FXUS64 KMOB 220158 CCA
AFDMOB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
757 PM CST MON DEC 21 2009
CORRECTED FOR TYPOS
.AVIATION (00 AND 06Z ISSUANCES)...VFR CONDITIONS CONTINUE THROUGH
THE PERIOD EXCEPT FOR LIGHT FOG DURING THE LATE NIGHT HOURS.
MOISTURE RETURN DURING THE DAY ON TUESDAY LOOKS SUFFICIENT TO ADD
SCATTERED CUMULUS CLOUDS BY MID AFTERNOON. /29
&&
** PREVIOUS DISCUSSION **
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT) TAKING A LOOK AT THE
CURRENT SITUATION OVER THE CONUS AND SURROUNDING AREAS...THE WATER
VAPOR IMAGERY SHOWS A CLOSED SYSTEM SPINNING OFF THE NEW ENGLAND
COAST. A SHORTWAVE WAS PASSING OVER THE GULF OF MEX ATTM. ANOTHER
CLOSED SYSTEM IS PUSHING ONSHORE OVER THE CA PACIFIC
NORTHWEST...SHARPENING AN UPPER RIDGE OVER THE WESTERN THIRD OF THE
CONUS. THE NEAR NEW ENGLAND UPPER SYSTEM IS SEEMINGLY TRYING TO
DANCE AROUND WITH A CLOSED SYSTEM JUST NORTH OF LAKE SUPERIOR.
IN THE LOWER LEVELS OF THE TROPOSPHERE...SURFACE HIGH PRESSURE WAS
ANALYZED OVER THE NORTHERN GULF COAST...STRETCHING NORTH ALONG THE
EAST SIDE OF THE MISS RIVER VALLEY. THE AIRMASS IS PRETTY DRY OVER
THE SOUTHEASTERN CONUS/LOWER MISS RIVER VALLEY...WITH PRECIP H20
VALUES REPORTED BETWEEN 0.2" AND 0.42".
FOR TONIGHT THROUGH TUESDAY...GUIDANCE IS ADVERTISING THE UPPER
SYSTEM OVER THE CA WEST COAST DIVING SOUTH...TO OVER THE GREAT BASIN
BY TUESDAY NIGHT. A VORT LOBE SWINGING NORTH OVER THE PLAINS AROUND
THE EAST SIDE OF THE SYSTEM WILL HELP TO PUSH THE SURFACE HIGH EAST
...RE-ESTABLISHING ONSHORE FLOW BY TUESDAY NIGHT OVER THE FA. A BLEND
OF THE MAV/MET TEMPS SO FAR SEEMS TO BE THE BEST VERIFIER(MAV A BIT
TOO COLD...THE MET A BIT TOO WARM). SO HAVE WENT THAT ROUTE FOR TEMPS
TONIGHT AND TUESDAY.
TUESDAY NIGHT INTO WEDNESDAY NIGHT...SHOWERS WILL GRADUALLY INCREASE
FROM THE WEST AS THE UPPER SYSTEM STARTS TO MOVE OVER THE SOUTHERN
PLAINS. HELPING IS AN UPPER PIECE OF ENERGY...SEEMINGLY EJECTED FROM
THE MAIN SYSTEM...MOVING OVER THE AREA WEDNESDAY INTO WEDNESDAY
NIGHT. THE MAIN SYSTEM PUSHES EAST OVER THE SOUTHERN
PLAINS...FORMING A SURFACE LOW NEAR THE TEX/MEX BORDER AND SWINGING
IT NORTH...TO OVER THE OK/KS/MO/AR JUNCTURE. SHOWERS WILL START
PUSHING OVER THE AREA LATE TUESDAY INTO WEDNESDAY....WITH COVERAGE
BECOMING MORE WIDESPREAD WEDNESDAY NIGHT.
.LONG TERM...(CHRISTMAS EVE ON) CHRISTMAS EVE THURSDAY IS WHERE
THINGS GET REALLY INTERESTING FOR THE FA. GUIDANCE IS ADVERTISING A
VORT LOBE SWINGING AROUND THE EAST SIDE OF THE SOUTHERN PLAINS UPPER
LOW...TIGHTENING THE GRADIENT OVER THE AREA. GUIDANCE IS PRETTY
CONSISTENT IN ENOUGH INSTABILITY FOR A FEW THUNDERSTORMS TO BECOME
STRONG...WITH GOOD DIRECTIONAL/SPEED SHEAR FOR SOME OF THESE STRONGER
STORMS TO ROTATE. SOME TIMING ISSUES EXIST BETWEEN THE 12Z
NAM/GFS/ECMWF...BUT FOR SEVERAL DAYS OUT...THESE DIFFERENCES ARE
SMALL. HAVE A FEELING WE WILL BE PUT UNDER A SLIGHT RISK FOR SEVERE
THUNDERSTORMS CHRISTMAS EVE.
THE SYSTEM PUSHES THE FRONT THROUGH LATE THURSDAY...BRINGING IN A
COOLER AIRMASS. IT'S NOT UNTIL A VORT LOBE SWINGS AROUND THE
BACKSIDE OF THE UPPER SYSTEM...LOCATED OVER IA BY LATE FRIDAY...THAT
A COLDER SHOT OF AIR PUSHES OVER THE FA FOR THE COMING WEEKEND.
&&
.MARINE...SURFACE HIGH PRESSURE OVER THE SOUTHEAST STATES WILL
GRADUALLY TRANSITION INTO A LARGE HIGH PRESSURE SYSTEM EXTENDING
DOWN THE EASTERN SEABOARD FROM NORTH OF THE GREAT LAKES. MARINE
WINDS BECOME EAST THEN SOUTHEAST AS THIS TRANSITION OCCURS. WINDS
GRADUALLY INCREASING AS THE NEXT COLD FRONT AND LOW PRESSURE TROUGH
APPROACH IN THE MID-WEEK PERIOD. WINDS AND SEAS INCREASING TO SMALL
CRAFT ADVISORY LEVELS DURING THE DAY THURSDAY AS THE FRONT
APPROACHES...CROSSING THE MARINE AREA THURSDAY AFTERNOON AND
EVENING. WOULD NOT BE SURPRISED TO SEE SOME DENSE FOG OVER THE
COOLER NEAR SHORE WATERS AND BAYS AS THE WARM AND MOIST SOUTHERLY
AIR FLOWS NORTHWARD IN ADVANCE OF THE FRONT AND SOUTH OF THE WARM
FRONT....MOST LIKELY WEDNESDAY AND WEDNESDAY NIGHT. FOLLOWING THE
FRONT...MODERATE TO STRONG WEST TO NORTHWEST WINDS WITH SLOWLY
SUBSIDING SEAS DROPPING BELOW 7 FEET THURSDAY NIGHT OR FRIDAY
MORNING. WINDS REMAINING NORTHWEST TO NORTHEAST 15 TO 20 KNOTS INTO
SATURDAY. /11
&&
.FIRE WEATHER...AS AN UPPER SYSTEM OVER THE SOUTHWESTERN STATES
SWINGS EAST THROUGH THE WEEK...LIGHT LOW LEVEL FLOW WILL BECOME
SOUTHERLY BY THE END OF TUESDAY...THEN INCREASE. MOISTURE LEVELS
ALSO INCREASING. THIS SYSTEM WILL PUSH A FRONT ACROSS THE AREA
THURSDAY INTO THURSDAY NIGHT. A COOLER...DRIER AIRMASS WILL THEN
MOVE IN FOR THE COMING WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
MOBILE 35 66 48 67 58 / 00 00 05 30 60
PENSACOLA 40 62 47 65 59 / 00 00 05 20 50
DESTIN 40 62 48 64 62 / 00 00 05 10 40
EVERGREEN 27 64 37 64 51 / 00 00 05 20 50
WAYNESBORO 29 64 43 62 49 / 00 00 10 50 70
CAMDEN 32 62 40 62 47 / 00 00 05 30 50
CRESTVIEW 24 64 37 66 52 / 00 00 05 10 40
&&
.MOB WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
FL...NONE.
MS...NONE.
GM...NONE.
&&
$$
11/16
