Severe Thunderstorm Warning 621, NWS Jackson, MS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
252 PM CDT WED JUL 30 2003

MAIN FORECAST CHALLENGE THIS PACKAGE:
RAIN CHANCES THROUGH THE ENTIRE FORECAST PACKAGE

A RATHER PREDICTABLE WEATHER PATTERN CONTINUES ACROSS THE FORECAST
AREA THIS AFTERNOON.  SUBJECTIVE ANALYSIS EARLY THIS AFTERNOON HAS
THE NOW STATIONARY FRONT FROM ABOUT SPRINGFIELD MISSOURI TO
CHATTANOOGA TENNESSEE.  AS EXPECTED...AN MCS DEVELOPED LATE LAST
NIGHT AND MOVED ACROSS THE MID-SOUTH OVERNIGHT.  WITH SEVERAL
SHORTWAVES CONTINUING TO MOVE ACROSS THE FORECAST AREA...I EXPECT
MORE OF THE SAME AGAIN TONIGHT.  IN FACT...RADAR SHOWS WHAT COULD BE
THE BEGINNINGS OF TONIGHTS COMPLEX JUST NORTHWEST OF THE ARKLATEX.

AS THE UPPER-LEVEL LOW PINWHEELS INTO THE GREAT LAKES REGION DURING
THE END OF THE WEEK...THE FRONT SHOULD MOVE A LITTLE FURTHER INTO
THE FORECAST AREA AND GRADUALLY WEAKEN.  ANOTHER FRONTAL SYSTEM IS
FORECAST TO GET CRANKED UP OVER THE CENTRAL AND NORTHERN PLAINS AND
MOVE INTO THE MID- AND LOWER MISSISSIPPI VALLEY BY SATURDAY.  WITH
SHORTWAVES CONTINUING TO ROTATE THROUGH THE LONGER WAVE TROUGH...
THIS SPELLS MORE OF THE SAME FOR THE SHORT TERM...WITH THE FOCUS FOR
CONVECTIVE ACTIVITY SHIFTING A LITTLE FURTHER SOUTH.  RELATIVELY
SPEAKING...FRIDAY COULD BE THE DRIEST DAY IN THE SHORT TERM...AS 850
MB THETA-E VALUES DROP TO ALMOST 330K OVER OUR NORTHERN COUNTIES.  I
PLAN ON LEAVING THE STATUS QUO GOING OVER OUR SOUTHERN
COUNTIES/PARISHES...BUT REDUCE THE RAIN CHANCES OVER OUR NORTHERN
COUNTIES A LITTLE.

REGARDING THE RISK OF SEVERE WEATHER...THE JET STRUCTURE IS SOMEWHAT
OUT OF PHASE WITH THE REST OF THE SYSTEM.  COMBINED WITH A RATHER
WEAK MID-LEVEL FLOW...THE RISK FOR WIDESPREAD SEVERE WEATHER IS
LOW.  HOWEVER...I CANNOT RULE OUT A FEW PULSE-TYPE STORMS THROUGH
THURSDAY.  LATE THIS WEEKEND BEARS WATCHING THOUGH...AS AN 80 KNOT
JET STREAK AT 200 MB DIVES SOUTHEAST INTO THE FORECAST AREA.  THE
SHEAR MAY BE A LITTLE BETTER ABOUT THIS TIME AS WELL.

UNFORTUNATELY...IT DOESNT LOOK LIKE THERELL BE A WHOLE LOTTA
CHANGE IN THE OVERALL WEATHER PATTERN FROM SUNDAY THROUGH
WEDNESDAY.  THE VARIOUS LONG RANGER MODELS...INCLUDING THE GFS...
CANADIAN...ECMWF...NOT TO MENTION THE ENSEMBLES...ALL MAKE IT VERY
HARD NOT TO LEAN TOWARD AT LEAST CLIMATOLOGICAL TEMPERATURES AND
RAIN CHANCES.  A FRONT IS EXPECTED TO REMAIN VERY NEAR THE FORECAST
AREA THROUGH WEDNESDAY... AS SEVERAL SHORTWAVES DIVE DOWN AND ENTER
THE BASE OF THE LONGWAVE TROUGH.  AMPLE BOUNDARY LAYER MOISTURE AND
VARIOUS OUTFLOW BOUNDARIES SHOULD ALLOW SOME SHOWERS AND
THUNDERSTORMS TO BE SEEN EACH DAY.  THE DIFFICULTY WILL COME IN
TRYING TO PINPOINT (AT LEAST THIS FAR OUT) EXACTLY WHEN AND WHERE
THEY WILL FIRE.  LIKE I SAID BEFORE...ILL HEAD TOWARD CLIMATOLOGY
WITH CHANCE WORDING FOR SHOWERS AND STORMS THROUGH THE EXTENDED.  I
MAY BUMP UP OVERNIGHT LOWS A TAD...BUT HIGHS SHOULD BE JUST ABOUT
NORMAL.

ISC GRIDS HAVE BEEN SENT.  PRELIMINARY NUMBERS ARE LISTED BELOW.
FIRST PERIOD RAIN CHANCES ARE SUBJECT TO CHANGE BASED ON THE LATEST
RADAR IMAGES.

FCSTID =   10
JAN   73  89  73  92 /  50  40  40  20
MEI   73  89  72  92 /  50  50  40  20

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

BUTTS

ARZ074-075-LAZ007>009-015-016-023>026-MSZ018-019-025>066-072>074-
312051-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE JACKSON MS
351 PM CDT WED JUL 30 2003

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

.DAY ONE...TONIGHT AND THURSDAY...

...THUNDERSTORMS...
ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE ACROSS SOUTHEAST
ARKANSAS...NORTHEAST LOUISIANA...AND CENTRAL MISSISSIPPI THIS
EVENING. GUSTY WINDS TO 40 MPH...FREQUENT LIGHTNING AND PERIODS
OF HEAVY RAINFALL CAN GENERALLY BE EXPECTED...WITH A FEW STORMS
BECOMING SEVERE AND PRODUCING WIND GUSTS TO 60 MPH.

A STATIONARY FRONT WILL CONTINUE TO SINK SOUTHWARD INTO THE
FORECAST AREA THIS EVENING. THIS BOUNDARY WILL COMBINE WITH
DAYTIME HEATING AND MOIST AIR TO CONTINUE TO SPARK CONVECTION
THROUGH MIDNIGHT.

ISOLATED SEVERE THUNDERSTORMS ARE ALSO EXPECTED THURSDAY
AFTERNOON ACROSS SOUTHEAST ARKANSAS...NORTHEAST LOUISIANA...AND
CENTRAL MISSISSIPPI. THE FRONT WILL CONTINUE TO DRIFT TO THE
SOUTH AS AN UPPER LEVEL DISTURBANCE ENHANCES LIFT. THESE FACTORS
WILL COMBINE WITH DAYTIME INSTABILITY TO PRODUCE THUNDERSTORMS.
AGAIN EXPECT GUSTY WINDS TO 40 MPH...PERIODS OF HEAVY RAINFALL
AND FREQUENT LIGHTING.

.DAYS TWO THROUGH SEVEN...THURSDAY NIGHT THROUGH WEDNESDAY...

...DAYS TWO AND THREE...THURSDAY NIGHT THROUGH SATURDAY...
ISOLATED SEVERE THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
MISSISSIPPI AND PORTIONS OF NORTHEAST LOUISIANA ON FRIDAY AND
SATURDAY. THESE STORMS WILL BE LOCATED GENERALLY ALONG AND SOUTH
OF HIGHWAY 84. WIND GUSTS TO 40 MPH...FREQUENT LIGHTENING AND
PERIODS OF HEAVY RAIN ARE EXPECTED WITH THESE STORMS...WITH A FEW
OF THE STORMS BECOMING SEVERE AND PRODUCING WIND GUSTS TO 60 MPH.

THE FRONT WILL STALL ACROSS SOUTHERN MISSISSIPPI AND BEGIN TO
LIFT NORTHWARD AS ANOTHER FRONTAL SYSTEM BEGINS TO APPROACH FROM
THE NORTHWEST. UPPER LEVEL DISTURBANCES WILL ALSO MOVE THROUGH
THE FORECAST REGION. AS THESE FACTORS COMBINE WITH DAYTIME
INSTABILITY...THEY WILL HELP TO FOCUS THE BEST CHANCE FOR
THUNDERSTORM ACTIVITY ACROSS SOUTHERN MISSISSIPPI.

...DAYS FOUR THROUGH SEVEN...SATURDAY NIGHT THROUGH WEDNESDAY...
STRONG THUNDERSTORMS ARE POSSIBLE ACROSS NORTHEAST
LOUISIANA...SOUTHEAST ARKANSAS...AND NORTH CENTRAL MISSISSIPPI ON
SUNDAY. THE STORMS WILL GENERALLY BE LOCATED ALONG AND NORTH OF
INTERSTATE 20. GUSTY WINDS...PERIODS OF HEAVY RAINFALL AND
FREQUENT LIGHTNING CAN BE EXPECTED WITH THESE STORMS.

AS THE FRONTAL SYSTEM APPROACHES THE FORECAST AREA FROM THE
NORTHWEST...THE JET STREAM WILL ALSO BE MOVING ACROSS NORTHERN
MISSISSIPPI ON SUNDAY AND WILL ENHANCE LIFT IN THAT REGION. THIS
WILL ALLOW STRONG THUNDERSTORMS TO BE POSSIBLE ALONG AND NORTH OF
INTERSTATE 20. THESE STORMS ARE NOT EXPECTED TO BECOME SEVERE 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 THIS EVENING.

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