Flash Flood Warning 23, NWS Jackson, MS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
340 AM CST MON FEB 23 2004

.DISCUSSION...FIRST ROUND OF WARM ADVECTION ISENTROPIC UPGLIDING
SHRA/ELEVATED TSRA WILL CROSS THE CWFA THROUGH EARLY THIS AFTERNOON.
MEANWHILE...MID LEVEL CLOSED LOW DEVELOPS OVER AZ TODAY UNDER A
STRONG SRN BRANCH UPPER JET AXIS DIVING WELL DOWN INTO MEXICO AND UP
INTO SERN STATES. SATELLITE CURRENTLY SENSING SOME SPOTS OF PRECIP
WATER VALUES NEAR 1.6 IN CENTRAL GULF SPREADING NWD TOWARD A
STATIONARY COASTAL FRONTAL ZONE THAT IS PROGGED TO MOVE VERY LITTLE
FOR NEXT SEVERAL DAYS.

.SHORT TERM...WIDESPREAD CLOUD COVER WILL HELP MAINTAIN MILD TEMP
REGIME AS AT LEAST TWO PRIMARY ROUNDS OF HEAVIER RAINFALL PASS
ACROSS THE REGION. MODELS RATHER CONSISTENT IN FOCUSING MOST OF
HEAVY RAIN OVER SRN MS WHERE MOST RECENT HEAVY RAINFALL EVENTS HAVE
BEEN OBSERVED OVER THE PAST MONTH. BEST K INDEXES...850MB THETA E
AIR OF 325-330K...LOW LEVEL MOISTURE CONVERGENCE...AND EVEN 200MB
DIVERGENCE ALL SUPPORT BEST RAINFALL OCCURRING OVER SRN MS. AS THE
FIRST OF MANY SHORTWAVES MOVE QUICKLY NEWD FROM SRN TX...IN THE
FIRST ROUND...QPF AMOUNTS OF 1 TO 1.5 INCHES ARE POSSIBLE ALONG THE
HIGHWAY 84 CORRIDOR WITH GENERALLY LESS THAN 1 INCH FARTHER N.
PRESENCE OF COASTAL FRONT AND CONTINUED UPGLIDE SHOULD BE ENOUGH FOR
SOME PERIODIC SHRA TONIGHT AND TUESDAY BEFORE THE SECOND HEAVY ROUND
ARRIVES. IN THAT SECOND ROUND...STILL EXPECTED FOR TUESDAY NIGHT...
AMOUNTS OF 1 TO 2 INCHES WILL BE POSSIBLE FOR NEARLY THE SAME
LOCATIONS. THESE PROJECTIONS WOULD LEAD TO NEEDING A FLOOD WATCH FOR
TUESDAY NIGHT INTO WEDNESDAY ACROSS SRN 1/3 OF CWFA ASSUMING THAT
THE INITIAL RAINS MATERIALIZE WHERE EXPECTED.

WILL ISSUE A FLOOD POTENTIAL OUTLOOK FOR THAT POSSIBILITY FOR NOW.
RAINFALL SHOULD FINALLY BEGIN DIMINISHING WEDNESDAY AS UPPER LOW
MOVES EWD ALONG INTERSTATE 10. BY EARLY THURSDAY...WRAP AROUND
MOISTURE SHOULD BE DRYING UP OVER ERN MS AS LOW LEVEL PACIFIC
AIRMASS MOVES INTO THE REGION.
&&

.LONG TERM...MID LEVEL SHORTWAVE RIDGE AXIS MOVES INTO THE SRN
UNITED STATES FRIDAY AND SATURDAY MAKING FOR A DRY AND WARMER FIRST
HALF OF THE WEEKEND. NEXT SRN STREAM IMPULSE HEADS IN FOR SUNDAY AND
MONDAY. AGAIN HERE...THE UKMET PROBABLY THE MODEL OF CHOICE WITH A
SLOWER AND STRONGER CLOSED LOW SYSTEM AT THE END OF THE FORECAST
PERIOD. WOULD LEAN TOWARD THIS SOLUTION WHICH HAS BEEN MORE CORRECT
IN THE RECENT SPLIT FLOW LONGWAVE PATTERN.
&&

JACKSON   56  48  59  47 /  90  70  70  90
MERIDIAN  54  49  61  49 /  90  70  70  90
&&

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE JACKSON MS
0643 AM CST MON FEB 23 2004

ARZ074-075-LAZ007>009-015-016-023>026-MSZ018-019-025>066-072>074-
241243-
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-
0643 AM CST MON FEB 23 2004

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

.DAY ONE...TODAY AND TONIGHT...

...FLOODING...
LOCALLY HEAVY RAINS ARE POSSIBLE ACROSS PORTIONS OF CENTRAL
MISSISSIPPI AND NORTHEAST LOUISIANA ALONG AND SOUTH OF THE
INTERSTATE TWENTY CORRIDOR  TODAY . RAINFALL TOTALS THROUGH THIS
PERIOD COULD REACH UP FROM ONE TO  ONE AND A HALF  INCHES  ACROSS
EAST LOUISIANA AND  SOUTH MISSISSIPPI. SUCH PRECIPITATION COULD
CAUSE PONDING OF WATER IN LOW LYING AREAS...ESPECIALLY
CONSIDERING THE RAINFALL RECEIVED IN THESE AREAS OVER THE PAST
MONTH.

RETURNING LOW LEVEL SOUTHERLY FLOW  HAS BROUGHT  ABUNDANT
MOISTURE INTO THE REGION EARLY TODAY.  THE HEAVIEST RAINFALL WILL
BE CONCENTRATED SOUTH OF INTERSTATE TWENTY WHERE AT LEAST ONE TO
ONE AND HALF  INCHES OF RAINFALL IS EXPECTED. EMBEDDED
THUNDERSTORMS  IN EAST LOUISIANA AND  SOUTH MISSISSIPPI WILL LEAD
TO LOCALLY HIGHER AMOUNTS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY...

...DAYS TWO AND THREE...TUESDAY AND WEDNESDAY...
A POWERFUL UPPER LEVEL LOW PRESSURE SYSTEM WILL CONTINUE TO
IMPACT THE REGION TUESDAY NIGHT THROUGH WEDNESDAY.  ONE STRONG
ASSOCIATED WAVE OF SURFACE LOW PRESSURE WILL SLIDE FROM WEST TO
EAST NEAR THE GULF COAST DURING THIS TIME PERIOD. THE EXACT PATH
OF THIS  SURFACE LOW IS  EXPECTED TO TAKE REMAINS UNCERTAIN.
GIVEN THE ENHANCED INSTABILITY AND WIND SHEAR ANTICIPATED IN
THEIR VICINITY...SEVERE THUNDERSTORMS CANNOT BE RULED OUT ACROSS
EXTREME SOUTHEASTERN MISSISSIPPI. THE MAIN RISK OF DAMAGING
STORMS IN THE FORECAST AREA WILL BE ALONG AND SOUTH OF THE
HIGHWAY 98 CORRIDOR  FOR TUESDAY NIGHT INTO EARLY WEDNESDAY.
ADDITIONALLY...THE POTENTIAL FOR LOCALLY HEAVY RAINFALL WILL
CONTINUE FOR TUESDAY NIGHT INTO WEDNESDAY
AS THE ASSOCIATED SURFACE LOW PASSES SOUTH OF THE REGION FOR
AREAS SOUTH OF INTERSTATE 20. THUNDERSTORMS WILL BE MORE LIKELY
SOUTH OF INTERSTATE 20.

...DAYS FOUR THROUGH SEVEN...THURSDAY THROUGH SUNDAY...
ANOTHER STRONG UPPER TROUGH WILL AFFECT THE REGION FROM THE
PLAINS ON SUNDAY WITH AN ASSOCIATED COLD FRONT. IT WILL HAVE
ENOUGH TIME TO BRING IN GOOD LOW LEVEL MOISTURE FROM THE GULF.
THIS WILL PROVIDE ENOUGH INSTABILITY FOR THE POSSIBILITY OF
SEVERE STORMS.

.SPOTTER CALL TO ACTION STATEMENT...
THE ACTIVATION OF STORM SPOTTERS...HAM RADIO OPERATORS...AND
EMERGENCY MANAGEMENT PERSONNEL...IN SUPPORT OF HAZARDOUS WEATHER
OPERATIONS....MAY BE NEEDED TUESDAY NIGHT AND WEDNESDAY...BUT NOT
EXPECTED TO BE NEEDED THURSDAY THROUGH SUNDAY.

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