000
FXUS64 KHUN 181031 AAA
AFDHUN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HUNTSVILLE AL
531 AM CDT TUE JUN 18 2013

.UPDATE...
FLOOD WATCH CANCELLED AND RAIN CHANCES LOWERED FIRST PERIOD

&&

.DISCUSSION...
WELL A CHANGE TO THE FORECAST LOOKS TO BE NEEDED A LITTLE SOONER THAN
XPCTED NOW WITH THE INFLUX OF DRIER AIR ALONG THE APPROACHING FRONT
BECOMING MORE APPARENT ACROSS THE MID SOUTH REGION. ANY REDEVELOPMENT
ALONG THE FRONT HAS BEEN MINIMAL THUS FAR...ALTHOUGH SOME ADDITIONAL
SHOWERS/TSTMS ARE CERTAINLY POSSIBLE ONCE DAYTIME HEATING COMMENCES.
THE PROB THOUGH OF MULTIPLE AREAS/CLUSTERS OF HEAVY RAINFALL/TSTMS
DEVELOPING LATER TODAY IS DIMINISHING...ESPECIALLY WITH ANY LINGERING
UPPER DISTURBANCES TO THE NW SHOWING MORE OF A WEAKENING TREND OVER
THE PAST FEW HRS. AS SUCH...THE THREAT FOR ANY WIDESPREAD FLOODING
CONCERNS LATER TODAY LOOKS TO HAVE ENDED...AND LIKEWISE THE FLASH
FLOOD WATCH HAS BEEN CANCELLED. RAIN CHANCES HAVE ALSO BEEN LOWERED
SOME TODAY GIVEN A MORE PRONOUNCED SURGE OF DRIER AIR GRADUALLY
BEGINNING TO OVERSPREAD THE WRN HALF OF THE AREA. THE PROB THOUGH FOR
BRIEF HEAVY RAINFALL DEVELOPING WITHIN ANY ADDITIONAL SHOWERS/TSTMS
IS STILL PRESENT...ALTHOUGH THIS THREAT WILL LIKELY DIMINISH AS WELL
HEADING INTO THE LATE AFTERNOON PERIOD WITH THE FRONT SETTLING WELL
INTO THE AREA.

09

&&

.AVIATION...
/ISSUED 1232 AM CDT TUE JUN 18 2013/
FOR 06Z TAFS... BAND OF THUNDERSTORMS ENTERING NWRN AL WILL APPROACH
KMSL AND PRODUCE MVFR AND POSSIBLY IFR CONDS DUE TO +RA AND LOWERED
CIG. GUSTY WINDS REMAIN PSBL AS WELL. THE STORMS SHOULD REACH THE
KHSV VCNTY BETWEEN 10-14Z PRODUCING SIMILAR CONDITIONS. CONFIDENCE
THEN DECREASES IN THE AREAL EXTENT OF SHRA AND TSRA DURING THE DAY ON
TUESDAY. WILL INCLUDE VCTS AT BOTH SITES UNTIL THE COLD FRONT ARRIVES
DURING THE AFTN HOURS, THEN FOLLOW WITH A VCSH BEHIND THE FRONT.
CIGS SHOULD REMAIN VFR OUTSIDE RAIN AREAS DURING THE PD.

KULA

&&

.PREV DISCUSSION...
/ISSUED 420 AM CDT TUE JUN 18 2013/
LATEST BATCH OF HEAVY RAIN/TSTMS FROM SRN MID TN SWD INTO N CNTRL AL
IS MAKING A GOOD PUSH TO THE E THIS EARLY TUE MORNING...AIDED BY A
CONTINUAL SURGE IN EWD MOVING UPPER DISTURBANCES. THIS LATEST UPPER
WAVE THOUGH MAY BE THE BEGINNING OF THE END AS FAR AS THE ACTIVE/WET
WX PATTERN IMPACTING MUCH OF THE TN VALLEY OVER THE LAST 24-48 HR.
00Z GFS SOLUTION HAS THE RAINFALL DIMINISHING QUITE A BIT LATER THIS
MORNING...AS THE WEAK FRONTAL BOUNDARY STRETCHING FROM MID TN SWWD
INTO THE LOWER MS VALLEY BEGINS TO SETTLE INTO THE AREA. THE LATEST
NAM MODEL ON THE OTHER HAND IS A BIT MORE AGGRESSIVE DEVELOPING
ADDITIONAL WAVES ALOFT TRAVERSING ALONG/BEHIND THE ONCOMING FRONT.
IR/WV SAT IMAGERY THOUGH IS SHOWING SOME DRIER AIR/DVM GRADUALLY
OVERSPREADING THE MIDSOUTH REGION FROM THE WNW. IT MAY BE A BIT TOO
OPTIMISTIC TO BUY OFF COMPLETELY ON THE LATEST GFS MODEL GIVEN THE
PROB FOR SOME ADDITIONAL DEVELOPMENT LATER THIS MORNING...AS LATENT
HEATING EFFECTS/AMPLE MOISTURE DEPTH INTERACT WITH LINGERING UPPER
DISTURBANCES TO THE W. NEVERTHELESS...WILL ADVERTISE A DIMINISHING
TREND IN PRECIP THIS AFTERNOON...AS SLIGHTLY DRIER AIR ALONG/BEHIND
THE APPROACHING FRONT FILTERS INTO THE REGION FROM THE N. LATEST
ECMWF SEEMS TO OFFER A NICE COMPROMISE BETWEEN THE 00Z GFS/NAM
SUPPORTING THIS FORECAST THINKING.

IN ANY CASE...GIVEN THE AIR MASS ACROSS THE REGION REMAINING VERY
TROPICAL IN NATURE...ADDITIONAL TSTM CELLS/CLUSTERS LATER TODAY WILL
BE CAPABLE OF PRODUCING HEAVY DOWNPOURS IN A SHORT PERIOD OF TIME.
GIVEN THE UNCERTAINTY WITH THE EXACT STRENGTH/TIMING OF THE INFLUX
OF DRIER AIR AS WELL COUPLED WITH THE PROB OF LINGERING UPPER WAVES
STRENGTHENING AS THEY APPROACH FROM THE W...WILL MAINTAIN THE FLASH
FLOOD WATCH FOR THE CNTRL/WRN AREAS THROUGH THE AFTERNOON PERIOD.
HOWEVER...PROVIDED THE CURRENT FORECAST THINKING HOLDS TRUE WITH A
DIMINISHING TREND IN PRECIP COVERAGE/INTENSITY XPCTED AROUND THE
START OF THE AFTERNOON PERIOD AS THE FRONT MOVES INTO THE AREA AND
WEAKENS...THE FLOOD WATCH MAY BE CANCELLED EARLY FOR SOME/ALL AREAS.

OTHERWISE...LITTLE CHANGE WAS MADE TO THE FORECAST STARTING TONIGHT.
RAINFALL SHOULD CONTINUE TO TAPER OFF FROM THE NW THIS EVENING AS
DRIER AIR CONTINUES TO FILTER INTO THE AREA. HIGH PRESSURE BUILDING
EWD ACROSS THE GREAT LAKES/MID ATLANTIC REGIONS WED MAY ALLOW FOR A
REINFORCING SURGE OF DRIER AIR SWD INTO THE TN VALLEY AREA...WHICH
SHOULD TRANSLATE INTO RELATIVELY QUIET WX INTO FRI. THE LATTER HALF
OF THE GLOBAL MODELS ARE SHOWING A GENERAL WEAKNESS ALOFT DEVELOPING
ACROSS THE REGION BY THE START OF THE WEEKEND...ALTHOUGH THE LACK OF
ANY SIG MOISTURE RETURN/FOCUS MECH LOOKS TO KEEP ANY SHOWERS/TSTM
DEVELOPMENT IN THE ISO CAT AT BEST.

09

&&

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

$$

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