190
FXUS64 KHUN 272329 AAA
AFDHUN
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HUNTSVILLE AL
530 PM CST FRI NOV 27 2009
UPDATE
FOR 00Z AVIATION DISCUSSION.
AVIATION
VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD.
DISCUSSION
/ISSUED AT 255 PM CST FRI NOV 27 2009/
BEAUTIFUL LATE FALL WEATHER CONTINUES ACROSS THE REGION FOR THE DAY
AFTER THANKSGIVING 2009. THE SHARP TROUGH FROM YESTERDAY QUICKLY
EXITED THE REGION AND HAS NOW CLOSED OFF OVER THE MID-ATLANTIC...
LEAVING BEHIND DRY NWLY FLOW AND SFC HIGH PRESSURE. DESPITE A VERY
COOL START /INCLUDING THE FIRST FREEZE FOR PARTS OF THE CWFA/...
TEMPS HAVE WARMED NICELY UNDER FULL SUNSHINE...INTO THE LOW/MID 50S.
FCST THRU THE NEXT 36 HRS OR SO REMAINS FOCUSED ON TEMPERATURES. THE
SFC HIGH CENTERED OVER LA WILL GRADUALLY SHIFT NEWD OVERNIGHT...
LIKELY ALLOWING FOR FULL RADIATIONAL COOLING. GIVEN CURRENT DEWPTS
AND MOS PROGGED TEMPS IN THE LOWER 30S...THIS LIKELY MEANS ANOTHER
SOLID IF NOT HARD FREEZE FOR MOST OF THE AREA...AND HAVE UNDERCUT
MOS BY 2-4 DEGREES. SINCE THE ENTIRE AREA EXPERIENCED FREEZING
CONDITIONS THIS MORNING...A FREEZE WARNING IS NO LONGER NEEDED.
TEMPERATURES WILL REBOUND NICELY SATURDAY AS WEAK WARM AIR ADVECTION
/WAA/ SETS UP ON THE BACK SIDE OF THE SFC HIGH. WHILE WAA LOOKS TOO
WEAK TO ADD MUCH TO MOS CONSENSUS...BOTH THE NAM AND GFS MOS HAVE
BEEN CONSISTENTLY TOO COOL LATELY. WILL TREND A BIT WARMER...LEAVING
MOST SPOTS IN THE MID 60S. THE LOW-LVL PATTERN WILL BE FAVORABLE FOR
DEVELOPMENT OF A STRONG INVERSION SATURDAY NIGHT...PSBLY RESULTING
IN A 10+ DEGREE GRADIENT BTWN RIDGETOP AND VALLEY IN NERN AL.
EXTENDED FCST REMAINS FAIRLY CONSISTENT...WITH A VERY PROGRESSIVE
TROUGH IMPACTING THE REGION LATE SUNDAY-EARLY TUESDAY...THEN A MUCH
SLOWER CUTOFF LOW MOVING ACROSS THE SERN CONUS WEDNESDAY-THURSDAY.
TIMING HAS SHIFTED SLIGHTLY EARLIER FOR BOTH ONSET AND EXIT...BUT
SUNDAY NIGHT-EARLY MONDAY STILL LOOK LIKE THE BEST CHANCE OF RAIN
FOR THE 1ST SYSTEM. AREAS TO THE N/W MAY HAVE A BETTER CHANCE OF
RAIN SINCE MOISTURE TRANSPORT SEEMS TO BE MAXIMIZED BEFORE THE FRONT
PUSHES THROUGH THE AREA...BUT REMAIN CONFIDENT IN MEASURABLE PCPN
FOR MOST IF NOT ALL OF THE CWFA. PREFRONTAL TEMPS MAY REACH INTO THE
MID 60S ONCE AGAIN SUNDAY /THOUGH CLOUDS MAY LIMIT THOSE HIGHS/...
BUT TEMPS SHOULD COOL BELOW NORMAL ONCE THE FRONT COMES THROUGH.
GFSX AND ENSEMBLE MEAN MOS HAS A GOOD HANDLE ON THIS.
MORE UNCERTAINTY EXISTS FOR THE MID-WEEK SYSTEM AS MODELS/ENSEMBLE
MEMBERS CONTINUE TO SHOW GREATER SPREAD IN THE TRACK AND INTENSITY
OF THE LOW. THE ECMWF HAS BEEN A BIT MORE CONSISTENT BUT INDICATES A
TYPICAL WET BIAS. HAVE KEPT A SLIGHTLY SLOWER PROGRESSION WITH THE
FCST POPS BUT FEEL THINGS SHOULD DRY OUT THURSDAY. NORTHERLY FLOW ON
THE BACK SIDE OF THE LOW WILL KEEP TEMPERATURES BELOW NORMAL THROUGH
THIS PART OF THE FCST. CLOUDS/RAIN MAY MEAN THAT THE GFSX/ENSEMBLE
MEAN TEMPS ARE TOO HIGH...BUT HAVE STUCK WITH THEM FOR NOW.
HUN WATCHES/WARNINGS/ADVISORIES
AL...NONE.
TN...NONE.
DISCUSSION...BCC
AVIATION...JLL
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