446
FXUS64 KMOB 082119
AFDMOB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
319 PM CST SUN NOV 8 2009
SHORT TERM
(TONIGHT THROUGH TUESDAY) QUITE A COMPLEX AND
CHALLENGING FORECAST WITH THE APPROACH OF HURRICANE IDA. HURRICANE
IDA HAS SLOWLY STRENGTHENED FOR MUCH OF THE DAY WITH THE SYSTEM
LOOKING IMPRESSIVE ON SATELLITE AND CANCUN RADAR. HOWEVER...THE LAST
FEW SATELLITE PICTURES SHOW A LITTLE MORE RAGGED CONVECTIVE ENVELOPE
WITH SIGNS OF SOUTHERLY SHEAR MAY BE STARTING TO AFFECT THE SYSTEM.
IDA IS FORECAST TO LEVEL OFF IN INTENSITY THIS EVENING AS IT
CONTINUES NORTH NORTHWESTWARD INTO THE GULF OF MEXICO. WEAKENING IS
STILL EXPECTED AS WE PROGRESS THROUGH THE DAY MONDAY AS IDA
APPROACHES MUCH COOLER GULF WATERS. IN ADDITION...UPPER LEVEL WINDS
WILL BEGIN TO BECOME MORE HOSTILE AS AN UPPER LEVEL TROUGH OVER
WESTERN TEXAS MOVES EAST TOWARD THE GULF. THIS SAME UPPER LEVEL
TROUGH WILL CONTINUE TO SEND IDA NORTHWARD AND IT IS EXPECTED TO
APPROACH THE NORTHERN GULF COAST BY LATE MONDAY NIGHT/EARLY TUESDAY
MORNING. THE BIG QUESTION MARK IS HOW FAST DOES IDA WEAKEN AND WILL
IT MAINTAIN TROPICAL CHARACTERISTICS AS IT APPROACHES OUR AREA?
THERE ARE DEFINITELY SOME MIXED SIGNALS OUT THERE AND FORECASTING
EXTRATROPICAL TRANSITION IS ALWAYS CHALLENGING. THE GFS HAS
DEVELOPED AN INTERESTING SCENARIO WHERE IT FORECASTS A BAROCLINIC
LOW TO DEVELOP IN THE WESTERN GULF TOMORROW...WHICH IN TURN HANGS UP
THE EASTWARD MOVING COLD FRONT. THIS ALLOWS IDA TO SHOOT
NORTH...REMAINING IN THE WARM SECTOR AND DELAYING A TRANSITION. IN
FACT...THE CYCLONE PHASE DIAGRAM CHART FROM THE GFS REVEALS THE MODEL
MAINTAINING A TROPICAL SYSTEM UP UNTIL LANDFALL. HOWEVER...EVEN WITH
THE TROUGH HOLDING BACK...THE COOLER WATER...COOLER DRIER
CONTINENTAL AIR...AND INCREASING SHEAR WOULD SUGGEST THE SYSTEM MAY
BEGIN TO LOSE ITS TROPICAL FEATURES. TO MAKE IT EVEN MORE
COMPLICATED...THE HURRICANE WILL BEGIN TO INTERACT WITH A STRONG
UPPER LEVEL JET STREAK TO ITS NORTH...WHICH MAY SERVE AS A STRONG
POLEWARD OUTFLOW...HELPING TO MAINTAIN ITS INTENSITY. ALL IN ALL...IT
IS GOING TO BE A VERY CLOSE CALL AND THE POSSIBILITY OF THIS SYSTEM
MAINTAINING THE PUNCH OF A CATEGORY ONE HURRICANE IS HIGH ENOUGH TO
WARRANT THE ISSUANCE OF A HURRICANE WATCH FOR OUR ENTIRE COAST.
IT SHOULD BE NOTED THAT IF INDEED IDA BECOMES EXTRATROPICAL...WE ARE
STILL LOOKING AT A SIGNIFICANT WIND AND COASTAL FLOODING IMPACT. AS
IDA TRANSITIONS...ITS WIND FIELD WILL BROADEN AND THE GRADIENT
BETWEEN IDA AND THE HIGH TO OUR NORTH WILL PUT US IN QUITE THE
'SQUEEZE PLAY'...RESULTING IN STRONG GRADIENT WINDS. GIVEN THE
POSSIBILITY OF SIGNIFICANT WINDS SPREADING INLAND...HAVE ALSO ISSUED
A INLAND TROPICAL STORM WIND WATCH FOR INLAND ZONES. IT IS IMPORTANT
TO STRESS NOT TO FOCUS ON WHETHER THIS IS TROPICAL OR NON TROPICAL.
INSTEAD...PREPARE FOR THE WINDS AND POTENTIAL COASTAL FLOODING
REGARDLESS. PLEASE REFER TO OUR HURRICANE LOCAL STATEMENTS FOR
SPECIFIC INFORMATION REGARDING THE THREATS ASSOCIATED WITH IDA.
TONIGHT LOOKS MOSTLY DRY WITH JUST INCREASING CLOUDS AND WINDS AS
THE PRESSURE GRADIENT BEGINS TO TIGHTEN. REALLY RAMP UP POPS BY
TOMORROW AFTERNOON WITH ALL ZONES CATEGORICAL TOMORROW NIGHT WITH
THE STORM APPROACHING THE COAST. HEAVY RAIN CERTAINLY A THREAT WITH
TOTALS OF 2-4 INCHES WITH ISOLATED 6 INCHES POSSIBLE. SINCE FLASH
FLOOD GUIDANCE IS RATHER HIGH...HAVE DECIDED TO HOLD OFF ON A FLASH
FLOOD WATCH FOR NOW. LATEST NHC TRACK HAS THE REMNANTS OF IDA
SHIFTING EAST OF THE AREA ON TUESDAY...AND WILL FOLLOW SUIT ON
REDUCING POPS FROM WEST TO EAST THROUGH THE DAY. STUCK CLOSE TO MOS
TEMPS THROUGH PERIOD. /34 JFB
LONG TERM
(TUESDAY NIGHT THROUGH SUNDAY) NO SIGNIFICANT CHANGES
TO THE EXTENDED FORECAST WITH ALL ATTENTION DEVOTED TO IDA. A RETURN
TO AUTUMN WEATHER IS ANTICIPATED MID TO LATE WEEK AS IDA MOVES OUT
AND HIGH PRESSURE BUILDS INTO THE FORECAST AREA IN THE WAKE OF A COLD
FRONT. LATEST GUIDANCE WAFFLING ON THE WEEKEND PATTERN...SO WILL
LEAVE SLIGHT CHANCE POPS IN FOR NOW...BUT SUSPECT THAT CAN BE TAKEN
OUT IN SUBSEQUENT FORECASTS. 34/JFB
AVIATION...(18Z ISSUANCE)
HIGH CLOUDS WILL CONTINUE TO OVERSPREAD
THE AREA THROUGH THIS EVENING. CIGS WILL GRADUALLY LOWER THROUGH THE
MORNING ON MONDAY. HOWEVER VFR CONDITIONS ARE EXPECTED THROUGH 18Z.
HOWEVER...WIND SPEEDS WILL CONTINUE TO INCREASE AS THE GRADIENT
BETWEEN HIGH PRESSURE TO OUR NORTH AND HURRICANE IDA INCREASES.
EASTERLY WINDS OF 10 TO 20 MPH WITH GUSTS TO 30 MPH CAN BE EXPECTED
THROUGH MONDAY MORNING. /13
MARINE
EASTERLY FLOW WILL CONTINUE TO INCREASE ACROSS THE MARINE
AREA AS HURRICANE IDA CONTINUES TO MOVE NORTHWARD. GALE CONDITIONS
ARE EXPECTED BY EARLY MONDAY MORNING WITH TROPICAL STORM CONDITIONS
POSSIBLE BY MONDAY AFTERNOON. AS HURRICANE IDA APPROACHES THE
CENTRAL GULF COAST MONDAY AFTERNOON AND EVENING...HURRICANE
CONDITIONS ARE POSSIBLE ACROSS PORTIONS OF THE MARINE AREA MONDAY
NIGHT. AS IDA MOVES INLAND LATE MONDAY NIGHT INTO TUESDAY MORNING
SHE WILL TRANSITION TO EXTRA TROPICAL AND DRAG A STRONG COLD FRONT
ACROSS THE MARINE AREA ON TUESDAY. THE GRADIENT WILL REMAIN TIGHT BEHIND
THE FRONT AS ANOTHER STRONG AREA OF HIGH PRESSURE BUILDS SOUTHWARD
THUS SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED IN THE WAKE OF THE
FRONT THROUGH THURSDAY. /13
PRELIMINARY POINT TEMPS/POPS
MOBILE 61 70 62 71 / 20 80 80 40
PENSACOLA 63 71 63 70 / 05 80 90 40
DESTIN 65 73 65 69 / 05 80 90 50
EVERGREEN 55 71 61 70 / 05 60 90 60
WAYNESBORO 56 69 58 71 / 10 70 80 40
CAMDEN 55 71 60 69 / 05 60 90 60
MOB WATCHES/WARNINGS/ADVISORIES
AL...HURRICANE WIND WATCH UNTIL 6 PM TUESDAY FOR THE FOLLOWING ZONES:
LOWER BALDWIN...LOWER MOBILE...UPPER BALDWIN...AND UPPER
MOBILE.
HURRICANE WATCH UNTIL 9 PM MONDAY FOR THE FOLLOWING ZONES: LOWER
BALDWIN...LOWER MOBILE...UPPER BALDWIN...AND UPPER MOBILE.
TROPICAL STORM WIND WATCH UNTIL 6 PM TUESDAY FOR THE FOLLOWING
ZONES: BUTLER...CHOCTAW...CLARKE...CONECUH...COVINGTON...
CRENSHAW...ESCAMBIA...MONROE...WASHINGTON...AND WILCOX.
FL...HURRICANE WATCH UNTIL 9 PM MONDAY FOR THE FOLLOWING ZONES:
COASTAL ESCAMBIA...COASTAL OKALOOSA...COASTAL SANTA ROSA...
INLAND ESCAMBIA...INLAND OKALOOSA...AND INLAND SANTA ROSA.
HURRICANE WIND WATCH UNTIL 6 PM TUESDAY FOR THE FOLLOWING ZONES:
COASTAL ESCAMBIA...COASTAL OKALOOSA...COASTAL SANTA ROSA...
INLAND ESCAMBIA...INLAND OKALOOSA...AND INLAND SANTA ROSA.
MS...TROPICAL STORM WIND WATCH UNTIL 6 PM TUESDAY FOR THE FOLLOWING
ZONES: GEORGE...GREENE...PERRY...STONE...AND WAYNE.
GM...HURRICANE WATCH UNTIL 9 PM MONDAY FOR THE FOLLOWING ZONES:
COASTAL WATERS FROM DESTIN TO PENSACOLA FL OUT 20 NM...
COASTAL WATERS FROM PENSACOLA FL TO PASCAGOULA MS OUT 20
NM...MOBILE BAY...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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