Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 202307 AAA
AFDMOB

AREA FORECAST DISCUSSION...UPDATE TO AVIATION
NATIONAL WEATHER SERVICE MOBILE AL
515 PM CST THU NOV 20 2014

.AVIATION...
00Z ISSUANCE...VFR CONDITIONS EXPECTED THROUGH THE FORECAST. WITH
SURFACE HIGH PRESSURE MOVING EAST OF THE FA...AM EXPECTING AN
INCREASE IN FLOW OFF THE GULF THROUGH THE LATTER 6 HRS OF THE
FORECAST...WITH AN INCREASE IN CLOUD COVER THERE-AFTER.

/16

&&

.SHORT TERM (TONIGHT AND FRIDAY)...SURFACE HIGH PRESSURE WILL
CONTINUE EASTWARD TOWARD THE MID ATLANTIC COAST BY FRIDAY AFTERNOON.
THIS WILL MAINTAIN A GENERALLY LIGHT EAST TO SOUTHEAST WIND FLOW
WITH GRADUALLY MODERATING TEMPS. OVERNIGHT LOWS WILL BE THE COLDEST
ACROSS NORTHEAST ZONES CLOSER TO THE SFC RIDGE. LOW 40S CAN BE
EXPECTED ACROSS SOUTHWEST AND COASTAL AREAS WHERE MOISTURE LEVELS
WILL BE ON THE INCREASE. UPPER HEIGHTS INCREASE ON FRIDAY IN
RESPONSE TO A SHORTWAVE DIGGING ACROSS THE SOUTHWEST STATES. THE
BUILDING HEIGHTS COMBINED WITH PARTLY TO MOSTLY SUNNY SKIES AND
INCREASING MOISTURE WILL ALLOW TEMPS TO REBOUND INTO THE MID AND
UPPER 60S. /13

.LONG TERM (FRIDAY NIGHT THROUGH THANKSGIVING DAY)...DRY WEATHER AND
NEAR SEASONAL TEMPERATURES WILL HOLD ON THROUGH FRIDAY NIGHT...BUT
DRAMATIC CHANGES WILL ARRIVE SHORTLY THEREAFTER. THIS IS DUE TO A
STRONG SHORTWAVE...CURRENTLY MOVING INTO CALIFORNIA...THAT WILL MOVE
ACROSS TEXAS ON SATURDAY AND BECOME NEGATIVE TILT LATE SATURDAY NIGHT
INTO SUNDAY MORNING AS IT MOVES INTO THE LOWER MS VALLEY. LOW LEVEL
WINDS WILL BEGIN TO STRENGTHEN ON SATURDAY ACROSS OUR AREA...WITH
ISENTROPIC LIFT BECOMING STRONGER AND DEEPER AS WE HEAD INTO LATE
SATURDAY AFTERNOON INTO SATURDAY EVENING AS A SECONDARY WARM FRONT
DEVELOPS OVER THE NORTHERN GULF. THIS RESULTS IN RAIN DEVELOPING OVER
THE GULF WATERS BY MIDDAY SATURDAY...SPREADING NORTH TO SOUTHERN
PORTIONS OF THE AREA SATURDAY AFTERNOON...WITH RAIN BECOMING
WIDESPREAD SATURDAY EVENING AS BETTER DEEP LAYER FORCING DEVELOPS.
GUIDANCE IS COMING INTO BETTER AGREEMENT THAT THE WARM FRONT (WELL
DEFINED IN THE SFC THETA-E)...WILL REMAIN NEAR OR JUST OFFSHORE
THROUGH MUCH OF THE NIGHT. THIS SERVES TO KEEP THE BEST SURFACE BASED
INSTABILITY OFFSHORE...WHICH IN TURN WOULD REDUCE THE RISK OF SEVERE
WEATHER. HOWEVER...THIS WOULD ALSO RESULT IN THE A GREATER THREAT FOR
HEAVY RAINFALL ALONG THE SOUTHERN HALF OF THE AREA WITH THE BOUNDARY
SERVING AS A DEFINED FOCUS. LOW LEVEL SOUTHERLY INFLOW WILL INCREASE
TO 40-50 KT WHILE PRECIPITABLE WATERS INCREASE TO 1.75 TO 2 INCHES.
AS A RESULT...HAVE ADDED THE MENTION OF HEAVY RAIN TO THE FORECAST
FOR SATURDAY NIGHT.

THE WARM FRONT LIKELY WILL GET A STRONGER PUSH INLAND BY EARLY
SUNDAY MORNING AS THE SHORTWAVE PIVOTS INTO MISSISSIPPI. MLCAPES OF
UP TO 500 J/KG ARE POSSIBLE SOUTH OF THE BOUNDARY...ESPECIALLY ACROSS
COASTAL AL/NW FL SUNDAY MORNING. AT THE SAME TIME...0-1 KM SHEAR OF
35 KT WITH 0-6 KM SHEAR OF 50 KT WILL BE VERY SUPPORTIVE OF ROTATING
THUNDERSTORMS. IN ADDITION...THE STRONG LINEAR FORCING IMMEDIATELY
AHEAD OF THE SHORTWAVE MAY FORCE A SQUALL LINE TO MOVE QUICKLY EAST
ACROSS THE REGION SUNDAY MORNING. DAMAGING WINDS AND ISOLATED
TORNADOES ARE BOTH THREATS WITH THIS SETUP WITH THE GREATEST SEVERE
WEATHER POTENTIAL BEING SOUTH OF THE HWY 84 CORRIDOR SOUTH TO THE
COAST. A MID LEVEL DRY SLOT WILL RAPIDLY ADVANCE FROM WEST TO EAST
SUNDAY MORNING...BRINGING THE THREAT OF SEVERE CONVECTION TO AN END
BY EARLY SUNDAY AFTERNOON. LOCALLY HEAVY RAINFALL WILL CONTINUE TO BE
A THREAT THROUGH THE MORNING AS WELL.

RAINFALL TOTALS ARE CURRENTLY FORECAST TO RANGE BETWEEN 2-4 INCHES
FOR MOST OF THE AREA...WITH LOCALLY HIGHER TOTALS OF 5-6 INCHES
POSSIBLE...ESPECIALLY ACROSS COASTAL AL/NW FL. DRY ANTECEDENT
CONDITIONS WILL LIKELY LIMIT THE THREAT OF FLASH FLOODING AND RIVER
FLOODING AS MANY RIVER STREAM FLOWS ARE AT OR BELOW NORMAL. THE MAIN
THREAT AT THIS TIME APPEARS TO BE URBAN AND SMALL STREAM FLOODING...
AS WELL AS LOCALIZED FLASH FLOODING IN URBAN AREAS...ESPECIALLY ALONG
THE I-10 CORRIDOR.

THE OVERALL EXTENT/TIMING OF SEVERE WEATHER AND HEAVY RAINFALL WILL
ULTIMATELY HINGE ON THE NORTHWARD MOVEMENT OF THE SECONDARY WARM
FRONT. THEREFORE...SOME UNCERTAINTY STILL EXISTS IN THE FORECAST. SPC
CURRENTLY HAS THE SW PORTION OF THE FORECAST AREA UNDER A SLIGHT RISK
OF SEVERE WEATHER THROUGH 6AM SUN AND THIS APPEARS REASONABLE. THE
SEVERE THREAT WILL LIKELY EXTEND FURTHER EAST FROM 6AM SUNDAY
THROUGH NOON.

ONLY A SMALL CHANCE OF SHOWERS CONTINUES SUNDAY NIGHT INTO EARLY
MONDAY ACROSS THE FAR EASTERN ZONES AS THE COLD FRONT TEMPORARILY
STALLS ALONG OR NEAR THE I-65 CORRIDOR. THE FRONT PUSHES EAST BY
MONDAY AFTERNOON/TUESDAY EVENING AS ANOTHER SHORTWAVE TROUGH EJECTS
EAST OUT OF THE PLAINS. ABOVE NORMAL TEMPS SUNDAY/MONDAY COOL TO
BELOW NORMAL BY MIDWEEK. GUIDANCE DIFFERS ON JUST HOW COOL IT WILL BY
THANKSGIVING...BUT TEMPERATURES ARE EXPECTED TO BE NEAR TO BELOW
NORMAL WITH DRY WEATHER PERSISTING. 34/JFB

&&

.MARINE...A SURFACE RIDGE OF HIGH PRESSURE ALONG THE NORTH CENTRAL
GULF COAST WILL CONTINUE TO SHIFT EAST THROUGH THE REMAINDER OF THE
WEEK IN RESPONSE TO A LOW PRESSURE SYSTEM APPROACHING FROM THE WEST.
EASTERLY WINDS AND SEAS WILL STEADILY BUILD FRIDAY THROUGH SATURDAY
REACHING SMALL CRAFT CONDITIONS BY EARLY SATURDAY. A STRONG
SOUTHERLY FLOW WILL DEVELOP SATURDAY NIGHT INTO EARLY NEXT WEEK WITH
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS EXPECTED...SOME
POSSIBLY BECOMING STRONG TO SEVERE...LATE SATURDAY NIGHT THROUGH
SUNDAY MORNING. A MODERATE NORTHERLY FLOW IS EXPECTED IN THE WAKE OF
WEAK COLD FRONT LATE MONDAY THROUGH TUESDAY. /13

&&

.PRELIMINARY POINT TEMPS/POPS...
MOBILE      41  69  48  68  61 /  00  00  10  40  90
PENSACOLA   42  69  50  68  63 /  00  00  10  40  90
DESTIN      46  66  51  68  64 /  00  00  10  30  90
EVERGREEN   33  67  38  67  57 /  00  00  05  20  90
WAYNESBORO  38  68  41  68  58 /  00  00  05  30  90
CAMDEN      32  66  39  66  56 /  00  00  05  20  90
CRESTVIEW   33  69  41  67  60 /  00  00  10  30  90

&&

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

$$







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