000
AXNT20 KNHC 121801
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
105 PM EST SAT DEC 12 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1745 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 5N10W 4N23W 2N35W EQ45W. WEAK 
CONVECTION IS FOUND FROM 3N-5N BETWEEN 37W-42W...  AND FROM 
3N-8N BETWEEN 9W-14W.

...DISCUSSION...

GULF OF MEXICO...
A 1014 MB LOW IS OVER THE NW GULF OF MEXICO NEAR 28N96W. A COLD 
FRONT EXTENDS SOUTH FROM THE LOW TO NEAR 23N95W...BENDING SW TO 
NEAR TUXPAN MEXICO. A WARM FRONT EXTENDS NE FROM THE LOW TO THE 
E GULF ALONG 28N93W 27N86W. A STATIONARY FRONT CONTINUES TO THE 
STRAITS OF FLORIDA AT 24N80W. A LINE OF CONVECTION IS LOCATED 
ALONG 30N89W 29N91W 28N92W. THIS SYSTEM IS BRINGING HEAVY 
SHOWERS AND POSSIBLE THUNDERSTORMS TO THE LOUISIANA COAST INTO 
NEW ORLEANS. WINDS N OF THE WARM AND STATIONARY FRONTS ARE FROM 
THE ENE AT 15-25 KTS. IN THE UPPER LEVELS...AN UPPER LEVEL HIGH 
IS CENTERED OVER CENTRAL CUBA PRODUCING SW UPPER LEVEL WINDS 
OVER THE ENTIRE GULF OF MEXICO. CONSIDERABLE UPPER LEVEL 
MOISTURE IS OVER THE N GULF...ENHANCING SHOWER POTENTIAL IN THIS 
REGION. THE REMAINDER OF THE GULF HAS STRONG SUBSIDENCE. 
EXPECT...THE SURFACE LOW TO MOVE NE TO S MISSISSIPPI NEAR 31N91W 
OVER THE NEXT 24 HOURS. AS THE LOW PROGRESSES NORTH 
EASTWARD...THE WARM FRONT WILL MOVE INLAND OVER THE N GULF 
STATES. 10-15 SE SURFACE FLOW WILL BE OVER MOST OF THE GULF E OF 
THE COLD FRONT.    

CARIBBEAN SEA... 
A RELATIVELY TIGHT SURFACE PRESSURE GRADIENT OVER THE CARIBBEAN 
IS PRODUCING STRONG TRADEWINDS. GALE FORCE WINDS ARE EXPECTED 
OVER THE NEXT 24 HOURS ALONG THE COAST OF N COLOMBIA FROM 
11N-14N BETWEEN 75W-78W. PATCHES OF BROKEN LOW CLOUDS WITH 
ISOLATED SHOWERS DOTS THE CARIBBEAN MOSTLY N OF 14N. IN THE 
UPPER LEVELS...AN UPPER LEVEL HIGH IS CENTERED OVER THE GREATER 
ANTILLES. STRONG SUBSIDENCE COVERS THE ENTIRE CARIBBEAN 
SUPPRESSING SIGNIFICANT CONVECTION. THEREFORE...LOOK FOR SHOWERS 
OVER THE NW CARIBBEAN AND YUCATAN PENINSULA OVER THE NEXT 24 
HOURS...AND LITTLE CHANGE ELSEWHERE.    

ATLANTIC OCEAN...
A COLD FRONT IS MOVING OVER THE CENTRAL ATLANTIC FROM 32N52W TO 
25N73W. A STATIONARY FRONT CONTINUES TO THE BAHAMAS AND STRAITS 
OF FLORIDA NEAR 24N80W. ISOLATED SHOWERS ARE WITHIN 90 NM N OF 
THE FRONTS. AS THE COLD FRONT CONTINUES TO MOVE 
EASTWARD...CONVECTION ASSOCIATED WITH THIS SYSTEM WILL BE NORTH 
OF 24N AND WEST OF 70W. A 1025 MB HIGH IS OVER THE CENTRAL 
ATLANTIC NEAR 26N45W PRODUCING FAIR WEATHER TO THE CENTRAL 
BASIN. A DISSIPATING COLD FRONT IS OVER THE E ATLANTIC MOVING 
EASTWARD ENTERING THE WEST AFRICA COAST FROM 30N10W TO 20N23W. 
SCATTERED LIGHT SHOWERS ARE WITHIN 60 NM OF THE FRONT. IN THE 
UPPER LEVELS...AN UPPER LEVEL RIDGE IS N OF 20N W OF 40W. AN 
UPPER LEVEL TROUGH IS OVER THE E ATLANTIC N OF 15N E OF 40W. AN 
EMBEDDED UPPER LEVEL LOW IS N OF THE CANARY ISLANDS NEAR 35N14W. 
ZONAL FLOW IS OVER THE REMAINDER OF THE AREA. 

$$

FG