Jan 05 Storm, Light Freezing Rain Possible

[Snowman]

I figured it was finally time to start a separate thread for what looks like our first brush with some wintry weather in this upcoming wintry weather period. Here is the take of some of the local national weather service offices in this early stage of the game. I will add the rest as they come out this morning. Even Huntsville is hinting at something in the 6-7th timeframe.

Nashville, Tn...

YET ANOTHER RAPIDLY MOVING
SFC/LL HIGH WILL RACE THROUGH SUNDAY NIGHT/MONDAY...BRINGING SHOWERS
BACK TO THE AREA MONDAY NIGHT/TUESDAY AS A WEAK LOW/DEEP MOISTURE
LIFT FROM THE NORTHERN GULF UP THE ATLANTIC COAST AHEAD OF A WEAK
SHORTWAVE.

Memphis, Tn...

MODELS ALSO DIFFER ON HOW FAR SOUTH COLD FRONT PUSHES SUNDAY NIGHT
BEFORE DEVELOPING ANOTHER SFC LOW ALONG FRONT WHICH WOULD PUT THE
MIDSOUTH INTO A OVERRUNNING PATTERN DURING THE MONDAY THROUGH
TUESDAY TIME FRAME. DEPENDING ON HOW DEEP THE COLD AIR IS IN PLACE
AND HOW CLOSE THE SFC LOW TRACKS TO THE CWA...THERE COULD BE SOME
PRECIP TYPE CONCERNS DURING THIS TIME FRAME. HOWEVER WITH THE
DIFFERENCES BETWEEN MODELS SOLUTIONS FROM FRIDAY NIGHT THROUGH
TUESDAY...CONFIDENCE IS VERY LOW IN REGARDS TO ANY POSSIBLE WINTER
PRECIP. FOR NOW WILL KEEP FCST IN FORM OF RAIN BUT STAY TUNED FOR
POSSIBLE CHANGES IN FUTURE FCSTS.

Huntsville, Al...

FOR THE TUE/WED TIME FRAME WHICH IS INTERESTING TO SAY THE LEAST.
THE ECMWF IS FURTHER NORTH...AND AS A COMPROMISE TRENDED TEMPS
DOWNWARD BUT NOT TO THE EXTENT THAT THE 00Z GUIDANCE CURRENTLY
DEPICTS. IF THE MORE SRN SOLN DOES PAN OUT...SOME WINTER TYPE
PRECIPITATION MAY COME INTO THE PICTURE FOR AREAS OF THE SOUTHEAST
FOR THE JAN 6/7 TIMEFRAME.

Paducah, Ky...

SIGNIFICANT QUESTION MARKS REMAIN WITH RESPECT TO THE MONDAY NIGHT
AND TUESDAY SYSTEM EARLY NEXT WEEK. THE MODELS TRENDED FARTHER SOUTH
WITH THE SURFACE LOW...UNTIL THE 00Z ECMWF CAME IN...AND MOVED THE
LOW BACK NW TOWARD OUR AREA. THE MODELS ARE IN AGREEMENT THAT A NORTHWARD
SURGE OF MOISTURE FROM THE GULF COAST REGION SHOULD OCCUR MONDAY NIGHT
INTO TUESDAY.

QUESTIONS INCLUDE...HOW FAR NORTH AND HOW COLD WILL IT BE WITH THE
PRECIP. DUE TO INCREASED UNCERTAINTY AND MODEL VARIABILITY WILL
KEEP POPS CONSERVATIVE...AND MENTION A RAIN/SNOW CHANCE...SO AS TO
KEEP THINGS SIMPLE...AND WE CAN ADJUST AS NEEDED WITH TIME.

Louisville, Ky...

HIGH PRESSURE BUILDS INTO THE AREA SUNDAY NIGHT AND MONDAY AND
CONDITIONS WILL REMAIN DRY WITH AVERAGE HIGHS AND LOWS. ANOTHER
DISTURBANCE IN THE SOUTHWEST FLOW WILL BRING A CHANCE FOR
PRECIPITATION TO THE AREA ON TUESDAY. THIS TIME...A WINTRY MIX OF
SNOW AND SLEET WILL BE POSSIBLE MONDAY NIGHT BEFORE CHANGING TO RAIN
TUESDAY WITH A RAIN/SNOW MIX ON TUESDAY NIGHT. HOWEVER...CONFIDENCE
IN THIS SYSTEM FOR MONDAY NIGHT THROUGH TUESDAY IS LOW.

[Curt]

6z and 12z GFS runs confirm much further track south. Looks like a classic winter precip track but not a ton of mositure and marginal cold temps. Alot to be ironed out between now and then but it at least is not SVR!

[Thundersnow]

12Z GFS run not great overall, compared to what we've been seeing.

There is still that potential on the 6th:

[bonzomemphis]

If I'm reading it right....looks like this data for Memphis is saying 0.17 inches of snow, but that's in liquid form, so if I'm not mistaken it would be around 2" of actual frozen precip.

That's assuming the ground is cold enough to initially support accumulation, which it probably won't be to start off with backside moisture.

Still lots of unknowns, but if the models aren't handling the cold air well and the low tracks a little further north giving better precip, it would be something to keep an eye out for.

http://coolwx.com/cgi-bin/getbufr.php?region=TN&stn=KMEM&model=gfs&time=current&field=prec

[Curt]

AFD from Springfield MO

THE NEXT STORM SYSTEM THAT COULD HAVE SOME IMPACT FOR SOUTHERN
MISSOURI WILL APPROACH EARLY NEXT WEEK.  MODELS CONTINUE TO TREND
THE TRACK OF THIS LOW FURTHER SOUTH.  IF THIS TREND CONTINUES...THEN
EXTREME SOUTHEAST KANSAS AND THE OZARKS WILL REMAIN DRY...AS
MOISTURE AND LIFTS WOULD BE CONFINED TO THE INTERSTATE 40 CORRIDOR
AND SOUTH.  WE STILL HAVE A MENTION OF SNOW CHANCES IN THE GRIDS
BEGINNING MONDAY NIGHT AND CONTINUING THROUGH TUESDAY.  IF THE LOW
CAN TRACK FURTHER NORTH...THEN SOUTHERN MISSOURI WOULD BE IN A
FAVORABLE POSITION FOR ACCUMULATING SNOW.  AT THIS TIME...IT DOESN`T
APPEAR AS THOUGH THAT WILL HAPPEN.

Looks like I-44 is out.

[Snowman]

I-44 out bodes well for us. Usually. 

Nashville...

LOW PRES S OF TX COAST MON WILL DEEPEN AND MOVE NE. CONCENSUS IS
STILL TO GO WITH EURO MODEL WHICH HAS LO MOVING INTO MID STATE
EARLY TUE AND TO THE GRTLKS BY TUE EVE...DRAGGING A COLD FRONT
ACROSS CWA TUE AND TUE NITE. WENT WITH LIKELY POPS MON NITE AND
TUE...AND A CHANCE OF R/S TUE NITE AS COLDER AIR SPILLS IN.

[Snowman]

Memphis...

A SOUTHWEST FLOW ALOFT DEVELOPS EARLY NEXT WEEK AS AN UPPER LEVEL
TROUGH DEEPENS OVER THE DESERT SOUTHWEST. A SURFACE LOW PRESSURE
SYSTEM IS FORECAST TO INTENSIFY ALONG THE GULF COAST AS THE TROUGH
PROGRESSES EASTWARD. THIS SHOULD SPREAD OVERRUNNING RAIN INTO THE
MIDSOUTH MONDAY NIGHT THROUGH WEDNESDAY. PRECIPITATION TYPE MIGHT
BE AN ISSUE ACROSS THE BOOTHEEL AND NORTHEAST ARKANSAS IF
SUFFICIENT COLD AIR IS PULLED DOWN ON THE BACKSIDE OF THE SYSTEM.
FOR NOW...WILL STICK WITH AN ALL LIQUID FORECAST.

[Snowman]

Paducah...

IN THE LONG TERM...SATURDAY THROUGH WEDNESDAY...POPS BECOME MORE OF
A QUESTION. FORECAST IS ONE OF LOW CONFIDENCE IN THIS
PERIOD...ESPECIALLY HEADING OUT INTO EARLY NEXT WEEK. THE FIRST OF
TWO SYSTEMS WILL BRING A COLD FRONT ACROSS THE AREA SATURDAY NIGHT
AND SUNDAY MORNING. PRECIPITATION WITH THIS SYSTEM SHOULD BE FAIRLY
LIGHT. TEMPERATURE PROFILES CONTINUE TO SUGGEST MAINLY RAIN...AND
ELEVATED INSTABILITY COULD LEAD TO A FEW THUNDERSTORMS AS WELL.

THE SECOND AND STRONGEST OF THE EXTENDED PERIOD SYSTEMS WILL
INFLUENCE THE REGION STARTING MONDAY NIGHT AND PERSISTING INTO
TUESDAY AND WEDNESDAY. FORECAST MODELS HAVE BEEN ALL OVER THE PLACE
WITH THIS SYSTEM...SO CONFIDENCE IN ANY ONE SOLUTION IS VERY LOW.
ENSEMBLE GUIDANCE AND A MENTAL AGGREGATE OF ALL MODEL SOLUTIONS
VIEWED THUS FAR WOULD TAKE THE TRACK OF THE SURFACE LOW SOMEWHERE
ACROSS THE TENNESSEE VALLEY. THIS WOULD MEAN MORE SNOW FOR OUR
NORTHERN COUNTIES...MORE RAIN IN THE SOUTH...AND A WINTRY MESS
SOMEWHERE IN THE MIDDLE. GIVEN THE LOW CONFIDENCE...WILL LEAVE IT AS
RAIN OR SNOW FOR NOW...ALLOWING FOR BETTER DEFINITION AS THE EVENT
DRAWS CLOSER. A TRANSITION TO ALL SNOW LOOKS MORE PROBABLE BY
WEDNESDAY AS COLD AIR IS DRAWN IN BEHIND THE DEPARTING SYSTEM.

[Moonpye]

Hope springs eternal!

Some nice snow would be a fantastic welcome-back-to-Paducah present. I'll take light snow, as well...just as long as something is falling from the sky. 

[servocrow]

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NASHVILLE TN
508 AM CST THU JAN 1 2009

TNZ005>011-022>034-056>066-075-077>080-093>095-021130-
STEWART-MONTGOMERY-ROBERTSON-SUMNER-MACON-CLAY-PICKETT-BENTON-
HOUSTON-HUMPHREYS-DICKSON-CHEATHAM-DAVIDSON-WILSON-TROUSDALE-
SMITH-JACKSON-PUTNAM-OVERTON-FENTRESS-PERRY-HICKMAN-LEWIS-
WILLIAMSON-MAURY-MARSHALL-RUTHERFORD-CANNON-DEKALB-WHITE-
CUMBERLAND-BEDFORD-COFFEE-WARREN-GRUNDY-VAN BUREN-WAYNE-LAWRENCE-
GILES-
508 AM CST THU JAN 1 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR MIDDLE TENNESSEE.

.DAY ONE...TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THERE IS A CHANCE OF SNOW NEXT WEEK. IT IS TOO SOON TO PREDICT
ACCUMULATING SNOW DUE TO THE UNCERTAINTY OF THE SYSTEM TRACK...
BUT THERE IS A CHANCE TUESDAY...POSSIBLY INTO WEDNESDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.

 

Positively scary.....

[Snowman]

Memphis AFD this morning. They seem a bit confused about the extended.

BY TUESDAY ANOTHER STORM BEGINS TO MOVE THROUGH. AGAIN
TEMPERATURES ON TUESDAY WILL BE SLIGHTLY ABOVE NORMAL BEFORE
COOLING ON WEDNESDAY. PRECIPITATION ON WITH THIS SYSTEM IS NOT
COMPLETELY CERTAIN...IT LOOKS TO START AS RAIN...HOWEVER...MAY END
WITH SOME SNOW...HEDGED IN FORECAST AND PUT RAIN OR SNOW IN GRIDS.

THE PATTERN LOOKS TO CONTINUE WITH STORMS MOVING ACROSS THE AREA
NEAR THE END OF THE FORECAST PERIOD.

[servocrow]

OHX AFD:

.......WILL RETURN HIGH TEMPS TO NEAR OR BELOW
SEASONAL LEVELS FOR NEXT WEEK.

AS FOR ANY PRECIP CHANCES IN THE EXTENDED...DEEP TROUGH WILL IMPACT
THE AREA ON WEDNESDAY. A SERIES OF DISTURBANCES MAY PRODUCE SOME
RAIN OR SNOW SHOWERS FOR TUES NT INTO WED. WILL UNDERCUT THE MEX
GUIDANCE IN TERMS OF HIGH TEMPS ON WEDNESDAY.

[Kevin]

 Was just reading AFD from MEG...made a mention of freezing rain/drizzle possibility Late Tonight...took a look and was actually a bit surprised at what I saw.

Shallow arctic airmass was moving into the Midsouth this evening...temperatures in the low 40s with the freezing line stretching from NW AR into SE MO...slowly pushing Southeast. This arctic push is not particularly strong...and won't go too far SE before being pushed back north by the approaching system as talked about for late Monday into Tuesday.

The tricky part is the 12z/18z NAM/GFS models indicate a weak wave with isentropic uplift increasing in the shallow arctic air around Daybreak Monday....continuing into early Monday Evening as the wave passes through. NAM/GFS forecast soundings are extremely close at many locations along and north of I-40 to freezing rain/drizzle potential...with the NAM most aggressive with the freezing line down to about interstate 40 itself (not surprising given its better vertical resolution). Temperatures remain nearly steady during the day as well under clouds/precip and with no significant surface WAA taking place as the wave moves through and isentropic uplift is at its strongest...with both models putting as much as .25" QPF into near freezing air. During Monday Evening...WAA increases ahead of developing surface low and increasing forcing/ascent that temperatures should rise some during the evening...ending any concern which may develop. As a side note...15z SREF also shows this potential...though a bit further north...just as far south as near JBR-DYR.

Let me emphasize that right now this is an extremely low confidence post...and I only post this as my curiosity was peaked. The arctic push is not strong...though still present...and if freezing temperatures even develop...the precip will have to develop within that air...and the best insentropic lift won't have to be much further south to miss favorable temperatures anyway. Temperatures...if they even reach freezing...probably won't be lower than 30 or 31...and more likely right at 32...so I can't envision significant problems anyway given recent warm temperatures....but its something to watch. The 0z model data may reverse things completely and this post will look stupid... icon_razz.gif

KMEM Surface Model Output has temperatures down to 33/34 during the event on the NAM...35/36 on the GFS...so close but at face value...just rain. Areas just north of there...from Wynne AR to Covington TN and Jackson...are right or barely below freezing. Just north of there...temperatures go back above freezing a bit as there is less QPF. In other words...in case you haven't figured it out...this is paper thin on how this goes. If you're reading this from this area...right now I wouldn't expect anything to happen. MEG is keeping all liquid for now pending the 00z data. We'll see what happens then...

For reference...here is the MEG discussion cited above...

WILL CONTINUE TO MONITOR POTENTIAL FOR FREEZING RAIN/DRIZZLE OVER
PORTIONS OF THE MID SOUTH LATER TONIGHT AS SHALLOW ARCTIC AIRMASS
CONTINUES TO WORK SOUTH INTO THE REGION. LATEST 18Z NAM SOUNDINGS
INDICATING THIS POTENTIAL AS FAR SOUTH AS THE INTERSTATE 40
CORRIDOR...MAINLY AFTER MIDNIGHT. WOULD LIKE TO WAIT AND SEE HOW
TEMPERATURES TREND OVER THE NEXT COUPLE OF HOURS AND ALSO GET A
LOOK AT NEW MODEL TRENDS BEFORE MAKING ANY DECISIONS CONCERNING
WINTER WEATHER POTENTIAL TONIGHT.

[StormNine]

Interesting.  Models don;t handle shallow arctic air well.  It seems to have that element of a surprise as a lot of things have to be ironed out.  We won't really know how it goes until the precip falls.  It is interesting.

[Snowman]

Nashville has introduced a wintry mix for today in the extreme nw corner of Middle Tennessee.