPERATURES WILL LOWER OVER THE NEXT SEVERAL DAYS AS EAST FLOW SETS UP OVER THE FORECAST AREA.

.LONG TERM...
A LOT OF UNCERTAINTY REMAINS AS FAR AS FREEZING RAIN EVENT SETTING UP FOR SATURDAY MORNING. UNCERTAINTIES ARISE FROM HOW SOON MOISTURE WILL INCREASE...STRENGTH OF WEDGE AND ISENTROPIC LIFT. PAST HISTORY INDICATES THAT A LOT OF MOISTURE IS NOT NECESSARY FOR LIGHT RAIN/FREEZING RAIN IN THESE SITUATIONS...AND IF WEDGE IS STRONGER THAN MODELS CURRENTLY INDICATING TEMPERATURES WILL BE BELOW FREEZING LONGER THAN MODELS CURRENTLY INDICATING AND FREEZING RAIN MAY NOT CHANGE OVER TO RAIN AS QUICKLY. WILL NOT DEVIATE MUCH FROM CURRENT FORECAST...AND ISSUE A WINTER STORM OUTLOOK FOR FREEZING RAIN ACROSS THE NORTHEAST AT THIS TIME. LATER SHIFTS MAY HAVE TO EXTEND AREA WESTWARD. WEDGE WILL BREAK DOWN ON MONDAY AS HIGH PRESSURE MOVES OFF TO THE NORTHEAST. MOISTURE WILL REMAIN OVER THE FORECAST AREA UNTIL SURFACE FRONT SWEEPS ACROSS FORECAST AREA DAY 7.

[DLI2k5]

I consider all of us SE and deep south folks a family and i want snow for all of us, that'd make the majority of us very happy i believe! But, i just looked at the local news here and they are saying all rain, maybe in the upstate like Greenville/Spartanburg area points north, may see some freezing rain. I sure hope Feb. brings us some snow, because things are looking rather bleak here for any more significant type winter weather situations. I am with Jeny too in not wanting any freezing rain. Did a number with the power here last winter and i lost it for 3 days! No repeats, no thanks man! I hope something good happens here as far as snow goes, and maybe sleet, but keep that freezing rain away from me!!!

[JenyEliza]

This is from NWS Birmingham, AL.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
340 PM CST WED JAN 26 2005

ALZ017>021-024>029-035>038-047-271000-
BLOUNT-CALHOUN-CHAMBERS-CHEROKEE-CHILTON-CLAY-CLEBURNE-COOSA-ETOWAH-JEFFERSON-LEE-RANDOLPH-SHELBY-ST CLAIR-TALLADEGA-TALLAPOOSA-
340 PM CST WED JAN 26 2005

...POTENTIAL FOR FREEZING RAIN IN PARTS OF EASTERN AND CENTRAL
ALABAMA FRIDAY NIGHT AND SATURDAY...

A LARGE COLD DOME OF HIGH PRESSURE IS FORECAST TO MOVE INTO THE ORTHEAST AND MID-ATLANTIC UNITED STATES LATE IN THE WEEK. THIS HIGH PRESSURE SYSTEM WILL SEND COLDER AIR DOWN THE EAST SIDE OF THE APPALACHIAN MOUNTAINS...WHICH WILL LIKELY START TO MOVE INTO PORTIONS OF EASTERN AND CENTRAL ALABAMA ON FRIDAY.

MEANWHILE...AN UPPER AIR DISTURBANCE WILL BEGIN TO DRAW MOISTURE FROM THE GULF OF MEXICO ABOUT THE SAME TIME...AND RAIN IS LIKELY ACROSS A LARGE PART OF ALABAMA BY FRIDAY NIGHT. AS THIS RAIN FALLS INTO THE COLD AIR AT THE SURFACE...THERE IS A CHANCE THAT IT COULD BE COLD ENOUGH TO FREEZE ON CONTACT WHEN IT REACHES THE GROUND.

AT THIS TIME...THE AREAS WITH THE BEST POTENTIAL FOR FREEZING RAIN FRIDAY NIGHT AND SATURDAY ARE THE EXTREME EAST AND NORTHEAST SECTIONS OF ALABAMA...ESPECIALLY HIGHER ELEVATIONS. HOWEVER...DEPENDING ON THE STRENGTH OF THE COLD AIR AT THE SURFACE...THERE IS A POSSIBILITY THAT SOME ICE COULD BE EXPERIENCED AS FAR WEST AND SOUTH AS ONEONTA...BIRMINGHAM...CLANTON...ALEXANDER CITY...AND
AUBURN.

KEEP IN MIND THAT THERE IS STILL A GREAT DEAL OF UNCERTAINTY
CONCERNING BOTH THE STRENGTH OF THE COLD AIR...AND THE TIMING AND AMOUNT OF RAINFALL ASSOCIATED WITH THIS EVENT. EVERYONE ACROSS EASTERN AND CENTRAL ALABAMA SHOULD KEEP UP TO DATE...AND FREQUENTLY CHECK FOR THE LATEST STATEMENTS AND FORECASTS REGARDING THIS POTENTIAL FREEZING RAIN EVENT.

$$

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