Flash Flooding in Mississippi, December 21 to 22, 2006

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
1024 PM CST THU DEC 21 2006

.UPDATE...WILL EXPAND THE FLASH FLOOD WATCH TO INCLUDE
WASHINGTON...CLARKE AND CHOCTAW COUNTIES IN SOUTHWEST ALABAMA.
BASED ON THE LATEST HPC EXCESSIVE RAINFALL GRAPHIC AND RAINFALL
RATES...THE RISK OF FLASH FLOODING HAS EXPANDED EASTWARD BUT STILL
INCLUDES SOUTHEAST MISSISSIPPI.  UPDATE OUT SOON. /29

*** PREVIOUS DISCUSSION FOLLOWS ***

.SHORT TERM TONIGHT THROUGH SUNDAY NIGHT...VERY SLOW EASTWARD
PROGRESSION OF THE PRECIPITATION BAND WILL ENCOMPASS THE ENTIRE
FORECAST AREA OVERNIGHT INTO FRIDAY MORNING. THERE IS THE POTENTIAL
FOR HEAVY RAIN...ESPECIALLY ACROSS THE NORTHWEST ZONES. A FLASH
FLOOD WATCH HAS BEEN ISSUED UNTIL NOON FRIDAY FOR THE INLAND
PORTIONS OF SOUTHEAST MISSISSIPPI. DUE TO THE SLOW MOVEMENT OF A
WEAK FRONT ACROSS THE SOUTHERN STATES TONIGHT AND EARLY
FRIDAY...ADDITIONAL RAINFALL AMOUNTS OF 3 TO 5 INCHES OF RAINFALL IS
POSSIBLE IN THE WATCH AREA. A COLD FRONT WILL MOVE OUT OVER THE GULF
LATE FRIDAY...WITH A RIDGE OF HIGH PRESSURE BUILDING IN FROM WEST.
THIS WILL GIVE A REPRIEVE FROM THE RAIN ON SATURDAY AS THE FRONT
STALLS OVER THE GULF. A MORE DYNAMIC UPPER LEVEL DISTURBANCE WILL
CROSS THE NORTHERN GULF LATE SATURDAY NIGHT AND SUNDAY...DEVELOPING
A STRONG SURFACE LOW PRESSURE AREA OVER THE NORTHEASTERN GULF ALONG
THE FRONT. THIS LOW WILL TRACK TO THE NORTHEAST TOWARD THE FLORIDA
PANHANDLE/BIG BEND REGION SUNDAY AND SUNDAY NIGHT...INCREASING RAIN
CHANCE ONCE AGAIN. WE WILL BE MOISTURE STARVED BY CHRISTMAS EVE AS
THIS SYSTEM MOVES OFF TO THE NORTHEAST...SO HAD TO MAKE MAJOR
DOWNWARD ADJUSTMENTS TO THE POPS (FROM LIKELY DOWN TO SLIGHT CHANCE)
IN THE TRANSITION PERIOD. /22

.LONG TERM MONDAY THROUGH WEDNESDAY...SURFACE HIGH PRESSURE AND A
COOLER STABLE AIR MASS WILL BUILD ACROSS THE FORECAST AREA IN THE
WAKE OF DEPARTING SURFACE LOW. HOWEVER...BASE OF A HIGHLY AMPLIFIED
TROUGH IN THE UPPER LEVELS WILL MOVE ACROSS THE DEEP SOUTH ON
CHRISTMAS DAY...SO KEPT SLIGHT CHANCE IN THE FORECAST. STRONG LARGE
HIGH PRESSURE WILL DOMINATE THE WEATHER PATTERN TUESDAY AND
WEDNESDAY...SO TOOK THE LIBERTY OF REMOVING CHANCES OF PRECIP FROM
THIS PORTION OF THE EXTENDED FORECAST TO BE MORE IN AGREEMENT WITH
THE SURROUNDING OFFICES. TEMPERATURES WILL BE VERY CLOSE TO NORMAL.
/22

&&

.MARINE...A WEAK FRONT SLIPS ACROSS THE COASTAL WATERS FRIDAY...
BRINGING AN INCREASED COVERAGE OF SHOWERS AND POSSIBLY A FEW
THUNDERSTORMS. THE FRONT STALLS OVER THE CENTRAL GULF EARLY IN THE
WEEKEND. A SURFACE FRONTAL LOW PRESSURE SYSTEM FORMS UP ON OLD GULF
FRONT SUNDAY. THE LOW TRACKS NORTHEAST THROUGH THE NORTHERN
GULF...LIFTING UP INTO THE CAROLINAS CHRISTMAS DAY. LATE IN THE
WEEKEND...BOATING CONDITIONS ARE FORECAST TO BECOME MORE HAZARDOUS
WELL OFFSHORE AS THE LOW MOVES THROUGH. CONDITIONS IMPROVE TUESDAY
AS HIGH PRESSURE SLIDES EAST ACROSS THE SOUTHERN STATES. /10

&&

.FIRE WEATHER...A SLOW MOVING FRONTAL BOUNDARY WILL BE MOVING SLOWLY
EAST TOWARD THE REGION THROUGH FRIDAY...KEEPING THINGS RATHER
UNSETTLED WITH NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS. A BREAK
IN THE RAINFALL IS EXPECTED ON SATURDAY...BUT RAINFALL POTENTIAL
INCREASES ONCE AGAIN SUNDAY AND SUNDAY NIGHT AS A LOW PRESSURE AREA
MOVES NORTHEAST FROM THE GULF OF MEXICO INTO THE FLORIDA PANHANDLE.
/22

&&

.PRELIMINARY POINT TEMPS/POPS...
MOBILE      62  68  46  68 / 100 100  50  10
PENSACOLA   64  71  53  67 / 100 100  60  10
DESTIN      64  71  56  68 / 100 100  70  20
EVERGREEN   61  67  48  69 / 100 100  50  10
WAYNESBORO  58  65  42  64 / 100 100  20  10
CAMDEN      59  66  46  67 / 100 100  30  10

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...FLASH FLOOD WATCH UNTIL NOON FRIDAY FOR THE FOLLOWING ZONES:
     CHOCTAW...CLARKE AND WASHINGTON.
FL...NONE.
MS...FLASH FLOOD WATCH UNTIL NOON FRIDAY FOR THE FOLLOWING ZONES:
     GEORGE...GREENE...PERRY...STONE...AND WAYNE.
GM...NONE.

&&

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE MOBILE AL
1118 AM CST THU DEC 21 2006

ALZ051>064-FLZ001>006-GMZ630-650-655-670-675-MSZ067-075-076-078-079-
221200-
COASTAL WATERS FROM DESTIN TO PENSACOLA FL OUT 20 NM-
WATERS FROM DESTIN TO PENSACOLA FL FROM 20 TO 60 NM-
COASTAL WATERS FROM PENSACOLA FL TO PASCAGOULA MS OUT 20 NM-
WATERS FROM PENSACOLA FL TO PASCAGOULA MS FROM 20 TO 60 NM-
MOBILE BAY-BALDWIN COASTAL-BALDWIN INLAND-BUTLER-CHOCTAW-CLARKE-
CONECUH-COVINGTON-CRENSHAW-ESCAMBIA-ESCAMBIA COASTAL-ESCAMBIA INLAND-
GEORGE-GREENE-MOBILE COASTAL-MOBILE INLAND-MONROE-OKALOOSA COASTAL-
OKALOOSA INLAND-PERRY-SANTA ROSA COASTAL-SANTA ROSA INLAND-STONE-
WASHINGTON-WAYNE-WILCOX-
1118 AM CST THU DEC 21 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR INLAND SOUTHEAST
MISSISSIPPI...SOUTHWEST ALABAMA...THE WESTERN FLORIDA
PANHANDLE...AND ADJACENT COASTAL WATERS.

.DAY ONE...TODAY THROUGH TONIGHT.

A LARGE SHIELD OF MODERATE TO HEAVY SHOWERS AND ISOLATED
THUNDERSTORMS WILL CONTINUE TO TRAIN OR MOVE OVER THE SAME AREAS OF
SOUTHEAST MISSISSIPPI AND THE INTERIOR OF SOUTHWEST ALABAMA THROUGH
THE DAY...CONTINUING INTO TONIGHT. THE MAIN AREAS AFFECTED LOOK TO BE
GENERALLY NORTHWEST OF INTERSTATE 65 THROUGH THE REMAINDER OF THE
DAY. 1 TO 2 INCHES OF ADDITIONAL RAIN CANNOT BE RULED OUT IN THESE
AREAS...WHICH COULD CAUSE SOME NUISANCE TYPE FLOODING IN LOWER LYING
AREAS...UNDERPASSES...AND OTHER POOR DRAINAGE AREAS. A LATER
ARRIVAL TO A MORE STEADY RAIN IS FORECAST INTO THE REMAINDER OF
THE AREA...INCLUDING THE GULF COAST.

SEVERE WEATHER IS NOT ANTICIPATED.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

A COLD FRONT MOVES ACROSS THE AREA FRIDAY...BECOMING STATIONARY
ACROSS THE SOUTH CENTRAL GULF OF MEXICO OVER THE WEEKEND.
PROJECTIONS ARE FOR 2 TO 4 INCHES OF STORM TOTAL RAINS ACROSS THE
FORECAST AREA BY FRIDAY NIGHT. THIS AMOUNT OF RAIN SHOULD NOT CAUSE
ANY SIGNIFICANT RIVER FLOODING BUT MAY CAUSE SOME MINOR FLOODING OF
LOW LYING AND POOR DRAINAGE AREAS. THE PROBABILITY FOR WIDESPREAD
HAZARDOUS WEATHER IS LOW AT THIS TIME.

ANOTHER ROUND OF RAINS AND ISOLATED THUNDERSTORMS IS EXPECTED
SATURDAY NIGHT AND SUNDAY AS LOW PRESSURE DEVELOPS ON THE STATIONARY
FRONT OVER THE WESTERN GULF AND MOVES RAPIDLY NORTHEAST.

BOATING CONDITIONS COULD BECOME HAZARDOUS LATE IN THE WEEKEND. WINDS
OVER THE MARINE AREA LOOK TO INCREASE AND SEAS BUILD BY SUNDAY AS THE
LOW DEVELOPS.

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW AT THIS
TIME TUESDAY AND WEDNESDAY AS HIGH PRESSURE SLIDES EAST OVER THE
SOUTHERN UNITED STATES.

.SPOTTER INFORMATION STATEMENT...

ACTIVATION OF STORM SPOTTERS OR EMERGENCY MANAGEMENT PERSONNEL FOR
SEVERE WEATHER OPERATIONS WILL NOT BE REQUIRED THROUGH TONIGHT.