FXUS64 KMOB 101105
AFDMOB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
505 AM CST THU DEC 10 2009
.SHORT TERM...(TODAY AND TONIGHT) FAVORABLE SIDE OF BROAD 140 KT
JET POSITIONED FROM WEST TO EAST FROM THE MID MS RIVER VALLEY TO THE
MID ATLANTIC SEABOARD CONTINUES TO GIVE WAY TO ENHANCED LIFT IN THE
MID TO UPPER LEVELS TO THE SOUTH...COUPLED WITH BETTER MOISTURE
MOSTLY OFFSHORE THIS MORNING...THUS GIVING WAY TO A BAND OF SHOWERS
STRETCHING FROM JUST SOUTH OF THE MOUTH OF THE MS RIVER TO THE
CENTRAL FL PANHANDLE. AS A RESULT A FEW EXTRA MID CLOUDS ALONG WITH
A BRIEF SHOWER OR SPRINKLE WILL POSSIBLE MAINLY EARLY THIS MORNING
MOSTLY ALONG THE NWFL COAST GENERALLY OVER EXTREME SOUTHERN OKALOOSA
COUNTY. OTHERWISE...STRONG COLD AIR ADVECTION WILL PREVAIL ACROSS
THE CENTRAL GULF COAST TODAY AND TONIGHT GIVING WAY TO ONE OF THE
DRIEST DAYS IN WEEKS TO THE REGION. AFTERNOON TEMPS WILL REMAIN ON
THE COOL SIDE WITH HIGHS RANGING FROM THE MID 50S OVER THE SOUTHERN
HALF OF THE CWA AND IN THE UPPER 40S TO THE LOWER 50S TO THE NORTH.
DUE TO THE POSITION OF UPPER JET STREAK TO THE NORTH CONSIDERABLE
HIGH CLOUDINESS MOVING FROM WEST TO EAST WILL CONTINUE FOR MOST
AREAS IN THE CWA TODAY AND TONIGHT POSSIBLE AFFECTING TEMPS A
TAD...SLIGHTLY COOLER THAN GUIDANCE THIS AFTERNOON AND SLIGHTLY
WARMER TONIGHT. AS A RESULT HAVE ADJUSTED THE CURRENT MAV NUMBERS
ACCORDINGLY. A LIGHT FREEZE WILL LIKELY OCCUR ALSO TONIGHT GENERALLY
OVER THE NORTHERN 2/3 OF THE CWA...OR NORTH OF A LINE FROM WIGGINS
MS TO NORTH OF CRESTVIEW FL. 32/EE
(FRIDAY THROUGH SATURDAY NIGHT) A SHORTWAVE MOVING OUT OF THE BAJA
WILL HELP TO INDUCE THE DEVELOPMENT OF A LOW PRESSURE SYSTEM OVER THE
WESTERN GULF ON FRIDAY. AS THE LOW ORGANIZES OVER THE GULF...ISENTROPIC
LIFT WILL GRADUALLY BEGIN TO INCREASE...FIRST HELPING TO THICKEN
CLOUD COVER OVER THE AREA DURING THE DAY FRIDAY. THE COMBINATION OF
THE INCREASING CLOUDS AND COLD HIGH PRESSURE TO THE NORTH WILL LIKELY
RESULT IN HIGHS ONLY REACHING THE MID TO UPPER 40S...EXCEPT FOR A FEW
50S ALONG THE IMMEDIATE COAST. WITH THE ISENTROPIC LIFT NOT
INCREASING IN EARNEST UNTIL LATE IN THE AFTERNOON AND CONSIDERING HOW
DRY THE LOW LEVELS WILL INITIALLY BE...DO NOT THINK THERE IS MUCH
CHANCE FOR SIGNIFICANT RAIN DURING THE DAY...WITH PERHAPS ONLY A FEW
SPRINKLES OR VERY LIGHT RAIN OCCURRING NEAR THE COAST. BY FRIDAY
NIGHT...UPPER LEVEL DIVERGENCE WILL BEGIN TO INCREASE ACROSS THE
REGION AS A POWERFUL UPPER JET SHIFTS EAST IN TANDEM WITH THE BAJA
SHORTWAVE. MEANWHILE...ISENTROPIC LIFT WILL CONTINUE TO INCREASE...
WITH LIFT NOTED IN THE 295-310 K LAYER. RAIN IS EXPECTED TO INCREASE
IN COVERAGE FROM SOUTH TO NORTH THROUGH THE NIGHT WITH MOST PLACES
SEEING RAIN BY DAYBREAK SATURDAY. WITH THE LOW STILL OVER THE WESTERN
GULF BY 12Z SATURDAY...ITS ATTENDANT FRONTAL BOUNDARY IS EXPECTED TO
REMAIN OVER THE NORTHERN GULF...KEEPING US FIRMLY IN THE COOL SECTOR.
SO WE ARE EXPECTING A VERY CHILLY RAIN OVERNIGHT WITH LOWS IN THE
UPPER 30S INLAND TO LOWER 40S ALONG THE COAST. DESPITE THE COLD AND
DRY AIRMASS INITIALLY OVER THE AREA...NO PRECIP TYPE CONCERNS ARE
ANTICIPATED AS WETBULB ZEROES ARE LOCATED WELL TO THE NORTH ACROSS
NORTH CENTRAL ALABAMA. PLUS...850MB TEMPS WILL WARM UP TO PLUS
10C...SO THE WARM RAIN WILL ALSO CONTRIBUTE TO MODIFYING THE SURFACE
TEMPS.
THE SFC LOW WILL MOVE TO THE NORTHWEST DURING THE DAY SATURDAY...BUT
WILL STAY RATHER WEAK OVER THE NW GULF AS THE CONTRIBUTING SHORTWAVE
WEAKENS AND BECOMES SHEARED OUT IN THE STRONG SEMI-ZONAL FLOW OVER
THE LOWER 48. AS A RESULT...THE WARM FRONT OVER THE NORTHERN GULF
WILL ONLY SLOW MOVE NORTH...STILL STAYING OFFSHORE FOR MUCH OF THE
DAY...KEEPING US ON THE COOL SIDE AND IN THE ZONE OF DEEP ISENTROPIC
LIFT. HAVE BUMPED UP POPS TO CATEGORICAL ALL AREAS. THE LOW WEAKENS
FURTHER SATURDAY NIGHT WITH THE WARM FRONT TRYING TO PUSH NORTH...BUT
WILL BE BATTLING THE RESIDUAL COLD AIR WEDGE LEFT IN PLACE BY THE
STRONG SFC HIGH OVER THE CAROLINAS. TRYING TO TIME WHEN THIS SHALLOW
COLD AIR WEDGE WILL WEAKEN IS ALWAYS DIFFICULT AND NOT ALWAYS HANDLED
WELL BY THE MODEL GUIDANCE. KEPT SATURDAY HIGHS IN THE UPPER 40S
NORTH TO UPPER 50S ALONG THE COAST. LOWS SATURDAY NIGHT VERY
DIFFICULT TO GET A HANDLE ON. WILL STAY COOLER FOR NOW...LOW 40S
NORTH TO MID 50S ON THE COAST. 34/JFB
.LONG TERM...(SUNDAY THROUGH WEDNESDAY) THE COOL AIR WILL CONTINUE TO
GIVE WAY AS THE SFC HIGH OVER THE EASTERN SEABOARD CONTINUES TO
WEAKEN AND RETREAT. THIS ALLOWS THE RESIDUAL WARM FRONT TO PUSH A
LITTLE FURTHER INLAND...ALTHOUGH IT BECOMES RATHER ILL DEFINED. GIVEN
THIS BOUNDARY IS PRESENT AND THE FACT THAT MODEL GUIDANCE BRINGS IN
SOME INSTABILITY DURING THE DAY...WILL KEEP A CHANCE POP GOING. RAIN
CHANCES SHOULD TAPER OFF SUNDAY NIGHT WITH LACK OF ANY DISCERNABLE
UPPER LEVEL FORCING AND A STABILIZING SFC LAYER. HIGHS APPROACH 70
CLOSE TO THE COAST SUNDAY WITH LOWER 60S INLAND. LOWS WILL ONLY BE IN
THE 50S TO NEAR 60.
THE BREAK IN PRECIP WILL BE SHORT LIVED AS YET ANOTHER COLD FRONT
WILL BEGIN TO APPROACH LATE MONDAY AND CROSS THE AREA TUESDAY/TUESDAY
EVENING. MONDAY WILL BE WELL ABOVE NORMAL TEMP WISE WITH HIGHS IN THE
LOW TO MID 70S. NOT CONFIDENT ON JUST HOW COOL IT WILL GET BEHIND THE
FRONT WEDNESDAY AS THE GFS IS TRENDING MUCH COLDER THAN THE ECWMF AS
A RESULT OF THE GFS BEING MORE PHASED WITH THE NORTHERN AND SOUTHERN
STREAMS. FOR NOW...WILL TREND SLIGHTLY BELOW CLIMO. 34/JFB
&&
.AVIATION...(12Z ISSUANCE) CONSIDERABLE HIGH CLOUDINESS FOR THE MOST
PART THROUGH TONIGHT WITH A MODERATE TO STRONG NORTHERN WIND FLOW
THROUGH TONIGHT. BETTER WINDS WILL BE CLOSER TO THE COAST AND DURING
THE DAY LIGHT HOURS DUE TO BETTER MIXING. OTHERWISE...NO MAJOR
CONCERNS. 32/EE
&&
.MARINE...A STRONG COLD FRONT WILL CONTINUE TO MOVE SOUTH OF THE
MARINE AREA THROUGH EARLY FRIDAY...THEN RETROGRADE SLOWLY NORTHWARD
AS A WARM FRONT THROUGH THE WEEKEND IN RESPONSE TO AN AREA OF LOW
PRESSURE DEVELOPING OVER THE NORTHWEST GULF...MOVING NORTHEAST
THROUGH MONDAY. A STRONG OFFSHORE FLOW WILL CONTINUE THROUGH TONIGHT
THEN BECOME MOSTLY EAST FRIDAY THROUGH EARLY SATURDAY AS THE AREA OF
LOW PRESSURE APPROACHES FROM THE WEST. AS RESULT SMALL CRAFT
ADVISORIES CONTINUE FOR THE ADJACENT GULF WATERS OUT TO 60 NM
THROUGH NOON ON SAT AND OVER MOBILE BAY MOSTLY DURING THE NIGHT AND
MORNING HOURS THROUGH FRI. A LIGHT TO MODERATE SOUTHERLY WIND FLOW
WILL DEVELOP BY EARLY SUNDAY AND CONTINUE THROUGH EARLY TUESDAY AS
THE AREA OF LOW PRESSURE APPROACHES THE LOUISIANA COAST AND MOVES
INLAND DURING THE DAY. SHOWERS AND THUNDERSTORMS ARE EXPECTED WITH
THIS SYSTEM BECOMING NUMEROUS AT TIMES SATURDAY AFTERNOON AND
SATURDAY NIGHT. A STRONG OFFSHORE FLOW IS EXPECTED IN THE WAKE OF A
COLD FRONT TUESDAY AFTERNOON. /32
&&
.FIRE WEATHER...MUCH DRIER AND COOLER AIR WILL CONTINUE TO FILTER
INTO THE REGION TODAY IN THE WAKE OF A COLD FRONT. HUMIDITIES WILL
DROP INTO THE 30-35 PERCENT RANGE FOR THE MAJORITY OF THE AFTERNOON.
DURATIONS OF LOW HUMIDITY ARE SUFFICIENT TO WARRANT AN UPGRADE TO A
RED FLAG WARNING ACROSS THE NW FL PANHANDLE. HUMIDITIES DROP BELOW 35
PERCENT ONCE AGAIN ON FRIDAY AFTERNOON...BUT DURATIONS CURRENTLY
APPEAR TO BE TOO SHORT TO ISSUE A FIRE WEATHER WATCH. WILL CONTINUE
TO MONITOR. 34/JFB
&&
.PRELIMINARY POINT TEMPS/POPS...
MOBILE 53 34 48 42 / 10 10 20 80
PENSACOLA 56 34 50 44 / 10 10 20 80
DESTIN 56 39 52 45 / 20 10 20 80
EVERGREEN 53 30 48 37 / 05 10 10 70
WAYNESBORO 50 30 47 37 / 05 10 10 70
CAMDEN 51 30 46 37 / 05 10 10 60
CRESTVIEW 55 33 49 39 / 10 10 20 80
&&
.MOB WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
FL...RED FLAG WARNING FROM NOON THURSDAY TO 4 PM THURSDAY FOR THE
FOLLOWING ZONES: COASTAL ESCAMBIA...COASTAL OKALOOSA...
COASTAL SANTA ROSA...INLAND ESCAMBIA...INLAND OKALOOSA...
AND INLAND SANTA ROSA.
MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL NOON THURSDAY FOR THE FOLLOWING
ZONES: AND MOBILE BAY.
SMALL CRAFT ADVISORY FROM 6 PM THURSDAY TO NOON FRIDAY FOR THE
FOLLOWING ZONES: AND MOBILE BAY.
SMALL CRAFT ADVISORY UNTIL NOON SATURDAY 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...WATERS FROM DESTIN TO PENSACOLA FL FROM 20 TO 60
NM...AND WATERS FROM PENSACOLA FL TO PASCAGOULA MS FROM 20
TO 60 NM.
&&
$$
