Excessive Heat and Heat in Alabama, July 14, 2015

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1053 AM CDT TUE JUL 14 2015

.UPDATE...TO TWEAK POP AND HIGH TEMPERATURES.

&&

.DISCUSSION...
MOSTLY CLOUDY CONDITIONS HAVE ALREADY DEVELOPED OVER MOST OF OUR
SOUTHERN MIDDLE TENNESSEE COUNTIES AND PORTIONS OF MADISON AND
JACKSON COUNTIES. THE CURRENT RUN OF THE NAM12 HAS A GOOD HANDLE ON
THIS CLOUD COVER...WHICH IS MOSTLY AN AREA OF THICKER HIGH CLOUDS.
BASED ON GUIDANCE FROM NAM12 AND CURRENT UPPER LEVEL FLOW...BELIEVE
THESE MOSTLY CLOUDY CONDITIONS WILL REMAIN IN PLACE ACROSS SOUTHERN
MIDDLE TN...JACKSON...MOST OF MADISON...AND NORTHERN LIMESTONE
COUNTIES THROUGH MUCH OF THE DAY. FURTHER SOUTH...INCLUDING THE
CITIES OF MADISON AND DECATUR...SKIES WILL REMAIN PARTLY CLOUDY UNTIL
AROUND 4 PM. THIS WILL ALLOW TEMPERATURES IN THOSE AREAS TO REACH THE
MID TO UPPER 90S...WITH DEWPOINTS REMAINING IN THE LOWER 70S. THIS
WILL KEEP OUR CURRENT HEAT ADVISORY IN PLACE AS HEAT INDEX VALUES
BEFORE 4 PM CLIMB TO BETWEEN 106 TO 110 DEGREES. ALTHOUGH IT MIGHT
BE ABLE TO BE EXPIRED A BIT EARLY DEPENDING ON CONVECTIVE
ACTIVITY/CLOUD COVER.

THE AREA OF HIGH PRESSURE THAT HAS BEEN IN CONTROL OF OUR WEATHER
OVER NORTHERN ALABAMA THE PAST FEW DAYS HAS SHIFTED FURTHER SOUTHEAST
INTO THE EASTERN GULF OF MEXICO THIS MORNING.

12Z UPPER AIR ANALYSIS SHOWS TWO MAIN BOUNDARIES IN PLACE AT THIS
TIME. ONE EXTENDS WEST SOUTHWEST FROM THE DECAYING MCS OVER EASTERN
TENNESSEE. THE OTHER IS OVER NW INDIANA AND SOUTHERN ILLINOIS. THE
LATTER WILL AFFECT THE AREA LATE THIS EVENING INTO THE OVERNIGHT
HOURS.

HOWEVER...THE BOUNDARY FURTHER SOUTH ACROSS SOUTHERN TN WILL BE THE
FOCUS FOR SHOWER AND THUNDERSTORM ACTIVITY...MAINLY LATE THIS
AFTERNOON INTO THE EARLY EVENING HOURS. ALTHOUGH ISOLATED STORMS
COULD FIRE AS EARLY AS 1 TO 3 PM IN SOUTHERN MIDDLE TENNESSEE.

EXPECT COVERAGE TO INCREASE...AND BECOME PREDOMINATELY SCATTERED
BETWEEN 4 AND 7 PM FOR MOST LOCATIONS NORTH OF THE TENNESSEE RIVER.
FURTHER SOUTH ACROSS CULLMAN COUNTY...SCATTERED ACTIVITY MAY NOT MAKE
IT IN UNTIL AROUND 7 PM. 30 TO 40 KTS OF WINDS AT 500 MB COUPLED
WITH DRY AIR ALOFT AND VERY STRONG INSTABILITY...WOULD BE SUPPORTIVE
OF STRONG TO SEVERE THUNDERSTORM DEVELOPMENT...CAPABLE OF PRODUCING
DAMAGING WINDS. ALSO STRONGER STORMS WILL BE CAPABLE OF PRODUCING
VERY HEAVY RAINFALL RATES...WITH PW VALUES FORECAST TO CLIMB TO 2.25
INCHES AT 7 PM. THEREFORE...FLASH FLOODING WILL BE A
CONCERN...ESPECIALLY WITH THE ORIENTATION OF THE BOUNDARY REMAINING
WEST TO EAST...DESPITE FAIRLY QUICK MOVEMENT OF STORMS THE EAST. KEPT
ONLY SCATTERED POP IN THE FORECAST THIS AFTERNOON...DUE TO THE WEAK
NATURE OF THE CONVERGENCE BOUNDARY IN PLACE ACTING AS A TRIGGER.

KTW

&&

.AVIATION...
/ISSUED 617 AM CDT TUE JUL 14 2015/
FOR 12Z TAFS...UPPER FLOW ACROSS THE TN VALLEY WILL CONTINUE THRU
WEDNESDAY. THIS MAY ALLOW A MCS TO APPROACH THE CWA BY THIS
AFTN/EVENING. ATTM THERE IS STILL UNCERTAINTY WITH TIMING AND
COVERAGE OF SHRA/TSRA. FOR NOW WILL GO WITH VCTS WORDING BETWEEN 22Z
AND 03Z FOR BOTH TAFS. THERE MAY BE ANOTHER ROUND OF PCPN BY
10Z AS A WEAK CDFNT APPROACHES THE CWA. WILL GO WITH VCSH WORDING
SINCE INSTABILITIES SHOULD BE WEAK AT THAT TIME. OTHERWISE MAINLY VFR
CONDITIONS ARE EXPECTED THRU THE FCST PERIOD...EXCEPT MVFR IN ANY
STRONG TSRA.

07

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ALZ001>007-016.

TN...NONE.
&&

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HUNTSVILLE AL
419 AM CDT TUE JUL 14 2015

ALZ001>010-016-TNZ076-096-097-141900-
LAUDERDALE-COLBERT-FRANKLIN AL-LAWRENCE-LIMESTONE-MADISON-MORGAN-
MARSHALL-JACKSON-DEKALB-CULLMAN-MOORE-LINCOLN-FRANKLIN TN-
419 AM CDT TUE JUL 14 2015

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH ALABAMA AND PORTIONS
OF SOUTHERN MIDDLE TENNESSEE.

.DAY ONE...TODAY AND TONIGHT...

A HEAT ADVISORY REMAINS IN EFFECT THROUGH 7 PM CDT TODAY FOR
PORTIONS OF NORTHWESTERN AND NORTH CENTRAL ALABAMA. HEAT INDICES ARE
LIKELY TO EXCEED 105 DEGREES THIS AFTERNOON ESPECIALLY WEST OF
INTERSTATE 65.

THUNDERSTORMS ARE EXPECTED TO DEVELOP BY THE AFTERNOON AND CONTINUE
INTO THE EVENING. SOME STORMS COULD BE STRONG TO SEVERE WITH DAMAGING
WIND GUSTS AS THE MAIN SEVERE WEATHER THREAT. LOCALLY VERY HEAVY
RAINFALL WITH FLASH FLOODING AND HAIL UP TO THE SIZE QUARTERS MAY
ALSO BE POSSIBLE. THE SEVERE WEATHER THREAT WILL BEGIN TO TAPER OFF
AFTER MIDNIGHT.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY...

A FEW THUNDERSTORM WILL BE POSSIBLE ON WEDNESDAY MORNING AND AFTERNOON
BUT NO SEVERE WEATHER IS EXPECTED. AFTER WEDNESDAY...ISOLATED TO
SCATTERED THUNDERSTORMS MAINLY DURING THE AFTERNOON AND EVENING WILL
CONTINUE THROUGH MONDAY. THE STRONGER STORMS DURING THIS PERIOD WILL
BE CAPABLE OF PRODUCING STRONG WIND GUSTS BUT THE THREAT FOR
WIDESPREAD SEVERE WEATHER WILL BE LOW.

OTHERWISE...TEMPERATURES WILL CONTINUE TO BE HOT THROUGH THE PERIOD
WITH HEAT INDICES GENERALLY AROUND 100 TO 105 DEGREES DURING THE
AFTERNOON EACH DAY. ADDITIONAL HEAT ADVISORIES MAY BE NECESSARY LATER
IN THE WEEK.

.SPOTTER CALL TO ACTION STATEMENT...

ACTIVATION OF STORM SPOTTERS AND EMERGENCY MANAGEMENT PERSONNEL MAY
BE POSSIBLE THIS AFTERNOON AND EVENING.