FXUS64 KMOB 252118
AFDMOB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
318 PM CST FRI DEC 25 2009
.SHORT TERM...(TONIGHT THROUGH SUNDAY NIGHT)TAKING A LOOK AT THE
CURRENT SITUATION OVER THE CONUS AND SURROUNDING AREAS...TWO SYSTEMS
HAVE MERGED...WITH A CLOSED LOW CENTERED OVER THE KS/MS STATE LINE.
WITH THE JOINING OF THE TWO UPPER SYSTEMS...THE SYSTEM HAS DEEPENED
SIGNIFICANTLY...SHARPENING THE UPPER RIDGES OVER THE EAST AND WEST
COASTS OF THE CONUS. THE FRONT WHICH PASSED OVER THE AREA LAST NIGHT
HAS MOVED TO THE EASTERN SEABOARD...WITH THE OCCLUDED PORTION OF THE
FRONT OVER THE NORTHERN PLAINS/OHIO RIVER VALLEY.
FOR TONIGHT THROUGH SATURDAY...GUIDANCE IS ADVERTISING A VORT LOBE
SWINGING AROUND...PUSHING SURFACE HIGH PRESSURE FROM OVER THE PLAINS
PAST THE FA OVER THE NORTHERN GULF COASTAL STATES. GUIDANCE IS ALSO
ADVERTISING A SHORTWAVE SWINGING EAST OVER THE GULF OF MEXICO. THE
TAIL END OF THIS SHORTWAVE STARTS TO ORGANIZE A SURFACE CIRCULATION
OVER THE WESTERN GULF OF MEXICO BY SATURDAY NIGHT.
SATURDAY NIGHT INTO SUNDAY NIGHT IS WHERE THE SHORT TERM GETS
INTERESTING. AS THE SHORTWAVE OVER THE GULF OF MEX MOVES EAST...AND
THE VORT LOBE CONTINUES TO SWING SOUTH AROUND THE BACKSIDE OF THE
UPPER LOW OVER THE PLAINS...GUIDANCE IS ADVERTISING A WEAKLY
ORGANIZED SYSTEM PASSING SOUTH OF THE AREA SUNDAY. THE GLOBAL MODELS
ARE PAINTING A WETTER PICTURE FOR LATE SATURDAY NIGHT INTO SUNDAY
NIGHT...WHILST THE HIGHER RESOLUTION NAM KEEPS THE RAIN MOSTLY
OFFSHORE. LOOKING AT THE MODEL SOUNDINGS CONCERNS ME...ESPECIALLY
LATE SATURDAY NIGHT INTO SUNDAY MOURNING. IT'S STILL PRETTY DRY IN
THE LOWER LEVELS...AND WITH VIRGA STARTING TO OVERSPREAD THE COASTAL
AREAS OF THE FA...A SMALL POSSIBILITY OF SLEEP EXISTS. IT'S A CASE
OF WHICH WILL WIN OUT...THE PUSH FROM THE VORT LOBE SWINGING AROUND
THE UPPER LOW OVER THE PLAINS...PUSHING THE ISENTROPIC LIFT SOUTH
ENOUGH FOR THE MAIN AREA OF SHOWERS TO SHIFT SOUTH OR NOT. HAVE TRIED
GO IN THE MIDDLE OF THE ROAD...PUSHING THE BEST CHANCE FOR ANY RAIN
SOUTH...TO MAINLY COASTAL AREAS. AM LEAVING OUT THE MENTION AF SLEET
ATTM...WITH TOO MANY IFS AND BUTS TO HAVE ANY CONFIDENCE OF ITS OCCURRENCE.
WHAT IS IN EVIDENCE IN THE MODELS IS SUNDAY NIGHT...THE NORTHERLY
PUSH FROM THE VORT LOBE BECOMES DOMINANT...PUSHING THE RAIN AREA
SOUTH OF THE FA.
.LONG TERM...(MONDAY ON)MONDAY INTO TUESDAY...THE VORT LOBE SWINGS
THROUGH...RE-ENFORCING THE NORTHERLY FLOW OVER THE AREA AND ALLOWING
SURFACE HIGH PRESSURE TO MOVE EAST...TO OVER THE MISS RIVER VALLEY.
ANOTHER UPPER SYSTEM HAS MOVES SOUTHEAST OVER THE SOUTHWESTERN
CONUS...THEN EAST...STARING TO MOVE OVER THE SOUTHERN PLAINS BY
TUESDAY NIGHT. AS THIS SYSTEM MOVES EAST-NORTHEAST OVER THE
PLAINS...LOWER MISS RIVER VALLEY AND SOUTHEASTERN CONUS(COURTESY OF
UPPER LEVEL HIGH PRESSURE OVER THE CARIBBEAN). A SURFACE LOW IS AGAIN
DEVELOPED OVER THE WESTERN GULF OF MEX AND TAKEN EAST-NORTHEAST. 12Z
ECMWF IS A BIT QUICKER/FARTHER NORTH WITH THIS SURFACE LOW'S
TRACK...MOVING IT OVER THE NORTH-CENTRAL GULF COAST. 12Z GFS KEEPS IT
FARTHER SOUTH...MOVING OVER THE SOUTHERN EDGE OF THE MARINE FA. BY
FRIDAY...AS THE UPPER SYSTEM MOVES OVER THE LOWER MISS RIVER VALLEY
TO THE SOUTHEASTERN CONUS...DRY NORTHERLY FLOW MOVES IN BEHIND THE
FRONT PUSHED ACROSS THE AREA THURSDAY NIGHT.
&&
.AVIATION...(18Z ISSUANCE)VFR CONDITIONS EXPECTED THROUGHOUT
THE PERIOD AS HIGH PRESSURE BUILDS OVER THE REGION. 12/DS
&&
.MARINE...HAD TO EXTEND THE SMALL CRAFT ADVISORY...EXCEPT FOR MOBILE
BAY...UNTIL 6 PM THIS EVENING AS A STRONG WEST TO NORTHWEST WIND
FLOW CONTINUES IN THE WAKE OF A COLD FRONT. AS THE FRONT CONTINUES
TO MOVE AWAY FROM THE MARINE AREA...AND HIGH PRESSURE BUILDS IN FROM
THE NORTH...WINDS WILL GRADUALLY BECOME MORE NORTHERLY AND DECREASE
THIS EVENING AND OVERNIGHT TONIGHT. A LIGHT TO MODERATE OFFSHORE
FLOW WILL THEN PERSIST THROUGH MONDAY...IN RESPONSE TO AN AREA OF
WEAK LOW PRESSURE TRACKING EAST OVER THE CENTRAL GULF OF MEXICO.
AREAS OF RAIN CAN BE EXPECTED AHEAD OF THE LOW BEGINNING LATE
SATURDAY NIGHT CONTINUING THROUGH SUNDAY NIGHT. A MODERATE TO OCNLY
STRONG OFFSHORE FLOW CAN BE EXPECTED ON TUESDAY AS A REINFORCING
SURGE OF COLDER AIR MOVES INTO THE SOUTHEASTERN STATES...BUT THE
FLOW WILL BECOME MORE EASTERLY ON WEDNESDAY AS YET ANOTHER AREA OF
LOW PRESSURE IS EXPECTED TO DEVELOP OVER THE WESTERN GULF AND BEGIN
TO MOVE TOWARD THE ALABAMA/FLORIDA COASTAL WATERS. 12/DS
&&
.FIRE WEATHER...AFTER A FRONTAL PASSAGE THURSDAY NIGHT...COOLER...
DRIER AIR WILL CONTINUE TO MOVE IN. AS TEMPERATURES WARM MORE
SATURDAY...AFTERNOON RELATIVE HUMIDITY VALUES ARE EXPECTED TO FALL
TO AROUND 30 PERCENT ALONG THE COAST...25 PERCENT WELL INLAND.
SATURDAY NIGHT THROUGH SUNDAY...AN UPPER SYSTEM WILL PASS SOUTH OF
THE AREA...BRINGING A CHANCE FOR RAIN SUNDAY...MAINLY TO AREAS
CLOSER TO THE COAST. NORTHERLY FLOW IS EXPECTED THROUGH THE WEEKEND
INTO THE COMING WEEK...WITH WEAKENING MONDAY NIGHT INTO TUESDAY AS
SURFACE HIGH PRESSURE PASSES NORTH OF THE AREA.
&&
.PRELIMINARY POINT TEMPS/POPS...
MOBILE 30 54 36 58 34 / 00 00 30 20 10
PENSACOLA 32 53 39 58 37 / 00 00 30 30 10
DESTIN 36 53 39 56 40 / 00 00 30 30 10
EVERGREEN 26 53 31 56 30 / 00 00 10 10 10
WAYNESBORO 26 54 31 55 30 / 00 00 10 10 10
CAMDEN 25 53 31 56 30 / 00 00 10 10 10
CRESTVIEW 26 53 35 59 32 / 00 00 30 30 10
&&
.MOB WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
FL...FIRE WEATHER WATCH FROM 11 AM SATURDAY TO 4 PM SATURDAY FOR THE
FOLLOWING ZONES: INLAND ESCAMBIA...INLAND OKALOOSA...AND
INLAND SANTA ROSA.
MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM FRIDAY 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.
&&
$$
