840
FXUS64 KMOB 132011
AFDMOB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
311 PM CDT THU AUG 13 2020
NEAR TERM UPDATE /NOW THROUGH FRIDAY/
AFTERNOON FORECAST REMAINS
ON TRACK WITH NO CHANGES NECESSARY AT THIS TIME. SLOW-MOVING
SHOWERS AND THUNDERSTORMS CONTINUE TO DEVELOP OVER SOUTHEAST
MISSISSIPPI THAT ARE FORECAST TO EXPAND TO THE SOUTHEAST INTO
SOUTHWEST ALABAMA THROUGH THE REMAINDER OF THE DAY. IN ADDITION,
ISOLATED SHOWERS AND A FEW STORMS HAVE FORMED ALONG A SEABREEZE
PUSHING INLAND ACROSS OUR COASTAL COUNTIES. THESE SHOWERS AND
STORMS WILL WILL CONTINUE TO EXPAND IN COVERAGE TO THE NORTH THIS
AFTERNOON. MINOR/NUISANCE FLOODING CONTINUES TO BE THE MAIN THREAT
TODAY AS THE DEEP STEERING FLOW REMAINS LIGHT COUPLED WITH DEEP
MOISTURE IN PLACE OVER THE REGION. GUSTY OUTFLOW WINDS FROM SOME
OF THE STRONGER THUNDERSTORMS ARE ALSO EXPECTED, WITH LOCALIZED
WIND GUST BETWEEN 40 TO 50 MPH POSSIBLE.
AN UPPER LEVEL SHORTWAVE OVER MISSISSIPPI WILL SLIDE EASTWARD
THROUGH THE NEAR TERM, WITH THE AXIS REACHING CENTRAL ALABAMA BY
NOON FRIDAY. A SECOND UPPER SHORTWAVE AND IMPULSES WILL APPROACH
THE AREA FROM THE NORTHWEST ON FRIDAY, CARVING OUT A LARGER UPPER
TROUGH OVER THE EASTERN CONUS BY LATE FRIDAY AFTERNOON. ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS WILL PERSIST INTO THE EARLY
EVENING HOURS, MAINLY ACROSS THE NORTHERN HALF OF THE FORECAST
AREA, FOLLOWED BY A BRIEF LULL IN ACTIVITY FROM MID EVENING
THROUGH ABOUT 4 AM. SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE
THEN FORECAST TO REDEVELOP LATE TONIGHT THROUGH DAYBREAK WITH THE
APPROACH OF THE SECOND UPPER SHORTWAVE. LOW TEMPERATURE TONIGHT
WILL CONTINUE TO BE IN THE 70S.
AN UNSETTLED WEATHER PATTERN WILL REMAIN THROUGH FRIDAY DUE TO
DECREASING DAYTIME STABILITY, WITH SBCAPES CLIMBING BACK TO
BETWEEN 1500 AND 2200 J/KG. ISOLATED POCKETS OF UP TO 3000 J/KG
MAY OCCUR ACROSS OUR COASTAL ZONES BY EARLY AFTERNOON WHERE
SURFACE DEWPOINTS WILL BE THE HIGHEST. DEEP MOISTURE WILL BE NO
PROBLEM AS PRECIPITABLE WATER VALUES FLUCTUATE BETWEEN 2.0 TO 2.4
INCHES THROUGH THE ENTIRE PERIOD.
THEREFORE, KEPT NUMEROUS SHOWERS AND THUNDERSTORMS IN THE
FORECAST ON FRIDAY, AND OUTFLOW WINDS FROM SOME OF THE STRONGER
THUNDERSTORMS, WITH LOCALIZED WIND GUST BETWEEN 40 TO 50 MPH,
REMAIN POSSIBLE. ADDITIONAL WIDESPREAD RAINFALL AMOUNTS THROUGH
THE PERIOD WILL LIKELY RANGE FROM 0.5 TO 1.5 INCHES, WITH
LOCALIZED HIGHER AMOUNTS UP TO 3 INCHES. HIGH TEMPERATURES FRIDAY
WILL RANGE FROM 86 TO 91 DEGREES, WITH HEAT INDICES IN THE MID TO
UPPER 90S. /22
SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/
AN UPPER LEVEL
TROUGH WILL BUILD OVER THE EASTERN CONUS THROUGH MUCH OF THE
WEEKEND, WITH AN UPPER RIDGE PERSISTING OVER THE DESERT SOUTHWEST.
BY LATE WEEKEND HOWEVER, THE TROUGH WILL LIFT TO THE NORTHEAST
SOMEWHAT AND THE RIDGE TO THE WEST WILL BUILD INTO THE REGION.
MEANWHILE, HIGH PRESSURE WILL CONTINUE OVER THE GULF OF MEXICO
THROUGH THE WEEKEND. A SURFACE BOUNDARY WILL ALSO SLOWLY SLIDE
OVER THE TENNESSEE VALLEY THROUGH SATURDAY. BY SUNDAY, THIS
FEATURE WILL PROGRESS SOUTHEAST TOWARDS THE EAST COAST. ANOTHER
COLD FRONT TO ITS NORTHWEST, WILL MOVE OVER THE MISSISSIPPI VALLEY
AND APPROACH THE SOUTHEASTERN CONUS DURING THIS TIME.
OVERALL, SCATTERED SHOWERS AND STORMS WILL BE THE THEME THROUGH
THE SHORT TERM PERIOD. EXPECTING ACTIVITY TO BEGIN OVER THE OPEN
GULF WATERS THROUGH THE LATE NIGHT/EARLY MORNING HOURS THEN
TRANSITION OVER LAND THROUGH THE DAY. PWATS WILL BE ELEVATED,
ESPECIALLY INITIALLY. VALUES WILL RANGE FROM 1.7-2.3 INCHES ON
SATURDAY (HIGHER VALUES TOWARDS THE COAST); HOWEVER, DEEP LAYER
MOISTURE WILL BE ON THE DECLINE BY LATE WEEKEND, WITH VALUES
BETWEEN 1.3-1.7 INCHES ON SUNDAY. THIS IS DUE TO COOLER, DRIER AIR
BEING BROUGHT DOWN FROM THE NORTH BY THE APPROACHING COLD FRONT.
MODEL MLCAPE VALUES WILL RANGE FROM 700-1000 J/KG THROUGH THE
WEEKEND AS WELL. THEREFORE, BETTER COVERAGE OF SHOWERS/STORMS IS
EXPECTED SATURDAY, WITH LESS COVERAGE ON SUNDAY. THIS IS REFLECTED
BY LIKELY POPS FOLLOWED BY CHANCE POPS, RESPECTIVELY. SHOWER AND
STORM ACTIVITY WILL THEN WANE BY SUNDAY NIGHT, WITH ONLY SOME
ISOLATED SHOWERS/STORMS ANTICIPATED.
HIGH TEMPERATURES WILL BE IN THE UPPER 80S TO LOWER 90S SATURDAY
BUT THEN WARM TO BE IN THE LOWER TO MID 90S BY SUNDAY AFTERNOON.
LOWS FRIDAY NIGHT ARE EXPECTED TO BE IN THE LOWER TO MID 70S NORTH
OF I-10 AND IN THE MID TO UPPER 70S SOUTH. LOWS THROUGH THE
WEEKEND WILL THEN BE ONLY A TOUCH COOLER. LASTLY, A LOW RISK OF
RIP CURRENTS CONTINUES THROUGH THE WEEKEND. /26
EXTENDED TERM /MONDAY THROUGH THURSDAY/
THROUGH MONDAY, THE UPPER
LEVEL TROUGH OVER THE EAST CONUS WILL BUILD OVER THE NORTHERN
GULF COAST YET AGAIN AND EVENTUALLY OVER THE ARKLATEX REGION, WITH
THE UPPER RIDGE OVER THE DESERT SOUTHWEST RETREATING BACK WEST.
THIS TROUGH WILL THEN AMPLIFY THROUGH THE WEEK. EXPECTING COLD
FROPA OVER THE NORTHERN GULF COAST THROUGH TUESDAY. A SURFACE LOW
WILL ALSO FORM OVER THE PANHANDLE OF FLORIDA TUESDAY AND PERSIST
OVER THIS AREA THROUGH THE REMAINDER OF THE EXTENDED TERM.
ADDITIONALLY, THE COLD FRONT IS EXPECTED TO STALL AND LINGER SOUTH
OF THE COAST OVER THE GULF DURING THIS TIME. A SHIFT TO A MORE
NORTHERLY WIND FLOW IS ANTICIPATED LATE WEEKEND THROUGH EARLY NEXT
WEEK WITH THIS COLD FROPA. SOUTHERLY FLOW IS NOT EXPECTED TO
RETURN UNTIL LATE NEXT WEEK.
THE AFOREMENTIONED PATTERN WILL RESULT IN DECREASING MOISTURE FOR
THE REGION. THIS IS REFLECTED IN DECLINING DEW POINTS FROM THE
LOWER TO MID 70S ON MONDAY TO THE MID TO UPPER 60S TO AROUND 70
DEGREES BY TUESDAY MORNING. EXPECTING DEW POINTS THROUGH THURSDAY
TO THEN MAINLY BE IN THE 60S NORTH OF I-10 AND IN THE UPPER 60S TO
LOWER 70S SOUTH. FURTHERMORE, PWATS WILL ONLY RANGE FROM ABOUT
1.2-1.6 INCHES DURING THIS TIME. THUS, CAPPED POPS GIVEN BY THE
BLENDED SOLUTION AT CHANCE FOR THE DURATION OF THE EXTENDED TERM.
MLCAPE VALUES SHOWN BY MODELS WILL ALSO RANGE FROM 500-1000 J/KG
FROM MONDAY THROUGH THURSDAY. ALL OF THIS WILL LEAD TO DAILY
CHANCES OF ISOLATED TO SCATTERED SHOWERS AND STORMS, BEGINNING
OVER THE OPEN GULF WATERS AND RIGHT ALONG THE COAST DURING THE
LATE NIGHT/EARLY MORNING HOURS THEN TRANSITIONING OVER LAND
THROUGH THE DAY. THIS ACTIVITY WILL THEN DECREASE THROUGH THE
EVENING EACH DAY.
COLD FROPA WILL ALSO BRING SOME RELIEF IN THE FORM OF SLIGHTLY
COOLER TEMPERATURES. AFTER HIGH TEMPERATURES IN THE LOWER 90S
MONDAY AFTERNOON, HIGHS WILL GENERALLY BE IN THE UPPER 80S TO
AROUND 90 DEGREES THROUGH THURSDAY. ALSO, LOWER DEW POINTS WILL
CAUSE HEAT INDICES TO ONLY TOP OUT IN THE MID 90S TUESDAY THROUGH
THURSDAY. LOWS WILL THEN BE IN THE UPPER 60S TO LOWER 70S OVER
INLAND AREAS AND MAINLY IN THE MID 70S RIGHT ALONG THE COAST. /26
MARINE
NO IMPACTS FORECAST EXCEPT WINDS AND WAVES HIGHER NEAR
STORMS EACH DAY. ENVIRONMENTAL CONDITIONS SUPPORT THE DEVELOPMENT
OF WATERSPOUTS EACH MORNING. /22
MOB WATCHES/WARNINGS/ADVISORIES
AL...NONE.
FL...NONE.
MS...NONE.
GM...NONE.
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