Severe Thunderstorm Warning 445, NWS Jackson, MS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
314 PM CDT FRI AUG 13 2010

...EXCESSIVE HEAT TO CONTINUE IN THE DELTA INTO THE WEEKEND...AND
EXPAND OVER MUCH OF THE AREA BY SUNDAY...

.SHORT TERM...COMPLEX FORECAST SCENARIO THIS AFTERNOON WITH MULTIPLE
WEATHER HAZARDS TO CONTEND WITH. FIRST OFF AS EXPECTED MORNING
CONVECTIVE BAND FROM N OF JAN TO N OF HEZ HAS DISSIPATED...WITH NEW
CONVECTION FIRING IN A RING ON THE DIFFERENTIAL HEATING BOUNDARY
SURROUNDING IT. A FEW POTENT STORMS HAVE BEEN OBSERVED DUE TO THE
DECENT INSTABILITY AND EXCESSIVE MOISTURE WITH PW VALUES OVER 2.5
INCHES AREAWIDE. COULD HAVE A FEW SVR AND FLASH FLOOD REPORTS INTO
THE EVENING...BUT EXPECT THIS ACTIVITY TO GRADUALLY DIMINISH WITH
LOSS OF DAYTIME HEATING. HOWEVER...GIVEN THE TROPICAL MOISTURE OVER
THE AREA AND THE PROXIMITY OF THE CIRCULATION ASSOCIATED WITH OLD TD
5...EXPECT THAT ACTIVITY COULD REDEVELOP AGAIN TOWARD MORNING AS IS
COMMON WITH THESE TROPICAL SYSTEMS. MOST LIKELY AREA FOR
REDEVELOPMENT WOULD BE ALONG AND SE OF NATCHEZ TRACE CORRIDOR CLOSER
TO THE REMNANT CIRCULATION AND IN AN AREA OF MID/UPPER LEVEL FORCING
AS SHOWN BY WEAK 500-300 MB Q-VECTOR CONVERGENCE. WENT WITH A BLEND
OF MAV/MET FOR POPS AND TEMPS TONIGHT.

FOR SATURDAY...MODELS AGREE ON TD 5 CIRCULATION CONTINUING TO LIFT
SLOWLY ENE ACROSS AL...WITH SOME SUBSIDENCE AND DRYING OF DEEP
MOISTURE MOVING IN TO NW SECTIONS OF FORECAST AREA. EXPECT TO SEE
BANDS OF SHRA/TSRA BUILD TO THE W OF THE REMNANT CIRCULATION SIMILAR
TO TODAY...WITH GREATEST COVERAGE ACROSS EASTERN AREAS. WILL CONTINUE
TO MENTION LOCALLY HEAVY RAINFALL IN HWO. MAV POPS OVERALL LOOK
REASONABLE. FOR SAT NIGHT INTO SUNDAY...LOW CONTINUES TO DRIFT A
LITTLE FARTHER AWAY...WHICH SHOULD GRADUALLY REDUCE POPS FROM THE W
SAT NIGHT. BY SUNDAY...FORECAST AREA WILL BE IN BETWEEN WEAK BOUNDARY
DROPPING IN FROM THE N AND TD 5 REMNANTS TO THE ESE OVER AL. MOISTURE
WILL REMAIN PLENTIFUL WITH PW VALUES AOA 2 INCHES...BUT NOT AS
EXCESSIVE AS CURRENTLY. WILL CARRY SLGT CHC TO CHC POPS AREAWIDE WITH
GREATEST POPS IN E WHERE MOISTURE IS BEST. MAV POPS LOOK OK.

AS FAR AS TEMPERATURES...WILL AGAIN BE VERY DIFFICULT OVER EASTERN
TWO-THIRDS OF AREA SAT AS WHERE CLOUDS/PCPN OCCUR GUIDANCE WILL
LIKELY BE SOMEWHAT TOO WARM...WHILE WHERE MORE BREAKS OCCUR MAX TEMPS
WILL BE READILY ACHIEVABLE. CURRENT HEAT ADVISORY COULD BE A BIT IFFY
ON THE EASTERN SIDE OF IT IF CLOUDS/RAIN SET UP RIGHT...BUT WILL
LEAVE FOR NOW. FARTHER NW INTO THE UPPER DELTA...CONFIDENCE IS HIGHER
THAT EXCESSIVE HEAT WILL OCCUR. LOOK TO BE MEETING THE 110 HEAT INDEX
FOR 3 HOUR CRITERIA IN THIS AREA TODAY. COOP OBSERVATIONS SHOW LOWS
HAVE ONLY BEEN GETTING DOWN TO AROUND 80 IN THESE AREAS LAST COUPLE
OF MORNINGS...AND SEE NO REASON TO EXPECT THAT SIMILAR OPPRESSIVE
CONDITIONS WILL NOT CONTINUE INTO THE WEEKEND. IN FACT...AS THE
BOUNDARY CURRENTLY OVER THE MIDWEST DROPS S...THERMAL RIDGE WILL
SHIFT MORE INTO THE AREA FROM THE NW...AND SHOULD ALSO SEE INCREASED
LOW LEVEL MOISTURE POOLING AHEAD OF BOUNDARY. HENCE WILL GO WITH AN
EXCESSIVE HEAT WARNING FOR THE FAR NW COUNTIES AND PARISHES THROUGH
THE WEEKEND. BY SUNDAY...AS INFLUENCE OF TD FIVE REMAINS BECOMES
SOMEWHAT LESS...EXPECT THAT HEAT WILL BUILD EAST INTO MORE OF THE
AREA. HENCE WILL EXTEND CURRENT HEAT ADVISORY INTO SUNDAY. WILL
LIKELY NEED TO EXPAND THAT ADVISORY AND EXTEND IT INTO MONDAY...BUT
WILL DEFER THIS TO LATER SHIFTS TO PINPOINT.

.LONG TERM...MONDAY THE HEAT SHOULD CONTINUE TO BE THE DOMINANT
FEATURE WITH VALUES AOA 100 COMMON ESPECIALLY NORTHERN AND WESTERN
AREAS. GFS HAS NOW COME INTO AGREEMENT WITH ECMWF IN TAKING REMNANTS
OF TD 5 BACK OVER THE FAR NORTHERN GULF AND THEN W ALONG THE COAST
INTO SE TX. THIS IS A CHANGE FROM OVERNIGHT WHEN GFS SHOWED SYSTEM
HAVING MORE OF A DIRECT IMPACT ON OUR AREA...AND IS A SOLUTION THAT
IS SUPPORTED BY 12Z GFS ENSEMBLE. IF THIS PANS OUT...THE LONG TERM
FORECAST WILL LIKELY NEED TO BE TRENDED DRIER AND WARMER...
ESPECIALLY TOWARD DAYS 6/7 WHEN THE 12Z MODELS SHOW 500 MB RIDGE AND
THERMAL AXIS BUILDING INTO THE AREA AGAIN AND INCREASE THE THREAT OF
MORE EXCESSIVE HEAT. FOR NOW HAVE ONLY MADE MINOR ADJUSTMENTS TO LONG
TERM...BUT LATER SHIFTS WILL HAVE TO LOOK AT THESE TRENDS CLOSELY.

&&

.AVIATION...SOLID PRECIP CHANCES WILL EXIST TODAY ACROSS THE S HALF
AND IMPACT THE 3 SOUTHERN SITES. AT THIS TIME...VFR CONDITIONS LOOK
TO PREVAIL THROUGH ATLEAST 06Z...OUTSIDE OF ANY CONVECTION. I WILL
TRY AND TIME STORMS IMPACTING THE SITES CLOSER AND HAVE RESTRICTED
CONDITIONS FOR A SHORTER DURATION. AS IMPACT ON ANY PARTICULAR SITE
BECOME MORE CLEAR...WILL AMD TO COVER THOSE. AT THIS TIME...HEAVY
PRECIP LOOKS TO REDUCE VIS TO AROUND 1SM WITH CEILINGS 1500-2500 FT.
THERE SEEMS TO BE THE POTENTIAL FOR ANOTHER ROUND OF MORNING
ACTIVITY TONIGHT...BUT WITH THE AXIS SHIFTED TOWARD THE I-59
CORRIDOR. WILL COVER THIS WITH VCSH AFTER 10Z FOR MEI/HBG. OUTSIDE
THAT...THERE COULD BE SOME TYPICAL MORNING MVFR VIS RESTRICTIONS
AFTER 09Z UNTIL 13Z.                                       /CME/

&&

.PRELIMINARY POINT TEMPS/POPS...
JACKSON       95  77  95  77 /  54  34  40  23
MERIDIAN      95  77  93  74 /  67  41  60  47
VICKSBURG     90  76  96  76 /  43  19  21  10
HATTIESBURG   94  76  92  76 /  75  42  65  40
NATCHEZ       89  75  94  76 /  51  20  39  10
GREENVILLE   102  77 100  79 /  17  16  15  21
GREENWOOD    100  76 100  78 /  23  19  25  24

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...HEAT ADVISORY UNTIL 7 PM CDT SUNDAY FOR MSZ026>033-036>039.

     EXCESSIVE HEAT WARNING FROM 7 AM SATURDAY TO 7 PM CDT SUNDAY FOR
     MSZ018-019-025-034-035-040-041.

     HEAT ADVISORY UNTIL 7 AM CDT SATURDAY FOR MSZ018-019-025-034-035-
     040-041.

     HEAT ADVISORY FROM 7 AM SATURDAY TO 7 PM CDT SUNDAY FOR MSZ042-
     047-053-059-060.

LA...EXCESSIVE HEAT WARNING FROM 7 AM SATURDAY TO 7 PM CDT SUNDAY FOR
     LAZ007>009.

     HEAT ADVISORY UNTIL 7 AM CDT SATURDAY FOR LAZ007>009.

     HEAT ADVISORY FROM 7 AM SATURDAY TO 7 PM CDT SUNDAY FOR LAZ015-
     016-023>026.

AR...EXCESSIVE HEAT WARNING FROM 7 AM SATURDAY TO 7 PM CDT SUNDAY FOR
     ARZ074-075.

     HEAT ADVISORY UNTIL 7 AM CDT SATURDAY FOR ARZ074-075.

&&

AEG/CME

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE JACKSON MS
458 AM CDT FRI AUG 13 2010

ARZ074-075-LAZ007>009-015-016-023>026-MSZ018-019-025>042-047-053-
059-060-141000-
ASHLEY-CHICOT-MOREHOUSE-WEST CARROLL-EAST CARROLL-RICHLAND-
MADISON LA-FRANKLIN LA-CATAHOULA-TENSAS-CONCORDIA-BOLIVAR-
SUNFLOWER-LEFLORE-GRENADA-CARROLL-MONTGOMERY-WEBSTER-CLAY-LOWNDES-
CHOCTAW-OKTIBBEHA-WASHINGTON-HUMPHREYS-HOLMES-ATTALA-WINSTON-
NOXUBEE-ISSAQUENA-SHARKEY-YAZOO-WARREN-CLAIBORNE-JEFFERSON-ADAMS-
458 AM CDT FRI AUG 13 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL MISSISSIPPI...
NORTHEAST LOUISIANA...AND EXTREME SOUTHEAST ARKANSAS.

.DAY ONE...TODAY AND TONIGHT

HIGH TEMPERATURES IN THE UPPER 90S TO NEAR 100 DEGREES WILL COMBINE
WITH HIGH HUMIDITY TO PRODUCE HEAT INDEX VALUES OF 106 TO 111 DEGREES
AGAIN THIS AFTERNOON. OVERNIGHT LOWS WILL ONLY FALL INTO THE MID TO
UPPER 70S PROVIDING LITTLE RELIEF FROM THE DAYTIME HEAT. A HEAT
ADVISORY IS IN EFFECT THROUGH SATURDAY AFTERNOON.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

HIGH TEMPERATURES IN THE UPPER 90S TO NEAR 100 DEGREES WILL COMBINE
WITH HIGH HUMIDITY TO PRODUCE HEAT INDEX VALUES OF 107 TO 112 DEGREES
SATURDAY AFTERNOON. A HEAT ADVISORY IS IN EFFECT THROUGH SATURDAY
AFTERNOON. COOLER TEMPERATURES ARE EXPECTED FOR SUNDAY BUT A HEAT
ADVISORY MAY NEED TO BE EXTENDED THROUGH SUNDAY FOR A PORTION OF THE
AREA.

.SPOTTER CALL TO ACTION STATEMENT...
THE ACTIVATION OF STORM SPOTTERS...HAM RADIO OPERATORS...AND
EMERGENCY MANAGEMENT PERSONNEL IN SUPPORT OF SEVERE WEATHER
OPERATIONS IS NOT EXPECTED THROUGH NEXT THURSDAY.

MSZ043>046-048>052-054>058-061>066-072>074-141000-
MADISON MS-LEAKE-NESHOBA-KEMPER-HINDS-RANKIN-SCOTT-NEWTON-
LAUDERDALE-COPIAH-SIMPSON-SMITH-JASPER-CLARKE-FRANKLIN MS-LINCOLN-
LAWRENCE-JEFFERSON DAVIS-COVINGTON-JONES-MARION-LAMAR-FORREST-
458 AM CDT FRI AUG 13 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL MISSISSIPPI...
NORTHEAST LOUISIANA...AND EXTREME SOUTHEAST ARKANSAS.

.DAY ONE...TODAY AND TONIGHT

HIGH TEMPERATURES IN THE MID TO UPPER 90S WILL COMBINE WITH HIGH
HUMIDITY TO PRODUCE HEAT INDEX READINGS OF 101 TO 106 DEGREES AGAIN
THIS AFTERNOON. MEANWHILE...THE REMNANTS OF TROPICAL DEPRESSION FIVE
OVER THE MISSISSIPPI COAST WILL ENHANCE THE POTENTIAL FOR LOCALLY
HEAVY RAINFALL ACROSS SOUTHERN AND CENTRAL MISSISSIPPI TODAY. LOCAL
RAINFALL AMOUNTS OF 1 TO 3 INCHES COULD FALL IN PLACES...LEADING TO
THE PONDING OF WATER IN LOW-LYING AND POOR DRAINAGE AREAS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THE WEAK LOW PRESSURE CENTER WILL MEANDER ACROSS SOUTHEAST MISSISSIPPI
AT LEAST THROUGH SATURDAY KEEPING SOME RISK FOR TROPICAL DOWNPOURS
AND ADDITIONAL RAINFALL AMOUNTS OF 1 TO 2 INCHES IN SOME LOCATIONS.
THE EVENTUAL DISSIPATION OF THIS SYSTEM IS QUITE UNCERTAIN AND WILL
NEED TO BE MONITORED INTO THE FIRST PART OF NEXT WEEK.

IN ADDITION...HIGH TEMPERATURES IN THE MID TO UPPER 90S WILL COMBINE
WITH HIGH HUMIDITY TO PRODUCE HEAT INDEX READINGS OF 100 TO 105 DEGREES
SATURDAY AFTERNOON.

.SPOTTER CALL TO ACTION STATEMENT...
THE ACTIVATION OF STORM SPOTTERS...HAM RADIO OPERATORS...AND
EMERGENCY MANAGEMENT PERSONNEL IN SUPPORT OF SEVERE WEATHER
OPERATIONS IS NOT EXPECTED THROUGH NEXT THURSDAY.

FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE AT
WWW.SRH.NOAA.GOV/JAN. THIS INCLUDES THE GRAPHICAL HAZARDOUS
WEATHER OUTLOOK.

22

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE JACKSON MS
1236 PM CDT FRI AUG 13 2010

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1106 AM     FLASH FLOOD      2 SW FAYETTE            31.69N 91.09W
08/13/2010                   JEFFERSON          MS   PUBLIC

            SEVERAL LOW LYING COUNTY ROADS COVERED WITH WATER WITH
            ESTIMATED 3-5 INCHES RAINFALL

&&

JALLEN

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE JACKSON MS
120 PM CDT FRI AUG 13 2010

MSZ064-065-131850-
COVINGTON MS-JEFFERSON DAVIS MS-
120 PM CDT FRI AUG 13 2010

SEVERAL CLUSTERS OF SLOW MOVING THUNDERSTORMS WERE PRODUCING VERY
HEAVY RAIN ACROSS PORTIONS OF JEFFERSON DAVIS AND COVINGTON COUNTIES
AT 118 PM CDT. THESE STORMS WERE PRODUCING RAINFALL RATES UP TO 2
INCHES PER HOUR. IF THIS SORT OF HEAVY RAINFALL CAN PERSIST...THEN
FLASH FLOODING WILL BECOME AND ISSUE AND A WARNING MAY BE NEEDED.

PEOPLE IN CENTRAL JEFFERSON DAVIS AND COVINGTON COUNTIES SHOULD
MONITOR THIS STORM CLOSELY.

CME

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