Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 150246 AAA
AFDMOB

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MOBILE AL
946 PM CDT SUN SEP 14 2014

.UPDATE...THE CURRENT FORECAST LOOKS TO BE IN GOOD SHAPE AND NO
SIGNIFICANT CHANGES ARE NEEDED. REGIONAL RADAR IMAGERY CONTINUES TO
SHOW ISOLATED TO SCATTERED SHOWERS DEVELOPING ACROSS PORTIONS OF
SOUTHEAST MS...SOUTHWEST AND SOUTH CENTRAL AL AND THE NORTHWEST FL
PANHANDLE ALONG AND NEAR A WEAK STATIONARY BOUNDARY THAT REMAINS IN
THE VICINITY OF THE REGION. WE WILL MAINTAIN 20-30 PERCENT COVERAGE
IN THE FORECAST THROUGH THE LATE EVENING HOURS. ISOLATED CONVECTION
SHOULD THEN MAINLY BECOME FOCUSED OFFSHORE AFTER MIDNIGHT THROUGH
THE EARLY MORNING HOURS MONDAY. /21

&&

.PREV DISCUSSION... /ISSUED 646 PM CDT SUN SEP 14 2014/

AVIATION (00Z ISSUANCE)...WILL BEGIN WITH VCSH UNTIL 03Z FOR
LINGERING CONVECTION WITH OTHERWISE VFR CONDITIONS THROUGH THE
NIGHT.  VCSH RETURNS BY 15Z WITH VCTS BY 18Z MONDAY AS CONVECTION
DEVELOPS THROUGH THE EARLY AFTERNOON...THEN WILL HAVE A TEMPO GROUP
FROM 19-23Z FOR MVFR CONDITIONS IN THUNDERSTORMS.  LIGHT EAST TO
SOUTHEAST WINDS BECOME SOUTH TO SOUTHEAST ON MONDAY. /29

*** PREVIOUS DISCUSSION ***

SHORT TERM (TONIGHT AND MONDAY)...SFC FRONTAL BOUNDARY OVER COASTAL
SECTIONS OF THE FCST AREA THIS AFTERNOON WILL REMAIN NEARLY
STATIONARY TONIGHT. A TROPICAL WAVE NOTED IN SFC DATA AND SATELLITE
IMAGERY OVER THE CENTRAL GULF OF MEXICO THIS AFTERNOON WILL CONTINUE
MOVING OFF TOWARD THE WEST THROUGH MONDAY. WITH THIS...THE NORTHEAST
TO EAST WIND FLOW OVER THE REGION WILL LIKELY BECOME MORE
SOUTHEASTERLY ON MONDAY...ALLOWING THE SFC BOUNDARY TO LIFT SLOWLY
BACK TO THE NORTH AND INTO THE INTERIOR PORTIONS OF MS/AL BY LATE
MONDAY. LATE THIS AFTERNOON AND INTO THE EARLY EVENING HOURS...THE
SEA BREEZE CIRCULATION IS THE PRIMARY DRIVING FORCE BEHIND CONVECTION
AS UPPER RIDGING HAS BUILT OVER THE REGION. ALL SHOWERS AND STORMS
THAT HAVE DEVELOPED THIS AFTERNOON THUS FAR HAVE BEEN GENERALLY ALONG
AND SOUTH OF THE I-10 CORRIDOR. EXPECT THESE TO MOVE SLIGHTLY FURTHER
INLAND...THEN BEGIN TO DISSIPATE SHORTLY AFTER SUNSET. ISOLATED
SHRA/TSRA WILL LIKELY CONTINUE OVER THE OFFSHORE GULF WATERS
OVERNIGHT. THE SFC BOUNDARY...COMBINED WITH LOW LEVEL MOISTURE
CONVERGENCE (PRIMARILY SOUTH OF THE BOUNDARY) AND AFTERNOON HEATING
ON MONDAY...WILL RESULT IN SCATTERED TO LOCALLY NUMEROUS SHOWERS AND
STORMS ON TOMORROW AFTERNOON (WITH THE BEST RAIN CHANCES GENERALLY
ALONG AND SOUTH-EAST OF I-65). WITH MUCH OF THE INTERIOR COUNTIES
JUST ON THE COOLER AND DRIER SIDE OF THE FRONT TONIGHT... MIN TEMPS
ARE EXPECTED TO BE IN THE UPPER 60S IN THOSE LOCATIONS. CLOSER TO THE
COAST AND SOUTH OF THE BOUNDARY...LOWS IN THE LOW TO MID 70S. MAX
TEMPS ON MONDAY GENERALLY IN THE LOWER 90S ACROSS THE ENTIRE
AREA...EXCEPT FOR A NARROW AREA ALONG THE IMMEDIATE COAST OF UPPER
80S TO NEAR 90. 12/DS

FOR MONDAY NIGHT THROUGH TUESDAY NIGHT...A STATIONARY FRONT
EXTENDING FROM A LOW OVER ONSLOW BAY WILL REMAIN STALLED ALONG THE
I-65 CORRIDOR. THIS WILL PROVIDE CONVECTIVE FORCING OF NUMEROUS
SHOWERS AND THUNDERSTORMS THROUGH MONDAY EVENING. GFS AND EURO MODELS
INDICATE IT WILL PUSH BACK OFFSHORE MONDAY NIGHT AND DRIFT BACK TO
THE NORTH TUESDAY TO JUST NORTH OF THE COASTLINE TUESDAY AFTERNOON.
THEN ON TUESDAY NIGHT IT WILL PUSH BACK SOUTH AGAIN OVER THE NORTHERN
GULF. AT THE SAME TIME AN UPPER LONG WAVE TROUGH WILL DEEPEN OVER THE
EASTERN UNITED STATES. THESE FEATURES WILL HELP MAINTAIN SUFFICIENT
STRENGTH OF FRONTAL VERTICAL CIRCULATIONS TO MAINTAIN SOME SEMBLANCE
OF CONVECTIVE FORCING. NUMERICAL OUTPUTS REGARDING THE THERMODYNAMIC
STATE OF THE ATMOSPHERE INCLUDE CAPE AVERAGING ABOUT 2400 WITH A
MAXIMUM OF 3600 J/KG...LIFTED INDEX -4 INDICATING "NUMEROUS"
THUNDERSTORMS...SIMILAR TO THE MOS NUMBERS BEING BROUGHT IN...AND
PRECIPITABLE WATER AROUND 2 INCHES. WE MIGHT SEE SOME CELL TRAINING
AND THEREFORE CONSIDER MOS CALCULATIONS OF LIKELY CHANCES OF
MEASURABLE RAIN TO BE SOUND. IT WILL MOST LIKELY BE SHORT PERIODS OF
HEAVY RAINFALL...GUSTY WINDS...AND FREQUENT LIGHTNING...AS THE MAIN
EFFECTS OF SOME THUNDERSTORMS TUESDAY AFTERNOON. AVERAGE RAINFALL
TOTALS WOULD RANGE FROM 0.5 TO 1.0 INCHES PER 24 HOUR PERIOD IN OUR
AREA TUESDAY WITH LOCALLY HIGHER RAINFALL 2 TO 3 INCHES POSSIBLE IN
ISOLATED LOCATIONS WITHIN THE SAME PERIOD. WHEN WE SEE THE FORECAST
SOUNDINGS...THE DEWPOINT DEPRESSION AVERAGES 6 TO 7 DEGREES BETWEEN
THE SURFACE AND 500 MB AND THAT TYPE OF ENVIRONMENT WOULD LIKELY NOT
BE A VERY EFFECTIVE RAINMAKER SINCE IT ALLOWS ENTRAINMENT OF AIR THAT
IS TOO LOW A HUMIDITY ON THE CUMULUS SCALE.

HIGHS WILL BE ABOUT 3 DEGREES BELOW THE MEAN TUESDAY...REBOUNDING TO
WITHIN A DEGREE WEDNESDAY. LOWS WILL BE RUNNING ABOUT 2 TO 3 DEGREES
BELOW NORMAL MONDAY NIGHT. 77/BD

LONG TERM (WEDNESDAY THROUGH SUNDAY)...NO CHANGES. THE DEEP UPPER
TROUGH OVER THE EASTERN UNITED STATES WILL PERSIST WEDNESDAY AND
THURSDAY...DAMPENING SOME LATE THIS WEEK. MEANWHILE A SURFACE RIDGE
DOMINATES THE PICTURE OVER EASTERN UNITED STATES THROUGH THE
REMAINDER OF THE LONG TERM. THIS WOULD BRING CLEAR TO PARTLY CLOUDY
AND SKIES AND RAIN FREE CONDITIONS THROUGH MUCH OF THE EXTENDED
PERIOD. HOWEVER BY FRIDAY WE ISOLATED POPCORN TYPE AFTERNOON SHOWERS
AND THUNDERSTORMS CONTINUING OVER THE WEEKEND.

HIGHS WILL BE AROUND 2 TO 3 DEGREES BELOW NORMAL THURSDAY THROUGH
SUNDAY. LOWS WILL BE COOLING TO ABOUT 2 TO 3 DEGREES BELOW NORMAL
TUESDAY NIGHT DECREASING TO 6 TO 8 DEGREES BELOW NORMAL IN SOME
INLAND LOCATIONS BY THE WEEKEND. 77/BD

MARINE...STALLED FRONTAL ZONE WILL BE DRAPED OVER THE COASTAL
WATERS THIS EVENING...WHILE A TROPICAL WAVE CONTINUES TO MOVE WEST
OVER THE CENTRAL GULF. A GENERAL LIGHT TO MODERATE NORTHEAST TO
EASTERLY WIND FLOW WILL CONTINUE OVER THE MARINE AREA OVER THE NEXT
SEVERAL DAYS...BECOMING A LITTLE MORE SOUTHEASTERLY AT TIMES NEAR
THE COAST DURING THE LATE AFTERNOON HOURS...ESPECIALLY ON MONDAY AS
THE DEPARTING TROPICAL WAVE ALLOWS FOR A SLIGHTLY MORE PREDOMINANT
LARGE SCALE SOUTHEASTERLY FLOW. A SURFACE HIGH PRESSURE RIDGE WILL
BUILD OVER THE EASTERN GULF BY MID WEEK...WITH WINDS BECOMING MORE
WESTERLY. SEAS WILL REMAIN GENERALLY 2-3 FEET ALL WEEK WITH LITTLE
CHANGE IN PREVAILING WIND SPEEDS OVER THE MARINE AREA. ISOLATED TO
OCNLY SCATTERED SHOWERS AND STORMS OVER THE COASTAL
WATERS...PRIMARILY OVERNIGHT AND EARLY MORNING HOURS. 12/DS

&&

.PRELIMINARY POINT TEMPS/POPS...
MOBILE      73  89  71  88  69 /  20  50  40  60  30
PENSACOLA   75  90  74  87  72 /  30  60  40  60  40
DESTIN      79  86  79  86  78 /  30  60  40  60  50
EVERGREEN   69  90  69  87  66 /  20  60  40  50  30
WAYNESBORO  67  90  67  87  66 /  20  30  30  50  20
CAMDEN      68  91  70  87  65 /  20  60  40  50  20
CRESTVIEW   70  91  71  88  69 /  20  60  40  60  40

&&

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

$$









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