111
FXUS64 KMOB 130459 AAB
AFDMOB
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MOBILE AL
1159 PM CDT MON AUG 12 2013
.AVIATION [13.06Z TAF ISSUANCE]...A PERSISTENT DEEP TROPICAL AIRMASS
WILL KEEP THE POTENTIAL OF A FEW SHOWERS GOING OVERNIGHT. CLOUD BASES
LOOK TO BE AT VFR LEVELS WITH CALM TO LIGHT WINDS. TUESDAY...SCATTERED
TO NUMEROUS SHRA/TSRA FORECAST THROUGH THE COURSE OF THE DAY WILL
BRING POTENTIAL OF LOCALLY HEAVY RAINS AT TIMES. VSBY BRIEFLY REDUCED
TO LIFR CATEGORIES IN THE STRONGER STORM CELLS TUESDAY ALONG WITH
BRIEF STRONG WIND GUSTS. /10
&&
.DISCUSSION... /ISSUED 359 PM CDT MON AUG 12 2013/
SHORT TERM (TONIGHT THROUGH TUESDAY)...AS MAIN UPPER SUPPORT
CONTINUES MOVES OFF AND DAMPENS TO THE EAST...EVENING SHOWERS AND
THUNDERSTORMS SHOULD BEGIN TO ERODE OFF MOSTLY FROM WEST TO
EAST...MOSTLY DURING THE EARLY TO MID EVENING HOURS WITH SOME
ISOLATED CONVECTION CONTINUING CLOSER TO THE COAST AND OFFSHORE. FOR
LATE TONIGHT INTO EARLY TUE ONLY WEAK LIFT IS NOTED IN THE MID LEVELS
WITH THE BETTER INSTABILITY OFFSHORE AND NEAR THE COAST SUPPORTING
THE DEVELOPMENT OF SCATTERED SHOWERS AND THUNDERSTORMS MOSTLY
OFFSHORE...NEARING THE COAST BY EARLY MORNING...SIMILAR TO THIS
MORNING. LATER IN THE DAY BETTER LIFT MOVING IN FROM THE NORTHWEST
SUPPORTS CONTINUED DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ACROSS
MOST OF THE CWFA LATE TUE MORNING AND TUE AFTERNOON. DUE TO SLIGHTLY
BETTER FORCING IN THE MID LEVELS WITH THIS NEXT ROUND ON TUE COMBINED
WITH THE CONTINUED DEEP LAYER MOISTURE IN THE LOWER LEVELS EXPECT
BETTER COVERAGE OF SHOWERS AND THUNDERSTORMS FOR LATE TUE MORNING
THROUGH TUE AFTERNOON. ALSO BY LATE TUE AFTERNOON SOME THUNDERSTORMS
COULD BE SLIGHTLY STRONGER THAN THE LAST COUPLE OF DAYS DUE TO THE
BETTER FORCING ALOFT. THIS PATTERN COULD ALSO LEAD TO SOME LOCALIZED
FLOODING BY LATE TUE ALSO. AS FOR TEMPS WILL LEAN TOWARDS THE WARMER
MAV GUIDANCE FOR LOWS TONIGHT AND UNDERCUT THE MAV GUIDANCE FOR HIGHS
TOMORROW DUE TO MORE CLOUDS AND THE BETTER COVERAGE OF PRECIP
THROUGHOUT MOST OF THE DAY. 32/EE
LONG TERM (TUESDAY NIGHT THROUGH MONDAY)...A BROAD UPPER LEVEL
TROUGH IS FORECAST TO AMPLIFY OVER THE SOUTHEAST MID TO LATE WEEK
WITH SEVERAL PIECES OF UPPER LEVEL ENERGY MOVING INTO THE BASE OF THE
TROUGH. IN ADDITION...A WEAK COLD FRONT IS FORECAST TO MOVE INTO THE
FORECAST AREA ON WEDNESDAY AND STALL WITH WEAK LOW PRESSURE CENTERS
DEVELOPING ALONG THE FRONT THROUGH THE END OF THE WEEK IN RESPONSE TO
THE AMPLIFIED UPPER LEVEL PATTERN. THESE FORCING MECHANISMS COMBINED
WITH PERSISTENT PRECIPITABLE WATERS OF 2.2-2.3 INCHES WILL SET THE
STAGE FOR ROUNDS OF HEAVY RAINFALL WEDNESDAY THROUGH FRIDAY. GIVEN
THIS PATTERN...OUR CONCERN FOR POSSIBLE FLOODING ISSUES IS
INCREASING... ESPECIALLY OVER COASTAL ALABAMA INTO THE WESTERN
FLORIDA PANHANDLE WHICH HAS SEEN RAINFALL VALUES 200-300% ABOVE
NORMAL IN THE PAST 60 DAYS. STORM TOTAL RAINFALL FORECASTS FROM THE
GFS/ECMWF SHOW GENERALLY 2-4 INCHES OF RAIN THROUGH FRIDAY...BUT
CONSIDERING THE HIGH PW AIRMASS AND THE FACT GLOBAL MODELS OFTEN
UNDERESTIMATE QPF IN THESE TROPICAL/SYNOPTICALLY FORCED
SETUPS...RAINFALL TOTALS COULD CERTAINLY BE DOUBLED IN MANY
LOCATIONS. WHILE NAILING DOWN SPECIFIC TOTALS IS DIFFICULT AT THIS
EARLY JUNCTURE...WE WILL UPDATE THE HAZARDOUS WEATHER OUTLOOK TO
MENTION THE INCREASED POTENTIAL FOR SIGNIFICANT RIVER RISES AND
FLOODING ISSUES MID TO LATE WEEK. WENT ON THE COOL SIDE OF GUIDANCE
FOR HIGHS BASED ON CLOUDS/RAIN.
UNCERTAINTY IN THE FORECAST INCREASES SIGNIFICANTLY OVER THE WEEKEND
AS THE GFS CONTINUES TO SHOW A TROPICAL WAVE MOVING OUT OF THE NW
CARIBBEAN AND ORGANIZING INTO A TROPICAL SYSTEM OVER THE SOUTH
CENTRAL GULF BY FRIDAY MORNING. THE GFS THEN BRINGS THE SYSTEM NORTH
AS A WEAK/SHEARED TROPICAL CYCLONE AS IT INTERACTS WITH THE
AFOREMENTIONED TROUGH AND BRINGS IT INTO THE FLORIDA PANHANDLE BY
LATE SATURDAY. THE ONLY SUPPORT THE GFS HAS AT THE MOMENT IS FROM THE
CANADIAN WHICH OFTEN DOES NOT HANDLE THE TROPICS WELL. THE ECMWF
CONTINUES TO SHOW NO SUCH FEATURE AS IT MOVES THE PARENT TROPICAL
WAVE INTO CENTRAL AMERICA. THE GFS ENSEMBLES ALSO SEEM TO BE SPLIT ON
DEVELOPMENT AS WELL. CONSIDERING THE TREMENDOUS UNCERTAINTY...WE WILL
CONTINUE TO LEAN TOWARD THE ECMWF FORECAST AND WILL KEEP A DAILY
CHANCE FOR RAIN AS THE UPPER LEVEL TROUGH PERSISTS OVER THE REGION
THROUGH NEXT MONDAY. WE WILL DEFINITELY HAVE TO KEEP A CLOSE EYE ON
THE TROPICS FOR THE NEXT SEVERAL DAYS. 34/JFB
&&
MARINE...HIGH PRESSURE OVER THE NORTH CENTRAL GULF WILL GRADUALLY
SHIFT WEST AND WEAKEN LATER THIS WEEK AS A DEEP TROF OF LOW PRESSURE
APPROACHES FROM THE NORTHWEST COMBINED WITH A WEAK AREA OF LOW
PRESSURE MOVING INTO THE LOWER GULF...POSSIBLY BECOMES BETTER
DEVELOPED LATER IN THE WEEK. WITH THIS PATTERN EXPECT BETTER
COVERAGE OF SHOWERS AND THUNDERSTORMS OVER THE MARINE AREA THROUGH
THE REMAINDER OF THE WEEK WITH WINDS AND SEAS GRADUALLY BUILDING BY
LATE IN THE WEEK. 32/EE
&&
.PRELIMINARY POINT TEMPS/POPS...
MOBILE 75 90 75 89 72 / 20 60 40 60 50
PENSACOLA 78 91 77 87 76 / 30 60 40 60 50
DESTIN 78 89 80 88 77 / 30 50 40 60 50
EVERGREEN 73 92 73 89 70 / 30 60 40 60 40
WAYNESBORO 73 91 74 88 69 / 30 70 40 60 40
CAMDEN 73 92 73 88 69 / 40 70 30 60 40
CRESTVIEW 73 92 73 90 71 / 20 60 40 60 50
&&
.MOB WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
FL...NONE.
MS...NONE.
GM...NONE.
&&
$$