000
FXUS64 KHUN 160532 AAC
AFDHUN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1232 AM CDT THU MAY 16 2013

.UPDATE...
FOR 06Z TAFS

&&

.DISCUSSION...
/ISSUED 909 PM CDT WED MAY 15 2013/
WHILE THE MAIN WEATHER STORY THIS EVENING ACROSS THE CONUS REMAINS
WITH THE CONVECTION ACROSS THE SOUTHERN PLAINS...THE TENNESSEE VALLEY
FORECAST FOR TONIGHT REMAINS PREDOMINANTLY A TEMPERATURE FORECAST.
CLOUD COVER WILL CONTINUE TO INCREASE AHEAD OF THIS NEXT
SYSTEM...SLOWING THE DIURNAL DROP IN TEMPERATURES ACROSS THE FORECAST
AREA.

HIGHS THIS AFTERNOON TOPPED OUT IN THE LOWER TO MID 80S...NEAR OR
JUST A COUPLE OF DEGREES WARMER THAN VALUES SEEN YESTERDAY. BY
8PM...CONDITIONS HAD COOLED SIGNIFICANTLY THOUGH...WITH KMSL THE
WARMEST SITE AT 74 DEGREES WHILE CLEARER SKIES OVER NE AL HAVE
ALLOWED FT PAYNE AND CULLMAN TO DROP INTO THE 60S. THIS IS SIMILAR TO
TEMPS SEEN AT THE SAME TIME LAST NIGHT THOUGH. A BROAD SWATH OF
MID/UPPER LEVEL MOISTURE AHEAD OF THE MID LEVEL WAVE IS PRODUCING THE
CLOUD COVER SEEN ON REGIONAL SATELLITE (HANDLED WELL BY THE GFS
ISENTROPIC OUTPUT AT THE 325K LVL...ARND 450MB/20KFT...AND ALSO AT
LOWER LEVELS) AND THIS WILL CONTINUE TO TRACK NE OVERNIGHT. THESE
CLOUDS SHOULD CONTINUE TO SLOW THE COOLING TREND ACROSS THE CWA BUT
LEAVE A W-E GRADIENT IN LOWS SIMILAR TO THAT SEEN LAST NIGHT. COOLEST
TEMPS SEEN EARLY THIS MORNING RANGED FROM 65 (KMSL) - 59 (KHSV) - 50
(4A9) SO HAVE INCREASED THE GOING FORECAST IN CENTRAL/WESTERN
PORTIONS OF THE CWA TO REMAIN CLOSE TO LOWS FROM LAST NIGHT. HAVE
KEPT THE FCST OF THE MID 50S IN NE AL SINCE MORE CLOUDS TONIGHT
SHOULD PREVENT THE SAME DROP.

THE ONLY OTHER CHANGE MADE TO THE GOING FORECAST WAS TO INCREASE THE
DEWPOINTS THROUGH THE OVERNIGHT PERIOD. CURRENT VALUES ARE IN THE
MID/UPPER 50S AND WEAK MOISTURE ADVECTION FROM LOCATIONS TO OUR SW
(WHERE TD VALUES ARE IN THE UPPER 50S/LOWER 60S) COMBINED WITH THE
REDUCED MIXING SHOULD KEEP TDS IN THE 50S THROUGH THE MORNING. EVEN
WITH THIS REMAINING MOISTURE...THE VIRGA SEEN ON REGIONAL RADAR
MOSAIC OVER N/CENTRAL MS WILL BE BATTLING WITH A RELATIVELY DRIER
NEAR SFC LAYER AS IT APPROACHES THE TN VALLEY. THIS SHOULD LEAD TO
ANY PRECIP HOLDING OFF UNTIL LATER IN THE MORNING TOMORROW...AT THE
EARLIEST.

CCC

&&

.AVIATION...
FOR 06Z TAFS...EVEN AS MORE HIGH/MID LVL CLOUDS CONTINUE TO STREAM
ACROSS THE TERMINALS THRU TOMORROW...VFR CONDITIONS ARE EXPECTED TO
PERSIST THRU THE PERIOD. SCT/ISOL -RA MAY ALSO DEVELOP ACROSS AL/TN
BTWN 14-18Z BUT SHOULD NOT IMPACT FLT CATEGORIES. AS THE SYSTEM TO
OUR W PUSHES CLOSER LATE IN THE PERIOD...CIGS SHOULD START TO DROP
BUT CAT DROPS ARE EXPECTED TO HOLD OFF UNTIL AFTER 06Z TOMORROW.

CCC

&&

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

$$

FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE
AT WEATHER.GOV/HUNTSVILLE.