010
FXUS64 KHUN 240008
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
708 PM CDT WED JUL 23 2008
UPDATE
CDFNT LOOKS TO BE ALONG THE AL/TN BORDER AT 7 PM. SKIES
HAVE CLEARED OUT/PCPN MOVED SOUTH OF THE CWA...AS DRIER/MORE
STABLE AIR BEGINS TO MOVE INTO THE CWA. WILL UPDATE ZONES TO
REMOVE MENTION OF PCPN AND EVENING WORDING. COULD SEE SOME PATCHY
FOG OVERNIGHT BUT WITH NORTH WINDS ARND 5 MPH AND LOWER DEWPOINTS
PROGGED TO MOVE ACROSS THE TN VALLEY...NOT EXPECTING WIDESPREAD/DENSE
FOG...SO WILL NOT MENTION IN ZONES FOR NOW.
ALREADY SENT UPDATED GRIDS AND WILL SEND ZONES OUT BY 730 PM.
AVIATION
MVFR CONDITIONS MAY BE POSSIBLE FOR PATCHY FOG
BETWEEN 10Z AND 14Z...OTHERWISE EXPECT VFR CONDITIONS FOR THE
REMAINDER OF THE TAF FCST.
PREV DISCUSSION... /ISSUED 355 PM CDT WED JUL 23 2008/
MESOSCALE UPDATE...
SEVERAL CLUSTERS OF PULSE THUNDERSTORMS CONTINUE ACROSS THE HUN CWFA
THIS AFTN. THE GOOD NEWS IS THAT AIR TEMPS ARE NOWHERE NEAR WHAT
THEY WERE YESTERDAY /MID-UPPER 80S VS. MID-UPPER 90S/ SO LOW-LEVEL
INSTABILITY HAS NOT BEEN SUFFICIENT FOR THE MICROBURST/WIND DAMAGE
SEEN MORE OFTEN YESTERDAY. IN TERMS OF RADAR...ENHANCED ELEVATED
CORES HAVE BEEN QUITE FLEETING AND HAVE BEEN PRECEDED BY A JUMP IN
THE NASA-LMA FLASH RATES...AND ONLY 1-2 STORMS HAVE DISPLAYED ANY
INTERESTING VELOCITY SIGNATURES. THE STORMS ARE NOW CONGEALING INTO
A LINE ALONG AND WEST OF THE HSV METRO AREA...AND THIS LIKELY
REFLECTS THE SFC COLD FRONT SINCE DEWPOINTS IN MID TN DROP QUICKLY
INTO THE LOW-MID 60S.
STORMS THUS FAR HAVE NOT BEEN DISPLAYING ANY TRENDS UPWARD OR
DOWNWARD...SO SCATTERED SPS-CRITERIA STORMS SEEM LIKELY TO CONTINUE
FOR THE NEXT HOUR OR TWO.
DISCUSSION...ISSUED 310 PM CDT WED JUL 23 2008...
ANALYSIS WISE...A COLD FRONT AS OF 3 PM EXTENDED FROM ALONG THE
MO/AR BORDER TO SOUTH OF NASHVILLE TO WESTERN VA. EARLIER PRE-
FRONTAL STRATUS DEVELOPMENT SOUTH OF THE FRONT DEFINITELY PUT A
DAMPER ON HIGH TEMPERATURES ACROSS THE TENNESSEE VALLEY COMPARED TO
THE PAST FEW DAYS. TEMPS THUS FAR RANGED FROM 86 AT FT PAYNE TO 88
AT VINEMONT. DESPITE THE COOLER TEMPS...LIFT PROVIDED BY THE
APPROACH OF THE COLD FRONT...EXISTING INSTABILITY AND PLENTY OF
MOISTURE HAS ALLOWED MORE SHOWERS AND T-STORMS TO RE-DEVELOP ACROSS
THE AREA. SOME OF THE STORMS HAVE BEEN SEVERE WITH THE PRIMARY
THREAT DAMAGING WINDS.
A BIGGER SCALE VIEW AT 500MB NOTED UPPER RIDGING EXTENDING NORTHWARD
FROM WEST TEXAS TO THE NORTHERN PLAINS...WITH A DEEP LOW MOVING OVER
SOUTHERN QUEBEC. HURRICANE DOLLY AS OF THIS WRITING WAS MAKING
LANDFALL OVER SOUTH PADRE ISLAND OF DEEP SOUTH TEXAS. A QUICK LOOK
AT SHORT AND LONG TERM GUIDANCE SUGGESTS THAT MOISTURE ASSOCIATED
WITH DOLLY WILL HAVE NO DIRECT AFFECT ON THE WEATHER LOCALLY.
HOWEVER...SOME THE MOISTURE FROM ITS REMAINS DRIFTING INTO THE
WESTERLIES COULD REACH THIS AREA IN A WEEK OR SO.
FOR THIS EVENING...A COLD FRONT IS SET TO MAKE A MOVE ACROSS THE
TENNESSEE VALLEY...WITH MORE SHOWERS AND T-STORMS FOR THE VERY SHORT
TERM INTO THE EVENING. SCATTERED CONVECTION THIS EVENING WILL END
FROM NORTH TO SOUTH AS THE COLD FRONT MOVES SOUTHWARD. CLOUDS ALSO
SHOULD DECREASE WITH MOSTLY CLEAR TO PARTLY CLOUDY SKIES BY THURSDAY
MORNING.
THURSDAY SHOULD BE A DRY AND MORE COMFORTABLE DAY...WITH HIGH TEMPS
IN NEAR SEASONABLE/AVERAGE READINGS AROUND 90. WILL CONTINUE THE DRY
TREND FOR THURSDAY NIGHT BY REMOVING ISOLATED CONVECTION MENTION.
HOWEVER SHOWERS AND T-STORMS RETURN ON FRIDAY AS A SOUTHERN FLOW
RETURNS WITH MORE MOISTURE AND INSTABILITY. FOLLOWED THE WETTER GFS
SOLUTION HERE...WITH THE NAM AND ITS MOS GUIDANCE FRIDAY AFTERNOON
STAYING DRY.
MORE OF A SUMMER TYPE PATTERN RETURNS FOR THE WEEKEND INTO THE
MIDDLE OF NEXT WEEK. PRESENT HEAT...MOISTURE AND AVAILABLE LIFT
TOGETHER WILL BE SUFFICIENT TO KEEP SOME CHANCES FOR SHOWERS AND
T-STORMS IN THE FORECAST. HIGH/LOW TEMPERATURES WILL AVERAGE AROUND
TO A TAD ABOVE SEASONABLE NORMS.
HUN WATCHES/WARNINGS/ADVISORIES
AL...NONE.
TN...NONE.
SS
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