1/25/11-1/26/11 Deep South Upper Level Low event

[Joe-Nathan]

FIRST EVENT JAN 28th-30th

GFS MODEL DATA:



TOTAL SNOW ACCUM:



SECOND EVENT LOOKS TO HAPPEN FEB 2nd - 5th:

GFS MODEL DATA:



SNOW TOTAL ACCUM:




GOOD LUCK!!!!

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Nashville

MONDAY NIGHT THROUGH TUESDAY NIGHT WILL BE MORE COMPLEX AND
POTENTIALLY SIGNIFICANT WITH VARIOUS SHORTWAVES OVER THE REGION
AND A POSSIBLE MAJOR EAST COAST STORM. FOR NOW WE WILL STICK WITH
MID LEVEL POPS FOR LIGHT SNOW. IF THINGS COME TOGETHER...SUCH AS
THE LATEST ECMWF SUGGESTS...THERE COULD BE A MAJOR SNOW EVENT.

LATE NEXT WEEK LOOKS VERY COLD WITH CONTINUING SHORTWAVES BRINGING
ON AND OFF CHANCES FOR SNOW SHOWERS.

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Alabamawx update

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Heavy snow on the NC Coast 4.3 inches

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Well you don't see this everyday

Winter Storm Warning

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC
306 PM EST SAT JAN 22 2011

...SNOW ACCUMULATIONS CONTINUE INTO THIS EVENING...

.LOW PRESSURE WELL OFFSHORE WILL MOVE ALONG THE SOUTHEAST COAST
THIS EVENING...RESULTING IN SNOW ACCUMULATIONS FOR EASTERN NORTH
CAROLINA COASTAL AREAS.

NCZ081-093>095-230300-
/O.CON.KMHX.WS.W.0002.000000T0000Z-110123T0300Z/
MAINLAND HYDE-CRAVEN-PAMLICO-CARTERET-
INCLUDING THE CITIES OF...NEW BERN...HAVELOCK...VANCEBORO...
ORIENTAL...ALLIANCE...BAYBORO...ARAPAHOE...MINNESO TT BEACH...
VANDEMERE...STONEWALL...MOREHEAD CITY...BEAUFORT...EMERALD ISLE...
NEWPORT
306 PM EST SAT JAN 22 2011

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 10 PM EST THIS
EVENING...

A WINTER STORM WARNING REMAINS IN EFFECT UNTIL 10 PM EST THIS
EVENING.

* ACCUMULATION: TOTAL SNOW ACCUMULATIONS 2 TO 4 INCHES ARE
EXPECTED THROUGH THIS EVENING. ISOLATED HIGHER AMOUNTS OF 5 TO 6
INCHES POSSIBLE.

* TIMING: SNOW WILL CONTINUE INTO THIS EVENING.

* IMPACTS: HAZARDOUS TRAVEL CONDITIONS WILL CONTINUE THROUGH EARLY
SUNDAY. SLIPPERY CONDITIONS WILL BE POSSIBLE ON
ROADWAYS...ESPECIALLY ON BRIDGES AND OVERPASSES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING FOR HEAVY SNOW MEANS SEVERE WINTER WEATHER
CONDITIONS ARE EXPECTED OR OCCURRING. SIGNIFICANT AMOUNTS OF
SNOW ARE FORECAST THAT WILL MAKE TRAVEL DANGEROUS.

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We will be streaming live this week and trying to not get stuck on the roads in Alabama :) Stormchaselive.com

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Almost a perfect setup for central and north AL

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EURO

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Alabamawx

Interesting Times Ahead

Bill Murray | 3:20 pm January 22, 2011 | Comments (1)
Last night, the GFS pretty much gave up the ghost on the upcoming major system that is headed our way this week. But today it kind of came back into reality with the idea of developing a major low in the Gulf of Mexico. The track and intensity of the low will determine how interesting our upcoming times turn out to be.
Tomorrow will feature a good supply of sunshine with highs in the lower 50s.
First, we will deal with a few light rain showers on Monday as the first weakening disturbance drags some upper level energy across the area. A second stronger disturbance will be heading our way during the day on Monday.

The red arrow points to the rain/snow line. That is the 540dkm 1000-500 mb thickness line, a good indication of where the rain/snow changeover will occur.
By Tuesday morning, the low will be getting its act together to the east of Brownsville, Texas. Heavier precipitation will spread into Alabama during the morning. There is a chance that the air could be cold enough for snow across parts of Alabama, perhaps as far south and east as the I-59 corridor.

As the low moves to near Jacksonville, Florida Tuesday afternoon, colder air on the backside could drive the rain/snow line far into South Alabama. If this solution turns out to be the correct one, there will likely be significant snow accumulations across parts of North and Central Alabama. But, it is too early to be thinking specific forecasts for now. Just know that this is a possibility.
FORECAST CONFIDENCE: 3/10 (low)
POTENTIAL STORM IMPACT: Low to Significant depending on track of the low and temperature profile
This is going to be an interesting situation and one that bears watching. For now, we will call for rain or snow changing to snow, with highs in the 30s, likely falling during the day.
Dry and chilly conditions will prevail into next weekend.

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HPC

DAY 3 SOUTHERN APPALACHIANS…
THE MODELS ARE FORECASTING A CYCLONE TO BEGIN DEVELOPING IN THE
GULF OF MEXICO AND TO MOVE INTO THE SOUTHEAST US THE LATTER HALF
OF DAY 3. DEVELOPING LOW LEVEL SOUTHERLY FLOW TURNS UPSLOPE IN
THE MOUNTAINS OF SOUTHEAST TN/NORTHERN GA/WESTERN NC…WITH SNOW
LIKELY DEVELOPING THE LAST SEVERAL HOURS OF DAY 3 AFTER SATURATION
OCCURS IN THE INITIALLY DRY AIRMASS. THE GFS SLOWED THE FORWARD
PROGRESSION OF THE DEVELOPING LOW…AND NOW IS IN GOOD AGREEMENT
WITH THE ECMWF/UKMET ON THE LOW TRACK THROUGH 00Z WED. MANUAL
PROGS BLENDED THE QPF AND THERMAL PROFILES OF THE 00-12Z ECMWF/12Z
GFS/09Z SREF MEAN. THE SLOWER NAM LOW TRACK WAS GIVEN LESS
WEIGHT.

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BMX

NATIONAL WEATHER SERVICE BIRMINGHAM AL
317 PM CST SAT JAN 22 2011

.DISCUSSION...

SKIES WILL REMAIN CLEAR THIS AFTERNOON WITH CLOUD COVER
INCREASING OVERNIGHT AS AN UPPER LEVEL SHORT WAVE APPROACHES FROM
THE WEST. TEMPS MANAGED TO WARM IN TO THE 40S AREA WIDE TODAY.
EXPECT LOWS TONIGHT TO ONCE AGAIN BE IN THE LOW TO MID 20S.

IT APPEARS AS THOUGH THE ONLY SYSTEM THAT WILL IMPACT THE AREA OVER
THE NEXT 7 DAYS WILL BE THE GULF LOW SYSTEM ON MON/TUE. WE ARE
CONTINUING TO WATCH THE THIS SYSTEM VERY CLOSELY. THE GOOD NEWS IS
THAT THE 12Z GFS HAS FINALLY SEEN THE LIGHT AND DECIDED TO COME IN
LINE WITH THE NAM/ECMWF/GEM. ALL MODELS ARE NOW SHOWING THE SAME
SYNOPTIC SET UP...WITH AN UPPER TROF DIGGING DOWN INTO THE LOWER MS
VALLEY BY TUE. THE ASSOCIATED SFC LOW DEVELOPS IN THE WESTERN GULF
ON MON AND MOVES EWD TOWARD THE FLORIDA PANHANDLE ON TUE. THERE
REMAINS SOME MINOR DIFFERENCES IN THE TIMING AND EXACT TRACK OF THE
LOW...BUT OVERALL MODEL GUIDANCE IS NOW MUCH EASIER TO WORK WITH.

A SHORT WAVE TROF WILL MOVE EWD ACROSS THE AREA SUN NIGHT INTO MON
BRINGING INCREASED CLOUD COVER TO THE AREA. MOISTURE WILL BE LIMITED SO
SCALED BACK ON POPS FOR MON. MOST MODEL SOUNDINGS LEAN TOWARD RAIN
BEING THE PRIMARY PRECIP TYPE...IF ANYTHING WERE TO REACH THE
GROUND...BUT THE GFS HINTS AT THE POSSIBILITY OF A BRIEF PERIOD OF
FREEZING RAIN EARLY MON MORNING. WILL NOT MENTION ANY FROZEN PRECIP
AT THIS TIME DUE TO VERY LOW CONFIDENCE.

THE BULK OF THE PRECIP WILL COME MON NIGHT AND TUE AS THE GULF LOW
MOVES ALONG THE LA/MS/AL COAST. ALL MODELS SHOW AT LEAST A HALF INCH
OF QPF ACROSS THE MAJORITY OF THE CWA...THEREFORE INCREASED POPS TO
LIKELY FOR MOST AREAS. THE PRECIP TYPE DURING THIS TIME FRAME WILL
MOST DEFINITELY BE ALL RAIN AS TEMPS IN THE LOWEST LEVELS (850MB-SFC)
ARE WELL ABOVE FREEZING. THE SFC LOW CONTINUES TO DEEPEN AS IT
PUSHES OFF TO THE EAST LATE TUE. PRECIP TYPE BECOMES A LITTLE MORE
DIFFICULT TUE EVNG AS THERE COULD BE AN OVERLAP IN THE MOISTURE AND
COOLER TEMPS THAT WILL MOVE IN BEHIND THE LOW PRESSURE CENTER.
PROFILES AFTER 00Z WED BECOME BOTH COOLER AND DRIER. IF THE MOISTURE
CAN HANG ON LONG ENOUGH THERE COULD BE A SWITCHOVER TO SNOW IN THE
NORTH. WILL KEEP RAIN OR SNOW WORDING IN ACROSS THE NORTH FOR NOW AS
MODELS KEEP TRYING TO DRY THINGS OUT RATHER QUICKLY IN THE ICE
CRYSTAL GROWTH ZONE BEFORE THE COLDER SFC TEMPS ARRIVE.

FOR THE PERIOD WED THRU FRI...A SERIES OF SHORT WAVES WILL TRAVERSE THE
REGION KEEPING SKIES AT LEAST PARTLY CLOUDY...ESPECIALLY ACROSS THE
NORTH. SFC FLOW WILL REMAIN OUT OF THE NW SO MOISTURE WILL BE VERY
LIMITED. THEREFORE WILL NOT CARRY ANYTHING HIGHER THAN 10 POPS THRU
THE PERIOD. TEMPS WILL REMAIN AT LEAST A FEW DEGREES BELOW NORMAL.
HIGHS WILL GENERALLY BE IN THE 40S WITH OVERNIGHT LOWS IN THE 20S.

19

&&

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....

Mesoscale Discussion 43 < Previous MD
MESOSCALE DISCUSSION 0043
NWS STORM PREDICTION CENTER NORMAN OK
0428 PM CST SAT JAN 22 2011

AREAS AFFECTED...OUTER BANKS OF ERN NC

CONCERNING...HEAVY SNOW

VALID 222228Z - 230030Z

BANDS OF HEAVY SNOW WITH OBSERVED RATES FROM 1 TO 2 IN/HR ALONG THE
OUTER BANKS WILL DIMINISH QUICKLY/SHIFT OFFSHORE JUST AFTER 00Z.

SNOWFALL RATES OF 1 TO 2 IN/HR HAVE BEEN REPORTED ACROSS ERN NC
WITHIN BANDS OF HEAVY SNOW GRADUALLY SHIFTING EWD /PER RECENT RADAR
IMAGERY/. THESE SNOW BANDS WERE IN ASSOCIATION WITH A VIGOROUS SHORT
WAVE TROUGH NOW JUST OFF THE CAROLINA COAST. STRONG UVV COINCIDENT
WITH THE DENDRITIC GROWTH ZONE /CENTERED AROUND 600 MB PER LATEST
NAM AND RUC FORECAST SOUNDINGS/ WILL REMAIN SUPPORTIVE OF INTENSE
SNOWFALL RATES. AS THE SHORT WAVE TROUGH SHIFTS FARTHER
OFFSHORE...HEAVY SNOW SHOULD RAPIDLY END OVER LAND BETWEEN 00-01Z
/PER LATEST HRRR AND SREF GUIDANCE/.

..GRAMS.. 01/22/2011


ATTN...WFO...MHX...

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Brian Peters

Very complex forecast to deal with when it comes to Tuesday especially. For today, however, we remain dry with a mix of sun and clouds and highs approaching the 50 degree mark during the afternoon. Changes get underway on Monday, but for the moment, I believe Monday will be a dry day as clouds continue to increase and thicken up.
An upper short wave trough coming out of the Southern Rockies will generate a surface low in the northwestern Gulf of Mexico Monday. That surface low will move along the Gulf coast Tuesday and into the Southwest Atlantic on Wednesday bringing rain to Central Alabama beginning Monday evening and continuing through much of Tuesday. While the surface low is in a nearly ideal position for bringing a winter weather event to the Southeast US, there are a number of concerns.
The first concern is whether it will be cold enough for snow. According to the latest models which seem to be in good agreement, it will not be cold enough. But there is a good deal of concern as to whether or not the models are handling the change in heat flux. There is not doubt that the precipitation will be snow well above the surface where it is very cold. This precipitation will transport cold downward – negative heat flux – and as Dr. Tim has pointed out in his discussion below posted last night, there is concern that the models may not be handling this well. If the models are not handling the negative heat flux appropriately, then the temperature profile in the lower portion of the atmosphere – ground to about 850 millibars – could be much colder than the models suggest. This could result in a rapid change to snow earlier with snow lasting a good deal longer and presenting a significant threat for us.
Another concern I have is the strength of the 850 millibar low. The models are in good agreement that the low at 850 will be fairly strong which means there could be a significant transport of warm air from the northern Gulf into North Alabama. This transport of heat could offset the cooling I mentioned in the paragraph above.
So at this time I am sticking with a mixture of snow and rain from late Tuesday afternoon or early Tuesday evening into early Wednesday morning with the main snow event across portions of Tennessee. Under this scenario, there is not likely to be any significant travel issues for Central Alabama.
But I caution anyone reading this to stay tuned for later developments. It will only require some subtle changes for the event to go more toward rain or more toward snow. If the weather is a concern for you, then it is wise to stay up with the latest changes as the whole weather system unfolds and we can be more certain on what will be happening.
The precipitation, no matter what type, should end early Wednesday. With clouds likely to stick around much of the day, look for snow flurries during the day Wednesday. With the upper long wave trough anchored over the eastern half of the country, we won’t be seeing a significant warm up any time soon. We could be seeing temperatures approaching 50 again by next Saturday with dry weather from Thursday into the weekend.
Peeking further in time – well into voodoo country – the GFS maintains the long wave trough over the eastern half of the country so the cold will continue under this pattern. With a continuation of strong impulses moving through the flow we will be seeing additional threats of winter weather, the timing of which is impossible to nail this far in advance.

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MOB

CANNOT RULE
OUT THE POTENTIAL OF SOME ISOLATED SEVERE TSTMS W/ UPDRAFTS THAT MAY
EXHIBIT ROTATION IN THESE AREAS. THE LOW LIFTS OFF TO THE ENE TUE NIGHT
BUT WILL LIKELY BE DEALING WITH SOME WRAP AROUND LOW CLOUDS IN ITS
WAKE. GFS/ECMWF/GEM MODELS VARY ON DEPTH OF COLD AIR THAT WILL BE
PULLED SOUTHWARD AS THE LOW EXITS ALONG W/ THEIR RESPECTIVE MOISTURE
SIGNALS. AT THIS TIME...WILL CALL FOR A COLD LIGHT RAIN TUE NIGHT AS
NOT ENOUGH MODEL CONSENSUS IS SEEN TO MENTION A BRIEF BOUT OF WINTRY
WEATHER AT THIS TIME. SOMETHING THAT WILL DEFINITELY NEED TO BE
MONITORED ON LATER FORECASTS.

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