Area Forecast Discussion
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FXUS64 KMOB 220527 AAB
AFDMOB

AREA FORECAST DISCUSSION...UPDATE TO AVIATION
NATIONAL WEATHER SERVICE MOBILE AL
1125 PM CST FRI NOV 21 2014

.AVIATION...
06Z ISSUANCE...VFR CONDITIONS EXPECTED OVERNIGHT THROUGH MOST OF
SATURDAY. SATURDAY EVENING...AS AN UPPER SYSTEM APPROACHES...
ISENTROPIC UPGLIDE IS EXPECTED TO SET UP OVER COASTAL AREAS...THEN
SHIFT INLAND AS A WARM FRONT ORGANIZES ALONG THE COAST. CIGS
DROPPING TO LOW MVFR LEVELS...WITH LOCAL IFR LEVELS...EXPECTED ALONG
THE COAST AS 06S SUNDAY APPROACHES. THE FARTHER INLAND ONE
GOES...CIGS WILL INCREASE TO GENERAL UPPER END MVFR/LOWER VFR
LEVELS. THIS IS AFTER THE FORECAST...BUT AS SUDNAY DAYTIME
APPROACHES...DECREASING CIGS ALONG WITH INCREASING PRECIP COVERAGE
LIKELY.

/16

&&

.SHORT TERM (TONIGHT THROUGH SUNDAY)...SURFACE HIGH PRESSURE WILL
CONTINUE TO MOVE EASTWARD AND OFF THE MID ATLANTIC COAST BY SATURDAY
AFTERNOON. THIS WILL RESULT IN AN CONTINUED EASTERLY FLOW THROUGH
SATURDAY AFTERNOON. AS THE UPPER LEVEL SHORTWAVE BEGINS TO EJECT
EASTWARD ON SATURDAY...MOISTURE LEVELS WILL INCREASE FROM THE SOUTH.
RAIN CHANCES WILL ALSO INCREASE DURING THE AFTERNOON ESPECIALLY NEAR
THE COAST AND OFFSHORE. THE HIGHEST PROBABILITIES WILL REMAIN
OFFSHORE THROUGH MUCH OF THE AFTERNOON WITH SCATTERED CHANCES ALONG
THE COAST. OVERNIGHT LOWS WILL AGAIN BE COOLER TO THE EAST UNDER THE
INFLUENCE OF THE SURFACE RIDGE WITH LOW 40S EXPECTED. MID AND UPPER
40S CAN BE EXPECTED ALONG THE COAST AND IN WESTERN ZONES. HIGHS ON
SATURDAY WILL BE IN THE MID AND UPPER 60S WITH THE FEW 70S POSSIBLE
ACROSS SOUTHEAST MISSISSIPPI. /13

DEEP LAYER LIFT WILL BEGIN TO INCREASE SATURDAY EVENING AS THE
VIGOROUS SHORTWAVE MOVES INTO EASTERN TEXAS. LOW TO MID LEVEL FLOW
WILL ALSO STRENGTHEN IN RESPONSE...RESULTING IN AN INCREASE IN
ISENTROPIC LIFT ACROSS THE AREA IN COMBINATION WITH THE ENHANCED
UPPER LEVEL DIVERGENCE. LIGHT TO MODERATE RAIN IS EXPECTED TO DEVELOP
OVER MUCH OF THE AREA THROUGH THE COURSE OF THE EVENING...WITH
LOCALLY HEAVY RAINFALL POSSIBLE CLOSER TO THE COAST WHICH WILL BE IN
CLOSER PROXIMITY TO A WARM FRONT OFFSHORE AND UNDER THE BEST UPPER
LEVEL DIVERGENCE. SOME GUIDANCE IS INDICATING A LARGE AREA OF
CONVECTION MAY DEVELOP OVER THE NORTHERN GULF IN THE EVENING AND
SPREAD NORTHEAST OVERNIGHT IN CONJUNCTION WITH A LOW LEVEL JET MAX
PROGGED TO DEVELOP MAINLY EAST OF OUR AREA. EXACTLY WHERE THIS
CONVECTION DEVELOPS WILL DETERMINE HOW MUCH RAIN WE RECEIVE SATURDAY
NIGHT...AND SOME UNCERTAINTY EXISTS. FOR NOW...WILL FOCUS THE
GREATEST CHANCE OF LOCALLY HEAVY RAINFALL AND HIGHEST RAIN CHANCES
OVER THE SOUTHERN ZONES. FURTHER ADJUSTMENTS WILL LIKELY BE NEEDED AS
THE EVENT UNFOLDS TOMORROW.

IT APPEARS THAT THERE WILL BE LITTLE TO NO RISK OF SEVERE WEATHER
SATURDAY EVENING AS GUIDANCE IS IN GOOD AGREEMENT THAT THE
INSTABILITY AND WARM FRONT WILL REMAIN OFFSHORE. THE WARM FRONT WILL
BEGIN TO LIFT NORTH OVERNIGHT AS THE SHORTWAVE MOVES FURTHER EAST
BECOMES NEGATIVE TILT OVER LOUISIANA. BOTH THE GFS AND ECMWF INDICATE
THE DEEP LAYER WIND FIELDS WILL DRAMATICALLY INCREASE ALONG AND AHEAD
OF THE SHORTWAVE...ESPECIALLY FROM 6AM TO NOON SUNDAY. WHILE STILL
UNCERTAIN...THE WARM FRONT MAY MOVE NORTH OF THE COAST DURING THE
PREDAWN HOURS SUNDAY...WITH A THREAT OF ISOLATED SEVERE STORMS.
HOWEVER...THE BEST TIME FRAME FOR SEVERE WEATHER WILL BE AFTER 6AM AS
THE WARM FRONT SURGES NORTH IN RESPONSE TO THE SHORTWAVE EJECTING
NORTHEAST. SCATTERED TO NUMEROUS THUNDERSTORMS WILL LIKELY DEVELOP
ALONG AND TO THE SOUTH OF THE WARM FRONT SUNDAY MORNING AS DEEP LAYER
ASCENT INCREASES AND MLCAPES CLIMB TO 350-600 J/KG. 0-1 KM SHEAR OF
40 KT COMBINED WITH 0-6 KM SHEAR OF 50-55 KT WILL BE VERY SUPPORTIVE
OF SEVERE THUNDERSTORMS...WITH DAMAGING WINDS AND TORNADOES POSSIBLE.
ANOTHER CONCERN IS THAT A SQUALL LINE MAY ORGANIZE OVER SOUTH CENTRAL
MS/LOUISIANA IN THE PREDAWN HOURS IMMEDIATELY AHEAD OF THE
SHORTWAVE...AND RAPIDLY MOVE EAST ACROSS THE FORECAST AREA SUNDAY
MORNING. IF THIS MATERIALIZES...THEN THE THREAT FOR DAMAGING WINDS
WILL BECOME ENHANCED WITH EMBEDDED TORNADOES ALSO POSSIBLE. THE MID
LEVEL DRY SLOT RAPIDLY ADVANCES FROM WEST TO EAST DURING THE MORNING
AND THE SEVERE WEATHER THREAT IS EXPECTED TO END OVER EASTERN ZONES
BY EARLY AFTERNOON.

RAINFALL TOTALS ARE UNCERTAIN...AS MENTIONED PREVIOUSLY. OVERALL...
EXPECT 1-2 INCHES OVER THE NORTHERN ZONES WITH 2-3 INCHES CLOSER TO
THE COAST. LOCALLY HIGHER TOTALS OF 4-5 INCHES ARE POSSIBLE...BUT
THAT POTENTIAL WILL LARGELY DEPEND ON THE CONVECTIVE EVOLUTION OVER
THE GULF SATURDAY EVENING. GIVEN THE DRY ANTECEDENT CONDITIONS...NO
FLASH FLOOD WATCH IS CURRENTLY PLANNED. HOWEVER...LOCALIZED FLOODING
IN URBAN AND POOR DRAINAGE AREAS WILL REMAIN A POSSIBILITY.

EVEN AS THE RAIN COMES TO AN END SUNDAY AFTERNOON...DEEP LAYER
SOUTHWEST FLOW AND WARM TEMPERATURES IN THE 70S ARE EXPECTED.
FORECAST SOUNDINGS STILL SHOW 35-40 KT OF WIND IN THE MIXED LAYER
WHICH WILL TRANSLATE TO WINDY CONDITIONS. FREQUENT GUSTS OF 30 TO 40
MPH ARE EXPECTED AND A WIND ADVISORY MAY BECOME NECESSARY. 34/JFB

.LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...THE COLD FRONT WILL
FINALLY GET A PUSH EAST LATE SUNDAY NIGHT INTO MONDAY WITH THE
BOUNDARY EXPECTED TO BE EAST OF THE AREA BY MONDAY EVENING. DEEP
LAYER MOISTURE IS PROGGED TO BE WELL EAST OF THE AREA BY MONDAY...AND
WILL SHOW A DRY FORECAST WITH THE FRONTAL PASSAGE. IT WILL TURN
PROGRESSIVE COOLER THROUGH MIDWEEK AS A LONGWAVE TROUGH GRADUALLY
MOVES FROM THE PLAINS EAST TO THE EASTERN SEABOARD BY THANKSGIVING
DAY. GUIDANCE IS BEGINNING TO TREND TOWARD A SOLUTION THAT SHOWS THE
STRONGEST PUSH OF COLD AIR ARRIVING ON THANKSGIVING INTO FRIDAY.
TEMPERATURES MAY NEED TO BE ADJUSTED FURTHER DOWNWARD IN SUBSEQUENT
FORECASTS. 34/JFB

&&

.MARINE...A MODERATE TO STRONG EASTERLY FLOW WILL CONTINUE THROUGH
SATURDAY NIGHT AS STRONG HIGH PRESSURE CONTINUES OVER THE MID
ATLANTIC AND AN AREA OF LOW PRESSURE APPROACHES FROM THE WEST. AS
THE LOW MOVES NORTHEAST ON SUNDAY...A STRONG SOUTH TO SOUTHWEST FLOW
WILL DEVELOP AND CONTINUE THROUGH EARLY MONDAY. SHOWERS AND
THUNDERSTORMS WILL ALSO INCREASE IN COVERAGE ACROSS THE MARINE AREA
SATURDAY AFTERNOON AND CONTINUE THROUGH SUNDAY MORNING. A COLD FRONT
WILL MOVE ACROSS THE AREA ON MONDAY WITH A NORTHERLY FLOW RETURNING.
/13

&&

.FIRE WEATHER...DRY WEATHER WILL PERSIST THROUGH EARLY SATURDAY
MORNING. BY SATURDAY AFTERNOON...SOME RAIN WILL BEGIN TO DEVELOP
CLOSE TO THE COAST WITH RAIN BECOMING WIDESPREAD SATURDAY NIGHT INTO
SUNDAY MORNING. SHOWERS AND THUNDERSTORMS WILL QUICKLY END FROM WEST
TO EAST SUNDAY MORNING...WITH MOST LOCATIONS DRY BY LATE SUNDAY
AFTERNOON. FAIR DISPERSIONS ON SATURDAY WILL BECOME GOOD ON SUNDAY
DUE TO STRONG SOUTHWESTERLY WINDS. DISPERSIONS ARE FORECAST TO
APPROACH 75 IN MANY LOCATIONS. FREQUENT WIND GUSTS OF 25 TO 35 MPH
ARE LIKELY SUNDAY AFTERNOON...WITH SOME GUSTS OF 40 MPH POSSIBLE.
34/JFB

&&

.PRELIMINARY POINT TEMPS/POPS...
MOBILE      49  69  60  77  61 /  00  30  90  90  10
PENSACOLA   51  67  61  76  63 /  00  30  90  90  20
DESTIN      51  67  62  73  64 /  00  30  90  90  20
EVERGREEN   41  67  57  75  59 /  00  10  90  90  10
WAYNESBORO  44  69  57  76  55 /  00  10  90  90  10
CAMDEN      40  67  55  75  57 /  00  10  90  90  10
CRESTVIEW   42  67  59  76  62 /  00  20  90  90  20

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
FL...NONE.
MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL NOON MONDAY 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...
     WATERS FROM PENSACOLA FL TO PASCAGOULA MS FROM 20 TO 60
     NM...

     SMALL CRAFT ADVISORY FROM 6 AM SATURDAY TO NOON MONDAY FOR THE
     FOLLOWING ZONES: CHOCTAWHATCHEE BAY...MISSISSIPPI SOUND...
     NORTHERN MOBILE BAY...PENSACOLA BAY SYSTEM...PERDIDO BAY...
     SOUTHERN MOBILE BAY...

&&

$$










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