Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 012201
AFDMOB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
401 PM CST SUN MAR 1 2015

.SHORT TERM [TONIGHT THROUGH MONDAY NIGHT]...ANOTHER
CHALLENGING FORECAST IN STORE FOR THE CENTRAL GULF COAST REGION
THROUGH THE NEXT 24 HOURS...WITH MORE POTENTIAL DENSE FOG IMPACTS
AND AN INCREASING CHANCE OF RAIN SHOWERS.

A GENERAL ZONAL FLOW PATTERN ALOFT CONTINUES ACROSS THE DEEP SOUTH
THIS AFTERNOON WHILE THE 18Z SURFACE ANALYSIS SHOWS A SURFACE RIDGE
OF HIGH PRESSURE STRETCHING FROM THE WESTERN ATLANTIC/EASTERN
SEABOARD TO THE SOUTHEASTERN STATES...AND A FRONTAL BOUNDARY
STRETCHING FROM CENTRAL LA INTO NORTHWEST MS. A MOIST EASTERLY
SURFACE FLOW PATTERN PREVAILS ACROSS OUR FORECAST AREA THIS
AFTERNOON...WHILE THE KMOB 88D VAD WIND PROFILER SHOWS WINDS QUICKLY
VEERING SOUTHERLY ABOUT 2000 FT OFF THE GROUND AND THROUGH THE MID
LEVELS OF THE ATMOSPHERE. LOW LEVEL ISENTROPIC ASCENT HAS KEPT LOW
CLOUDS STRONGLY IN PLACE ACROSS OUR CWFA THIS AFTERNOON WITH
TEMPERATURES ONLY HAVING WARMED INTO THE MID 50S TO AROUND 60 AS OF
3 PM CST. MOST OF THE FOG HAS DISSIPATED OVER INLAND PORTIONS OF THE
CWFA THIS AFTERNOON...BUT AREA MARINE AND BEACH CAMS AND
OBSERVATIONS NEAR THE IMMEDIATE COAST INDICATE DENSE FOG HOLDING
OVER BAYS/SOUNDS AND OVER THE NEAR SHORE WATERS. A SHORTWAVE TROUGH
CROSSING INTO MS/AL WAS AIDING IN THE DEVELOPMENT OF SCATTERED TO
NUMEROUS SHOWERS OVER MUCH OF CENTRAL LA INTO SOUTHWEST AND CENTRAL
MS ALONG AND AHEAD OF THE FRONTAL BOUNDARY THIS AFTERNOON. A FEW
EMBEDDED THUNDERS  TORMS WITH BOTH CLOUD TO CLOUD/CLOUD TO GROUND
LIGHTNING WERE NOTED JUST WEST OF OUR CWFA.

THE LATEST SHORT TERM FORECAST SOUNDINGS CONTINUE TO SHOW A
SATURATING LOW LEVEL PROFILE THIS EVENING INTO LATE TONIGHT...WITH
FOG LOOKING TO LIKELY RE-DEVELOP/SPREAD INLAND NEAR THE COAST THIS
EVENING AND ACROSS MUCH OF THE REST OF THE CWFA OVERNIGHT. GIVEN THE
ONGOING DENSITY OF FOG NOTED OVER THE BAYS/SOUNDS THIS AFTERNOON...
CONFIDENCE HAS INCREASED THAT DENSE FOG WILL DEVELOP OVER AT LEAST
COASTAL PORTIONS OF THE CWFA THIS EVENING/TONIGHT...AND WILL OPT TO
ISSUE A DENSE FOG ADVISORY FOR THE COASTAL COUNTIES THROUGH EARLY
MONDAY MORNING. LATER SHIFTS WILL CONTINUE TO MONITOR OBSERVATIONS
AND EXPAND FARTHER INLAND IF NEEDED. DEEP LAYER MOISTURE WILL
CONTINUE TO BE FOCUSED FROM LA INTO CENTRAL MS AND NORTHWEST AL
THROUGH MONDAY...BUT ENOUGH LIFT WILL BE AVAILABLE TO CARRY A LOW
CHANCE OF RAIN SHOWERS PRIMARILY OVER THE NORTHWESTERN HALF OF OUR
AREA TONIGHT AND MONDAY. ENOUGH INSTABILITY MAY ALSO BE AVAILABLE TO
PRODUCE ISOLATED THUNDERSTORMS OVER INTERIOR SOUTHEAST MS AND
SOUTHWEST AL. WILL KEEP RAIN CHANCES IN THE SLIGHT CATEGORY OVER THE
REMAINDER OF THE CWFA. FOG SHOULD PERSIST INTO THE MORNING...BUT
UNCERTAINTY EXISTS ON HOW LONG IT WILL LINGER...PARTICULARLY NEAR
THE COAST. GIVEN TRENDS THAT OCCURRED TODAY...WILL AT LEAST OPT TO
CARRY PATCHY FOG NEAR THE COAST INTO THE EARLY AFTERNOON MONDAY. WE
HAVE TRENDED HIGH TEMPERATURES BELOW GUIDANCE ACROSS THE REGION
GIVEN THE EXPECTED CLOUD COVER. /21

MONDAY NIGHT...SURFACE HIGH PRESSURE IS PROGGED TO MOVE OFF THE MID
ATLANTIC AND NORTHEAST COAST MONDAY NIGHT. A LIGHT SOUTHEAST FLOW
MAINTAINS A MILD TEMPERATURE REGIME WITH LOWS RANGING FROM THE UPPER
HALF OF THE 50S TO LOWER 60S. A DIFFUSE SURFACE TROUGH OF LOW
PRESSURE OVER THE SOUTHERN STATES WILL SUPPORT A SMALL CHANCE OF
SHOWERS. AREAS OF NIGHTTIME FOG COULD LOWER VISIBILITY TO LESS THAN A
MILE AT SEVERAL LOCATIONS AS WELL...WHICH COULD PROVE HAZARDOUS FOR
NIGHTTIME DRIVING. /10

.LONG TERM [TUESDAY THROUGH SUNDAY]...A LIGHT ONSHORE FLOW CONTINUES
TUESDAY WITH SURFACE HIGH PRESSURE OVER THE WESTERN ATLANTIC. WITH GULF
MOISTURE PRESENT (PRECIPITABLE WATER VALUES NEAR 1.3 INCHES)...ISENTROPIC
UPGLIDE OPERATING ON THIS MOISTURE FAVORS A SMALL CHANCE OF SHOWERS
TO CONTINUE IN THE FORECAST. MEANWHILE...NEXT COLD FRONT EXITS THE
PLAINS AND HEADS SOUTHEAST TUESDAY NIGHT...BECOMING ALIGNED FROM THE
APPALACHIANS TO EASTERN TEXAS BY DAYBREAK WEDNESDAY. THE FRONT MAKES
A CLOSER APPROACH FROM THE NORTHWEST DURING THE DAY WEDNESDAY WITH
CHANCES OF SHOWERS AND STORMS TRENDING HIGHER. THE LACK OF A STRONG
LOW LEVEL WIND PROFILE AHEAD OF THE FRONT AND MARGINAL INSTABILITY
LOOKS TO KEEP THE RISK OF SEVERE WEATHER LOW AT THIS TIME ON
WEDNESDAY. THE FRONTAL PASSAGE AND ITS ASSOCIATED WIND SHIFT COMES
ACROSS THE CENTRAL GULF COAST WEDNESDAY NIGHT. THE 01.12Z OPERATIONAL
GFS IS A LITTLE FASTER AT BRINGING THE FRONT THROUGH THAN BOTH THE
NAM AND ECMWF. THE FRONTAL SLOPE IS VERY SHALLOW WITH A NORTHERLY
FLOW ONLY CONFINED TO THE LOWEST 2000 FT. ABOVE THIS LAYER...A WELL
DEFINED SOUTHWEST FLOW LOOKS TO MAINTAIN CLOUD COVER AND POST
FRONTAL...COLD RAIN CHANCES FROM THE EARLY MORNING HOURS TO THE
BEGINNING OF THE AFTERNOON ON THURSDAY. DAILY HIGHS ON THURSDAY LOOK
TO BE HOLDING NEARLY STEADY OR POSSIBLY SHOWING A SLOW FALLING TREND
THROUGH THE COURSE OF THE DAY. THURSDAY`S HIGHS ARE FORECAST IN THE
LOWER/MID 40S NORTHWEST OF I-65 TO 53 TO 58 OVER THE WESTERN FLORIDA
PANHANDLE.

THE ECMWF HAS TRENDED SOUTH WITH THE PRECIPITATION AXIS THURSDAY
AFTERNOON INTO FRIDAY MORNING...BECOMING BETTER ALIGNED WITH THE
GFS. AT THIS TIME...IT APPEARS THIS LIMITS THE RISK OF WINTRY
PRECIPITATION BY FRIDAY MORNING WHEN LOWS RANGE FROM THE MID 20S OVER
THE FAR NORTHWEST ZONES TO MID 30S EAST. HEADING INTO THE
WEEKEND...HIGH PRESSURE SETS UP ACROSS THE SOUTHERN U.S. WITH HIGHS
MOSTLY IN THE FULL RANGE OF THE 50S UNDER MOSTLY CLOUDY SKIES DUE TO
THE PRESENCE OF A HIGH LEVEL WEST SOUTHWEST FLOW PERSISTING OVER THE
REGION. OVERNIGHT LOWS SHOW A GRADUAL MODIFICATION OVER THE
WEEKEND...BUT STILL BELOW SEASONAL NORMAL...UPPER 30S/LOWER 40S
INTERIOR TO MID 40S COAST BY SUNDAY MORNING. OUT OF RESPECT FOR ANY
MID LEVEL IMPULSES EMBEDDED IN THE HIGH LEVEL WEST SOUTHWEST FLOW...A
SMALL CHANCE OF SHOWERS WILL BE IN THE FORECAST NEXT WEEKEND. /10

&&

.AVIATION...
01.18Z TERMINAL FORECAST DISCUSSION...
IFR TO LIFR CIGS AND MVFR TO IFR VISIBILITY REDUCTIONS DUE TO FOG
WILL CONTINUE TO IMPACT THE REGION THROUGH MONDAY MORNING. FOG COULD
BE REDUCED TO LIFR LEVELS TONIGHT AND EARLY MONDAY MORNING. RAIN
CHANCES WILL INCREASE TONIGHT AND MONDAY...PRIMARILY ACROSS
SOUTHEAST MS AND SOUTHWEST AL. /21


&&

.MARINE...AN EARLIER MARINER REPORT INDICATED THAT VISIBILITY WAS
REDUCED TO AS LOW AS A FEW HUNDRED FEET OVER MOBILE BAY EARLY THIS
AFTERNOON...AND AREA MARINE/BEACH CAMS INDICATE DENSE FOG STILL
HOLDING STRONG...PARTICULARLY FROM PENSACOLA BAY AND WESTWARD
THROUGH MOBILE BAY AND LIKELY THE MISSISSIPPI SOUND. BEACH CAMS ALSO
SHOW DENSE FOG JUST SOUTH OF PENSACOLA/ORANGE/GULF SHORES BEACHES.
FOG IS EXPECTED TO HOLD STRONG THROUGH AT LEAST MONDAY MORNING. WE
HAVE OPTED TO EXPAND THE DENSE MARINE FOG ADVISORY TO INCLUDE THE
NEAR SHORE AL/NORTHWEST FL COASTAL WATERS...IN ADDITION TO BAYS AND
SOUNDS...EFFECTIVE THROUGH 9 AM CST MONDAY.

OTHERWISE...EAST TO SOUTHEAST FLOW DIMINISHES TONIGHT WHILE A
SURFACE RIDGE ALONG THE EASTERN SEABOARD CONTINUES TO SHIFT
EASTWARD. ANOTHER BROAD RIDGE WILL THEN BECOME REINFORCED FROM THE
PLAINS INTO THE TN/MS VALLEY REGION TUESDAY INTO WEDNESDAY BEHIND
THE NEXT COLD FRONT. ONSHORE FLOW WILL INCREASE LATE TUESDAY THROUGH
WEDNESDAY NIGHT AHEAD OF THE NEXT APPROACHING COLD FRONT. STRONG
OFFSHORE FLOW IN THE WAKE OF THE FRONT WILL DEVELOP EARLY THURSDAY
MORNING AND CONTINUE THROUGH EARLY FRIDAY MORNING BEFORE DIMINISHING
LATE IN THE WEEK AS A STRONGER RIDGE BUILDS ACROSS THE EASTERN AND
SOUTHERN STATES. SMALL CRAFT ADVISORIES WILL LIKELY BECOME NECESSARY
LATE WEDNESDAY NIGHT OR EARLY THURSDAY MORNING INTO THURSDAY NIGHT.
/21


&&

.PRELIMINARY POINT TEMPS/POPS...
MOBILE      54  68  58  72  62 /  30  30  20  20  20
PENSACOLA   55  67  60  72  63 /  20  20  20  10  20
DESTIN      57  65  60  68  63 /  20  20  20  10  20
EVERGREEN   53  69  58  77  64 /  20  30  20  20  20
WAYNESBORO  54  66  57  75  63 /  40  50  30  20  30
CAMDEN      54  66  57  77  64 /  30  50  20  20  20
CRESTVIEW   54  69  59  76  62 /  20  20  20  10  20

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...DENSE FOG ADVISORY FROM 6 PM SUNDAY TO 9 AM MONDAY FOR THE
     FOLLOWING ZONES: LOWER BALDWIN...LOWER MOBILE...

FL...DENSE FOG ADVISORY FROM 6 PM SUNDAY TO 9 AM MONDAY FOR THE
     FOLLOWING ZONES: COASTAL ESCAMBIA...COASTAL OKALOOSA...
     COASTAL SANTA ROSA...

MS...NONE.
GM...DENSE FOG ADVISORY UNTIL 9 AM MONDAY FOR THE FOLLOWING ZONES:
     CHOCTAWHATCHEE BAY...COASTAL WATERS FROM DESTIN TO
     PENSACOLA FL OUT 20 NM...COASTAL WATERS FROM PENSACOLA FL
     TO PASCAGOULA MS OUT 20 NM...MISSISSIPPI SOUND...NORTHERN
     MOBILE BAY...PENSACOLA BAY SYSTEM...PERDIDO BAY...SOUTHERN
     MOBILE BAY...

&&

$$







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