Special Weather Statement, NWS Jackson, MS

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON MS
858 AM CDT WED JUL 18 2012

.UPDATE...AT LEAST TWO DISTINCT MCV SYSTEMS ROTATING AROUND THE GA TUTT
CIRCULATION THIS MORNING...ONE NEAR THE MS COAST AND ANOTHER IN NW AL
HEADING SW. AIRMASS FEATURING 2 INCH PWATS ALONG THE MS/AL BORDER
SHOULD BE THE FOCUS FOR INITIAL SHRA/TSRA DEVELOPMENT THAT WILL
INCREASE/SPREAD SWWD DURING THE AFTERNOON. HAVE BOOSTED POPS ALONG AND
E OF THE NATCHEZ TRACE PARKWAY WITH LIKELY CATEGORY INCLUDING GUSTY
WINDS IN THE I-59/HIGHWAY 45 CORRIDORS. THE WWD EXTENT OF THE RAINS
IS A TOUGH CALL HOWEVER...MORNING MICROBURST CHECKLISTS IN THE
RISK/LIKELY RANGE AS NEARLY 4K J/KG SBCAPES OCCUR WITH SURFACE
DEWPOINTS AT 72-74F. DCAPES OF 1000-1100J/KG ARE ALSO FAVORABLE.

MEANWHILE...HOTTEST HEAT INDEXES 105-107F SHOULD NOT LAST MORE THAN
AN HOUR OR TWO...MAINLY IN THE DELTA COUNTIES. NO OTHER ADJUSTMENTS
FOR NOW AND UPDATES SHOULD BE POSTED./40/

&&

.AVIATION...THINNING CLOUD DEBRIS IN ERN MS WILL GIVE WAY TO
DEVELOPING BROKEN CUMULUS FIELD 3-5K FEET THROUGH EARLY AFTERNOON.
SCATTERED TSRA ALONG THE AL/MS BORDER SHOULD SPREAD SWWD AND BECOME
NUMEROUS ALONG AND E OF THE NATCHEZ TRACE FROM 19Z-03Z AS AN UPPER
LEVEL SHEAR AXIS ROTATES IN FROM THE E. ELSEWHERE...VFR SHOULD
DOMINATE THE AREA THROUGH THURSDAY WITH LOCALIZED MVFR VSBYS LIKELY
IN THE EARLY MORNING HOURS 08-13Z...MAINLY NEAR PREVIOUS SHRA
LOCATIONS THAT OCCUR DURING THE AFTERNOONS. OVERALL SURFACE WINDS
WILL BE WSWLY 4-8KT EACH DAY...EXCEPT GUSTY AT 35-50KTS WITH THE
MOST INTENSE STORMS...BEFORE DYING OFF TO LESS THAN 5KTS DURING THE
OVERNIGHT PERIODS. /40/

&&

.PREV DISCUSSION... /ISSUED 352 AM CDT WED JUL 18 2012/
SHORT TERM(TODAY THRU THURSDAY NIGHT)...ANOTHER DAMP PERIOD LOOKS TO
BE SETTING UP FOR THE THE CWA DURING THIS PERIOD AS MID/UPPER HIGH
CENTERS LOOK TO BECOME ANCHORED OVER THE CENTRAL PLAINS AND OFF THE
EAST COAST OF FLORIDA. RESULTING TROFFINESS BETWEEN THESE FEATURES
WILL ALLOW TUTT LOW...PRESENTLY OVER GA...TO BECOME MORE OF A SHEAR
AXIS ACROSS THE SE STATES WITH TIME AND PROVIDE JUST ENOUGH MID/UPPER
LEVEL INSTABILITY DURING DAYTIME HEATING TO PRODUCE SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS. THESE STORMS WILL LIKELY PRODUCE
LOCALIZED HEAVY RAIN CONSIDERING THE RICHNESS OF MOISTURE (PW/S
AROUNS 2 INCHES) IN PLACE AND THE WEAK MEAN LAYER FLOW AS STORM
PROPAGATION WILL BE SERVED MORE BY COLD POOL BOUNDARY INTERACTIONS.

A THREAT FOR WET MICROBURSTS WILL EXIST AT LEAST FOR TODAY AS MODELS
AGREE WITH VERTICAL TOTALS NEAR 30C AND DCAPES AROUND 1000 J/KG.
THESE VALUES LOWER SOMEWHAT DURING THE DAY THURSDAY.

WENT CLOSE TO MOS POPS...ADJUSTING UPWARD TO THE EAST WHERE BEST
INSTABILITY WILL RESIDE. MOS MAX TEMPS LOOKED A BIT HIGH WITH THE
EXPECTED CONVECTION...SO CUT A FEW DEGREES...ONCE AGAIN...ESPECIALLY
TO THE EAST./26/

LONG TERM...FRIDAY THROUGH NEXT TUESDAY...THE GLOBAL MODELS AND
ENSEMBLES CONTINUE TO GENERALLY AGREE THAT THE CENTER OF THE
SUBTROPICAL RIDGE WILL BE OVER THE PLAINS WHILE AREAS ALONG AND EAST
OF THE MS RIVER WILL BE UNDER A WEAK MEAN TROUGH...WHICH WILL EXTEND
DOWN TO THE ARKLAMISS REGION. THE CENTER OF THE MEAN TROUGH EAST OF
THE REGION WILL BRING A SERIES OF WEAK DISTURBANCES/CONVECTIVE
COMPLEXES(MCS) FROM THE NORTH. SOME OF THE MODELS TRY TO BRING A WEAK
BACKDOOR SURFACE BOUNDARY ACROSS THE NORTHERN PORTION OF THE REGION
OVER THE WEEKEND...WHICH WILL PROVIDE SOME LIMITED LIFT.

DEEP LAYER MOISTURE WILL BE PLENTIFUL DURING THE PERIOD WITH
PRECIPITABLE WATER AROUND AROUND 2 INCHES...WHICH WILL SUPPORT
LOCALLY HEAVY DOWNPOURS. THERE MAY BE SOME STRONG STORM POTENTIAL
FRIDAY INTO SATURDAY PRIMARILY FOR GUSTY WINDS. FOR SUNDAY NIGHT
INTO THE TUESDAY OF NEXT WEEK DAY THE SUBTROPICAL HIGH IS FORECAST
TO INTENSIFY AND EXPAND AS IT CONTINUES TO BUILD WESTWARD AND
SOUTHEASTWARD. BY THE MIDDLE OF THE WEEK IT WILL EXTEND FROM THE
CENTRAL PLAINS THROUGH THE ARKLAMISS INTO THE SOUTHEAST US. WITH THE
PROGRESSION OF THE MEAN RIDGE THIS WILL REDUCE OUR RAIN CHANCES FOR
THE AFTERNOON AND EARLY EVENING HOURS FOR NEXT WEEK.

ONCE AGAIN FOR THE LAST THREE NIGHTS THERE ARE SOME SIGNIFICANT
DIFFERENCES BETWEEN THE WARMER GFS AND SLIGHTLY COOLER 80S ECMWF. WENT
CLOSER TO THE WARMER GFS AND CUT TEMPS SLIGHTLY FROM A BLEND OF
ENSEMBLES...MEX AND GMOS. ON POPS WENT CLOSE TO A BLEND OF GMOS AND
MEX MOS GUIDANCE./17/

&&

.AVIATION...
ISOLATED MVFR VSBYS AROUND 3 MILES WILL BE POSSIBLE THIS
MORNING FROM KGTR-KMEI-KHBG DUE TO RESIDUAL LOW LEVEL MOISTURE FROM
OVERNIGHT CONVECTION IN SE MS/AL. OTHERWISE...VFR CONDITIONS WILL
EXIST UNTIL AROUND 18/1800Z WHEN SCATTERED TO NUMEROUS THUNDERSTORMS
DEVELOP ESPECIALLY BETWEEN KGTR-KMEI-KHBG. CEILINGS AND VSBYS WILL
BRIEFLY DROP TO IFR IN CLOSE PROXIMITY TO THE STORMS. CONDITIONS WILL
IMPROVE BY 19/0200Z...BUT MVFR VSBYS WILL DEVELOP MOST AREAS
THEREAFTER./26/

&&

.PRELIMINARY POINT TEMPS/POPS...
JACKSON       96  73  92  74 /  46  24  51  40
MERIDIAN      92  72  91  73 /  66  43  60  53
VICKSBURG     94  74  93  72 /  19  13  43  28
HATTIESBURG   93  74  90  74 /  69  27  64  34
NATCHEZ       92  73  92  73 /  43  15  47  18
GREENVILLE    95  76  93  75 /  20  12  48  25
GREENWOOD     95  74  94  75 /  34  24  56  36

&&

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE JACKSON MS
336 AM CDT WED JUL 18 2012

ARZ074-075-LAZ007>009-015-016-023>026-MSZ018-019-025>066-072>074-
190845-
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-MADISON MS-LEAKE-NESHOBA-KEMPER-
WARREN-HINDS-RANKIN-SCOTT-NEWTON-LAUDERDALE-CLAIBORNE-COPIAH-
SIMPSON-SMITH-JASPER-CLARKE-JEFFERSON-ADAMS-FRANKLIN MS-LINCOLN-
LAWRENCE-JEFFERSON DAVIS-COVINGTON-JONES-MARION-LAMAR-FORREST-
336 AM CDT WED JUL 18 2012

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

.DAY ONE...TODAY AND TONIGHT

ISOLATED BRIEF STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE THIS
AFTERNOON AND EARLY EVENING. WINDS GUSTS FROM 40 TO 60 MPH AND HAIL
UP TO THE SIZE OF QUARTERS WILL BE POSSIBLE IN THESE STORMS. THE
GENERAL SLOW MOVEMENT WITH THE HEAVIER STORMS MAY ALSO PRODUCE LOCALIZED
FLOODING.

INCREASING MOISTURE AND INSTABILITY FROM THE EAST WILL COMBINE WITH
DAYTIME HEATING TO PRODUCE SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ACROSS THE REGION THIS AFTERNOON AND EVENING. THE
STORMS WILL DIMINISH BY MIDNIGHT.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

NO WIDESPREAD HAZARDOUS WEATHER EXPECTED.

.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 TUESDAY.

FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE AT
WWW.SRH.NOAA.GOV/JAN.

26

MSZ030-031-033-038-039-045-046-181825-
WINSTON MS-OKTIBBEHA MS-NOXUBEE MS-NESHOBA MS-LOWNDES MS-KEMPER MS-
CLAY MS-
1213 PM CDT WED JUL 18 2012

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE JACKSON MS
1213 PM CDT WED JUL 18 2012

...THUNDERSTORMS BUILDING FOR THE GOLDEN TRIANGLE...SOME STRONG...

SCATTERED STRONG THUNDERSTORMS CAPABLE OF PRODUCING PENNY SIZE HAIL
AND 40 MPH WINDS WERE DEVELOPING ACROSS THE GOLDEN TRIANGLE REGION
DOWN TO MACON AND DE KALB...MOVING SOUTHEAST AT 20 MPH. THESE STORMS
SHOULD INCREASE THROUGH THE MID AFTERNOON HOURS AND A FEW SEVERE
THUNDERSTORM WARNINGS ARE POSSIBLE.

VERY HEAVY RAIN ALONG WITH CLOUD TO GROUND LIGHTNING STRIKES WILL BE
POSSIBLE WITH ANY STORMS. KEEP AN EYE TO THE SKY AND BE READY TO
MOVE INDOORS WHEN STORMS OCCUR.

HIGH WINDS CAN BRING DOWN TREES AND LARGE LIMBS RESULTING IN SERIOUS
INJURY OR PROPERTY DAMAGE. EXERCISE EXTREME CAUTION WHEN OUTDOORS
DURING SUCH STRONG WINDS...AND BE ESPECIALLY AWARE OF OLDER TREES.

PEOPLE IN CLAY...KEMPER...LOWNDES...EASTERN NESHOBA...NOXUBEE...
OKTIBBEHA AND EASTERN WINSTON COUNTIES SHOULD MONITOR THE STORMS
CLOSELY.

LAT...LON 3259 8839 3259 8914 3374 8900 3375 8871
      3368 8871 3369 8850 3367 8849 3368 8841
      3370 8840 3369 8837 3375 8832 3375 8825
TIME...MOT...LOC 1708Z 335DEG 14KT 3358 8885

40