FXUS64 KMOB 041755
AFDMOB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
1154 AM CST FRI DEC 4 2009
AVIATION (18Z ISSUANCE)...SWATH OF STRATUS/STRATOCUMULUS HAS BROKEN
UP OVER MOB AND BFM BUT REMAINS OVER PNS. HAVE GONE WITH PREVAILING
VFR AT MOB AND BFM WITH MVFR CEILINGS CONTINUING AT PNS...BUT THEN
VFR CONDITIONS FOR ALL THREE BY 22Z. HAVE INCLUDED TEMPO GROUPS AT
MOB AND BFM FOR OCCASIONAL PATCHES OF STRATOCUMULUS THAT MOVE ACROSS
THE AREA...AND A TEMPO GROUP FOR PNS FOR LIKEWISE SCATTERED CLOUDS
AT PNS UNTIL 22Z. MVFR CEILINGS SET IN ACROSS THE AREA BY 1Z WITH
CEILINGS LOWERING THROUGH 5Z AS OVERRUNNING INTENSIFIES AND
SUBCLOUD AIR MOISTENS. HAVE STARTED WITH PREVAILING VERY LIGHT RAIN
AT 1Z WITH A TEMPO GROUP FROM 1 TO 5Z THEN PROB30 FROM 5Z TO 11Z FOR
PERIODS OF MODERATE RAIN. THERE IS A SLIGHT POSSIBILITY THAT SOME
SNOW MAY MIX IN WITH THE RAIN AT MOB AND BFM PROBABLY BETWEEN 8-11Z
BUT HAVE NOT INCLUDED IN THE TAFS AT THIS TIME AND WILL REASSESS AT
00Z TAF CYCLE. CEILINGS LIFT BY 13Z WITH CLEARING EXPECTED LATER
IN THE DAY. /29
&&
** PREVIOUS DISCUSSION **
SHORT TERM...(TODAY AND TONIGHT)...LATEST REASONING IN THE SHORT
TERM HAD LEAD ME TO COMMIT TO A WINTER WEATHER ADVISORY ONLY FOR
LATE TONIGHT...GENERALLY WHERE THE WINTER WEATHER WATCH WAS EARLIER.
ALSO ADDED ADJACENT COUNTIES TO THE EAST OF THE WATCH TO THE NEW
ADVISORY. LATEST MODEL GUIDANCE PREFERABLY A MIX OF THE GFS...ECMWF
AND NAM SHOW HIGHER MOISTURE FURTHER TO THE EAST THAN EARLIER
ANTICIPATED RESULTING IN LOWER POPS FOR MOST AREAS OF THE
CWFA...WITH HIGHER PRECIP MOVING OFF TO THE EAST QUICKER ALSO AFTER
MIDNIGHT TONIGHT. LATEST MODEL SOUNDINGS STILL DEPICT NEAR FREEZING
TEMPS NEAR THE SFC BY 12Z SAT...MOSTLY OVER WESTERN AND NORTHERN
SECTIONS OF THE CWFA WITH MID LEVEL MOISTURE DRYING FROM WEST TO
EAST BETWEEN 06 AND 12Z SAT. DUE TO TEMPS IN THE MIDDLE 30S FOR MANY
AREAS INLAND BY THE LATE EVENING HOURS WILL LIKELY SEE TEMPS BEGIN
TO WET BULB LATE THIS EVENING. ALOFT...LATEST THICKNESS VALUES STILL
SUPPORT RAIN AND SNOW MIXED THEN CHANGING TO MAINLY LIGHT SNOW AFTER
MIDNIGHT DUE TO LIMITED MOISTURE LATER IN THE NIGHT. ALSO
NOTED...FAVORABLE REGION FOR ENHANCED LIFT OF UPPER JET STREAK NOW
LOOKS TO BE MORE TO THE EAST OR OUT OF PHASE THAN EARLIER
ANTICIPATED REDUCING OR LIMITING THE THREAT FOR ANY SIGNIFICANT
BANDING OF SNOW ACROSS THE CWFA SAT MORNING. AS FOR TEMPS WILL GO A
TAD LOWER THAN THE MAVMOS FOR HIGHS TODAY AND TAD HIGHER OVERNIGHT.
/32
&&
.SHORT TERM [SATURDAY THROUGH MONDAY]...BRIEF CLEARING SATURDAY
AFTERNOON UNDER SOME ISENTROPIC SINKING/COMPRESSION THEN SKY WILL
CLOUD UP AGAIN WITH VERY SLIGHT ISENTROPIC LIFTING IN THE MID
LAYERS. WATER VAPOR INSUFFICIENT TO BRING A SIGNIFICANT CHANCE OF
RAIN THROUGH MONDAY.
/77
.LONG TERM [MONDAY NIGHT THROUGH THURSDAY]...A FEW CHANGES WERE MADE
TO THE EXTENDED FORECAST. A SURFACE HIGH WILL DOMINATE THE REGION
THROUGH EARLY NEXT WEEK, FOLLOWED BY ANOTHER DEEPENING LOW OVER THE
WESTERN GULF AROUND MIDWEEK. THE GULF LOW WILL MOVE EAST FRIDAY
NIGHT BRINGING COLDER AIR SOUTHWARD. IF THIS PHASES WITH WATER VAPOR
MAXIMA THERE COULD BE A HINT AT A WINDOW FOR SOME TYPE OF
PRECIPITATION LATE IN THE WEEK FAR INLAND BUT THERE IS LITTLE
CONFIDENCE IN PINPOINTING WHAT TYPE IT WILL BE THIS FAR AHEAD. AT
THE MOMENT WE WOULD SAY LIQUID BY SHEER CLIMATOLOGY.
/77
&&
AVIATION...(12Z ISSUANCE)...OVC CEILINGS AT 010 TO 020 THROUGHOUT
MOST OF THE DAY LOWERING TO BELOW 010 AT TIMES TONIGHT AND EARLY SAT
MORNING THEN GRADUALLY IMPROVING LATE SAT AFTERNOON AND SAT NIGHT. A
MODERATE NORTHERLY WIND TODAY WILL BUILD SLIGHTLY TONIGHT AND
SATURDAY MORNING THEN GRADUALLY DECREASE SAT AFTERNOON.
/32
&&
MARINE...AN AREA OF LOW PRESSURE TRACKING EAST ACROSS THE CENTRAL
GULF COMBINED WITH HIGH PRESSURE BUILDING SOUTHEASTWARD OVER THE
CENTRAL PART OF THE COUNTRY WILL BRING A STRONG NORTHERLY WIND
FLOW OVER THE MARINE AREA THROUGH MIDDAY SATURDAY. AHEAD OF THE LOW
AREAS OF RAIN...POSSIBLY HEAVY A TIMES MAINLY WELL OFFSHORE...CAN BE
EXPECTED MOSTLY THIS EVENING THEN TAPERING OFF FROM WEST TO EAST
EARLY SAT MORNING. NORTHERLY WINDS AND SEAS WILL GRADUALLY SUBSIDE
LATE SATURDAY AND EARLY SATURDAY EVENING AS THE AREA OF LOW PRESSURE
CONTINUES TO TRACK WELL EAST OF THE MARINE AREA. NORTHERLY WINDS AND
SEAS WILL BUILD SLIGHTLY EARLY SUNDAY DUE TO COLD AIR DRAINAGE. A
MODERATE TO STRONG SOUTHERLY WIND FLOW WILL DEVELOP LATE TUESDAY
INTO WEDNESDAY AS HIGH PRESSURE TO THE NORTH MOVES EAST AND A
DEVELOPING TROUGH OF LOW PRESSURE APPROACHES FROM THE WEST.
/32
&&
.FIRE WEATHER...SURFACE HIGH WILL DOMINATE THROUGH TODAY THEN MOVING
EAST. SURFACE CYCLOGENESIS WILL START OVER THE WEST AND SOUTHWEST
GULF ON FRIDAY FORMING A DEEPENING LOW. LIGHT NORTH TO NORTHEAST
FLOW WILL DOMINATE THROUGH THE WEEK. STRATIFORM RAIN WILL MOVE IN
OFF THE GULF BY FRIDAY AFTERNOON. MINIMUM HUMIDITY WILL NOT REACH
CRITERIA AND DISPERSION WILL BE CLOSE TO AVERAGE FOR TIME OF DAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
MOBILE 53 33 54 30 / 20 70 05 05
PENSACOLA 56 38 55 34 / 20 80 10 05
DESTIN 56 41 56 39 / 30 80 10 05
EVERGREEN 52 35 51 23 / 10 60 10 05
WAYNESBORO 50 31 51 24 / 20 50 05 05
CAMDEN 50 35 49 24 / 10 50 10 10
CRESTVIEW 54 36 53 24 / 20 80 10 05
&&
.MOB WATCHES/WARNINGS/ADVISORIES...
AL...WINTER WEATHER ADVISORY FROM 11 PM FRIDAY TO 9 AM SATURDAY FOR
THE FOLLOWING ZONES: CHOCTAW...CLARKE...MONROE...UPPER
BALDWIN...UPPER MOBILE...WASHINGTON...AND WILCOX.
FL...NONE.
MS...WINTER WEATHER ADVISORY FROM 11 PM FRIDAY TO 9 AM SATURDAY FOR
THE FOLLOWING ZONES: GEORGE...GREENE...PERRY...STONE...AND
WAYNE.
GM...SMALL CRAFT ADVISORY FROM 6 PM FRIDAY TO 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...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.
&&
$$
