Flash Flooding in Alabama, May 23, 2009

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MOBILE AL
745 AM CDT SAT MAY 23 2009

.UPDATE...THE AREA OF SFC LOW PRESSURE OVER THE GULF OF MEXICO IS
NOW CENTERED ABOUT 75 MILES SOUTH OF THE MOBILE AND CONTINUING TO
MOVE NORTHWARD. SATELLITE IMAGERY...RADAR DATA...AND SURFACE
OBSERVATIONS INDICATE THAT THE SYSTEM HAS CHANGED LITTLE IN
ORGANIZATION DURING THE LAST FEW HOURS. ADDITIONAL DEVELOPMENT OF
THIS SYSTEM IS BECOMING LESS LIKELY...SINCE THE CENTER WILL BE
MOVING ONSHORE ALONG THE MISSISSIPPI OR ALABAMA COAST LATER THIS
MORNING OR EARLY THIS AFTERNOON. THE NATIONAL HURRICANE CENTER NOW
INDICATES THAT THERE IS A LOW CHANCE...LESS THAN 30 PERCENT...OF
THIS SYSTEM BECOMING A TROPICAL CYCLONE BEFORE IT REACHES THE COAST
LATER TODAY. REGARDLESS OF DEVELOPMENT...HEAVY RAINS AND OCNL GUSTY
WINDS (UP TO AROUND 25 MPH...SLIGHTLY HIGHER NEAR THE COAST) ARE
EXPECTED ACROSS THE FCST AREA TODAY. RADAR AND UPPER AIR
OBSERVATIONS INDICATE THAT THE MID LEVEL CIRCULATION...WHICH IS
DISPLACED WELL NORTH OF THE SFC CENTER...IS CURRENTLY MOVING ASHORE
OVER MOBILE COUNTY OF ALABAMA. MOST OF THE HEAVY RAINFALL IS
ASSOCIATED WITH THIS FEATURE...AND RAINFALL TOTALS OF UP TO AROUND 2
INCHES PER HOUR WILL BE LIKELY ACROSS MOBILE COUNTY THIS EARLY
MORNING. THIS HEAVY RAIN WILL LIKELY LIFT NORTHWEST INTO INTERIOR
SOUTHEAST MISSISSIPPI LATER THIS MORNING. A FLASH FLOOD WATCH IS IN
EFFECT FOR THESE AREAS. STORM TOTAL RAINFALL ACCUMULATIONS ARE
EXPECTED TO BE 2 TO 4 INCHES WITH ISOLATED HIGHER TOTALS. THIS COULD
CAUSE SOME FLASH FLOODING AND LOCALIZED RUN-OFF...BUT SHOULD NOT BE
ENOUGH TO SIGNIFICANTLY EFFECT AREA RIVER STAGES. WILL CONTINUE TO
MONITOR THIS. ALONG THE COASTLINE...WE HAVE UPDATED THE COASTAL
FLOOD STATEMENT TO HIGHLIGHT THE POSSIBILITY OF SOME MINOR BEACH
EROSION AND SOME MINOR COASTAL FLOODING...PARTICULARLY AT PREVIOUSLY
ERODED AREAS...SUCH AS THE WEST END OF DAUPHIN ISLAND. AS THE LOW
MOVES ASHORE LATER TODAY...INCREASED SOUTHERLY WINDS WILL BRING
COASTAL WATER LEVELS UP THROUGH THIS AFTERNOON. MINOR COASTAL
FLOODING WITH TIDES POSSIBLY NEAR 3 FEET ABOVE NORMAL WILL BE
POSSIBLE IN THE LATE MORNING AND EARLY AFTERNOON HOURS AS WE
TRANSITION THROUGH ASTRONOMICAL HIGH TIDE. DANGEROUS RIP CURRENTS
WILL BE LIKELY ALONG AREA GULF BEACHES TODAY.  12/DS

...PREVIOUS FCST DISCN FROM 515 AM CDT SAT MAY 23 2009 FOLLOWS...

.SHORT TERM (TODAY AND TONIGHT)...A WET AND BREEZY MORNING WILL
CONTINUE ACROSS THE CENTRAL GULF COAST AS AN AREA OF LOW PRESSURE
CURRENTLY LOCATED ABOUT 140 MILES SOUTH OF MOBILE CONTINUES TO TRACK
NORTHWESTWARD. A COORDINATION CALL WITH THE NATIONAL HURRICANE
CENTER THIS MORNING INDICATED THAT WHILE THE SYSTEM HAS BECOME
SLIGHTLY BETTER ORGANIZED AND THEY HAVE NOW INDICATED A HIGH
PROBABILITY THAT THE SYSTEM MAY REACH TROPICAL DEPRESSION STATUS
BEFORE A LANDFALL ALONG THE MISSISSIPPI COAST BY AROUND 18Z TODAY...
THAT THE MID LEVEL CENTER REMAINS SEPARATED FROM THE SFC CENTER AND
SOME SHEAR IS CONTINUING TO KEEP DEEPER CONVECTION EAST OF THE
PRIMARY SFC CENTER. AS A RESULT...NHC WILL NOT BE INITIATING ANY
ADVISORIES DURING THE PREDAWN HOURS THIS MORNING. THEY DO INDICATE
HOWEVER THAT THE SYSTEM COULD BECOME A TROPICAL DEPRESSION AT ANY
TIME BEFORE MOVING INLAND LATER TODAY...SO THE SYSTEM SHOULD CONTINUE
TO BE MONITORED. WHETHER THE SYSTEM DEVELOPS FURTHER OR NOT...WE
WILL EXPERIENCE HEAVY RAIN...GUSTY WINDS AND ABOVE NORMAL TIDES
TODAY. AS THE WINDS BECOME MORE SOUTHERLY TODAY DANGEROUS RIP
CURRENTS WILL ALSO REMAIN LIKELY ALONG AREA BEACHES. HEAVY RAIN TO
THE NORTH OF THE LOW WILL MOVE NORTHWARD ACROSS THE FCST AREA THIS
MORNING. THE HEAVIEST RAINS ARE EXPECTED ACROSS SOUTHEAST MISSISSIPPI
AND PORTIONS OF SOUTHWEST ALABAMA. RAINFALL AMOUNTS IN THIS AREA ARE
EXPECTED TO RANGE FROM 2 TO 4 INCHES. A FLASH FLOOD WATCH HAS BEEN
ISSUED THROUGH THIS AFTERNOON FOR THIS AREA AS ADDITIONAL HEAVY RAINS
ARE POSSIBLE THROUGH THE DAY DEPENDING ON WHERE CONVERGENCE BANDS SET
UP ON THE EASTERN SIDE OF THE LOW AS IT MOVES INLAND. CHANCES OF RAIN
WILL DECREASE TO SCATTERED LATE TONIGHT AS THE LOW PRESSURE SYSTEM
PULLS FARTHER AWAY TO THE NORTHWEST. CLOUDS AND RAIN WILL HOLD HIGH
TEMPS DOWN INTO THE UPPER 70S TODAY WITH LOWS TONIGHT AROUND 70.
13/JC.12/DS

THIS AFTERNOONS WET MICROBURST RISK IS UNLIKELY.

(SUNDAY THROUGH MONDAY NIGHT)...A DEEP SOUTHERLY FLOW WILL PERSIST ACROSS
THE FCST AREA WITH THE REGION REMAINING ON THE WET SIDE OF THE SLOWLY
MOVING AREA OF LOW PRESSURE. THIS WILL RESULT IN A CONTINUATION OF
THE RAINY PATTERN OVER THE AREA...BUT A LITTLE MORE DIURNALLY DRIVEN
WITH THE HIGHER RAIN CHANCES IN THE AFTERNOONS...LOWER RAIN CHANCES
AT NIGHT. EVEN THOUGH MORE OF A DIURNAL RAIN PATTERN IS EXPECTED...
RAIN CHANCES WILL STILL BE MUCH ABOVE NORMAL...WITH LIKELY DAYTIME
POPS AND CHANCE NIGHTTIME POPS. THE PERSISTENT CLOUDS AND RAINS WILL
ALSO KEEP DAYTIME TEMPS BELOW NORMAL...GENERALLY IN THE UPPER 70S AND
LOWER 80S. OVERNIGHT LOWS WILL RANGE FROM THE MID 60S TO THE LOWER
70S. THE ONSHORE WIND FLOW WILL ALSO CONTINUE TO RESULT IN AN
INCREASED THREAT (HIGH RISK) OF DANGEROUS RIP CURRENTS IN THE SURF
ZONE AT AREA BEACHES THROUGH SUNDAY AND PERHAPS INTO MEMORIAL DAY.
12/DS

&&

.LONG TERM (TUESDAY THROUGH FRIDAY)...REALLY NOT A LOT OF CHANGE
DURING THE LONG TERM PERIOD FROM PREVIOUS. RAIN CHANCES WILL LOWER
SLIGHTLY...BUT REMAIN IN THE FCST...FOR THE REMAINDER OF THE WEEK AS
THE LOW PRESSURE AREA LIFTS AWAY FROM THE SOUTHEASTERN STATES. A MOIST
SOUTHERLY LOLVL WIND FLOW WILL PERSIST OVER THE REGION THROUGH
MIDWEEK...THE WINDS WILL BECOME MORE WESTERLY DURING THE LATE PART
OF THE WEEK AS A TROF MOVES INTO THE REGION FROM THE WEST. POPS
RANGING FROM 30 TO 50 PERCENT DURING THE DAYTIME HOURS AND 20 TO 30
PERCENT OVERNIGHT WILL CONTINUE. WENT SLIGHTLY BELOW MAV MOS
GUIDANCE FOR DAYTIME HIGHS IS SOME LOCATIONS AS ABUNDANT CLOUD COVER
AND RAINFALL COVERAGE WILL CONTINUE THROUGH MOST OF THE FCST
PERIOD...GENERALLY ACCEPTED MAV MOS NIGHTTIME LOW TEMPS. 12/DS

&&

.AVIATION (23/12Z ISSUANCE)...IFR CEILINGS EXPECTED AT ALL TAF SITES
THROUGH THE MORNING HOURS WITH HEAVY RAIN AND GUSTY WINDS. CIGS
INCREASE SOMEWHAT THIS AFTERNOON TO MVFR...HOWEVER RAIN CHANCES WILL
REMAIN HIGH AND A DROP TO IFR IS POSSIBLE IN AND NEAR SCATTERED TO
NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS THIS AFTERNOON AND
EVENING. IMPROVING CONDITIONS EXPECTED OVERNIGHT WITH CIGS
INCREASING TO VFR. 13/JC

&&

.MARINE...AN AREA OF LOW PRESSURE ABOUT 140 MILES SOUTH OF MOBILE
WILL CONTINUE TO MOVE TO THE NORTHWEST TODAY BRING WIDESPREAD
SHOWERS AND THUNDERSTORMS ALONG WITH GUSTY WINDS TO THE MARINE AREA.
SUSTAINED WINDS IN THE 20 TO 25 KNOT RANGE SHOULD BE EXPECTED ACROSS
MOST OF THE MARINE AREA...WITH LOCALLY HIGHER GUSTS...ESPECIALLY NEAR
CONVECTION. AS THE LOW MOVES WEST OF THE MARINE AREA...WINDS WILL
BECOME SOUTHERLY AND GRADUALLY DECREASE AS THE LOW MOVES INLAND LATE
THIS AFTERNOON AND TONIGHT. A GENERALLY LIGHT ONSHORE FLOW WILL FOLLOW
THROUGH MIDWEEK. 13/JC

&&

.FIRE WEATHER...BREEZY AND RAINY CONDITIONS EXPECTED ACROSS MOST OF
THE AREA TODAY...WITH RAIN CHANCES REMAINING HIGH OVER THE NEXT
SEVERAL DAYS. NO FIRE WEATHER WATCHES OR WARNINGS NEEDED. 12/DS

&&

.PRELIMINARY POINT TEMPS/POPS...
MOBILE      80  69  81  69 / 100  50  70  40
PENSACOLA   80  70  80  70 / 100  60  70  40
DESTIN      80  71  79  72 /  80  70  60  40
EVERGREEN   78  68  81  66 / 100  70  70  40
WAYNESBORO  78  67  82  67 / 100  60  70  40
CAMDEN      77  68  81  66 / 100  70  70  40

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...FLASH FLOOD WATCH UNTIL 7 PM SATURDAY FOR THE FOLLOWING ZONES:
     LOWER BALDWIN...LOWER MOBILE...UPPER BALDWIN...UPPER
     MOBILE...AND WASHINGTON.

FL...NONE.
MS...FLASH FLOOD WATCH UNTIL 7 PM SATURDAY FOR THE FOLLOWING ZONES:
     GEORGE...GREENE...PERRY...STONE...AND WAYNE.

GM...SMALL CRAFT ADVISORY UNTIL 7 PM SATURDAY FOR THE FOLLOWING
     ZONES: AND MOBILE BAY.

     SMALL CRAFT ADVISORY UNTIL 10 PM SATURDAY FOR THE FOLLOWING
     ZONES: COASTAL WATERS FROM DESTIN TO PENSACOLA FL OUT 20
     NM...COASTAL WATERS FROM PENSACOLA FL TO PASCAGOULA MS OUT
     20 NM...WATERS FROM DESTIN TO PENSACOLA FL FROM 20 TO 60
     NM...AND WATERS FROM PENSACOLA FL TO PASCAGOULA MS FROM 20
     TO 60 NM.

&&

HAZARDOUS WEATHER OUTLOOK...MESOSCALE UPDATE...
NATIONAL WEATHER SERVICE MOBILE AL
1027 AM CDT SAT MAY 23 2009

ALZ051>064-FLZ001>006-GMZ630-650-655-670-675-MSZ067-075-076-078-
079-241200-
CHOCTAW-WASHINGTON-CLARKE-WILCOX-MONROE-CONECUH-BUTLER-CRENSHAW-
ESCAMBIA-COVINGTON-UPPER MOBILE-UPPER BALDWIN-LOWER MOBILE-
LOWER BALDWIN-INLAND ESCAMBIA-COASTAL ESCAMBIA-INLAND SANTA ROSA-
COASTAL SANTA ROSA-INLAND OKALOOSA-COASTAL OKALOOSA-MOBILE BAY-
COASTAL WATERS FROM PENSACOLA FL TO PASCAGOULA MS OUT 20 NM-
COASTAL WATERS FROM DESTIN TO PENSACOLA FL OUT 20 NM-
WATERS FROM PENSACOLA FL TO PASCAGOULA MS FROM 20 TO 60 NM-
WATERS FROM DESTIN TO PENSACOLA FL FROM 20 TO 60 NM-WAYNE-PERRY-
GREENE-STONE-GEORGE-
1027 AM CDT SAT MAY 23 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST
MISSISSIPPI...SOUTHWEST ALABAMA...THE WESTERN FLORIDA PANHANDLE
...AND THE ADJACENT GULF COASTAL WATERS OF ALABAMA AND NORTHWEST
FLORIDA.

.DAY ONE...TODAY AND TONIGHT.

...SURFACE LOW MOVING INLAND WILL BRING GUSTY WINDS AND TORNADO
THREAT IS INCREASING EAST OF I-65 THIS AFTERNOON...

THROUGH EARLY AFTERNOON...THE CENTER OF A STRONG LOW PRESSURE SYSTEM
WILL SLOWLY MOVE FROM MOBILE COUNTY ALABAMA NORTHWARD ALONG THE
ALABAMA AND MISSISSIPPI STATE LINE. BANDS OF SHOWERS AND
THUNDERSTORMS PRODUCING VERY HEAVY RAINFALL OF ONE TO TWO INCHES PER
HOUR WILL CONTINUE TO SPREAD INLAND ACROSS SOUTHEAST MISSISSIPPI AND
SOUTHWESTERN ALABAMA. SUSTAINED WINDS OF 20 TO 30 MPH WITH FREQUENT
GUSTS BETWEEN 35 AND 55 MPH ARE ALSO POSSIBLE. RADAR OBSERVATION
SUPPORTS THIS.

...A FLASH FLOOD WATCH IS IN EFFECT THROUGH THIS EVENING...
THE GOOD NEWS IS THAT THE LOW PRESSURE IS MOVING TO THE NORTH
QUICKLY AND THIS WILL CUT DOWN ON RAINFALL AMOUNTS LEAVING THREE TO
FIVE INCH TOTALS LOCALLY WITH A GENERAL ONE TO THREE INCHES OVER THE
REGION.  A FLASH FLOOD WARNING OR TWO MAY BE ISSUED TODAY ON A LOCAL
BASIS. THUS...A WIND ADVISORY IS IN EFFECT UNTIL 4 PM CDT THIS
AFTERNOON.

...A COASTAL FLOOD WARNING IN EFFECT UNTIL 6 PM CDT THIS EVENING...
INCREASED SOUTHERLY WINDS AND SWELLS WILL BRING COASTAL WATER LEVELS
UP AND ONTO BEACH AREAS OF MOBILE COUNTY...ESPECIALLY THE WEST END
OF DAUPHIN ISLAND...THROUGH THIS AFTERNOON. THIS WILL RESULT IN
MAJOR BEACH EROSION AND COASTAL FLOODING PARTICULARLY AT PREVIOUSLY
ERODED AREAS SUCH AS THE WEST END OF DAUPHIN ISLAND. TIDES OF 2 TO 3
FEET ABOVE PREDICTED ARE OCCURRING AS WE TRANSITION THROUGH
ASTRONOMICAL HIGH TIDE.

...AREA RIVERS ARE NOT EXPECTED TO GO INTO FLOOD...

...HIGH RISK FOR RIP CURRENTS TODAY AND TONIGHT...
THE SURF WILL BE ROUGH THROUGH SUNDAY ALONG AREA BEACHES DUE TO
WINDS BECOMING ONSHORE AND A RELATIVE HIGH TIDAL RANGE.

...SMALL CRAFT ADVISORY IN EFFECT TODAY OFFSHORE AND ALONG AREAS
BAYS AND WATERWAYS...
OVER THE MARINE AREA...WINDS WILL TURN SOUTHEAST TODAY AS THE LOW
PRESSURE MOVES AWAY FROM THE COAST. WINDS AND SEAS WILL REMAIN IN
THE SMALL CRAFT ADVISORY RANGE AND BAYS AND WATERWAYS WILL BE VERY
ROUGH THIS MORNING... SUBSIDING TO ROUGH LATE.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH THROUGH FRIDAY.

GOOD CHANCES OF SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH
MONDAY AS A LOW PRESSURE TROUGH LINGERS ACROSS THE AREA. LOCALLY
HEAVY RAINFALL WILL REMAIN A POSSIBILITY THROUGH MONDAY. THE
REMAINDER OF THE WEEK WILL FEATURE SCATTERED MAINLY AFTERNOON AND
EARLY EVENING SHOWERS AND THUNDERSTORMS.

THE HIGH RISK OF RIP CURRENTS IN THE SURF ZONE AT AREA BEACHES WILL
CONTINUE OVER THE HOLIDAY WEEKEND.

.SPOTTER INFORMATION STATEMENT...

ACTIVATION OF EMERGENCY MANAGEMENT AND STORM SPOTTERS FOR SEVERE
WEATHER IS NOT EXPECTED.