FXUS62 KTAE 080126
AFDTAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
825 PM EST MON DEC 7 2009
.UPDATE...
00Z WATER VAPOR AND H4 RUC ANALYSIS SHOWING AN INCREASINGLY
DISTURBED UPPER LEVEL PATTERN ACROSS THE CONUS. TROUGHING IS
BEGINNING TO AMPLIFY ACROSS THE INTERMOUNTAIN WEST AS A STRONG
SHORTWAVE EJECTS EASTWARD FROM THE CALIFORNIA COAST TOWARD THE
FOUR-CORNERS REGION. THIS ENERGY WILL EVOLVE OVER THE NEXT 24 TO 48
HOURS INTO A SIGNIFICANT STORM SYSTEM THAT WILL EFFECT THE MAJORITY
OF THE CONTINENTAL UNITED STATES. FURTHER DOWNSTREAM INTO THE
CENTRAL AND EASTERN STATES WE CURRENTLY FIND A MORE ZONAL
PATTERN...HOWEVER THIS WILL CHANGE INTO THE MIDWEEK PERIOD.
AT THE SURFACE...FORECAST AREA IS BETWEEN HIGH PRESSURE OVER THE
CENTRAL APPALACHIANS AND TROUGHING EXTENDING FROM THE WESTERN GULF
OF MEXICO TO LA. ALSO ANALYZING A WEAK SURFACE TROUGH ACROSS THE FL
PENINSULA. WEAK ISENTROPIC UPGLIDE ASSOCIATED WITH THIS FEATURE
INTO THE SUWANNEE RIVER VALLEY HAS RESULTED IN A FEW SHOWERS THIS
EVENING. RUC/GFS BOTH SHOWING THIS BEST LIFT PUSHING NORTH AND EAST
OVER THE NEXT SEVERAL HOURS AND THEREFORE SHOULD SEE MOST OF THIS
LIGHT SHOWER ACTIVITY COME TO AN END.
WARM FRONTAL FEATURE IS ANTICIPATED TO EXPAND EASTWARD ALONG THE
NORTHERN GULF COAST LATER TONIGHT AND EARLY TUESDAY AS LOW PRESSURE
DEVELOPS EAST INTO THE CENTRAL AND SOUTHERN PLAINS. DEEP LAYER
ISENTROPIC ASCENT WILL EXPAND ACROSS THE REGION ALONG AND NORTH OF
THIS SURFACE FRONT. GENERALLY THE LIFT AND BEST MOISTURE
PROFILE...AND RESULTING BEST RAIN CHANCES/COVERAGE...LOOK TO COME
TOGETHER TO THE NORTH AND NORTHWEST OF OUR ZONES. HOWEVER DO EXPECT
A SCATTERING OF SHOWERS TO BREAK OUT OVER OUR ZONES...WITH HIGHEST
POPS (60-70%) ACROSS THE NW HALF OF THE AREA. THE OVERALL LIFT MAY
MAKE IT DIFFICULT TO BREAK OUT OF THE MORNING STRATUS DECK...
ESPECIALLY NORTH OF THE FLORIDA BORDER. DESPITE THE TEMPERATURE
POTENTIAL OF THE ATMOSPHERE BEING QUITE WARM...THE CLOUDIER
CONDITIONS SHOULD KEEP TEMPS IN CHECK...AND HAVE LOWERED EXPECTED
HIGH TEMPS BY A FEW DEGREES.
WARM FRONT LIFTS NORTH OF THE REGION DURING THE EARLY EVENING HOURS.
THIS WILL SEND THE BEST LIFT EVEN FURTHER NORTH AND LIKELY TO SEE A
BREAK IN ANY SHOWER ACTIVITY FOR AT LEAST THE EVENING HOURS...BEFORE
THE APPROACHING COLD FRONT BRINGS THE THREAT FOR SHOWERS AND STORMS
BACK TO OUR WESTERN ZONES LATE AT NIGHT.
IN THE WAKE OF THE WARM-FRONT...SOUTHERLY FLOW WILL BRING MID AND
EVEN UPPER 60S DEWPOINT OVER THE COASTAL WATERS. LATEST MODIS SST
HAVE OUR SHELF WATERS IN THE UPPER 50S AND LOWER 60S. THIS HIGHER
DEWPOINTS OVER THE SHELF WATERS LOOK TO SET UP A DECENT CHANCE AT
SEA FOG DEVELOPMENT. HAVE ADDED PATCHY FOG TO THE GRIDS ALONG AND
SOUTH OF THE I-10 CORRIDOR TUESDAY EVENING/OVERNIGHT AS ANTICIPATE
AT LEAST SOME OF THIS SEA FOG TO ADVECT ONSHORE AFTER SUNSET.
&&
.AVIATION...
CIGS AND VIS WILL CONTINUE TO LOWER THROUGHOUT THE EVENING AS FOG IS
ANTICIPATED AT ALL TERMINALS. PFN...DHN...AND ABY EXPECTED TO STAY
AROUND ALT AIRPORT THRESHOLDS...WHILE TLH AND VLD DIP DOWN TO
LANDING MINIMUMS THROUGH THE OVERNIGHT AND EARLY MORNING HOURS. LOW
CLOUDS SHOULD STICK AROUND THROUGH THE DAY ON TUESDAY AND ALL
TERMINALS ARE EXPECTED TO REMAIN SOCKED IN THROUGH AT LEAST THE
AFTERNOON HOURS. LIGHT WINDS AT THE SFC ARE EXPECTED TO VEER FROM NE
TO MORE EASTERLY THROUGH THE OVERNIGHT HOURS...THEN VEER MORE TO THE
SE BY TUESDAY AFTERNOON AND EVENING. THIS VEERING SHOULD BRING AN
INCREASE IN MOISTURE TO THE REGION. RAIN CHANCES INCREASE BEGINNING
TUESDAY AFTERNOON FROM WEST TO EAST. DHN AND ABY HAVE THE HIGHEST
CHANCE FOR SHOWERS IN THE AFTERNOON BUT NOT CONFIDENT ON TIMING...SO
SHOWERS WERE LEFT OUT OF THIS TAF CYCLE FOR NOW.
&&
.MARINE...A WARM FRONT WILL DEVELOP ACROSS THE COASTAL WATERS
OVERNIGHT AND TUESDAY MORNING SHIFTING WINDS FROM NORTHEAST TO
SOUTHEAST. IN THE WAKE OF THE FRONT...SOUTHERLY FLOW WILL INCREASE
OVER THE WATERS THROUGH WEDNESDAY...REACHING SMALL CRAFT CRITERIA
TUESDAY NIGHT. A COLD FRONT WILL THEN CROSS THE NORTHEAST GULF LATER
WEDNESDAY. OFFSHORE FLOW CLOSE TO 20 KNOTS IS EXPECTED THROUGH
THURSDAY MORNING BEHIND THE FRONT. WINDS AND SEAS WILL REMAIN
ELEVATED BUT VEER TO THE EAST LATE IN THE WORK WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TALLAHASSEE 53 70 61 77 50 / 20 50 30 60 20
PANAMA CITY 55 68 65 75 51 / 10 50 40 60 10
DOTHAN 50 64 61 74 41 / 10 70 50 50 10
ALBANY 48 64 60 76 44 / 10 70 50 60 10
VALDOSTA 51 68 61 78 51 / 20 60 30 50 30
CROSS CITY 53 74 62 77 55 / 30 30 20 50 40
APALACHICOLA 56 69 65 76 53 / 10 40 30 50 20
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
GA...NONE.
FL...NONE.
GM...NONE.
&&
$$
UPDATE...MROCZKA
AVIATION...BARRY/FOURNIER
MARINE...CAMP/MROCZKA
