000
AXNT20 KNHC 182356
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
705 PM EST FRI DEC 18 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 
2330 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 9N15W 4N25W 4N39W 1N50W. WIDELY 
SCATTERED MODERATE CONVECTION IS FROM 3N TO 10N BETWEEN 14W-22W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 2200 UTC...A COLD FRONT IS ANALYZED OVER NORTHEAST 
FLORIDA...EXTENDING SOUTHWARD ALONG 30N81W 25N82W 20N84W 17N86W. 
A LINE OF HEAVY SHOWERS AND THUNDERSTORMS IS LOCATED 50-100 NM 
AHEAD OF THE FRONT ALONG 80W FROM 21N TO 30N...CROSSING THE 
STATE OF FLORIDA AND THE FLORIDA STRAIGHTS. THIS LINE IS MOVING 
EASTWARD INTO THE WESTERN ATLANTIC OCEAN AND THE WESTERN 
BAHAMAS. WINDS BEHIND THE FRONT ARE RANGING BETWEEN 25 KTS AND 
30KTS WITH GUSTS TO GALE FORCE CRITERIA. HOWEVER...WINDS ARE 
EXPECTED TO DECREASE OVERNIGHT...AS THE FRONTAL SYSTEM LEAVES 
THE REGION AND SURFACE HIGH PRESSURE OVERTAKES THE NW BASING. 
LOOK FOR NORTHERLY SURFACE FLOW WITH COLD AIR ADVECTION TO 
DOMINATE THE ENTIRE GULF OF MEXICO OVER THE NEXT 24 HOURS.  

CARIBBEAN SEA...
AS OF 2300 UTC...A COLD FRONT IS ANALYZED OVER THE NW CARIBBEAN 
ALONG 22N83W 20N84W 17N86W. A LINE OF CONVECTION AHEAD OF 
THE FRONT IS MOVING EASTWARD AND PRODUCING MODERATE SHOWER 
ACTIVITY SOUTH OF CUBA AND WEST OF JAMAICA. THIS LINE IS 
EXPECTED TO WEAKEN AS IT MOVES INTO AN AREA OF HIGH PRESSURE 
OVER THE CENTRAL BASIN. SURFACE OBSERVATIONS CONTINUE TO REVEAL 
STRONG EASTERLY TRADEWINDS ACROSS THE REMAINDER OF THE 
CARIBBEAN. THE STRONGEST WINDS REMAIN NEAR THE COASTS OF 
COLOMBIA AND VENEZUELA. RADAR IMAGERY DISPLAYS PATCHES OF BROKEN 
LOW CLOUDS WITH ISOLATED SHOWERS OVER THE NORTHERN BASIN. HIGH 
PRESSURE CONTINUES TO SUPPRESS DEEP CONVECTION OVER THE 
REMAINDER OF THE BASIN. LOOK FOR TRADEWINDS AND SHOWERS TO 
PERSIST OVER THE LEEWARD ISLANDS AND PUERTO RICO OVER THE NEXT 
24 HOURS.  

ATLANTIC OCEAN...
A COLD FRONT IS OVER CENTRAL AND WESTERN ATLANTIC FROM 30N36W TO 
24N42W. A STATIONARY FRONT CONTINUES TO THE EASTERN BAHAMAS 
ALONG 22N56W TO 23N68W. SCATTERED MODERATE CONVECTION IS OVER 
THE CENTRAL ATLANTIC EAST OF THE COLD FRONT FROM 23N TO 32N 
BETWEEN 30W-40W. SCATTERED SHOWERS ARE WITHIN 30 NM OF THE 
REMAINDER OF THE STATIONARY FRONT. A 1018 MB HIGH IS OVER THE 
EASTERN ATLANTIC NEAR 23N20W. OVER THE NEXT 24 HOURS LOOK FOR A 
LOW PRESSURE SYSTEM TO HEAD OUT OF THE EASTERN US COAST AND MOVE 
INTO THE WESTERN ATLANTIC...BRINGING CONVECTION TO THAT REGION. 
ALSO...EXPECT THE FRONT OVER THE CENTRAL ATLANTIC TO MOVE AND 
EXPAND EAST WITH ADDITIONAL SHOWERS MOVING INTO THE EASTERN 
ATLANTIC REGION. 

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

$$

GARCIA