Area Forecast Discussion
Issued by NWS Huntsville, AL

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000
FXUS64 KHUN 200257
AFDHUN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
957 PM CDT TUE AUG 19 2014

.UPDATE...
EVENING UPDATE TO PUBLIC FORECAST.

&&

.DISCUSSION...
THE CURRENT SHORT TERM GRIDS ARE IN GOOD CONDITION THIS EVENING...
WITH ONLY MINOR CHANGES REQUIRED. THE PRIMARY FORECAST CONCERN FOR
THE REMAINDER OF THE NIGHT IS POTENTIAL FOR REDEVELOPMENT OF SHOWERS
AND THUNDERSTORMS ALONG THE SOUTHERN END OF A MID-LEVEL WAVE SHIFTING
SOUTHEASTWARD ACROSS ILLINOIS/INDIANA/KENTUCKY. LATEST WV/IR
SATELLITE DATA SUGGEST THAT COVERAGE OF NOCTURNAL STORMS WILL BE
GREATEST TO THE NORTH/EAST OF THE AREA...AND CLOSER TO STRONGEST
SYNOPTIC SCALE ASCENT ASSOCIATED WITH MID-LEVEL CIRCULATION CURRENTLY
OBSERVED MOVING EASTWARD ACROSS THE ILLINOIS/INDIANA BORDER. THIS...
COUPLED WITH LACK OF LOW-LEVEL CONVERGENCE AND A RATHER STRONG
INVERSION SEEN IN EVENING RAOB DATA FROM KOHX ARGUE FOR A REDUCTION
IN POPS TO THE SLIGHT CHANCE RANGE FOR MOST OF THE REGION. HOWEVER...
SLIGHTLY HIGHER POPS WILL BE RETAINED FOR SOUTHERN MIDDLE TENNESSEE
AND NORTHEAST ALABAMA...AS THIS REGION WILL BE CLOSER TO ASCENT
ASSOCIATED WITH THE MID-LEVEL WAVE. ADDITIONAL STORMS -- ASSOCIATED
WITH THE PASSING WAVE OR ANY OUTFLOW BOUNDARIES FROM NOCTURNAL
CONVECTION TO THE NORTH -- MAY DEVELOP IMMEDIATELY AFTER SUNRISE
TOMORROW AS THE AIRMASS BEGINS TO DESTABILIZE. OTHERWISE...
TEMPERATURE/DEWPOINT AND WIND GRIDS LOOK GOOD WITH NO CHANGES PLANNED
AT THIS TIME.

70/DD

&&

.AVIATION...
/ISSUED 656 PM CDT TUE AUG 19 2014/
FOR 00Z TAFS...VFR CONDS WILL PREVAIL AT THE MSL/HSV TERMINALS THRU
THE EARLY EVENING HOURS...WITH FEW LINGERING CU ARND 4 KFT BENEATH
SCT CI. THERE IS STILL UNCERTAINTY REGARDING POTENTIAL IMPACTS FROM
TSRA CURRENTLY ACROSS WRN KY. THIS ACTIVITY WILL TRACK GENERALLY
SEWD...WITH MOST OF THE CONVECTION REMAINING TO THE N/E OF THE
TERMINALS. HOWEVER...AMDS MAY BE REQUIRED TO INTRODUCE VCTS/CB --
ESPECIALLY DURING THE 20/05-09Z TIMEFRAME. REGARDLESS...CLOUDS WILL
INCREASE OVERNIGHT AS THE DISTURBANCE PASSES BY TO THE NE...WITH BKN
LAYERS OF SC/AC BTWN 3500-8000 FT. A LOWER LAYER OF STRATOCU MAY ALSO
DEVELOP ARND 1500 FT...WITH POTENTIAL FOR REDUCED VSBY IN BR ARND
SUNRISE. VFR CONDS ARE EXPECTED TOMORROW...WITH SCT HIGH-BASED CU AND
A WEST FLOW OF 5-10 KTS.

70/DD

&&

.PREV DISCUSSION...
/ISSUED 237 PM CDT TUE AUG 19 2014/
IR/VISIBLE SATELLITE ANALYSIS AT 19Z INDICATED THAT THE FORECAST AREA
WAS IN BETWEEN SHORT WAVES AT 500 MILLIBARS. AREA 88-D RADARS
INDICATED THAT THERE WERE ONLY A FEW WIDELY SCATTERED SHOWERS
DEVELOPING IN MIDDLE TENNESSEE AND INTO EAST TENNESSEE. TEMPS WERE IN
THE MID TO UPPER 80S ACROSS THE FORECAST AREA.

THE SHORT TERM MODELS ARE STILL IN GOOD AGREEMENT TONIGHT THAT
ANOTHER 500 MILLIBAR SHORT WAVE WILL MOVE SOUTHEAST OUT OF SOUTH
CENTRAL KENTUCKY INTO EAST TENNESSEE BY 12Z WEDNESDAY. THERE IS THE
POSSIBILITY THAT A FEW SCATTERED SHOWERS/STORMS WILL DEVELOP ALONG
THE SOUTHERN EDGE OF THE VORT MAX AS IT TRACKS EAST OF THE FORECAST
AREA. WILL CONTINUE WITH LOW CHANCE POPS FOR THE FORECAST AREA FOR
ESPECIALLY AFTER MIDNIGHT.

WILL CONTINUE WITH A SLIGHT CHANCE OF SHRA/TSRA FOR WEDNESDAY AS
ANOTHER WEAK VORT MAX IS EXPECTED TO DROP SOUTHEAST IN THE SLIGHT
NORTHWEST FLOW THROUGH SOUTHERN MIDDLE TENNESSEE AND INTO MAINLY
NORTHEAST ALABAMA. WILL TREND TOWARD THE SLIGHTLY COOLER NAM TEMPS
FOR AFTERNOON HIGHS.

BY THURSDAY...A STRONG UPPER LEVEL RIDGE OF HIGH PRESSURE WILL
CONTINUE TO BUILD EAST INTO THE TENNESSEE VALLEY REGION. MODEL
SOUNDINGS ARE INDICATIVE OF A STRONGER CAP WITH TIME AND WILL KEEP
OUT THE MENTION OF ANY PRECIP THROUGH THE UPCOMING WEEKEND AND
MONDAY. WILL TREND CLOSER TO MODEL GUIDANCE THROUGH THE LATTER PART
OF THIS WEEK...WEEKEND AND THROUGH THE REST OF THE EXTENDED FORECAST
PERIODS. HAVE BUMPED UP TEMPS SLIGHTLY TO CORRESPOND TO EXPECTED
HOT TEMPS AND EXPECT THAT HIGH PRESSURE RIDGE WILL HOLD OVER THE AREA
INTO MONDAY.

BY BETWEEN MONDAY AND TUESDAY...THE MODELS INDICATE THAT THE EASTERN
SECTION OF THE PERSISTENT UPPER RIDGE WILL FINALLY RETROGRADE JUST
ENOUGH ON TUESDAY THAT THERE COULD BE A LITTLE MORE INSTABILITY...LESS
OF A MID LEVEL CAP...WHICH COULD AID IN THE DEVELOPMENT OF A FEW
THUNDERSTORMS. HAVE ADDED IN A SLIGHT CHANCE OF SHOWERS/STORMS BY
TUESDAY AFTERNOON. WILL KEEP TEMPS HOT THROUGH THE EXTENDED FORECAST
..BUT WILL BACK OFF ON HIGHS ON TUESDAY DUE TO MORE CLOUDS POSSIBLE
AND A SLIGHTLY WESTWARD MOVEMENT OF THE RIDGE.

TT

&&

.HUN WATCHES/WARNINGS/ADVISORIES...

AL...NONE.

TN...NONE.

&&

$$

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


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