829
FXUS64 KMOB 072136
AFDMOB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
336 PM CST SAT NOV 7 2009
SHORT TERM
(TONIGHT THROUGH MONDAY NIGHT) VERY QUIET WEATHER EXPECTED
THROUGH MUCH OF SUNDAY WITH TROPICAL STORM IDA NOT YET IN THE GULF
AND HIGH PRESSURE RIDGING DOWN FROM THE MID ATLANTIC STILL BEING THE
MAIN INFLUENCE ON OUR WEATHER. A MORE ESE COMPONENT TO THE WIND TODAY
HAS ALLOWED DEWPOINTS TO CLIMB ACROSS THE AREA...SO NOT EXPECTING
LOWS TO BE AS COLD TONIGHT. LOWS IN THE LOW 40S FAR INLAND TO MID 50S
ALONG THE COAST. HIGH TOMORROW IN THE MID TO UPPER 70S WITH MID AND
HIGH LEVEL CLOUDS INCREASING THROUGH THE DAY.
OF COURSE THE BIG STORY CONTINUES TO BE THE EVOLUTION OF TROPICAL
STORM IDA. IDA IS CURRENTLY LOCATED OVER THE NW CARIBBEAN SEA AND IS
VERY NEAR HURRICANE STRENGTH AS IT CONTINUES TO MOVE NORTHWARD. THERE
IS A GOOD CHANCE THAT IDA WILL REACH HURRICANE STRENGTH IN THE NEXT
12-18 HOURS AS IT TRAVERSES THE VERY WARM CARIBBEAN WATERS.
HOWEVER...AS IT ENTERS THE GULF OF MEXICO...IT WILL ENCOUNTER A LESS
CONDUCIVE ENVIRONMENT AS WATER TEMPS COOL AND UPPER LEVEL WINDS
BECOME MORE HOSTILE. THE GFS AND ECMWF HAVE COME INTO MUCH BETTER
AGREEMENT ON ACCELERATING IDA NORTHWARD AHEAD OF AN APPROACHING MID
LEVEL TROUGH AND ATTENDANT COLD FRONT. BOTH THE GFS AND ECMWF SHOW
IDA NEARING THE AL/NW FL COASTS BY EARLY TUESDAY MORNING.
HOWEVER...BASED ON THE LATEST MOTION AND POSITION...THESE MODELS MAY
A LITTLE TOO FAR TO THE WEST. REGARDLESS...IDA IS EXPECTED TO ENTER
OUR COASTAL WATERS BY MONDAY NIGHT/EARLY TUESDAY...BUT IN A WEAKENED
STATE AS IT MOVES OVER WATERS TEMPS IN THE UPPER 70S AND EXPERIENCES
INCREASINGLY HOSTILE UPPER LEVEL WINDS. THE EXPECTATION IS FOR IDA TO
BEGIN INTERACTING WITH A COLD FRONT AND TRANSITION TO AN
EXTRATROPICAL STORM SYSTEM. EVEN WITH IDA WEAKENING...THERE WILL BE A
LARGE PRESSURE GRADIENT IN PLACE BETWEEN IDA AND HIGH PRESSURE
LOCATED TO THE NORTH. THIS CAUSES A DRAMATIC INCREASE IN EAST TO EAST
SOUTHEAST WINDS ALONG THE COAST AND OFFSHORE BEGINNING SUNDAY NIGHT.
AT THE SAME TIME...LARGE SWELLS FROM IDA WILL BEGIN ARRIVING EARLY
MONDAY MORNING THROUGH TUESDAY. COMBINE ALL OF THIS WITH ASTRONOMICAL
HIGH TIDES RUNNING 1.0 TO JUST OVER 1.5 FEET...AND THE STAGE IS SET
FOR SOME COASTAL FLOODING ISSUES...ESPECIALLY IN THE TYPICALLY
VULNERABLE LOCATIONS. CURRENT THINKING IS THAT TOTAL TIDE HEIGHTS
WILL REACH ABOUT 3 TO 4 FEET...BUT COULD BE HIGHER IF IDA STRENGTHENS
FURTHER. THEREFORE...HAVE ISSUED A COASTAL FLOOD WATCH FOR ALL
COASTAL ZONES.
IT APPEARS THAT THE FIRST HALF OF SUNDAY NIGHT WILL REMAIN RAIN FREE
WITH JUST SMALL CHANCES ENTERING THE WESTERN ZONES EARLY MONDAY
MORNING. RAINFALL WILL BEGIN TO SPREAD IN FROM WEST TO EAST DURING
THE DAY MONDAY AND PERSIST INTO TUESDAY AS THE AFOREMENTIONED
MID LEVEL TROUGH'S DYNAMICS COMBINES WITH THE MOISTURE AND LIFT FROM
IDA. CERTAINLY COULD BE SOME HEAVY RAINFALL WITH STORM TOTALS IN THE
2 TO 4 INCH RANGE. BASED ON THE LATEST FLASH FLOOD GUIDANCE AND THE
EXPECTED DURATION OF THE EVENT...SIGNIFICANT FLOODING ISSUES ARE NOT
ANTICIPATED.
AS THE LOW PRESSURE CENTER NEARS THE COAST MONDAY NIGHT INTO EARLY
TUESDAY...WIND GUSTS OF UP TO 40 MPH ALONG THE COAST ARE A
POSSIBILITY. WILL HIGHLIGHT THIS POTENTIAL IN THE HWO.
STAYED CLOSE TO GFS MOS ON TEMPS WITH HIGHS TEMPERED MONDAY WITH RAIN
AND CLOUDS AND LOWS ABOVE NORMAL. 34/JFB
LONG TERM
(TUESDAY THROUGH SATURDAY) MODEL DIFFERENCES ARISE BY LATE
IN THE DAY TUESDAY ON HOW TO HANDLE THE EVOLUTION OF IDA'S REMNANT
LOW. THE GFS QUICKLY SHIFTS THE LOW EAST ALONG WITH THE
FRONT...BRINGING AN END TO MUCH OF THE RAIN BY LATE TUESDAY AFTERNOON
WHILE THE ECMWF SHIFTS IDA BACK SOUTH INTO THE GULF WITH RAIN
LINGERING INTO TUESDAY NIGHT. FOR NOW WILL STICK CLOSE THE MOS
GUIDANCE AND END MOST POPS BY EARLY TUESDAY EVENING. SOME FINE TUNING
TO THIS FORECAST WILL CERTAINLY BE NEEDED.
WEDNESDAY THROUGH THURSDAY LOOK DRY AND SEASONABLE AS ANOTHER HIGH
PRESSURE SYSTEM SHIFTS TO THE EASTERN SEABOARD. A RETURN TO ABOVE
NORMAL TEMPS POSSIBLE FRI/SAT AS AN UPPER LEVEL RIDGE BUILDS OVER THE
SOUTHEAST AND A SURFACE FRONT STALLED OVER THE GULF BEGINS TO RETREAT
NORTH. HAVE ADDED A SLIGHT CHANCE POP TO SATURDAY BASED ON THE 12Z
GFS/ECMWF SHOWING PRECIP DEVELOPING ALONG THE WARM FRONT. 34/JFB
AVIATION...VFR THROUGH THE FORECAST
AS HIGH PRESSURE MAINTAINS
CONTROL OVER THE AREA. /13
MARINE
THE GRADIENT BETWEEN HIGH PRESSURE OVER THE SOUTHEAST
STATES AND MUCH LOWER PRESSURES OVER THE SOUTHERN GULF OF MEXICO AS
A RESULT OF TROPICAL STORM IDA WILL RESULT IN INCREASING EASTERLY
FLOW OVER THE NEXT FEW DAYS. TROPICAL STORM IDA IS CURRENTLY LOCATED
IN THE WESTERN CARIBBEAN SEA AND WILL MOVE INTO THE SOUTHERN GULF OF
MEXICO THROUGH THE YUCATAN CHANNEL OVER THE NEXT FEW DAYS. THIS WILL
CAUSE WINDS TO CONTINUE TO INCREASE ALONG WITH RAPIDLY BUILDING SEAS
SUNDAY INTO MONDAY. GALE CONDITIONS ARE POSSIBLE LATE SUNDAY THROUGH
MONDAY NIGHT BEYOND 20 NM OFFSHORE. IDA WILL RAPIDLY BECOME EXTRA
TROPICAL AS SHE NEAR THE NORTH CENTRAL GULF. AS THE REMNANTS OF IDA
MOVE OUT OF THE AREA...A STRONG OFFSHORE FLOW WILL FOLLOW TUESDAY
NIGHT THROUGH EARLY THURSDAY. PLEASE REFER TO THE LATEST FORECASTS
AND DISCUSSIONS BY THE NATIONAL HURRICANE CENTER IN MIAMI ON THE
TRACK OF TROPICAL STORM IDA. /13
FIRE WEATHER
NO CONCERNS. HUMIDITY WILL BE INCREASING SUNDAY AND
MONDAY ALONG WITH AN INCREASE IN WINDS WELL IN ADVANCE OF THE
APPROACH OF TROPICAL STORM IDA. A SOAKING RAIN IS EXPECTED MONDAY
INTO TUESDAY. 34/JFB
PRELIMINARY POINT TEMPS/POPS
MOBILE 54 77 63 72 / 00 05 30 80
PENSACOLA 55 76 63 74 / 00 05 20 70
DESTIN 60 76 65 74 / 00 05 10 60
EVERGREEN 45 76 56 72 / 00 05 10 70
WAYNESBORO 46 75 58 69 / 00 05 20 80
CAMDEN 43 75 55 70 / 00 05 10 70
MOB WATCHES/WARNINGS/ADVISORIES
AL...COASTAL FLOOD WATCH FROM 6 PM SUNDAY TO 6 AM TUESDAY FOR THE
FOLLOWING ZONES: LOWER BALDWIN...AND LOWER MOBILE.
FL...COASTAL FLOOD WATCH FROM 6 PM SUNDAY TO 6 AM TUESDAY FOR THE
FOLLOWING ZONES: COASTAL ESCAMBIA...COASTAL OKALOOSA...AND
COASTAL SANTA ROSA.
MS...NONE.
GM...SMALL CRAFT ADVISORY FROM NOON SUNDAY TO 6 PM TUESDAY FOR THE
FOLLOWING ZONES: AND MOBILE BAY.
SMALL CRAFT ADVISORY UNTIL 6 PM TUESDAY FOR THE FOLLOWING ZONES:
COASTAL WATERS FROM DESTIN TO PENSACOLA FL OUT 20 NM...AND
COASTAL WATERS FROM PENSACOLA FL TO PASCAGOULA MS OUT 20
NM.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT MONDAY FOR THE FOLLOWING
ZONES: WATERS FROM DESTIN TO PENSACOLA FL FROM 20 TO 60
NM...AND WATERS FROM PENSACOLA FL TO PASCAGOULA MS FROM 20
TO 60 NM.
GALE WATCH FROM MIDNIGHT MONDAY TO 6PM TUESDAY FOR THE FOLLOWING
ZONES: WATERS FROM DESTIN TO PENSACOLA FL FROM 20 TO 60 NM...AND
WATERS FROM PENSACOLA FL TO PASCAGOULA MS FROM 20 TO 60 NM.
SMALL CRAFT ADVISORY FROM MIDNIGHT TUESDAY TO 6 PM TUESDAY FOR
THE FOLLOWING ZONES: WATERS FROM DESTIN TO PENSACOLA FL
FROM 20 TO 60 NM...AND WATERS FROM PENSACOLA FL TO
PASCAGOULA MS FROM 20 TO 60 NM.
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