Severe Thunderstorm Warning 215, NWS Jackson, MS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
410 PM CDT SAT JUN 29 2002

FORECAST PROBLEM THIS PACKAGE...
SHOWER AND THUNDERSTORM CHANCES

OVER THE NEXT FEW DAYS...IT LOOKS LIKE SLIGHTLY DRIER AIR WILL
GRADUALLY FILTER INTO THE FORECAST AREA.  THERES NOT MUCH
DIFFERENCE IN THE MAJOR SHORT-TERM MODELS.  HOWEVER...ILL LEAN A
LITTLE MORE TOWARD THE AVN SOLUTION SINCE IT SEEMS TO HAVE A
SLIGHTLY BETTER GRASP ON THE MOISTURE FIELDS.

FOR THE VERY NEAR-TERM...FIRST PERIOD RAIN CHANCES WILL BE BASED ON
CURRENT RADAR TRENDS.  ILL PLAN ON CARRYING SCATTERED COVERAGE
ACROSS MAINLY EASTERN SECTIONS...WITH ISOLATED COVERAGE ELSEWHERE.

A 500 MB SHEAR AXIS...REMAINED ACROSS NORTHERN MISSISSIPPI AS OF THE
1200 UTC ANALYSIS THIS MORNING.  THIS AXIS IS PROGGED TO GRADUALLY
BECOME PINCHED OFF THROUGH MONDAY...AS RIDGING WORKS ITS WAY INTO
THE FORECAST AREA FROM THE NORTH AND SOUTH.  THE RESULTANT NORTHERLY
WIND COMPONENT (ALBEIT LIGHT) WILL DRY OUT THE ATMOSPHERE JUST A
BIT.  PRECIPITABLE WATER VALUES BETWEEN 1.75 AND 2 INCHES OVER THE
FORECAST AREA THIS MORNING SHOULD DROP SOME QUARTER TO HALF INCH
THROUGH MONDAY MORNING.  THIS STILL LEAVES PRECIPITABLE WATER VALUES
MORE THAN 100 PERCENT OF NORMAL FOR THIS TIME OF YEAR.  ALSO...A 500
MB THERMAL TROUGH WILL SERVE TO INCREASE INSTABILITY OVER THE AREA
TOMORROW AFTERNOON.  SO WITH A LITTLE MORE SUNSHINE EXPECTED...IM
TENTATIVELY PLANNING ON RAISING SHOWER AND THUNDERSTORM CHANCES
SLIGHTLY FOR SUNDAY.  WITH A FOCUSING MECHANISM THATS GRADUALLY
WEAKENING...I WOULD EXPECT A MORE DIURNAL TREND AND WILL WORD AS
SUCH IN THE ZONES.

THE COLD POCKET OF AIR AT 500 MB WILL MOVE EAST MONDAY...AS A
SURFACE LOW DEVELOPS NEAR COASTAL ALABAMA.  THIS FEATURE SHOULD
GENERALLY REMAIN OVER SOUTH-CENTRAL ALABAMA/NORTHERN FLORIDA
PANHANDLE EARLY IN THE WEEK...KEEPING MOST OF THE PRECIPITATION
(ASSOCIATED WITH THIS SYSTEM) EAST OF THE FORECAST AREA.  CLOSER TO
HOME...A WEAK UPPER-ATMOSPHERIC FLOW WILL CONTINUE WITH PRECIPITABLE
WATER VALUES REMAINING MORE THAN 100 PERCENT OF NORMAL.  STEEPENING
MID-TROPOSPHERIC LAPSE RATES SHOULD ALLOW SHOWER AND THUNDERSTORM
COVERAGE TO REMAIN SLIGHTLY BETTER THAN NORMAL...WITH NO MAJOR
CHANGE EXPECTED THROUGH TUESDAY.

FOR DAYS 4 THROUGH 7 (WEDNESDAY THROUGH SATURDAY)...IT LOOKS LIKE
THE MEDIUM-RANGE MODELS ARE GENERALLY IN AGREEMENT ON THE FINAL
OUTCOME.  LOW PRESSURE OVER THE NORTHERN FLORIDA PENINSULA WILL KEEP
MOISTURE PLENTIFUL ACROSS THE REGION INTO MID-WEEK.  AS THAT SYSTEM
MOVES EAST...RIDGING SHOULD BUILD INTO THE FORECAST AREA AT ALL
LEVELS FOR THE END OF THE WEEK.  THE AVN EXTENDED REDUCES BOUNDARY
LAYER MOISTURE TO AROUND 50 PERCENT OVER MUCH OF THE AREA BY
FRIDAY.  HOWEVER...THIS IS PROBABLY IN RESPONSE TO THE SLIGHTLY
STRONGER RIDGING EXHIBITED BY THE MODEL IN COMPARISON TO OTHER
MODELS.  SO FOR THE TIME BEING...I WONT MAKE MANY CHANGES IN THE
EXTENDED.

PRELIMINARY NUMBERS FOLLOW BELOW.

FCSTID = 10
JAN  71  92  71  92 /  20  30  30  40
MEI  70  91  70  92 /  30  40  30  40

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

BUTTS

ARZ074-075-LAZ007>009-015-016-023>026-MSZ018-019-025>066-072>074-
301200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE JACKSON MS
259 PM CDT SAT JUN 29 2002

...THUNDERSTORMS...
SCATTERED THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND
EVENING... ACROSS SOUTHEAST ARKANSAS... NORTHEAST LOUISIANA...
AND MUCH OF CENTRAL AND SOUTH MISSISSIPPI. NO SEVERE STORMS ARE
ANTICIPATED.

A MOIST AND UNSTABLE AIRMASS CONTINUES TO BE IN PLACE OVER THE
LOWER MISSISSIPPI VALLEY. SHOWERS AND THUNDERSTORMS ARE EXPECTED
TO CONTINUE DEVELOPING AS DAYTIME HEATING CONTINUES. LOCALLY
HEAVY RAINFALL... FREQUENT LIGHTNING... AND WIND GUSTS TO 50 MPH
ARE LIKELY WITH THE STRONGEST STORMS.  THE MOST WIDESPREAD
THUNDERSTORM ACTIVITY WILL OCCUR BETWEEN 4 PM AND 9 PM.

THE ACTIVATION OF STORM SPOTTERS...HAM RADIO OPERATORS...AND
EMERGENCY MANAGEMENT PERSONNEL SHOULD NOT BE NEEDED THROUGH
TONIGHT.

...FLOODING...
DUE TO A MOISTURE LADEN AIRMASS... THUNDERSTORMS WILL PRODUCE
LOCALLY SIGNIFICANT RAINFALL AMOUNTS IN SHORT TIME DURATIONS.
PONDING OF WATER ON ROADS AND IN LOW LYING AREAS MAY OCCUR...
ALONG AND EAST OF THE INTERSTATE 55 CORRIDOR.  DRIVERS SHOULD
EXERCISE CAUTION ON WET ROADWAYS TO AVOID HYDROPLANING.

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