Severe Thunderstorm Warning 423, NWS Jackson, MS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
335 PM CDT MON AUG 12 2002

FORECAST CONCERNS CONTINUE TO REVOLVE AROUND THE APPROACHING STRONG
NRN/CNTRL PLAINS SHORTWAVE TROUGH AND ITS AFFECTS ON THE LOWER MS
VALLEY REGION. ETA HAS COME INTO MUCH BETTER ALIGNMENT WITH THE
WETTER AVN. BOTH MODELS NOW PORTRAY A RATHER ACTIVE CONVECTIVE
PATTERN TUESDAY AND WEDNESDAY OVER THE FORECAST AREA AS THE
FOREMENTIONED SHORTWAVE ENERGY INTERACTS WITH COPIOUS MOISTURE.

FOR TONIGHT...SCATTERED SHOWER/TSTM ACTIVITY CURRENTLY IN PLACE OVER
THE WRN HALF OF AREA SHOULD DIMINISH RAPIDLY WITH SUNSET. WILL KEEP
SMALL EVENING PRECIP CHANCES IN MOST PLACES. OVERNIGHT...WITH HIGH
PRECIP WATER AIRMASS OVER REGION (PW > 2 IN) AND LOW LEVEL SOUTHERLY
FLOW...WILL CONTINUE POSSIBILITY FOR ISOLATED SHOWERS WRN HALF OF
AREA.

FOR TUES/TUES NIGHT...DAYTIME HEATING WILL ONCE AGAIN ACT ON THE
VERY MOIST AND UNSTABLE AIRMASS BRINGING SCATTERED TO NUMEROUS
AFTN/EVNG SHOWERS/STORMS. EXPECT BETTER COVERAGE OVER ERN HALF OF
AREA THAN EXPERIENCED TODAY. FORECAST IS A LITTLE MORE QUESTIONABLE
FOR TUESDAY NIGHT. BOTH AVN AND ETA INDICATE THAT A PIECE OF ENERGY
OVER THE NRN GULF WILL DEVELOP NEWD AHEAD OF APPROACHING SHORTWAVE
TROUGH ACROSS SRN/CNTRL ZONES OVERNIGHT. THE AVN HAS BEEN PERSISTENT
WITH THIS FEATURE...BUT LOOKS KIND OF SPURIOUS ATTM. HAVE OPTED TO
GO WITH CHANCE POPS EVERYWHERE FOR NOW.

FOR WEDNESDAY...EXPECT A RATHER ACTIVE DAY AS CONVECTIVE COMPLEX IS
EXPECTED TO DEVELOP AND TRAVERSE FORECAST AREA DURING THE LATE
MORNING/AFTN HOURS. SHORTWAVE TROUGH DEPICTED BY THE MODELS IS
UNUSUALLY STRONG FOR MID AUGUST. AVN/ETA CONTINUE TO INDICATE
SIGNIFICANT LOWERING OF THE DYNAMIC TROPOPAUSE OVER THE OZARKS TUES
NIGHT WITH 2 PVUS BELOW 400MB. AN IMPRESSIVE LOW LEVEL THETAE RIDGE
WILL FEED ANY CONVECTIVE COMPLEXES UNDER RIGHT ENTRANCE REGION OF
UNSEASONABLY STRONG UPPER JET. WILL GO LIKELY PRECIP CHANCES ALL
ZONES FOR NOW.

IN THE EXTENDED...THE SHORTWAVE TROUGH WILL SHEAR OUT AS IT GETS
DEFLECTED BY STRONG SOUTHEAST US RIDGE. THIS WILL LEAVE MOISTURE AND
A WEAK FOCUS FOR ADDITIONAL MAINLY DIURNAL CONVECTIVE PRECIP
THURSDAY INTO SATURDAY. RIDGE SHOULD BEGIN TO DOMINATE WEATHER MORE
SUNDAY AND MONDAY RESULTING IN HOTTER AFTN TEMPS AND LESSER PRECIP
CHANCES.

PRELIM NUMBERS...
JAN 72/88/72/88/72 26463
MEI 69/90/71/88/71 14464

.JAN...
AR...NONE.
LA...NONE.
MS...NONE.

43

ARZ074-075-LAZ007>009-015-016-023>026-MSZ018-019-025>066-072>074-
131200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE JACKSON MS
201 PM CDT MON AUG 12 2002

...THUNDERSTORMS...
ISOLATED TO SCATTERED THUNDERSTORMS WILL CONTINUE THIS AFTERNOON
AND EVENING OVER EXTREME SOUTHEAST ARKANSAS AND NORTHEAST
LOUISIANA...AS WELL AS MUCH OF MISSISSIPPI. THUNDERSTORMS WILL BE
MOST NUMEROUS ALONG AND WEST OF A LINE FROM NEAR GORE
SPRINGS...TO PELAHATCHIE...TO MAGEE... TO CAMP SHELBY. SEVERE
WEATHER NOT IS EXPECTED. HOWEVER...ISOLATED STORMS MAY PRODUCE
FREQUENT DANGEROUS LIGHTNING...WIND GUSTS TO 45 MPH...AND BRIEF
HEAVY RAINFALL.

VICKSBURG...NATCHEZ...GREENWOOD...GREENVILLE...AND THE
METROPOLITAN JACKSON AREA WILL ALL BE AFFECTED BY THESE
STORMS...AS THE STRONGEST STORMS CONTINUE TO DEVELOP IN THE
DEEPER MOISTURE WEST OF INTERSTATE 55 THROUGH THE EVENING. MOST
OF THE THUNDERSTORM ACTIVITY WILL DEVELOP IN THE HEAT OF THE
AFTERNOON AND THEN GRADUALLY DISSIPATE AFTER SUNSET. BY 10
PM...MOST OF THE SHOWERS AND THUNDERSTORMS WILL HAVE ENDED.

SOUTH WINDS AT 5 TO 10 MPH WILL PUMP ADDITIONAL WARM...MOIST AIR
INTO THE LOWER MISSISSIPPI RIVER VALLEY TONIGHT THROUGH TUESDAY.
THIS WILL SET THE STAGE FOR A REPEAT OF TODAYS WEATHER STARTING
TUESDAY MORNING.

ACTIVATION OF EMERGENCY MANAGEMENT...STORM SPOTTER AND HAM RADIO
PERSONNEL SHOULD NOT BE NECESSARY THROUGH TONIGHT.

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