000
AXNT20 KNHC 112351
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
705 PM EST FRI DEC 11 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER 
OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2315 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 6N11W 3N30W 4N44W 3N51W. SCATTERED 
MODERATE CONVECTION IS FROM 3N-6N BETWEEN 11W-15W. SIMILAR 
CONVECTION IS FROM 1N-5N BETWEEN 26W-35W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 2100 UTC...A STATIONARY FRONT ENTERS THE SE GULF THROUGH THE 
FLORIDA STRAITS AND CONTINUES TO 26N87W WHERE IT EXTENDS WESTWARD AS 
A WARM FRONT INTO A 1013 MB LOW CENTERED NEAR 26N96W. A COLD FRONT 
EXTENDS FROM THE LOW TO 24N98W AND INLAND ACROSS NE MEXICO. A 
SURFACE TROUGH ALSO EXTENDS FROM THE LOW TO THE EASTERN BAY OF 
CAMPECHE NEAR 19N92W. SCATTERED SHOWERS COVER A MAJORITY OF THE GULF 
NORTH OF THESE FRONTS. MOSAIC DOPPLER RADAR IMAGERY INDICATES THESE 
SHOWERS OVER THE EXTREME SOUTHERN FLORIDA PENINSULA AND FLORIDA 
KEYS...AS WELL AS ALONG THE TEXAS AND SE CONUS GULF COAST. MOST OF 
THE ACTIVITY OVER THE NORTHERN GULF FALLS BENEATH MOIST SWLY FLOW 
ALOFT BETWEEN AN UPPER LEVEL TROUGH ACROSS THE SW CONUS AND AN UPPER 
LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER THE NW CARIBBEAN. AS 
THE LOW LOCATED IN THE WESTERN GULF DRIFTS NORTHWARD OVER THE NEXT 
24 HOURS...AN AREA OF STRONG EASTERLY WINDS NORTH OF THE WARM FRONT 
WILL LIFT NORTHWARD AS WELL LEAVING MOSTLY S-SE WINDS AND A WEAK 
COLD FRONT DRAPED FROM S/CENTRAL LOUISIANA TO THE NE MEXICO COAST BY 
LATE SATURDAY.

CARIBBEAN SEA... 
AN UPPER LEVEL RIDGE IS CENTERED OVER THE NW CARIBBEAN NEAR 20N81W 
WITH STRONG SUBSIDENCE AND DRY AIR NOTED ON WATER VAPOR IMAGERY 
COVERING MUCH OF THE CARIBBEAN SEA AND CENTRAL AMERICA. MOSTLY FAIR 
WEATHER CONTINUES ACROSS THE BASIN WITH MODERATE TO STRONG EASTERLY 
TRADES EXPECTED TO PERSIST THROUGH TUESDAY. HOWEVER...A FEW AREAS OF 
ISOLATED LOW-LEVEL SHOWERS ARE OCCURRING ACROSS THE NW CARIBBEAN 
FROM 16N-20N BETWEEN 80W-87W AND OVER THE N/CENTRAL CARIBBEAN N OF 
16N BETWEEN 64W-76W...INCLUDING PUERTO RICO...THE MONA PASSAGE...AND 
HISPANIOLA.

ATLANTIC OCEAN...
A COLD FRONT EXTENDS ACROSS THE SW NORTH ATLC ENTERING THE 
DISCUSSION AREA NEAR 32N61W CONTINUING SW ALONG 27N71W TO THE 
CENTRAL BAHAMAS NEAR 25N76W AND CONTINUING AS A STATIONARY FRONT 
ACROSS THE FLORIDA STRAITS AND INTO THE SE GULF OF MEXICO. ISOLATED 
SHOWERS ARE WITHIN 90 NM EITHER SIDE OF THE COLD FRONT. LINGERING 
ISOLATED SHOWERS FOLLOW NW OF THE FRONT ACROSS THE REMAINDER OF THE 
W ATLC AS A RIDGE BUILDS IN N OF 26N W OF 70W. THE COLD FRONT IS 
SUPPORTED ALOFT BY AN UPPER LEVEL LONGWAVE TROUGH LOCATED WELL NORTH 
OF THE AREA ACROSS THE NW NORTH ATLC. FARTHER EAST...THE CENTRAL 
ATLC IS UNDER THE INFLUENCE OF A BROAD SURFACE RIDGE ANCHORED BY A 
1025 MB HIGH CENTERED NEAR 29N45W BRINGING GENERALLY FAIR WEATHER 
BETWEEN 30W-60W. HOWEVER...AN UPPER LEVEL TROUGH AXIS EXTENDS INTO 
THE DISCUSSION AREA ACROSS THE EASTERN ATLC NEAR 32N16W EXTENDING SW 
ALONG 20N23W TO 18N43W. THIS UPPER LEVEL TROUGH SUPPORTS A COLD 
FRONT THAT ENTERS NEAR 32N14W AND EXTENDS SW ALONG 26N20W BECOMING 
MORE DIFFUSE TO 23N30W AND THEN AS A SURFACE TROUGH TO 21N42W. 
SCATTERED SHOWERS AND POSSIBLE ISOLATED TSTMS AREA WITHIN 60 NM OF 
THE COLD FRONT N OF 26N WITH LINGERING ISOLATED SHOWERS WITHIN 75 NM 
EITHER SIDE OF THE REMAINDER OF THE BOUNDARY TO 42W.
 
$$
HUFFMAN