FXUS64 KHUN 072321 AAA
AFDHUN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HUNTSVILLE AL
520 PM CST MON DEC 7 2009

.UPDATE...
FOR 00Z AVIATION.
&&

.AVIATION...
SHRA CONTINUE TO AFFECT PARTICULARLY THE KHSV TERMINAL...WITH MVFR 
VISBY BETWEEN SHOWER BURSTS...AND IFR VISBY IN THE SHOWERS. RADAR 
SHOWS THIS BAND WILL CONTINUE FOR AT LEAST A FEW HOURS...SO WILL 
KEEP THE STATUS QUO GOING AT LEAST THAT LONG. ONLY VCSH AT KMSL. 
WILL INDICATE A BREAK A FEW HOURS EITHER SIDE OF MIDNIGHT...BUT AM 
NOT TOTALLY SOLD ON IT. THEN THE NEXT ROUND OF RAIN PICKS UP...AND 
IFR VISBY AND/OR CIGS LOOK FAIRLY LIKELY AS THAT RAIN MOVES IN. 
WOULD NOT BE SHOCKED TO SEE LIFR...BUT NOT PREPARED TO PUT THAT IN 
TAF THIS FAR OUT.
&&

.DISCUSSION...
SOME ACTIVE WX IS STILL XPCTED TO IMPACT THE TN VALLEY STARTING TUE 
AND CONTINUING THROUGH EARLY WED. IN THE SHORT TERM THOUGH...SOME 
LIGHT RAIN CONTINUES TO MOVE ACROSS THE AREA THIS AFTERNOON AIDED BY 
A PASSING WEAK SHRTWV ALOFT. ANY RAINFALL THOUGH SHOULD BE COMING TO 
AN END THIS EVENING ALTHOUGH CLOUDY CONDITIONS WILL PERSIST WITH 
LITTLE CHANGE IN TEMPS XPCTED. RAINFALL/SHOWERS WILL THEN BEGIN TO 
RETURN TO THE AREA FROM THE W AFTER MIDNIGHT AS A SECOND EMBEDDED 
SHRTWV ALOFT BEGINS TO MOVE ACROSS THE AREA. LIGHT TO MODERATE 
RAINFALL IS XPCTED TO BE ONGOING TUE MORNING WITH SFC WINDS 
INCREASING OUT OF THE SE.

WX CONDITIONS ARE XPCTED TO BE GRADUALLY DETERIORATING DURING THE 
DAY TUE AS A STRONG/DEEPENING AREA OF LOW PRESSURE OUT OF THE SW 
STATES MOVES EWD ACROSS THE CNTRL/SRN PLAINS. THE LATEST MODEL 
SUITES REMAIN CONSISTENT WITH ADVERTISING AMPLE LEVELS OF MOISTURE 
TRANSPORT STREAMING INTO THE SE REGION AHEAD OF THE SFC LOW. IN 
ADDITION...STRONG MID/UPPER LEVEL FORCING...ALONG WITH DEEP LAYER 
SHEAR AND BOUNDARY LAYER WINDS AOA 50 KTS...ARE XPCTED TO BE IN 
PLACE ACROSS THE TN AND OH VALLEYS. THIS MAY RESULT IN BOUTS OF 
LOCALLY HEAVY RAINFALL AND STRONG GUSTY WINDS ON TUE. SFC BASED 
INSTABILITY THOUGH REMAINS THE ONE FACTOR IN QUESTION...ESPECIALLY 
AS FAR N AS THE CNTRL TN VALLEY. AS OF NOW...THE LATEST GUIDANCE 
SUGGEST LITTLE IF ANY INSTABILITY IN PLACE WHICH MAY ONLY TRANSLATE 
INTO PREDOM SCATTERED EMBEDDED TSTMS TUE EVENING. GIVEN THE STRENGTH 
THOUGH OF THE SHEAR AND LOW LEVEL INFLOW...CAN NOT RULE OUT A FEW 
STRONG/MARGINALLY SEVERE TSTMS LATE TUE AFTERNOON AND EVENING WITH 
THE POTENTIAL FOR BRIEF DAMAGING WIND GUSTS. OUTSIDE OF ANY 
CONVECTIVE DEVELOPMENT...STRONG GRADIENT FLOW MAY STILL RESULT IN 
WINDS GUSTING AROUND 40 TO 45 MPH MIXING DOWN TO THE SFC. RAINFALL 
AND SFC WINDS ARE THEN XPCTED TO TAPER OFF DURING THE DAY WED AS THE 
SFC LOW RACES TOWARD THE GREAT LAKES REGION.

STRONG/COLD HIGH PRESSURE OUT OF THE NW STATES IS THEN XPCTED TO 
SETTLE INTO THE REGION ON THU. MOD POLAR AIR MASS LOOKS TO REMAIN IN 
PLACE THROUGH FRI...BEFORE SHIFTING TOWARD THE MIDDLE ATLANTIC BASIN 
ON SAT AS ANOTHER SFC WAVE OUT OF THE WRN GULF MOVES EWD ACROSS THE 
CNTRL GULF COAST REGION...WITH ISOLATED/SCATTERED SHOWERS RETURNING 
TO THE TN VALLEY. OVERALL TEMPS THU AND FRI LOOK TO RUN 5 TO 10 F 
BELOW NORMAL BEFORE WARMING CLOSER TO SEASONAL VALUES THIS WEEKEND.
&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&

$$

DISCUSSION...09
AVIATION...JE/23