Area Forecast Discussion
Issued by NWS Huntsville, AL

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000
FXUS64 KHUN 100003 AAA
AFDHUN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HUNTSVILLE AL
703 PM CDT WED JUL 9 2014

.UPDATE...
FOR 00Z TAFS

&&

.DISCUSSION...
/ISSUED 335 PM CDT WED JUL 9 2014/
RAIN AND CONVECTION THIS MORNING, COMBINED WITH THE LINGERING CLOUD
COVER, HAS SIGNIFICANTLY STUNTED CONVECTIVE DEVELOPMENT THIS
AFTERNOON. AS OF 19Z/2 PM CDT, THERE ARE ONLY A FEW ISOLATED/WIDELY
SCATTERED STORMS OVER SOUTHERN TENNESSEE AND NORTHWEST ALABAMA.
TEMPERATURES ACROSS THE HUN CWFA HAVE ALSO BEEN HELD TO THE LOW-MID
80S. THE DRIVING COLD FRONT AND MID-LEVEL SHORTWAVE ARE STILL NORTH
OF INTERSTATE 40 IN MIDDLE TENNESSEE.

THE HIGH-RESOLUTION WRF MODELS FROM 12Z ARE HANDLING THE ONGOING
SITUATION PRETTY WELL, AND THEY ARE STILL SOMEWHAT OPTIMISTIC ABOUT
ADDITIONAL STORM DEVELOPMENT--ALBEIT SCATTERED IN NATURE--AS THE
AFTERNOON AND EVENING WEAR ON. THE MOST RECENT HRRR IS A BIT MORE
AGGRESSIVE, DEVELOPING A CLUSTER OF STORMS THAT TRACKS ACROSS THE
AREA. WHILE THE LOW AND MID-LEVEL FORCING IS REASONABLY GOOD, LIMITED
INSTABILITY WILL LIMIT THE CONVECTION SOMEWHAT. POPS WILL BE KEPT IN
THE CHANCE/SCATTERED RANGE BASED ON THIS HIGH-RES OUTPUT. THE GFS MOS
LOOKS TOO LOW GIVEN THE CLOUD COVER AND PRECIP EXPECTED, SO THE
FORECAST WILL TREND TOWARD THE WARMER NAM.

AS NOTED ON WATER VAPOR IMAGERY, SIGNIFICANTLY DRIER AIR WILL PUSH
INTO THE AREA--AT LEAST ALOFT--FOR TOMORROW. THERE WILL NOT BE AS
MUCH DRYING NEAR THE SURFACE, SO THERE MAY BE ENOUGH MOISTURE FOR
SOME SHOWER AND STORM DEVELOPMENT TOMORROW WHEN A SECONDARY SHORTWAVE
PIVOTS ACROSS THE REGION. 12Z/09 MOS CONSENSUS HAS TRENDED DRIER
THAN PREVIOUS RUNS. IT WILL BE A LITTLE WARMER, SURFACE MOISTURE
WILL BE A LITTLE LOWER, BUT PWATS ARE EXPECTED TO BE 1.25 INCHES OR
LESS. SO A SLIGHTLY DRIER SOLUTION SEEMS REASONABLE, BUT ISOLATED-
SCATTERED SHOWERS/STORMS STILL ARE A POSSIBILITY.

DEEPER DRIER AIR (PWATS AROUND AN INCH OR LESS) WILL PUSH IN BEHIND
THIS SECONDARY SHORTWAVE, MAKING FOR A DRIER AND WARMER FRIDAY. THIS
DRY SPELL WILL NOT LAST FOR LONG, AS MOISTURE WILL QUICKLY FILTER
BACK INTO THE AREA OVER THE WEEKEND, ALLOWING FOR A FEW SHOWERS AND
STORMS TO DEVELOP MAINLY EACH AFTERNOON. HIGHS WILL BE A LITTLE
ABOVE NORMAL BUT THE GFS MOS IS THOUGHT TO BE TOO WARM AS IT HAS
BEEN RUNNING 2-3 DEGREES TOO HOT SO FAR THIS SUMMER.

THEN WE WILL DO ALL OF THIS ALL OVER AGAIN. A LARGE, DEEP LONGWAVE
TROUGH IS EXPECTED TO CARVE OUT OVER THE UPPER MIDWEST AND GREAT
LAKES, PUSHING A FRONT INTO THE TENNESSEE VALLEY LATE TUESDAY OR
EARLY WEDNESDAY. THE GFS/ECMWF INDICATE RENEWED CONVECTION, POSSIBLY
IN THE FORM OF MCSS, STARTING AS EARLY AS MONDAY NIGHT. ENSEMBLES AND
OPERATIONAL MODELS ARE IN VERY GOOD AGREEMENT ON THIS PATTERN, SO
CONFIDENCE IN THIS SCENARIO IS ABOVE AVERAGE. THEREFORE HAVE RAISED
THE POPS FOR MONDAY NIGHT THROUGH WEDNESDAY, THOUGH IT IS STILL A
LITTLE PREMATURE TO BE SPECIFIC ON TIMING OR THREATS. TEMPERATURES
SHOULD SETTLE BACK CLOSER TO NORMAL FOR MID JULY DURING THIS STRETCH.

BCC

&&

.AVIATION...
FOR 00Z TAFS...VFR CONDITIONS WILL PREVAIL THROUGH THE SHORT TERM
HOURS AT KHSV AND KMSL. SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
MOVE THROUGH KHSV IN THE NEXT HOUR OR SO. MORE REDEVELOPMENT IS
POSSIBLE THROUGH MIDNIGHT. AFTER MIDNIGHT...MVFR TO IFR CIGS AND VIS
MAY AFFECT BOTH TERMINALS. CONDITIONS WILL IMPROVE WITH THE SUNRISE.
WINDS WILL ALSO BECOME NORTHERLY BY MORNING AS A COLD FRONT PASSES
THROUGH THE AREA.

JMS

&&

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

$$

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



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