Area Forecast Discussion
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000
FXUS62 KTAE 270912
AFDTAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
512 AM EDT MON APR 27 2015

.NEAR TERM [THROUGH TODAY]...

WATER VAPOR IMAGERY THIS MORNING SHOWS A WELL DEFINED MID AND
UPPER LEVEL MOISTURE PLUME STREAMING ACROSS THE AREA ORIGINATING
FROM SUBTROPICAL JET. A BAND OF RAIN AND THUNDERSTORMS HAS
DEVELOPED ALONG THIS PLUME OVER THE COASTAL WATERS. HI-RES MODELS
GENERALLY LIFT THIS NORTHWARD A BIT THROUGH THE DAY TODAY...
ALTHOUGH THE HEAVIEST OF IT WILL PROBABLY STAY OFFSHORE. RAIN
CHANCES WILL BE HIGHEST SOUTH OF I-10 LATER THIS AFTERNOON CLOSE
TO THE COAST. AFTERNOON HIGHS ARE GENERALLY EXPECTED TO BE IN THE
LOW TO MID 80S.


.SHORT TERM [TONIGHT THROUGH WEDNESDAY]...

A SURFACE LOW SHOULD BEGIN TO TAKE SHAPE BY TONIGHT NEAR THE
LOUISIANA COASTLINE WITH MODEST CYCLOGENESIS CONTINUING AS THE LOW
PROGRESSES INTO SOUTH GEORGIA BY WEDNESDAY. CONFIDENCE IS
RELATIVELY HIGH IN THAT SERIES OF EVENTS, AS WELL AS THE OVERALL
SYNOPTIC SETUP - WITH A STRENGTHENING MID-UPPER LEVEL JET BUILDING
EAST ALONG THE GULF COAST TUESDAY AND WEDNESDAY ON THE SOUTHERN
PERIPHERY OF AN EJECTING WAVE. HOWEVER, THE DETAILS REALLY MATTER
IN THIS CASE, AND THERE IS STILL QUITE A BIT OF DISAGREEMENT ON
THE PLACEMENT OF CONVECTION AS NEAR IN THE FUTURE AS TONIGHT. IN
GENERAL, WE EXPECT AN INCREASE IN RAIN AND THUNDERSTORMS FROM
LATER TONIGHT AND INTO TUESDAY, AS IS HINTED AT BY A FAIR NUMBER
OF MODELS (ALTHOUGH PLACEMENT OF QPF MAXIMA DIFFERS). THIS SHOULD
LARGELY BE DRIVEN BY GRADUALLY INCREASING ISENTROPIC ASCENT IN THE
LOWER LEVELS OF THE ATMOSPHERE, ALTHOUGH SOME EASTWARD PROGRESSION
OF UPSTREAM CONVECTION IS ALSO POSSIBLE - PARTICULARLY ON TUESDAY.

THE MAIN QUESTION IS WHAT WILL OCCUR AS AN EML PLUME CURRENTLY
SITUATED OVER SOUTH TEXAS BEGINS NOSING INTO THE EASTERN GULF
COAST ABOVE A RELATIVELY MOIST BOUNDARY LAYER AHEAD OF THE SURFACE
COLD FRONT. THERE APPEAR TO BE SEVERAL (STILL UNCERTAIN) CHANCES
FOR SEVERE WEATHER. THE FIRST WOULD BE WITH SOME ELEVATED
CONVECTION ON THE EDGE OF THE ADVANCING EML PLUME TUESDAY
AFTERNOON AS MID-LEVEL LAPSE RATES STEEPEN. THE SECOND WOULD BE
CONVECTIVE REDEVELOPMENT ALONG THE SURFACE COLD FRONT SOUTH OF THE
LOW LATE TUESDAY AFTERNOON AND INTO TUESDAY NIGHT.

THE TUESDAY AFTERNOON AND TUESDAY NIGHT RISK WILL PROBABLY BE
CONTINGENT UPON THE AMOUNT OF CONVECTION OVER THE NORTHEAST GULF
OF MEXICO OVER THE PRECEDING 36 HOURS, AS SOME MODELS WITH MORE
CONVECTIVE ACTIVITY OVER THE NEXT DAY OR SO SUPPRESS THE HIGHER
SBCAPE VALUES FURTHER SOUTH. THAT BEING SAID, MOST MODELS DO SHOW
AT LEAST SOME RECOVERY. THE 00Z GFS, FOR EXAMPLE, PUSHES AN MCS
SOUTHEAST THROUGH THAT SECTION OF THE GULF ON TUESDAY BUT STILL
DEVELOPS A PLUME OF 1000-1500 J/KG OF MLCAPE ALONG THE COLD FRONT
BY 00Z WEDNESDAY. THEREFORE, WE DO EXPECT A CORRIDOR OF MODERATE
INSTABILITY TO BUILD BACK INTO THE AREA FROM WEST TO EAST LATE IN
THE AFTERNOON OR EVENING. THE AMOUNT OF REDEVELOPMENT IS ALSO
QUESTIONABLE, HOWEVER ANY STORMS DEVELOPING IN THAT ENVIRONMENT
WITH MODERATE INSTABILITY AND 0-6KM SHEAR APPROACHING 70 KNOTS
COULD EASILY BE SEVERE.

A FEW LINGERING SHOWERS MAY BE POSSIBLE ON WEDNESDAY, BUT OVERALL
THE AREA WILL BE DRYING OUT WITH SLIGHTLY BELOW NORMAL TEMPS.


.LONG TERM [WEDNESDAY NIGHT THROUGH MONDAY]...

DEEP NORTHWEST FLOW AND SURFACE HIGH PRESSURE SHOULD KEEP THE
EXTENDED FORECAST DRY AND RELATIVELY SUNNY, A CHANGE OF PACE FROM
MOST OF APRIL. TEMPERATURES SHOULD BE NEAR NORMAL.

&&

.AVIATION...

[THROUGH 12Z TUESDAY] MAINLY VFR CONDITIONS ARE EXPECTED TO
PREVAIL. SOME SHOWERS AND ISOLATED THUNDERSTORMS MAY AFFECT ECP
THIS AFTERNOON ON OCCASION...BUT THE HEAVIEST ACTIVITY IS EXPECTED
TO REMAIN OFFSHORE. TOWARDS THE END OF THE PERIOD ON TUESDAY
MORNING...ADDITIONAL SHOWERS AND THUNDERSTORMS MAY MOVE IN FROM
THE WEST...MAINLY AFFECTING ECP AND TLH.

&&

.MARINE...

WINDS MAY APPROACH 15 KNOTS AT TIMES ON TUESDAY AFTERNOON AND
TUESDAY NIGHT. BEHIND A COLD FRONT ON WEDNESDAY, WINDS WILL
INCREASE TO ADVISORY LEVELS AND REMAIN AT THOSE LEVELS THROUGH
THURSDAY. SHOWERS AND THUNDERSTORMS WILL BE LIKELY AT TIMES OVER
THE NEXT SEVERAL DAYS, THROUGH TUESDAY NIGHT, AND SOME OF THE
STORMS COULD PRODUCE GUSTY WINDS AT TIMES. MARINERS SHOULD BE
AWARE THAT THIS HAZARD COULD BE RELATIVELY COMMON OVER THE COASTAL
WATERS IN THAT TIME FRAME. WE ARE ALSO EXPECTING A HIGH RISK OF
RIP CURRENTS ALONG THE PANHANDLE BEACHES WITH INCREASING SURF (TO
3 TO 4 FEET) ON TUESDAY.

&&

.FIRE WEATHER...

HAZARDOUS FIRE WEATHER CONDITIONS ARE NOT EXPECTED OVER THE NEXT
SEVERAL DAYS.

&&

.HYDROLOGY...

AN EL NINO-LIKE PATTERN HAS RENDERED A WETTER-THAN-NORMAL APRIL
FOR THE AREA, WITH SEVERAL OF OUR AREA RIVERS REACHING ACTION
STAGE AND EVEN A FEW THAT REACHED FLOOD STAGE OVER THE PAST WEEK.
ONLY TWO SITES REMAINED IN FLOOD STAGE AT THIS TIME, THOUGH BOTH
HAVE PEAKED AND CONTINUE TO FALL- THE CHOCTAWHATCHEE RIVER AT
BRUCE AND THE APALACHICOLA RIVER AT BLOUNTSTOWN.

RAIN WILL BE IN THE FORECAST THROUGH WEDNESDAY, WITH THE PRIMARY
CHANCES OF HEAVY RAINFALL FROM LATE TONIGHT INTO TUESDAY EVENING.
AVERAGE RAINFALL AMOUNTS ACROSS THE AREA SHOULD BE IN THE 1 TO 2
INCH RANGE THROUGH WEDNESDAY, BUT ISOLATED TOTALS AROUND DOUBLE
THAT WILL BE POSSIBLE - ESPECIALLY IN THE FLORIDA PANHANDLE AND
BIG BEND. THEREFORE, WHILE WIDESPREAD FLASH FLOODING IS UNLIKELY,
AN ISOLATED EPISODE OR TWO OF FLASH FLOODING CANNOT BE RULED OUT.
ON THE LARGER RIVERS, THE MODERATE TO HEAVY RAIN SHOULD LEAD TO
SOME ADDITIONAL RISES BUT MOST RIVERS SHOULD STAY BELOW FLOOD
STAGE. RIVERS MORE LIKELY TO REACH FLOOD STAGE WOULD BE THE
CHOCTAWHATCHEE RIVER AND APALACHICOLA RIVER.

&&

.PRELIMINARY POINT TEMPS/POPS...

TALLAHASSEE   85  65  76  66  77 /  40  60  60  50  30
PANAMA CITY   80  67  76  68  72 /  60  80  60  40  20
DOTHAN        81  61  73  61  72 /  10  50  60  50  40
ALBANY        81  60  72  60  73 /   0  40  60  50  40
VALDOSTA      83  63  74  63  77 /   0  50  60  60  40
CROSS CITY    82  65  78  67  79 /  50  70  60  70  40
APALACHICOLA  80  69  78  70  75 /  60  80  60  40  20

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AL...NONE.
GM...NONE.
&&

$$

NEAR TERM...DVD
SHORT TERM...LAMERS
LONG TERM...LAMERS
AVIATION...DVD
MARINE...LAMERS
FIRE WEATHER...DVD
HYDROLOGY...KM/JF/AL



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