Area Forecast Discussion
Issued by NWS Huntsville, AL

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000
FXUS64 KHUN 231555 AAB
AFDHUN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1055 AM CDT SAT AUG 23 2014

.UPDATE...
INTRODUCED ISOLATED THUNDER FOR THE AFTERNOON/EARLY EVENING FOR
OUR CENTRAL/WESTERN AREA. MINOR ADJUSTMENTS TO CLOUD COVER...
HIGH TEMPERATURES AND DEWPOINTS.

&&

.DISCUSSION...
SUMMER HEAT DEFINITELY IS IN FULL SWING ACROSS THE TENNESSEE VALLEY
THIS MORNING...AS UPPER LEVEL RIDGING REMAINS IN PLACE ACROSS THE
SOUTHERN STATES. THE UPPER HIGH FROM A 500MB PERSPECTIVE WAS
SITUATED OVER THE AR/LA/MS REGION WITH MAX HEIGHTS IN THE 592/593
DECAMETER RANGE. THIS ALONG WITH A STRONG AUGUST SUN...WILL BRING
VERY WARM TO HOT HIGH TEMPERATURES ACROSS THE REGION THIS AFTERNOON.
THIS HEAT...ALONG WITH DEWPOINT VALUES IN LOWER 70S WILL PUSH HEAT
INDICES UP TO AROUND 105 DEGREES FOR MUCH OF THE AREA THIS
AFTERNOON. GIVEN THAT IT IS A SUNNY DAY WITH MANY FOLKS OUTDOORS...A
RISK FOR HEAT RELATED ILLNESSES REMAIN ELEVATED. THE NEW NAM WAS
PRONOUNCEDLY COOLER THAN ITS 00Z RUN...SHOWING HIGHS IN THE UPPER
80S/LOW 90S...WHILE THE LAMP/GFS/ECMWF MAINTAINED MID 90S. SO
ERRING ON THE SIDE OF CAUTION...WILL LEAN TOWARD THE HOTTER
NUMBERS...AND KEEP THE HEAT ADVISORY IN PLACE FOR NOW.

ANOTHER CHALLENGE THIS AFTERNOON ARE SLIM CHANCES OF CONVECTION.
LATE NIGHT SHOWER/T-STORM ACTIVITY TO OUR NORTH HAS SENT AN OUTFLOW
BOUNDARY SOUTHWARD ACROSS NORTHERN ALABAMA THIS MORNING. THIS
FEATURE...DESPITE WARM MID LEVEL TEMPERATURES...COULD PROVIDE A FOCI
FOR ISOLATED CONVECTION FORMATION FURTHER TO THE SOUTH AND WEST
THIS AFTERNOON. THE SLIGHT CHANCE WE ALREADY HAVE GOING FOR OUR NE
AREA (SOUTHERN MIDDLE TENNESSEE AND NE ALABAMA) LOOK GOOD. UPDATES
FOR THE REST OF TODAY HAVE BEEN SENT.

RSB

&&

.AVIATION...
/ISSUED 637 AM CDT SAT AUG 23 2014/
FOR 12Z TAFS...ONCE MORNING MVFR FOG LIFTS AT KMSL...VFR CONDITIONS
WILL PREVAIL AT KHSV AND KMSL THROUGH THE TAF PERIOD. BEST CHANCE OF
AFTERNOON SHOWERS/THUNDERSTORMS WILL BE IN THE KHSV AREA AND EAST BUT
ALSO INCLUDED IT IN THE KMSL TAF. FOG DOES NOT LOOK AS PROMINENT FOR
TOMORROW NIGHT SO LEFT IT OUT OF THIS TAF ISSUANCE.

JMS

&&

.PREV DISCUSSION...
/ISSUED 354 AM CDT SAT AUG 23 2014/
WENT WITH A BLEND OF NAM AND GFS FOR THIS FCST PACKAGE.

AN UPPER RIDGE WAS CENTERED OVER THE SRN MS RIVER VALLEY WITH A
LARGE MCS OVER THE NRN PLAINS AND A WEAK DISTURBANCE MOVING ACROSS
WRN KY. TEMPS ARND THE TN VALLEY WERE IN THE LOW/MID 70S WITH
DEWPOINTS ARND 70. ALSO PATCHY FOG WAS BEGINNING TO FORM IN A FEW
LOCATIONS...NOT EXPECTING ANY WIDESPREAD DENSE FOG THIS MRNG.

TEMPS TODAY WILL AGAIN BE IN THE MID 90S WITH A FEW LOCATIONS REACHING
THE UPPER 90S. HEAT ADVISORY CRITERIA MAY BE MARGINAL TODAY BUT
SINCE IT IS THE WEEKEND AND THIS IS A FAIRLY LONG STRETCH OF MID 90S
TEMPS...WILL KEEP THE ADVISORY GOING FOR NOW. ANYWAY YOU CUT IT...IT
WILL BE A HOT/HUMID DAY. WILL KEEP A LOW POP ACROSS OUR NERN ZONES
THIS AFTN/EVENING DUE TO THE WEAK DISTURBANCE OVER KY MOVING SE ON
THE EAST SIDE OF THE UPPER RIDGE.

BY SUNDAY...WITH EASTERLY LOW LEVEL FLOW DUE TO A BACKDOOR TYPE OF
CDFNT...SHOULD SEE A LITTLE MORE COVERAGE OF SHRA/TSRA ACROSS THE
CWA. IF GFS IS CORRECT IT LOOKS LIKE THE BEST CHC OF PCPN WILL BE
SUNDAY NIGHT AND INTO MONDAY MRNG. AS A DRIER/STABLE AIRMASS
CONTINUES TO MOVE ACROSS THE CWA ON MONDAY...THE PCPN WILL TAPER OFF
BY THE AFTN. MONDAY NIGHT SHOULD BE DRY.

TUESDAY/WEDNESDAY...EXPECT DRY AND LESS HUMID WX CONDITIONS DURING
THIS TIMEFRAME...WITH TEMPS NEAR NORMAL VALUES. ALSO GFS SHOWS A
POSSIBLE TROPICAL SYSTEM MOVING ALONG THE EAST COAST THAT SHOULD NOT
HAVE ANY AFFECT ON OUR WX ACROSS THE TN VALLEY. STAY TUNED.

THURSDAY/FRIDAY...GFS SHOWS A CDFNT ENTERING NW AL BY THURSDAY AFTN
AND OUT OF THE CWA BY FRIDAY AFTN. WHILE ECMWF KEEPS THE CDFNT OVER
THE MIDWEST DURING THIS TIMEFRAME. IF GFS IS ON THE MONEY...NEXT
WEEKEND IS SHAPING UP TO BE NICE ONE...WITH NO PCPN AND TEMPS IN THE
80S/LOWS IN THE 60S. WE WILL SEE.

07

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...HEAT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR ALZ001>010-016.

TN...HEAT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR TNZ076-096-097.

&&

$$

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


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