000
AXNT20 KNHC 180000
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
705 PM EST THU DEC 17 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 
2330 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 6N12W 4N22W 3N38W 2N49W. 
SCATTERED SHOWERS ARE WITHIN 90 NM OF THE AXIS FROM 2N TO 5N 
BETWEEN 12W AND 20W.

...DISCUSSION...

GULF OF MEXICO...
A 1008 MB LOW IS OVER THE NW GULF OF MEXICO NEAR 27N93W. A 
TIGHT SURFACE PRESSURE GRADIENT IS OVER THE NW GULF OF MEXICO 
PRODUCING GALE FORCE WINDS FROM 26N-28N W OF 92W... AND S OF 22N 
W OF 93W. A STATIONARY FRONT EXTENDS E FROM THE LOW CENTER TO 
CENTRAL FLORIDA ALONG 28N88W 28N83W. A COLD FRONT EXTENDS S FROM 
THE LOW CENTER TO THE BAY OF CAMPECHE TO 18N91W. A LINE OF 
SCATTERED MODERATE CONVECTION IS 100 NM AHEAD OF THE COLD FRONT 
FROM 20N-26N BETWEEN 87W-90W. RADAR IMAGERY SHOWS ANOTHER AREA 
OF MODERATE CONVECTION NORTH OF THE WARM FRONT FROM 28N TO 30N 
BETWEEN 92W-94W. LOOKING AT UPPER LEVEL DATA...A DEEP TROUGH IS 
MOVING INTO THE WESTERN GULF PRODUCING SW FLOW OVER THE ENTIRE 
GULF OF MEXICO. THEREFORE...SIGNIFICANT UPPER LEVEL MOISTURE IS 
FEEDING THE SFC LOW THAT IS CURRENTLY IMPACTING THE NORTHERN 
GULF COAST FROM LOUISIANA TO THE WESTERN FLORIDA PANHANDLE. 
SHORT RANGE FORECAST MODELS SHOW THIS LOW PRESSURE SYSTEM MOVING 
NE INTO SOUTH CENTRAL GEORGIA OVER THE NEXT 24 HOURS WITH 
RAPIDLY DECREASING SFC CENTER PRESSURE TO AROUND 996 MB. 

CARIBBEAN SEA...
UPPER LEVEL HIGH PRESSURE CONTINUES TO DOMINATE THE CARIBBEAN 
BASIN...BRINGING STRONG SUBSIDENCE AND SUPPRESSING SIGNIFICANT 
CONVECTION IN THIS REGION. THEREFORE...ONLY PATCHES OF BROKEN 
LOW CLOUDS WITH ISOLATED SHOWERS COVER THE 
CARIBBEAN...ESPECIALLY OVER THE CENTRAL AND EASTERN CARIBBEAN E 
OF 74W. LOOK FOR MORE WEAK CONVECTION ENTERING THE NORTH WESTERN 
CARIBBEAN OVER THE NEXT 24 HOURS. 

ATLANTIC OCEAN...
A COLD FRONT IS MOVING INTO THE CENTRAL ATLANTIC FROM 30N46W TO 
24N60W INTO THE NORTHERN BAHAMAS. A STATIONARY FRONT CONTINUES 
TO CENTRAL FLORIDA NEAR 27N80W. SCATTERED SHOWERS ARE 50 NM 
AHEAD OF THE COLD FRONT FROM 26N TO 30N. AN UPPER LEVEL TROUGH 
IS ANALYZED OVER THE CENTRAL AND EASTERN ATLANTIC...SUPPORTING 
THE WEATHER ACTIVITY EAST OF THE MENTIONED COLD FRONT. 
HOWEVER...ANOTHER COLD FRONT IS FOUND OVER THE EASTERN ATLANTIC 
EXTENDING 30N16W TO 20N26W. SCATTERED MODERATE CONVECTION IS 
EAST OF THIS FRONT MOVING INTO THE WESTERN AFRICA COAST. EXPECT 
BOTH COLD FRONTS TO CONTINUE TO MOVE EASTWARD OVER THE NEXT 24 
HOURS WITH ADDITIONAL SHOWERS AND CONVECTION.  

FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE.

$$

GARCIA