860
FXUS64 KOHX 031729
AFDOHX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NASHVILLE TN
1129 AM CST SUN MAR 3 2013

.UPDATE...

18Z TAF DISCUSSION.

&&

.AVIATION...

BNA/CKV...STRATOCU AROUND 3500 FT HAS FORMED NEAR THESE AIRPORTS
THIS MORNING DUE TO MOISTURE TRAPPED BENEATH THE STOUT INVERSION
ON THE 12Z OHX SOUNDING. STILL ANTICIPATING VFR CONDITIONS
THROUGHOUT THE TAF PERIOD WITH STRATOCU DISSIPATING BY
EVENING...THEN MID LEVEL CLOUD COVER FROM 6-12K FT SPREADING
ACROSS TERMINALS TONIGHT AHEAD OF THE NEXT STORM SYSTEM. LIGHT
NORTHWEST WINDS TODAY WILL VEER AROUND THE DIAL TO SOUTHEASTERLY
BY MONDAY MORNING.

CSV...MORE WIDESPREAD MVFR STRATUS CONTINUES TO SPREAD ONTO THE
PLATEAU AS NORTHWESTERLY FLOW PROVIDES WEAK UPSLOPE...WITH RADAR
INDICATING SCATTERED LIGHT SNOW SHOWERS CONTINUING AS WELL. MODELS
NOT HANDLING CIGS OR PRECIP WELL...SO WILL CALL FOR MVFR CIGS INTO
THE EVENING BEFORE IMPROVEMENT BUT THEY COULD CERTAINLY CONTINUE
LONGER. LIGHT SNOW SHOWERS WILL CONTINUE TO WEAKEN THROUGH THE
AFTERNOON AS UPPER TROUGH SHIFTS OFF THE EAST COAST...AND WILL
ONLY MENTION FOR THE NEXT FEW HOURS. MID LEVEL CLOUD COVER WILL
SPREAD ACROSS CSV LATE IN THE TAF PERIOD AHEAD OF THE NEXT STORM
SYSTEM.

&&

.PREV DISCUSSION... /ISSUED 947 AM CST SUN MAR 3 2013/

UPDATE...MID MORNING VISIBLE SATELLITE IMAGERY SHOWS CLOUDS
MAINLY OVER THE EASTERN THIRD OF OUR AREA. MORE
INTERESTINGLY...THE IMAGE SHOWS THE VARIABLE NATURE OF THE SNOW
THAT FELL ACROSS MID TN...INCLUDING EFFECTS FROM TERRAIN AND THE
BANDED NATURE OF SOME OF THE SNOW SHOWERS. COMPARISON WITH A
DETAILED TOPOGRAPHIC MAP SHOWS THAT SMALL ELEVATION DIFFERENCES OF
JUST A COUPLE HUNDRED FEET PLAYED A BIG ROLE IN THE SNOW
ACCUMULATIONS.

FOR TODAY...THE MAIN AREA OF CLOUDS AND FLURRIES OVER THE EASTERN
THIRD WILL CONTINUE TO BREAK UP...BUT SOME SCT STRATO CU
WILL DEVELOP ACROSS THE AREA...AND SOME PATCHES OF HIGH CLOUDS
WILL MOVE IN LATER THIS AFTERNOON. MARCH SUN WILL WARM
TEMPERATURES INTO THE LOWER 40S. ANY LINGERING ICE PATCHES WILL BE
GONE SOON...AND THE SNOW WILL DISAPPEAR QUICKLY AS WELL.

13

PREV DISCUSSION... /ISSUED 511 AM CST SUN MAR 3 2013/

UPDATE...ADDED AVIATION SECTION FOR 12Z TAF`S.

AVIATION...BNA/CKV/CSV...HIGH PRESSURE BUILDING INTO MIDDLE
TENNESSEE FROM THE WEST THIS MORNING, WITH CLOUDS FINALLY ERODING
FROM WEST TO EAST AND JUST SOME LEFTOVER FLURRIES STILL IN CLOUDED
AREAS. ONCE THE LOW CLOUDS MOVE OUT THIS MORNING, EXPECT VFR WX
THE REST OF THE WAY.

PREV DISCUSSION... /ISSUED 406 AM CST SUN MAR 3 2013/

DISCUSSION...

FOR THE SHORT TERM...

THESE PERSISTANT FLURRIES HAVE BEEN LARGELY DRIVEN BY H5 VORTICITY
GENERATION DUE TO SOUTHWARD DIVING SHORTWAVES. THE LOW THESE
SHORTWAVES ARE ROTATING AROUND WILL PUSH EASTWARD AND WITH IT...THE
FLURRY ACTIVITY. TEMPERATURE ARE EXPECTED TO RISE INTO THE 40S TODAY
DUE TO THE ABILITY FOR THE SFC TO FINALLY SEE SOME SUNLIGHT. A BRIEF
WINDOW OF CLEARING WILL BE SEEN THIS AFTERNOON BEFORE HIGH CLOUDS
MOVE IN TONIGHT. SHOULD SEE ANOTHER COLD NIGHT TOMORROW NIGHT THOUGH
ALBEIT A FEW DEGREES WARMER THAN THIS MORNING. ONLY MINOR CHANGES
WERE MADE IN THE SHORT TERM GRIDS...MOST NOTABLY THE PERSISTANCE OF
FLURRIES ON THE EXTREME EASTERN PLATEAU TO 18Z DUE TO THE MODELS
BEING A LITTLE TOO QUICK TO EXIT THE UPPER LEVEL SYSTEM AND ITS
FLURRY MAKING LIFT. RADAR TRENDS INDICATE THESE FLURRIES COULD LAG
ANOTHER COUPLE HOURS OUT EAST.

FOR THE EXTENDED...

THE FOCUS WAS ON THE NEXT H5 CLOSED LOW PASSAGE ON TUESDAY.IT
APPEARS THAT THE EURO AND GFS HAVE COME A LITTLE MORE IN LINE WITH
THE DEPICTION OF THE H5 LOW TRANSLATION. CURRENTLY...THE LOW IS
DEPICTED TO PASS DIRECTLY OVER MIDDLE TN BY 06Z WEDNESDAY. THE COLD
FRONT ASSOCIATED WITH IT HAS PRETTY MEAGER LIFT AND LACK OF
APPRECIABLE INSTABILITY WILL MAKE THIS ONLY A VERY SLIGHT THUNDER
THREAT. HAVING SAID THAT...BOTH MODELS DO PRODUCE A WARM SECTOR NOSE
THAT EXTENDS INTO CENTRAL KENTUCKY WITH SOMEWHAT DECENT 500 MB FLOW
AND A 30 KT LLJ. FORECAST SOUNDINGS DONT GENERATE APPRECIABLE
CAPE...ALTHOUGH NON-ZERO. THEREFORE WENT AHEAD AN INCLUDED A SLIGHT
CHC OF THUNDER TUESDAY.

MORE NOTABLY...BOTH MODELS WRAP AROUND MOISTURE AND BRING IN VERY
COLD 850 MB TEMPS...ON THE ORDER OF -10C...QUICKLY BEHIND THE FRONT.
THIS WILL QUICKLY TRANSITION LIGHT RAIN INTO A MIX AND INTO SNOW BY
06Z WEDNESDAY. DIFFICULT TO IMAGINE MUCH ACCUMULATION WITH THAT
ACTIVITY HOWEVER SINCE HIGHS WILL REACH THE 50S EARLIER THAT DAY AND
GROUNDS SHOULD BE WELL ABOVE FREEZING.

BEYOND THAT...UPPER LEVEL RIDGING WILL BEGIN TO BUILD INTO MS VALLEY
AND THUS WARM MIDDLE TN INTO THE 60S BY NEXT WEEKEND. SHOULD SEE A
VERY NICE LATE WEEK AND WEEKEND WITH WARMER AND DRIER CONDITIONS
EXPECTED IN BOTH LONG RANGE MODELS.

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHAMBURGER