FXUS62 KTAE 280120
AFDTAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
820 PM EST FRI NOV 26 2009

.DISCUSSION...00 UTC SURFACE ANALYSIS SHOWS HIGH PRESSURE CENTERED 
ABOUT 30 MILES SOUTH OF LAKE CHARLES LA. LIGHT NORTHWESTERLY FLOW 
RESULTED IN A VERY DRY AIRMASS ACROSS THE REGION TODAY WITH 
DEWPOINTS FOR A BRIEF TIME DROPPING INTO THE LOWER 30S. DEWPOINTS 
ARE NOW IN THE UPPER 30S AND EVEN IN THE LOW 40S IN A FEW PLACES 
INLAND. 

INFRARED SATELLITE IMAGERY SHOWS A VERY THICK LAYER OF CIRRUS MOVING 
OVER THE REGION. THIS CIRRUS HAS DEFINITELY LIMITED THE DROP IN 
TEMPERATURES AFTER SUNSET. IN FACT...BETWEEN 00Z AND 01Z 
TEMPERATURES ACTUALLY ROSE A DEGREE OR TWO IN SOME LOCATIONS. 
THUS...WITH THE THICK CIRRUS CANOPY IN PLACE...RADIATIONAL COOLING 
WILL BE CONSIDERABLY LIMITED. 

UPPER AIR DATA THIS EVENING CONTINUES TO SHOW AN EXTREMELY DRY 
ATMOSPHERE BELOW THE CIRRUS LAYER. THE PRECIPITABLE WATER VALUE 
REMAINED AT A VERY DRY 0.16 INCHES. THIS VERY DRY ATMOSPHERE WOULD 
OTHERWISE PROVE VERY EFFECTIVE AT RADIATING HEAT TONIGHT IF THE 
CIRRUS WERE NOT IN PLACE. THUS...IF ANY GAPS IN THE CIRRUS CANOPY 
CAN DEVELOP TONIGHT AND PERSIST LONG ENOUGH...TEMPERATURES COULD 
DROP A LITTLE LOWER THAN CURRENTLY EXPECTED. 

THERE IS A NOTICEABLE THINNING OF THE CIRRUS FROM THE FLA BIG BEND 
STRETCHING BACK TO AN AREA SOUTH OF MOBILE. THIS THIN AREA IS PROGGED
IN THE MODEL DATA WELL AND SHOULD BE MOVING OVER OUR REGION BETWEEN 
03Z AND 08Z. WITH THE DRY LOW LEVEL ENVIRONMENT THERE IS SOME 
CONCERN OF TEMPERATURES DROPPING INTO THE LOW TO MID 30S. 
HOWEVER...WITH SO MUCH CIRRUS OVER THE GULF...IT SEEMS PRUDENT TO 
RAISE TEMPERATURES OVERNIGHT BETWEEN 2 AND 4 DEGREES DUE TO ALL THE 
CLOUD COVER. GIVEN THE INCREASE IN TEMPERATURES AND THE HIGHER 
LIKELIHOOD OF TEMPERATURES IN THE MID TO UPPER 30S OVERNIGHT...WILL 
NOT ISSUE A FROST ADVISORY AND HANDLE ANY POTENTIAL FROST FORMATION 
WITHIN THE POINT-AND-CLICK FORECAST AND ZONES. 

THE REMAINDER OF THE FORECAST IS ON TRACK WITH NO OTHER CHANGES 
NEEDED. HAVE A GREAT NIGHT! 

&&

.MARINE...WINDS RUNNING GENERALLY BETWEEN 10 AND 15 KNOTS FROM THE 
NORTHWEST TONIGHT. AS THE SURFACE RIDGE ABOUT 200 NM WEST OF THE 
WATERS MOVES FURTHER EAST TONIGHT...EXPECT WINDS TO GRADUALLY WEAKEN 
WITH TIME. 

&&

.AVIATION...EXPECT VFR CONDITIONS TO PREVAIL THROUGH THE PERIOD WITH 
VERY LIGHT N-NW WINDS...BUT CI AND CS BETWEEN 20K AND 25K FT WILL BE 
ON THE INCREASE FROM WEST TO EAST ACROSS THE CWA THROUGHOUT THE 
NIGHT...ESPECIALLY AT THE SOUTHERN TAF SITES OF PFN...TLH...AND 
VLD. DHN MAY VACILLATE BETWEEN SCT AND BKN...WHILE ABY MAY REMAIN 
SCT THROUGHOUT MUCH OF THE PERIOD.

&&

.TAE WATCHES/WARNINGS/ADVISORIES...

AL...NONE.
GA...NONE.
FL...RED FLAG WARNING SATURDAY AFTERNOON ALL BUT GULF AND FRANKLIN   
     COUNTIES.
 
     FIRE WEATHER WATCH SUNDAY AFTERNOON FOR THE FOLLOWING ZONES:    
     DIXIE...JEFFERSON...LAFAYETTE...MADISON...TAYLOR.

GM...NONE.  

&&

$$

AVIATION...GOULD
REST OF DISCUSSION...GODSEY