Christmas Eve/Day Winter WX Event - Midsouth

[GeneratorPower]

It isn't too early to talk about the potential Winter WX for the Midsouth/Texas. I just spoke with the Meteorologist-In-Charge for the NWS Huntsville, Alabama office who said that he has been watching the model runs carefully for Texas/Arkansas because he will be traveling there for Christmas break.

He indicated that in his estimation, these areas are seeing a bigger threat than our area (North Alabama/Deep South) for winter WX.

I am a bit skeptical of any outcome, actually, because it is just so far out. When we get closer it will become more clear. I just wanted to bait you TX/AR folks with a little tidbit from the NWS local office here.

Check out the AFDs for areas around the Midsouth, and see their thoughts.

[gboudx]

Thanks. Ask your MIC to contact the DFW NWS and find out their thoughts. As of this mornings AFD, it's rain for us only. But that's what they are saying publicly.

[HarlequinBoy]

Yeah, I read the AFD Huntsville discussion.. they're Grinch comment was kind of funny.


Memphis says there's a chance for some winter weather somewhere in the Mid-South so it's something to watch.
----------
HIGH PRESSURE SHOULD BUILD BACK INTO THE REGION FOR A COUPLE OF
DAYS...AT LEAST INTO SATURDAY. ANOTHER PROGRESSIVE MOVING CLOSED
LOW IS EXPECTED TO DEVELOP OVER SOUTHERN TEXAS OVER THE WEEKEND
AND MOVE THROUGH THE LOWER MS RIVER VALLEY SUNDAY THROUGH TUESDAY.
THIS WILL RESULT IN ANOTHER CHANCE FOR PRECIPITATION. 00Z RUN OF
THE GFS/EUROPEAN ARE BOTH IN AGREEMENT WITH THE HANDLING OF THE
SYSTEM...FOR NOW. AS IT CURRENTLY STANDS...THERE IS A POSSIBILITY
OF WINTRY WEATHER SOMEWHERE ACROSS THE MID SOUTH DURING THIS TIME
PERIOD. AM NOT YET BRAVE ENOUGH TO MENTION THIS IN THE FORECAST
AND WOULD PREFER TO SEE A FEW MORE RUNS.

[x-y-no]

HPC discussion has a Gulf low lifting across the FL panhandle and up the east coast on day 6 and following.

12Z GUIDANCE IS LARGELY SUPPORTIVE OF EARLIER HANDLING OF SYSTEMS
OVER THE WRN US...BUT HAS DONE LITTLE TO CLARIFY SITUATION OVER
THE EAST...PARTICULARLY WITH REGARD TO WAVE LIFTING FROM GOMEX
D5-6. AT ONE EXTREME IS THE GEM GLOBAL MODEL...WHICH LIFTS
CYCLONE STRAIGHT UP MS VALLEY...WHILE AT THE OTHER IS THE NOGAPS
WHICH HOLDS THE SYSTEM OVER THE NERN GULF THRU F144. GFS AND
UKMET PROGRESS SFC LOW TO GA/SC BY D6. WITH THE MAJORITY OF THE
GUIDANCE DIRECTING THE MAIN CIRCULATION E OF THE
APPALACHIANS...FEEL COMFORTABLE LEAVING PRELIM FORECAST
ALONE...WHICH TRACKED LOW FROM THE FL PANHANDLE TO THE CAROLINA
COAST CHRISTMAS AND THE DAY AFTER. WHETHER SYSTEM LIFTS NWD
FASTER THAN EARLIER THINKING IS STILL VERY MUCH UNCERTAIN AS
INDICATED BY THE LARGE SPREAD IN CURRENT MODEL CYCLE.

[JenBayles]

Y'all might want to check out the TX winter weather thread. There's a great discussion from pro met "jeff" posted by Yankeegirl concerning this event.

[HarlequinBoy]

Thanks, Jen. It was very informative!


Memphis Afternoon Discussion
----
THE BIG QUESTION MARK COMES LATE IN THE EXTENDED. ANOTHER PIECE OF
PACIFIC ENERGY IS FORECAST TO DIG INTO THE SOUTHWEST U.S. AND
PROGRESS TOWARD THE SOUTHEAST BY CHRISTMAS DAY. SURFACE
CYCLOGENESIS TAKES PLACE OVER THE NORTHERN GULF OF MEXICO AND
THIS LOW TRACKS NORTHEAST AS THE UPPER ENERGY LIFTS INTO THE LOWER
MS VALLEY. CONCEPTUALLY...THIS IS A VERY FAVORABLE PATTERN FOR THE
POTENTIAL OF WINTER WEATHER ACROSS THE MIDSOUTH. THE TRACK OF THE
UPPER LOW WOULD SIGNAL THE POSSIBLE FORMATION OF DEFORMATION BAND.
THE MODELS ARE ACTUALLY COMING INTO AGREEMENT WITH THIS TYPE OF
SCENARIO. HOWEVER...THE BIG CAVEAT IS THE AMOUNT OF COLD AIR THAT
WILL BE AVAILABLE FOR THIS SYSTEM. THE 12Z GFS IS WARMER THAN
PREVIOUS RUNS BUT STILL BORDERS ON BEING COLD ENOUGH FOR SOME
SNOW. THE 12Z EURO ON THE OTHER HAND IS MUCH MUCH WARMER WITH THE
MODEL LAGGING THE NORTHERN STREAM ENERGY BACK BEHIND THE SOUTHERN
SHORTWAVE. GIVEN THAT THIS POTENTIAL EVENT IS 6 DAYS AWAY AND
THERE ARE SERIOUS QUESTIONS REGARDING THE DEGREE OF COLD
AIR...WILL NOT INCLUDE ANY WINTRY WORDING IN THE FORECAST. RAIN
CHANCES HAVE BEEN BUMPED UP SLIGHTLY FOR CHRISTMAS EVE AND CHRISTMAS
DAY WITH TEMPERATURES FORECAST TO BE SLIGHTLY BELOW NORMAL. WE
WILL CONTINUE TO CLOSELY MONITOR THIS SYSTEM.
----

So at least the possibility hasn't been ruled out yet.

The main hitch to the forecast is cold air.


I think they're doing the smart thing and leaving any wintry precip out for now.

[Brent]

ON SUNDAY A DEEP TROUGH WILL BE NEARLY CUTOFF OVER NORTHERN MEXICO
WITH SURFACE FRONTOGENESIS UNDERWAY OVER THE NORTHERN GULF INTO EAST
TEXAS. A SURFACE LOW WILL DEVELOP LONG THE NORTHERN GULF COAST...
OR POSSIBLY JUST INLAND AND TRACK RAPIDLY TO THE NORTHEAST SUNDAY
NIGHT. THIS SCENARIO IS USUALLY THE PREFERRED PATTERN FOR WINTRY
PRECIPITATION IN CENTRAL ALABAMA...BUT IN THIS CASE THE AIR
PRECEDING THE DEVELOPMENT OF THE LOW WILL BE TOO WARM. INSTEAD...
STRONG TO POSSIBLY SEVERE WEATHER IN THE FORM OF THUNDERSTORMS
LOOKS MORE LIKELY.



At least we will get some rain out of this. We really need it, it's been pretty dry all month.

[Brent]

From HUN:

THE GFS MODEL FORECAST SOUNDINGS INDICATE
THAT A PERIOD OF LIGHT SNOW COULD OCCUR IN THE HIGHER ELEVATIONS OF
SOUTHERN MIDDLE TN AND NORTHEAST AL CHRISTMAS NIGHT. WE WILL NOT
MENTION THAT POSSIBILITY IN THE FORECAST AT THIS TIME PENDING
CONSISTENCY WITH THE SURFACE LOW TRACK IN LATER MODEL RUNS.

BMX:

CHRISTMAS DAY AND NIGHT LOOK INTERESTING AS 500MB COLD POCKET
MOVES ACROSS ALABAMA. GFS HAS BEEN VERY ERRATIC WITH TRACK AND
STRENGTH OF THIS UPPER COLD POCKET BUT FREEZING LEVEL WILL BE
NEAR 1500 FEET AGL ACROSS NORTH ALABAMA MONDAY NIGHT WITH DEEP
LAYER OF MOISTURE STILL ACROSS AREA. THIS TYPE OF SYSTEM DOES NOT
TYPICALLY PRODUCE MUCH PCPN...BUT SOMETHING TO KEEP AN EYE ON. AT
THIS TIME...KEPT SLIGHT CHANCE OF LIGHT RAIN IN FOR MONDAY NIGHT.

[Brent]

Look at this.

[HarlequinBoy]

NWS in Paducah is now calling for 1-2 inches of snow Monday night.

And Memphis has updated zones to put a 60% chance of rain or snow across the entire CWA for Monday night, and also Monday afternoon across northern zones.


I still don't expect to see anything here, but at least there's a glimmer of hope!

[HarlequinBoy]

Memphis AFD..

THE MODELS CONTINUE TO SUGGEST A SPLIT UPPER LEVEL FLOW PATTERN
THROUGH THE WEEKEND...WITH AN UPPER LOW PRESSURE SYSTEM NOW
DEVELOPING OVER THE SOUTHWEST U.S. AND A SERIES OF SHORTWAVES
PROPAGATING EAST ACROSS THE NORTHERN PORTIONS OF THE COUNTRY. THE
UPPER LEVEL LOW PRESSURE SYSTEM SHOULD CONTINUE MOVING EAST IN THE
SOUTHERN STREAM TOWARDS THE LOWER MISSISSIPPI VALLEY BY SUNDAY
EVENING. AT THE SAME TIME...THE NORTHERN SHORTWAVE TROUGH OF
INTEREST...CURRENTLY OFF THE PACIFIC NORTHWEST COAST...WILL MOVE
SOUTHEAST AND BEGIN TO DIG ACROSS THE CENTRAL STATES AND TOWARD
THE MID SOUTH AS UPPER RIDGING BUILDS OVER THE WESTERN ATLANTIC
AND INTERMOUNTAIN WEST. THE BIGGEST CHANGES IN THE MEDIUM RANGE
MODEL GUIDANCE THIS PERIOD IS MUCH BETTER AGREEMENT WITH THE
INTERACTION BETWEEN THE NORTHERN AND SOUTHERN STREAM SYSTEMS. MOST
OF THE GUIDANCE IS NOW INDICATING THAT THESE FEATURES WILL
ATTEMPT TO PHASE OVER THE MISSISSIPPI VALLEY REGION. AS THE UPPER
FEATURES PHASE...SUFFICIENT SOUTHERN STREAM MOISTURE SHOULD REMAIN
IN PLACE AS A POLAR AIRMASS FILTERS INTO THE REGION FROM THE
NORTHWEST LATER CHRISTMAS DAY AND INTO CHRISTMAS NIGHT. AS THIS
OCCURS...THERE WILL BE THE POSSIBILITY THAT RAIN WILL CHANGE TO
SNOW FROM WEST TO EAST ACROSS THE AREA LATER MONDAY AFTERNOON INTO
MONDAY NIGHT. THERE STILL REMAINS CONCERNS WITH TEMPERATURE
PROFILES WITHIN THE BOUNDARY LAYER...BUT AS THE UPPER TROUGH
OVERSPREADS THE AREA DURING THIS PERIOD...CONTRIBUTIONS FROM
DYNAMIC PROCESSES (COOLING) AND LOW LEVEL COLD ADVECTION INTO THE
BACKSIDE OF THE SYSTEM WILL INCREASE THE THREAT FOR WINTER
WEATHER. OF COURSE WE ARE STILL MORE THAN 3 DAYS FROM THIS EVENT
AND THERE UNDOUBTEDLY WILL BE ADDITIONAL CHANGES IN THE SPECIFIC
DETAILS. BUT WITH IMPROVING MODEL CONTINUITY...ESPECIALLY WITH
REGARDS TO THE LARGE SCALE PATTERN...CONFIDENCE IS INCREASING WITH
RESPECT TO THE POSSIBILITIES OF A PERIOD OF WINTER WEATHER LATER
CHRISTMAS DAY AND CHRISTMAS NIGHT. SINCE THERE IS STILL SOME
UNCERTAINTY WITH PRECIPITATION TYPE...HAVE INTRODUCED RAIN OR SNOW
WORDING FOR MONDAY AFTERNOON AND NIGHT. WE WILL CONTINUE TO REFINE
THE SPECIFICS AS WE CLOSE IN ON THE EVENT.

[Brent]

BMX:

SURFACE LOW WILL DEEPEN RAPIDLY AS IT MOVES UP THE EAST MONDAY
NIGHT AND TUESDAY. COLD AIR WILL BE PULLED RAPIDLY SOUTHWARD INTO
ALABAMA MONDAY NIGHT WITH DEEP CLOSED UPPER LOW FORECAST TO DIVE
SOUTHEASTWARD TOWARDS AREA. IT BECOMES A LITTLE INTERESTING LATE
MONDAY NIGHT AS SOUNDING PROFILES GO QUICKLY BELOW FREEZING WITH
DEEP MOISTURE STILL IN PLACE. ADDED A MIXTURE OF RAIN/SNOW FOR
LATE MONDAY NIGHT ACROSS NORTHERN COUNTIES AND FLURRIES ACROSS NE
COUNTIES TUESDAY MORNING. BOUNDARY LAYER TEMPERATURES WILL LIKELY
STAY ABOVE FREEZING...SO ANY FROZEN STUFF WILL MELT ON CONTACT
WITH WARM GROUND CONDITIONS.

HUN:

NOW FOR THE BIG QUESTION...WILL IT SNOW (QUESTION MARK) WELL...FCST
SNDINGS INDICATE SOME SNOW MAY BEGIN MIXING WITH THE RAINFALL LATE
MONDAY NIGHT ACROSS PORTIONS OF THE TN VALLEY. IN THE HIGHER
ELEVATIONS OF NE AL AND ALONG THE CUMBERLAND PLATEAU...RAIN MAY
TRANSITION INTO ALL SNOW BEFORE DAYBREAK TUESDAY. THE COMBINATION OF
COLD AIR ADVECTION AND EVAP COOLING SHOULD CAUSE ANY LIQUID PRECIP
STILL FALLING ACROSS THE TN VALLEY TO TRANSITION INTO SNOW EARLY TUE
MORNING.

FFC:

SHOULD BEGIN TO GET INTO SOME WRAP-AROUND MOISTURE LATE MONDAY NIGHT/TUESDAY
MORNING... WHICH AT THAT TIME THICKNESSES MAY BE COLD ENOUGH FOR
RAIN/SNOW MIX ACROSS THE NORTH. THIS WILL NEED TO BE WATCHED AND
ADJUSTED IF LATER RUNS SUPPORT IT.

Zone forecast for here:

Monday Night...Mostly cloudy. A slight chance of rain through the night. A slight chance of snow after midnight. Lows in the upper 30s. Chance of precipitation 20 percent.

[Brent]

0z GFS continues to look promising.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_078s.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_084s.gif

[Brent]

BMX:

MONDAY NIGHT...AS IF THE FORECAST WAS NOT DIFFICULT ENOUGH...THE
CHALLENGE CONTINUES INTO MONDAY NIGHT. THE UPPER LOW PLACEMENT HAS
MOVED FURTHER SOUTH OVER THE LAST SEVERAL DAYS. IT WILL NOW TRACK
OVER THE NORTHERN HALF OF ALABAMA. NOW THE QUESTION BECOMES HOW
MUCH MOISTURE WILL BE AVAILABLE AND WHAT ABOUT THE COLD AIR?
LOOKED AT A FEW FORECAST SOUNDINGS FOR
HAMILTON...BIRMINGHAM...ANNISTON...AND CENTRE. MOISTURE DOES NOT
BECOME PRESENT ACROSS THE CRITICAL -10 DEGREE DENDRITIC GROWTH ZONE
UNTIL AFTER 06Z. THE SOUNDINGS FOR EACH OF THOSE LOCATIONS
SUPPORTS ICE CRYSTALS IN THE DENDRITIC GROWTH ZONE REGION AND A
COLD SOUNDING UNTIL CLOSE TO THE SURFACE. IN FACT HAVE A FORECAST
LOW TUESDAY MORNING FOR HAMILTON OF 32 DEGREES. TAKING THE WET
BULB FACTOR INTO ACCOUNT AT OTHER LOCATIONS IT WILL MOST LIKELY
SNOW FOR SEVERAL LOCATIONS ACROSS NORTHERN HALF OF THE COUNTY
WARNING AREA. THE SURFACE WILL BE WARM SO DON/T EXPECT ANY
ACCUMULATIONS EXCEPT FOR MAYBE PROTECTED GRASSY AND METAL
SURFACES. THE MODELS WILL HAVE A FEW DAYS TO CHANGE AND MODIFY SO
WILL CONTINUE TO MONITOR THIS VERY CLOSELY.

[Lindaloo]

In February of 06, I went to Roswell, GA (north of Atlanta) and I was just lucky enough to see some very nice big snowflakes.

[Opal storm]

NWS forecasting Christmas night snow for Birmingham.

Monday Night: A chance of rain, mixing with snow after midnight. Mostly cloudy, with a low around 33. Chance of precipitation is 30%.

[HarlequinBoy]

Christmas Day: Periods of rain, mixing with snow after 3pm. High near 45. Breezy, with a northwest wind between 10 and 20 mph, with gusts as high as 30 mph. Chance of precipitation is 100%.

Monday Night: Snow likely, mainly before midnight. Cloudy and blustery, with a low around 30. Chance of precipitation is 60%.

Forecast for Tunica, MS.

And Memphis put out a Special Weather Statement.

...WINTER WEATHER IS POSSIBLE CHRISTMAS AFTERNOON INTO MONDAY NIGHT...

AN EVOLVING STORM SYSTEM OVER THE BIG BEND OF TEXAS WILL BEGIN TO
APPROACH THE MID SOUTH SUNDAY NIGHT AND INCREASE RAIN CHANCES.
WIDESPREAD RAIN WILL OCCUR EARLY CHRISTMAS DAY.

A COLD FRONT WILL MOVE INTO THE MID SOUTH CHRISTMAS MORNING
PROVIDING LOW LEVEL COLD AIR. BY CHRISTMAS AFTERNOON...RAINFALL
WILL BEGIN TO MIX WITH OR CHANGE TO SNOW BY MONDAY NIGHT. THE SNOW
WILL TAPER OFF BY TUESDAY MORNING.

THERE IS STILL SOME UNCERTAINTY AS TO CRITICAL TEMPERATURES.
HOWEVER LIGHT ACCUMULATIONS WILL BE POSSIBLE BEGINNING CHRISTMAS
AFTERNOON THROUGH TUESDAY MORNING. IN ADDITION...STRONG NORTHERLY WINDS
WILL CAUSE WIND CHILLS TO FALL AS LOW AS THE UPPER TEENS CHRISTMAS
DAY INTO MONDAY NIGHT.

I'm still not getting my hopes up!

[Janie2006]

Things are looking better for Brent and Micah, though Birmingham thinks that the best chances for wintry precip remain north and west of that city. That being said, this is a developing wx situation and things can change.

[Opal storm]

.LONG TERM (CHRISTMAS DAY THROUGH NEXT FRIDAY)...THE LOW LIFTS TO
THE NORTHEAST CHRISTMAS DAY AND A COLDER/MORE STABLE AIRMASS FILTERS
INTO THE REGION IN ITS WAKE. THE SUFFICIENTLY COLD AIRMASS FOR
WINTRY PRECIP APPEARS TO STAY NORTHWEST OF OUR AREA LONG ENOUGH TO
ALLOW THE DEEP MOISTURE TO EXIT FAR ENOUGH TO THE EAST...THEREFORE
THE POTENTIAL FOR A WHITE CHRISTMAS IS FORECAST TO REMAIN NORTH OF
OUR FORECAST AREA.

[Brent]

Things are looking better for Brent and Micah, though Birmingham thinks that the best chances for wintry precip remain north and west of that city. That being said, this is a developing wx situation and things can change.

Yeah... and I'm actually ESE of Birmingham. But there's a 2,400 foot mountain within an hour of here. It gives me an idea we've done before.