000
AXNT20 KNHC 312351
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
705 PM EST THU DEC 31 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.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 8N10W 7N23W 3N40W 3N51W. 
ISOLATED MODERATE CONVECTION IS FROM 3N-6N BETWEEN 20W-26W. 
SCATTERED SHOWERS ARE WITHIN 120 NM OF THE AXIS BETWEEN 
26W-40W.  

...DISCUSSION...

GULF OF MEXICO...
AS OF 2100 UTC...A 1016 MB LOW IS CENTERED INLAND OVER SOUTH 
GEORGIA NEAR 32N84W. A COLD FRONT EXTENDS SW FROM THE LOW TO THE 
W GULF OF MEXICO ALONG 29N86W 25N94W. 5-10 KT NW WINDS ARE 
BEHIND THE FRONT. THE REMAINDER OF THE GULF OF MEXICO HAS 10 KT 
SE RETURN FLOW. NO PRECIPITATION IS NOTED IN THE GULF ON 
SATELLITE IMAGERY OR ON RADAR. IN THE UPPER LEVELS...A RIDGE 
WITH AXIS ALONG 70W IS PRODUCING SW UPPER LEVEL FLOW OVER THE 
GULF. UPPER LEVEL MOISTURE WITH BROKEN HIGH CLOUDS ARE OVER THE 
CENTRAL GULF FROM 22N-29N. 90-110 KT 25O MB WINDS ARE NOTED OVER 
THE N GULF N OF 25N. EXPECT IN 24 HOURS...FOR A REINFORCING COLD 
FRONT THAT IS PRESENTLY INLAND OVER THE NORTH GULF STATES TO 
SWEEP DOWN OVER THE GULF AND EXTEND FROM CENTRAL FLORIDA TO THE 
YUCATAN PENINSULA WITH SHOWERS. 25-30 KT NORTHERLY WINDS WILL BE 
BEHIND THIS FRONT WITH A LOT OF COLD AIR ADVECTION. 

CARIBBEAN SEA...
THE TAIL END OF A DISSIPATING COLD FRONT IS OVER THE LEEWARD 
ISLANDS...AND SOUTH OF PUERTO RICO AND HISPANIOLA ALONG 18N60W 
17N70W. BROKEN TO OVERCAST LOW CLOUDS WITH SCATTERED SHOWERS ARE 
WITHIN 60 NM OF THE FRONT. 15-20 KT NW WINDS ARE NORTH OF THE 
FRONT. FRESH TO STRONG TRADEWINDS ARE OVER THE REMAINDER 
CARIBBEAN SEA AND CENTRAL AMERICA. BROKEN LOW CLOUDS WITH 
ISOLATED SHOWERS ARE SOUTH OF JAMAICA FROM 15N-18N BETWEEN 
77W-80W...AND OVER WESTERN PANAMA...COSTA RICA...NORTHERN 
NICARAGUA...AND HONDURAS. IN THE UPPER LEVELS...AN UPPER LEVEL 
RIDGE IS PRODUCING NW UPPER LEVEL WINDS OVER THE W CARIBBEAN AND 
CENTRAL AMERICA. ZONAL FLOW IS OVER THE REMAINDER OF THE 
CARIBBEAN. VERY STRONG SUBSIDENCE IS OVER THE ENTIRE CARIBBEAN 
AND CENTRAL AMERICA SUPPRESSING DEEP CONVECTION. EXPECT OVER THE 
NEXT 24 HOURS FOR CONVECTION TO BE OVER THE YUCATAN PENINSULA 
AND THE NW CARIBBEAN...AND S OF HISPANIOLA. 

ATLANTIC OCEAN...
A 1029 MB HIGH IS CENTERED NEAR BERMUDA AT 33N64W MOVING E. 
RIDGING IS PRODUCING NE-E FLOW OVER THE W ATLANTIC. A COLD FRONT 
EXTENDS FROM THE THE EASTERN ATLANTIC NEAR 32N35W TO THE LEEWARD 
ISLANDS ALONG 20N50W 18N60W. SCATTERED MODERATE CONVECTION IS 
WITHIN 180 NM E OF THE FRONT N OF 27N. SCATTERED SHOWERS ARE 
WITHIN 60 NM OF THE REMAINDER OF THE FRONT. A 1022 MB HIGH IS 
OVER THE E ATLANTIC NEAR 31N22W. IN THE UPPER LEVELS...A RIDGE 
IS OVER THE W ATLANTIC W OF 50W. AN UPPER LEVEL TROUGH IS 
FURTHER E OVER THE CENTRAL ATLANTIC BETWEEN 40W-50W. UPPER LEVEL 
ZONAL FLOW IS OVER THE REMAINDER OF THE ATLANTIC. EXPECT OVER 
THE NEXT 24 HOURS...FOR THE FRONT TO MOVE E TO THE E ATLANTIC 
NEAR 25W WITH CONVECTION. ALSO EXPECT A NEW COLD FRONT TO BE 
OVER THE W ATLANTIC FROM 32N77W TO CENTRAL FLORIDA WITH 
CONVECTION.   

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

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FORMOSA