Monday, August 25, 2008

Forecast discussion from Huntsville NWS

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HUNTSVILLE AL
927 AM CDT MON AUG 25 2008

.MESOSCALE UPDATE... TO ADDRESS TORNADIC MINI-SUPERCELL THREAT AND
ADJUST FOR HOURLY TRENDS BASED ON CURRENT WEATHER.
&&

.DISCUSSION...
T.D. FAY HAS NOW BEGUN TO DRIFT NORTHWARD TO JUST E OF JACKSON MS.
TORNADO OUTBREAK IS UNFOLDING IN CENTRAL AND SE AL AT THIS HOUR
WITH NUMEROUS MINI-SUPERCELL BANDS AND SEGMENTS ROTATING N-NW.
RAINFREE ZONE IN THE TN VALLEY HAS A FEW CLOUD BREAKS ALREADY
WITH SOLAR HEATING ALREADY PUSHING TEMPS CLOSE TO 80F. IF READINGS
PUNCH INTO THE L-M80S...WE SHOULD SEE ADDITIONAL...PERHAPS ISOLD
MINI-SUPERCELLS DEVELOP. REDSTONE ARSENAL'S 12Z RAOB INDICATES A
B+ OF 588 J/KG...AND 0-1KM SRH OF 115 M2/S2. THESE VALUES WILL
ONLY CLIMB RAPIDLY AS HEATING CONTINUES AND FAY TRAVELS FURTHER
N-NE TODAY . IN FACT...FORECAST RUC PROFILES BY 18Z SUGGEST 0-1KM
EHI OF 2-3 UNITS. THE SPC SLIGHT RISK HAS BEEN PUSHED NORTH TO
THE TN RIVER AS OF LAST UPDATE AS WELL. CONVERGENCE ZONE/INVERTED
TROF WILL BE ANCHORED OVER OUR AREA LATE THIS AFTERNOON AND
EVENING...WITH STRONG DEEP LAYER CONVERGENCE INDICATED. THUS...THE
FLASH FLOOD WATCH IS LOOKING VERY GOOD AT THIS POINT FOR TONIGHT.
&&

.AVIATION /FROM 12Z TAFS/...
NO CHANGES.

INITIAL RAIN BAND FROM TD FAY CONTINUES TO PUSH NORTH ACROSS CNTRL
AL. AT ITS CURRENT PACE...IT COULD REACH BOTH KHSV AND KMSL BTWN
14-16Z SHOULD IT HOLD TOGETHER. EXPECT GENERALLY -RA WITH THIS
FEATURE. CIGS HAVE BOUNCED FROM VFR TO MVFR OVERNIGHT BUT EXPECT
MVFR CONDITIONS TO WIN OUT AS MOISTURE/RAIN INCREASE FROM THE
SOUTH. AS FAY INCHES CLOSER...GREATEST POTENTIAL FOR WIDESRPEAD
RAINFALL WILL DEVELOP LATE THIS AFTN AND PERSIST THROUGH THIS
EVNG. HAVE ADDRESSED THIS WITH PREVAILING -SHRA /MVFR/ WITH OCNL
IFR CIGS AND/OR VSBY POSSIBLE WITHIN EMBEDDED HEAVIER RAIN BANDS.
TS SHOULD REMAIN MINIMAL TODAY DUE TO MOIST/GEN STABLE AIRMASS.
&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...FLASH FLOOD WATCH FROM 7 PM CDT THIS EVENING THROUGH TUESDAY
EVENING FOR THE FOLLOWING ZONES: COLBERT...CULLMAN...DE
KALB...FRANKLIN AL...JACKSON...LAUDERDALE...LAWRENCE...
LIMESTONE...MADISON...MARSHALL...MORGAN.

TN...FLASH FLOOD WATCH FROM 7 PM CDT THIS EVENING THROUGH TUESDAY
EVENING FOR THE FOLLOWING ZONES: FRANKLIN TN...LINCOLN...
MOORE.

&&

$$


UPDATE...KULA
AVIATION...DJN

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