Severe Thunderstorm Warning 509, NWS Jackson, MS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
405 PM CDT FRI AUG 12 2005

.DISCUSSION...
NUMEROUS SHOWERS AND THUNDERSTORMS HAVE BEEN FORMING THIS AFTERNOON
ACROSS PORTIONS OF CENTRAL MISSISSIPPI...MAINLY COINCIDENT WITH A
WEAK LOW LEVEL CONVERGENT BOUNDARY AND MINOR DEFORMATION ALOFT
ASSOCIATED WITH FLOW AROUND A TUTT LOW CLOSING IN FROM THE SOUTH.
MEANWHILE...DRIER AIR FILTERING IN FROM THE WEST IN ANTICYCLONIC LOW
LEVEL FLOW IS SUPPRESSING CONVECTIVE DEVELOPMENT TO ISOLATED AT BEST
WEST OF THE NATCHEZ TRACE CORRIDOR. TEMPERATURES HAVE BEEN VERY WARM
WHERE PRECIPITATION HAS BEEN SCARCE WITH UPPER 90S REGISTERED UP IN
PORTIONS OF THE ARKLAMISS DELTA.

FOR THIS EVENING...NUMEROUS STORM OUTFLOW BOUNDARIES ALREADY ON THE
MOVE WILL CONTINUE TO KICK UP AT LEAST ISOLATED CONVECTION ACROSS
MOST OF THE FORECAST AREA THROUGH EARLY THIS EVENING. I ANTICIPATE
ACTIVITY WILL BE MOST ABUNDANT AFTER 00Z IN EASTERN MISSISSIPPI
WHERE THE ATMOSPHERE REMAINS VERY UNSTABLE AND RELATIVELY UNTAPPED
THUS FAR. I SUSPECT STRONG CONVECTION WILL CONTINUE TO OCCUR THROUGH
AT LEAST 7 OR 8 PM AS THE RATHER HIGH INSTABILITY LEVELS (SB CAPES
NEAR 3500 J/KG) TAKE A WHILE TO SUBSIDE. OTHERWISE...LOOK FOR
MOST...IF NOT ALL...OF THE PRECIP TO BE GONE BY MIDNIGHT WITH LOTS
OF CONVECTIVE DEBRIS HANGING ABOUT THROUGH THE NIGHT. LOWS WERE KEPT
NEAR MAV GUIDANCE WITH MINIMAL FOG OR LOW CLOUD DEVELOPMENT
ANTICIPATED DUE TO THE MENTIONED CONVECTIVE DETRITUS BEING ABOUT.

FOR SATURDAY...LOWER LEVEL ANTICYCLONIC FLOW WILL EDGE FURTHER EAST
INTO THE FORECAST AREA...BRINGING DRIER AIR (AND LOWER PRECIPITABLE
WATER VALUES) WITH IT. THE TUTT LOW WHICH IS ENHANCING CONVECTION
THIS AFTERNOON WILL BE LOCATED FURTHER TO THE NORTH TOMORROW WITH
THE FAVORABLE EAST AND SOUTHEAST QUAD OF THE FEATURE OVER MOB AND
BHMS AREAS. ANY LOW LEVEL CONVERGENCE SHOULD BE CONFINED TO MAINLY
FAR EASTERN ZONES AND POPS WERE PUT IN CHANCE RANGE HERE.
ELSEWHERE...POPS WERE KEPT IN SLIGHT CHANCE RANGE (OR LESS IN THE
ARKLAMISS DELTA) WHERE DRY AIR AND SUBSIDENCE MAY END UP RULING THE
DAY. MAV POP NUMBERS ARE VERY PESSIMISTIC THOUGH...AND I COULD NOT
GO QUITE THAT PESSIMISTIC GIVEN RECENT TRENDS AND EXPECTED LACK OF
CAPPING. ENDED UP UPPING THOSE NUMBERS BY 10 TO 15 POINTS.
TEMPERATURES WILL BE VERY WARM FOR TOMORROW WITH UPPER 90S SPREADING
A LITTLE FURTHER EAST AND SOUTH AND MOST AREAS AT LEAST GETTING INTO
THE MID 90S. /BB/

SUNDAY AND MONDAY...DECENT AGREEMENT EXHIBITED AMONGST THE SHORT
RANGE MODELS. TUTT LOW WILL CONTINUE TO SLIDE NORTHEAST INTO NW GA
ON SUNDAY AND WEAK WEST-SOUTHWESTERLY FLOW WILL DEVELOP IN ITS WAKE
AS BROAD RIDGING BEGINS TO BUILD OVER THE LOWER MS RIVER VALLEY
REGION. 925/850MB TEMPS ARE CONDUCIVE TO CONTINUED LOW/MID 90F HIGH
TEMPS ACROSS THE AREA...AND WITH DECENT LOW LEVEL MOISTURE LINGERING
OVER THE AREA AND A FEW WEAK IMPULSES IN THE FLOW ALOFT...HAVE
MAINTAINED SLIGHT CHC/LOW END CHC POPS. HIGHEST POPS (NEAR CLIMO)
HAVE BEEN PLACED OVER EASTERN/SOUTHERN ZONES. MAVMOS TEMPS STILL
SUGGESTING UPPER 90S/NEAR 100F IN THE DELTA REGION AGAIN THIS RUN.
THIS HAS BEEN A CONSISTENT ISSUE WITH THE GFS SO FAR THIS SUMMER.
WHEN 850MB TEMPS ARE PROGGED IN THE LOW 20S C (AS IS THE CASE
HERE)...MAV HAS BEEN TOO AGGRESSIVE IN WARMING KGLH/KTVR/KGWO. THUS
HAVE CUT TEMPS AT THESE SITES BY A FEW DEGREES TO MAINTAIN A MID 90S
MANTRA.

TUESDAY THROUGH FRIDAY...LATEST MED RANGE GUIDANCE AND ENSEMBLES
OFFERING LITTLE CHANGE TO THE FORECAST FOR THIS PERIOD. THE REGION
WILL BE LOCKED UNDER RIDGING ALOFT WITH A BERMUDA HIGH PRESSURE
GAINING CONTROL AT THE SFC. 850MB TEMPS WILL REMAIN IN THE UPPER
TEENS TO AROUND 20C...SUPPORTING TYPICAL SUMMER HEAT IN THE 92-96 F
RANGE. 700MB TEMPS WILL ALSO BE ON THE RISE UNDER THE RIDGE...
BETWEEN 8 AND 10 C. THESE FEATURES ALONE WILL NOT BE ABLE TO TOTALLY
THWART AFTERNOON CONVECTIVE DEVELOPMENT GIVEN CONTINUED SFC
DEWPOINTS IN THE LOWER 70S. HOWEVER...WEAK TO NIL FLOW ALOFT WITH
THE RIDGE AXIS NEARLY ON TOP OF THE AREA IMPLIES SLOW
MOVING/DRIFTING MOVEMENT TO ANYTHING THAT DEVELOPS. THUS HAVE HELD
POPS DOWN AT OR BELOW CLIMO IN THE SLIGHT CHC TO LOW END CHC
CATEGORY./GAGAN/

&&

.AVIATION...
LOTS OF CONVECTIVE DEBRIS AROUND THIS EVENING WILL LIMIT FOG AND LOW
CLOUD DEVELOPMENT...ALTHOUGH ISOLATED LIFR FLIGHT CONDITIONS CANNOT
BE RULED OUT AT ANY STATION AFTER MIDNIGHT. HOWEVER...EXPECT
PREVAILING MVFR MAINLY AFTER MIDNIGHT IN MOST AREAS WITH TEMPORARY
IFR AT MEI...JAN AND HBG AROUND DAWN. MOST OF THE AFTERNOON STORM
DEVELOPMENT TOMORROW SHOULD OCCUR AT JAN...MEI AND HBG. /BB/

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.

&&

SHORT TERM:BRYANT
LONG TERM:GAGAN

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE JACKSON MS
339 PM CDT FRI AUG 12 2005

ARZ074-075-LAZ007>009-015-016-023>026-MSZ018-019-025>066-072>074-
132039-
ADAMS-ASHLEY-ATTALA-BOLIVAR-CARROLL-CATAHOULA-CHICOT-CHOCTAW-
CLAIBORNE-CLARKE-CLAY-CONCORDIA-COPIAH-COVINGTON-EAST CARROLL-
FORREST-FRANKLIN LA-FRANKLIN MS-GRENADA-HINDS-HOLMES-HUMPHREYS-
ISSAQUENA-JASPER-JEFFERSON-JEFFERSON DAVIS-JONES-KEMPER-LAMAR-
LAUDERDALE-LAWRENCE-LEAKE-LEFLORE-LINCOLN-LOWNDES-MADISON LA-
MADISON MS-MARION-MONTGOMERY-MOREHOUSE-NESHOBA-NEWTON-NOXUBEE-
OKTIBBEHA-RANKIN-RICHLAND-SCOTT-SHARKEY-SIMPSON-SMITH-SUNFLOWER-
TENSAS-WARREN-WASHINGTON-WEBSTER-WEST CARROLL-WINSTON-YAZOO-
339 PM CDT FRI AUG 12 2005

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

.DAY ONE...TONIGHT AND SATURDAY...

...THUNDERSTORMS...
A FEW STRONG THUNDERSTORMS WILL BE POSSIBLE THIS EVENING ACROSS
THE FORECAST AREA.  THE MAIN RISK WITH THE STRONGER STORMS WILL
BE WIND GUSTS UP TO 50 MILES AN HOUR AND FREQUENT CLOUD TO GROUND
LIGHTNING STRIKES.

VERY ISOLATED INTENSE THUNDERSTORM DEVELOPMENT WILL BE POSSIBLE
AGAIN SATURDAY AFTERNOON...BUT MAINLY ALONG AND EAST OF THE
NATCHEZ TRACE CORRIDOR. AGAIN...THE MAIN RISK WITH THE STRONGER
STORMS DURING THIS TIME PERIOD WILL BE WIND GUSTS UP TO 50 MILES
AN HOUR AND FREQUENT CLOUD TO GROUND LIGHTNING STRIKES.

THE ATMOSPHERE ACROSS MOST OF THE REGION EARLY THIS EVENING...AND
AGAIN TOMORROW AFTERNOON...WILL BE MODERATELY TO HIGHLY
UNSTABLE...FUELING A FEW VIGOROUS THUNDERSTORMS. LOW VALUES OF
WIND SHEAR WILL RESULT IN PULSE CONVECTION WHICH IS GENERALLY
JUST CAPABLE OF BRIEF WIND GUSTS AND EPISODES OF FREQUENT CLOUD
TO GROUND LIGHTNING.

...FLOODING...
DUE TO THEIR RELATIVELY SLOW MOVEMENT...STRONGER THUNDERSTORMS
ALONG AND EAST OF THE NATCHEZ TRACE CORRIDOR MAY PRODUCE 1 TO 2
INCHES OF RAINFALL WITHIN A SHORT AMOUNT OF TIME EARLY THIS
EVENING...AND AGAIN SATURDAY AFTERNOON.  THIS MAY RESULT IN THE
PONDING OF WATER ON AREA ROADWAYS AND OTHER LOW-LYING AREAS.

.DAYS TWO THROUGH SEVEN...SATURDAY NIGHT THROUGH FRIDAY...

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.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 ANTICIPATED THROUGH FRIDAY...AUGUST 19.

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

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE JACKSON MS
355 PM CDT FRI AUG 12 2005

MSZ054>056-122145-
COPIAH-SIMPSON-SMITH-
355 PM CDT FRI AUG 12 2005

...STRONG THUNDERSTORMS CONTINUE TO DEVELOP OVER SIMPSON...SMITH
AND COPIAH COUNTIES...

AT 355 PM...NATIONAL WEATHER SERVICE RADAR INDICATED SCATTERED
THUNDERSTORMS STRETCHING FROM NEAR CRYSTAL SPRINGS...TO TO MAGEE...
TO HOMEWOOD. THE STORMS WERE SOUTH AROUND 10 MPH. EXPECT
FREQUENT CLOUD TO GROUND LIGHTNING...TORRENTIAL DOWNPOURS...WIND
GUSTS UP TO 45 MPH AND SMALL HAIL.

REMEMBER...LIGHTNING IS A KILLER AND EVEN MODERATE WINDS CAN
SOMETIMES KNOCK LARGE TREE LIMBS TO THE GROUND CAUSING DAMAGE
TO PROPERTY OR LIFE. MOVE INDOORS TO A STURDY BUILDING DURING
THUNDERSTORMS.

7

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE JACKSON MS
407 PM CDT FRI AUG 12 2005

MSZ032-033-038-122200-
CHOCTAW-OKTIBBEHA-WINSTON-
407 PM CDT FRI AUG 12 2005

...STRONG THUNDERSTORMS WERE SLOWLY DRIFTING SOUTH OVER
CHOCTAW...OKTIBBEHA AND WINSTON COUNTIES...

AT 407 PM...NATIONAL WEATHER SERVICE RADAR INDICATED A STRONG
THUNDERSTORMS NEAR STURGIS MOVING SOUTH NEAR 10 MPH. EXPECT
FREQUENT CLOUD TO GROUND LIGHTNING...TORRENTIAL DOWNPOURS...WIND
GUSTS UP TO 45 MPH AND SMALL HAIL.

REMEMBER...LIGHTNING IS A KILLER AND EVEN MODERATE WINDS CAN
SOMETIMES KNOCK LARGE TREE LIMBS TO THE GROUND CAUSING DAMAGE
TO PROPERTY OR LIFE. MOVE INDOORS TO A STURDY BUILDING DURING
THUNDERSTORMS.

7

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE JACKSON MS
455 PM CDT FRI AUG 12 2005

MSZ038-039-045-046-122230-
KEMPER-NESHOBA-NOXUBEE-WINSTON-
455 PM CDT FRI AUG 12 2005

...STRONG THUNDERSTORMS CONTINUE TO SLOWLY SOUTH OVER WINSTON...
NOXUBEE...NORTHERN NESHOBA AND NORTHERN KEMPER...

AT 455 PM...NATIONAL WEATHER SERVICE RADAR INDICATED A FEW
THUNDERSTORMS STRETCHING FROM NEAR CRAWFORD TO NOXAPATER MOVING
SOUTH NEAR 10 MPH. EXPECT FREQUENT CLOUD TO GROUND LIGHTNING...
TORRENTIAL DOWNPOURS...WIND GUSTS UP TO 45 MPH AND SMALL HAIL.

REMEMBER...LIGHTNING IS A KILLER AND EVEN MODERATE WINDS CAN
SOMETIMES KNOCK LARGE TREE LIMBS TO THE GROUND CAUSING DAMAGE
TO PROPERTY OR LIFE. MOVE INDOORS TO A STURDY BUILDING DURING
THUNDERSTORMS.

7

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE JACKSON MS
554 PM CDT FRI AUG 12 2005

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

0550 PM     HAIL             POCAHONTAS              32.47N 90.29W
08/12/2005  0.88 INCH        HINDS              MS   LAW ENFORCEMENT

            MADISON CO SHERRIFS OFFICE REPORTED DIME TO NICKEL SIZE
            HAIL FALLING IN POCOHONTAS.

&&

BRYANT

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