FXUS64 KOHX 050339 AAA
AFDOHX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NASHVILLE TN
939 PM CST FRI DEC 4 2009

.UPDATE...
LOOKING AT CURRENT REGIONAL RADAR MOSAIC...MOISTURE STREAMING
INTO MID STATE FROM NW MS AND N AL...MAINLY ALONG AND S OF
I-40 AND ACROSS THE CUMBERLAND PLATEAU REGION. NO REPORTS OF
SNOWFALL PRESENTLY ACROSS THE MID STATE OR MS OR AL. SFC LOW
CONTINUES TO REMAIN ACROSS N CNTRL GULF AND IS EXPECTED TO MOVE
NEWD TO OFF THE SC COAST LATER IN THE DAY ON SAT. BUT AS IT
MOVES...IT WILL CONTINUE TO USHER IN MOISTURE ACROSS THE MID STATE
THE REMAINDER OF TONIGHT INTO SAT MORNING...BEFORE AN UPPER
LEVEL TROUGH PASSAGE MOVES SNOWFALL POTENTIAL E AND STARTS THE
PROCESS OF CLEARING SKIES W TO E ACROSS THE AREA BY THE AFTERNOON
HOURS.

OOZ KOHX SOUNDING PROFILE DEPICTING MID LEVEL CLOUDINESS
WELL...WITH PCPN WATER VALUES AROUND .4 INCH AND A WET BULB ZERO
HEIGHT OF ONLY 590 FT. THICKNESS VALUES PROCESSED FROM THE KOHX
00Z SOUNDING SHOWING THAT THRESHOLDS FOR SNOW DEVELOPMENT HAD
NOT YET BEEN REACHED AT THAT TIME. LATEST NAM/RUC MODELS SHOWING
CURRENTLY THAT MOST OF MID STATE DOES HAVE BOTH 1000-850 MB AND
1000-500 MB THICKNESS VALUES BELOW THE 1300M/5400M THRESHOLDS FOR
SNOWFALL DEVELOPMENT AND THIS IS EXPECTED TO CONTINUE TO LAST
THRU AT LEAST NOON ON SAT.

LATEST NAM/RUC GENERALLY INITIALIZING WELL ON SNOWFALL MOVEMENT
AND AMOUNTS ACROSS THE MID STATE...AND THESE CONTINUE TO BE IN
RANGE OF CURRENT FORECASTED VALUES. STILL EXPECT TOTAL SNOWFALL
ACCUMULATIONS TO RANGE FROM LIGHT ACCUMULATIONS MAINLY ALONG AND
EAST OF I-65 TO 1 TO 2 INCHES ACROSS THE CUMBERLAND PLATEAU
REGION...WITH 2 TO 3 INCHES STILL POSSIBLE ACROSS CUMBERLAND AND
FENTRESS COUNTIES. HOWEVER...LOOK FOR 3 INCH AMOUNTS TO BE
ISOLATED AT BEST IN LOCATIONS ACROSS THESE COUNTIES.

THUS...WILL CONTINUE WITH WINTER WEATHER ADVISORY FROM MIDNIGHT
TO NOON CST SAT FOR LOCATIONS ACROSS THE CUMBERLAND PLATEAU REGION.
WILL UPDATE TO REFRESH ANY WORDING NEEDED. WILL ALSO DO THE SAME
WITH THE SPECIAL WEATHER STATEMENT.

TEMPS PRESENTLY MAINLY IN THE LOWER 30S WITH DEWPOINTS IN THE
MID 20S WITH N SFC WINDS AROUND 5 MPH. CURRENT TEMPS IN LINE WITH
CURRENT FORECASTED VALUES AND EXPECTED OVERNIGHT LOWS AND WIND
SPEEDS ARE EXPECTED TO DECREASE AT LEAST GENERALLY A COUPLE OF
MPH...SO THE FORECAST FOR LIGHT NORTH WINDS IS STILL IN GOOD
SHAPE.

THUS...ONLY UPDATE NEEDED WILL BE FOR CLOUDY SKIES ALL AREAS
TONIGHT...AS 00Z NAM RUN SHOWING SKIES ACROSS FAR NW COUNTIES
BECOMING BKN BY AROUND SUNRISE.
&&

.PREV DISCUSSION... /ISSUED 224 PM CST FRI DEC 4 2009/ 

.DISCUSSION...SURFACE MAP AT 20Z SHOWS RIDGE OF HIGH PRESSURE TO
OUR NORTH, WITH A 1029 MB HIGH CENTERED OVER EASTERN TEXAS, AND A
DEEP LOW DEVELOPING OVER THE GULF OF MEXICO. DESPITE THE LACK OF
LOW CLOUDS OVER MOST OF MIDDLE TENNESSEE, TEMPERATURES HAVE BEEN
SLUGGISH, AND STILL HAVE NOT REACHED 40 DEGREES IN MANY AREAS.

MODELS BRING THE GULF LOW ACROSS FLORIDA TO THE WESTERN CARIBBEAN
BY 06Z, AND OFF THE CAROLINA COAST BY 12Z. A BROAD AREA OF
OCCLUDED FRONTAL MOISTURE WILL SWING AS FAR WESTWARD AS MIDDLE
TENNESSEE, AND WILL BRING SNOW LATE TONIGHT AND TOMORROW MORNING
TO MUCH OF EASTERN MIDDLE TENNESSEE, ESPECIALLY THE CUMBERLAND
PLATEAU.

TEMPERATURES WILL SETTLE INTO THE MID AND UPPER 20'S OVERNIGHT
ACROSS THE MID STATE. THICKNESSES AT 00Z THIS EVENING WILL ALREADY
BE BELOW THRESHOLDS NECESSARY FOR SNOW AT BOTH 1000-850 MB AND
1000-500 MB, WILL DROP EVEN LOWER BY 12Z, AND WILL REMAIN BELOW
1300M/5400M EVEN AT 18Z, SO AM CONFIDENCE PRECIPITATION WILL FALL
AS SNOW.

ACCUMULATIONS WILL RANGE FROM A TRACE AT NASHVILLE TO 2-3 INCHES
IN PARTS OF CUMBERLAND AND FENTRESS COUNTIES. WILL THEREFORE
EXTEND THE SNOW ADVISORY FOR THE PLATEAU UNTIL 18Z TOMORROW.

AFTERWARD, LOOK FOR A GENERALLY COOL WEEK AHEAD. THE NEXT BIG
WEATHER SYSTEM WILL COME THROUGH TUESDAY AND TUESDAY NIGHT, BUT IT
SHOULD BE JUST RAIN.
&&

.OHX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST 
SATURDAY FOR TNZ011-032>034-065-066-078>080.

&&
$$
31/JBW