Area Forecast Discussion
Issued by NWS Mobile, AL

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000
FXUS64 KMOB 190926
AFDMOB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
426 AM CDT FRI SEP 19 2014

.SHORT TERM (TODAY AND TONIGHT)...THE COMBINATION OF A WEAK FRONT
JUST OFFSHORE ALONG WITH A SHORTWAVE MOVING OVER THE REGION HAS
RESULTED IN SIGNIFICANT CONVECTION OVER THE GULF WATERS EARLY THIS
MORNING. THE BEST CHANCE FOR CONVECTION OVER LAND AREAS THROUGH
EARLY MORNING WILL BE CLOSER TO THE IMMEDIATE COAST WHICH IS IN THE
VICINITY OF THE FRONTAL BOUNDARY. THE FORECAST FOR LATER TODAY IS A
LITTLE MORE UNCERTAIN AS GUIDANCE VARIES GREATLY ON CONVECTIVE
CHANCES. WHAT IS CERTAIN IS THAT THE AFOREMENTIONED SHORTWAVE WILL
MOVE EAST OF THE REGION BY MIDDAY WITH SIGNIFICANTLY DRIER AIR FROM
500 MB AND ABOVE MOVING INTO THE AREA ON THE BACKSIDE OF THE TROUGH.
MEANWHILE...THE STALLED FRONT NEAR THE COAST WILL BEGIN TO MOVE BACK
NORTH IN RESPONSE TO DIURNAL HEATING. JUST HOW FAR NORTH THE
BOUNDARY MAKES IT WILL DETERMINE WHERE STORM DEVELOPMENT WILL BE
POSSIBLE AS SIGNIFICANT MIXING OF DEWPOINTS IS LIKELY TO THE NORTH
OF THE BOUNDARY. GIVEN THE INCREASING MID-UPPER LEVEL DRYING AND
SUBSIDENCE TODAY...WILL CAP RAIN CHANCES AT 20-30%...WITH THE BEST
CHANCES OCCURRING ACROSS THE COASTAL COUNTIES AS THESE AREAS ARE
MOST LIKELY TO BE ON THE UNSTABLE SIDE OF THE BOUNDARY.

THE FRONT MOVES BACK TO THE SOUTH TONIGHT AS HIGH PRESSURE
STRENGTHENS OVER THE EASTERN SEABOARD AND RIDGES INTO THE SOUTHEAST
STATES. WILL MAINTAIN A SLIGHT CHANCE OF RAIN TO THE SOUTH OF THE
BOUNDARY. THE FRONT STALLS ALONG THE COAST OR JUST OFFSHORE
OVERNIGHT.

STAYED CLOSE TO GUIDANCE ON TEMPS WITH HIGHS REACHING THE UPPER 80S
TO NEAR 90. LOWS TONIGHT FALL INTO THE MID 60S WELL INLAND AND
AROUND 70 ALONG AND SOUTH OF THE I-10 CORRIDOR. 34/JFB

(SATURDAY THROUGH SUNDAY)...ACCORDING TO SHORT RANGE GFS...NAM...AND
EURO CALCULATIONS...AN UPPER LEVEL TROUGH WILL DEEPEN AND DEVELOP
INTO A CLOSED LOW AND IN OVER SOUTHEAST GEORGIA AND ITS OFFSHORE
REGIONS EARLY SATURDAY. A RIDGE WILL INTENSIFY OVER TEXAS FROM THE
RIO GRANDE VALLEY TO THE HILL COUNTRY AND EDWARDS PLATEAU REGION
KEEPING A DRY NORTHWEST FLOW ALOFT. A SURFACE RIDGE WILL EXTEND FROM
THE SOUTHERN APPALACHIANS AND WESTERN PIEDMONT REGION SOUTHWEST TO
THE CENTRAL GULF COAST ON SATURDAY. THIS FEATURE WILL BRING US LIGHT
NORTHEAST WINDS WITH LOWS RANGING FROM THE MID AND UPPER 60S INLAND
TO AROUND 70 NEAR THE COAST. THE UPPER LEVEL LOW WILL TO DRIFT AROUND
IN THE VICINITY OF NORTH FLORIDA AND SOUTHEAST GEORGIA AND THE
ADJACENT COASTAL WATERS SATURDAY...WHILE RIDGING ALOFT EXTENDS ACROSS
THE LOWER MISSISSIPPI AND TENNESSEE VALLEY REGION. DRY NORTH WINDS
ALOFT WILL CONTINUE SATURDAY. ISOLATED CONVECTION COULD BE RULED OUT
NEAR THE SEABREEZE BUT OUR CONFIDENCE REMAINS HIGH ENOUGH IN THE MOS
GUIDANCE AS WELL AS AVAILABLE WATER VAPOR AND INCREASING STABILITY
FROM THE PHYSICAL CALCULATIONS TO KEEP POPS BELOW 20 PERCENT ACROSS
OUR REGION SATURDAY AFTERNOON. PRECIPITABLE WATER STAYS AROUND OR
SLIGHTLY ABOVE AN ONE INCH ACROSS OUR AREA THROUGH SATURDAY AND
SUNDAY. LIFTED INDEX IS ABOUT +1.0 TO +1.5 OR SO CAUSING US TO
BELIEVE IT WOULD BE A DRY FORECAST THROUGH SUNDAY AT LEAST. HIGHS
SHOULD RANGE FROM THE MID 80S NEAR THE COAST TO THE UPPER 80S TO
AROUND 90 INLAND. 77/BD

.LONG TERM [SUNDAY NIGHT THROUGH THURSDAY]...A DRY NORTH UPPER FLOW WILL
PERSIST SUNDAY BEFORE THAT 500 MB RIDGE TO THE WEST OF US MOVES EAST
INTO OUR REGION BY EARLY NEXT WEEK. A WEAK FRONT WILL PUSH SOUTHWARD
INTO MISSISSIPPI AND ALABAMA EARLY MONDAY ON THE HEELS OF A
PERTURBATION MOVING SOUTHEAST ACROSS THE OHIO AND TENNESSEE VALLEYS
AROUND THE BASE OF A MID LEVEL TROUGH OVER THE EAST COAST. WE CAN SEE
THIS WEAK FRONT PUSHING INTO THE COASTAL REGION BY OVERNIGHT MONDAY
INTO TUESDAY MORNING BUT IT WILL NOT DO MUCH FOR RAIN SINCE THE
PRECIPITABLE WATER WILL NOT GET MUCH ABOVE 1.5 INCHES AND LIFTED
INDEX WILL STAY AROUND -1 TO -2. ONCE IT SWEEPS THE REGION THE
PRECIPITABLE WATER WILL DROP TO 0.75 INCHES AND LIFTED INDEX WILL
CLIMB TO +4 INDICATING A DRY FORECAST MONDAY NIGHT AND TUESDAY IN THE
DRY NORTHERLY FLOW PATTERN. WE KEPT A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS ALONG AND AHEAD OF THE APPROACHING FRONT MONDAY
AFTERNOON AND EVENING...AND WILL MAINTAIN A SLIGHT CHANCE OF SHOWERS
AND THUNDERSTORMS IN THE FORECAST ACROSS MOST LOCATIONS.
THEREAFTER...THAT RIDGE WILL CONTINUE TO BUILD OVER THE TEXAS HILL
COUNTRY KEEPING A DRY NORTHWEST FLOW ALOFT AND FORMING A WEAK LOW
ALOFT OFF THE FLORIDA COASTAL BEND IN THE NORTHEAST GULF OF MEXICO BY
WEDNESDAY. OUR REGION WILL REMAIN UNDER THE INFLUENCE OF THIS FEATURE
THROUGH THURSDAY WITH SCATTERED SHOWERS AND THUNDERSTORMS MOSTLY
OFFSHORE WITH A SLIGHT CHANCE ALONG THE DIURNAL EVOLUTION OF THE
SEABREEZE ELSEWHERE. TEMPERATURES REMAINING CLOSE TO SEASONAL. 77/BD

&&

.AVIATION...
12Z ISSUANCE
PREDOMINATE VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. BEST
CHANCE FOR AN ISOLATED STORM WILL BE ALONG THE I-10 CORRIDOR TODAY
AS A WEAK FRONT MOVES BACK INLAND. BRIEF MVFR/IFR CONDITIONS LIKELY
WHERE STORMS DEVELOP. STORM CHANCES DIMINISHES TONIGHT AS THE FRONT
MOVES BACK SOUTH. 34/JFB

&&

.MARINE...EAST-SOUTHEAST FLOW WILL GRADUALLY STRENGTHEN TODAY INTO
EARLY SATURDAY...BECOMING PREDOMINATELY EASTERLY TONIGHT...AS HIGH
PRESSURE STRENGTHENS OVER THE EASTERN SEABOARD AND BUILDS INTO THE
SOUTHEAST STATES. EXERCISE CAUTION LEVELS WILL LIKELY BE REACHED
OVER THE OPEN GULF WATERS TONIGHT INTO SATURDAY MORNING WITH SEAS
BUILDING TO 2-4 FT WITHIN 20 NM AND 3-5 FT FURTHER OFFSHORE. WINDS
AND SEAS DIMINISH FOR THE END OF THE WEEKEND INTO EARLY NEXT WEEK AS
THE HIGH WEAKENS. A COLD FRONT WILL APPROACH FROM THE NORTH ON
TUESDAY...WITH THE BOUNDARY STALLING ALONG THE COAST OR JUST
OFFSHORE. THE PRESSURE GRADIENT TIGHTENS BY TUESDAY NIGHT AND
EASTERLY WINDS ARE FORECAST TO INCREASE.

NUMEROUS SHOWERS AND THUNDERSTORMS WILL PERSIST OVER THE GULF WATERS
THIS MORNING WITH ACTIVITY GRADUALLY DIMINISH THIS AFTERNOON INTO
TONIGHT. WINDS AND SEAS WILL BE LOCALLY HIGHER IN THE STRONGER
STORMS. 34/JFB

&&

.PRELIMINARY POINT TEMPS/POPS...
MOBILE      89  70  88  70  89 /  30  20  10  10  10
PENSACOLA   89  71  86  71  87 /  30  20  10  10  10
DESTIN      88  72  85  73  86 /  30  20  10  10  20
EVERGREEN   90  65  87  65  90 /  20  20  05  10  10
WAYNESBORO  90  67  89  65  90 /  20  10  10  10  10
CAMDEN      90  65  88  66  90 /  20  10  05  10  10
CRESTVIEW   90  64  87  64  89 /  30  20  10  10  10

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
FL...NONE.
MS...NONE.
GM...NONE.
&&

$$








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