000
AXNT20 KNHC 240513
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
105 AM EST THU DEC 24 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0515 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 7N11W 5N20W 2N45W 1N50W. 
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 3N-5N 
BETWEEN 24N-28N. WIDELY SCATTERED MODERATE CONVECTION IS FROM 
2N-4N BETWEEN 21W-23W...FROM 2N-3N BETWEEN 25W-28W...AND FROM 
3N-4N BETWEEN 30W-32W. 

...DISCUSSION...

GULF OF MEXICO...
RETURN FLOW WITH A TIGHT SURFACE GRADIENT IS PRODUCING 20-25 KT 
SE SURFACE WINDS OVER THE GULF OF MEXICO AND FLORIDA. BROKEN TO 
OVERCAST MULTILAYERED CLOUDS COVERS THE GULF AND FLORIDA. A 
997 MB LOW IS CENTERED OVER CENTRAL TEXAS NEAR 32N101W. A COLD 
FRONT EXTENDS S TO N MEXICO. IN THE UPPER LEVELS...70-90 KT 
ZONAL FLOW WITH CONSIDERABLE UPPER LEVEL MOISTURE COVERS THE 
ENTIRE GULF. EXPECT OVER THE NEXT 24 HOURS...THE SURFACE LOW 
OVER TEXAS TO DEEPEN TO 989 MB AND MOVE TO CENTRAL ARKANSAS. A 
COLD FRONT WILL EXTEND S FROM THIS LOW TO THE CENTRAL GULF OF 
MEXICO ALONG 90W WITH PREFRONTAL CONVECTION EXTENDING OVER THE 
NE GULF.   

CARIBBEAN SEA...
A 1009 MB LOW IS CENTERED S OF HAITI NEAR 17N73W. A SURFACE 
TROUGH EXTENDS S FROM THE LOW CENTER TO N COLOMBIA NEAR 10N74W. 
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS OVER THE 
CENTRAL CARIBBEAN FROM 13N-15N BETWEEN 70W-71W...AND INLAND OVER 
VENEZUELA FROM 9N-11N BETWEEN 69W-72W. ISOLATED MODERATE 
CONVECTION IS OVER HISPANIOLA AND PUERTO RICO FROM 17N-20N 
BETWEEN 65W-70W. MOSTLY FAIR WEATHER IS OVER THE W CARIBBEAN AND 
CENTRAL AMERICA W OF 75W. IN THE UPPER LEVELS...A SHARP TROUGH 
IS OVER THE W CARIBBEAN W OF 75W. AN UPPER LEVEL RIDGE IS OVER 
THE REMAINDER OF THE CARIBBEAN PRODUCING SW UPPER LEVEL WINDS. 
SIGNIFICANT UPPER LEVEL MOISTURE IS OVER THE NE CARIBBEAN N OF 
15N BETWEEN 60W-72W WHILE STRONG SUBSIDENCE IS OVER THE 
REMAINDER OF THE CARIBBEAN. EXPECT OVER THE NEXT 24 HOURS FOR 
THE SURFACE LOW AND TROUGH TO DISSIPATE WITH CONVECTION 
REMAINING OVER THE LEEWARD ISLANDS.  

ATLANTIC OCEAN...
A DISSIPATING COLD FRONT EXTENDS FROM THE EASTERN ATLANTIC NEAR 
30N12W TO THE CENTRAL ATLANTIC AT 21N40W. A STATIONARY FRONT 
CONTINUES TO N OF HISPANIOLA NEAR 21N70W. WIDELY SCATTERED 
MODERATE CONVECTION IS OVER THE E ATLANTIC NEAR THE CANARY 
ISLANDS FROM 27N-32N BETWEEN 10W-18W. A REINFORCING COLD FRONT 
IS OVER THE E ATLANTIC ALONG 32N17W 28N26W 28N40W. SCATTERED 
SHOWERS ARE WITHIN 60 NM OF THIS FRONT. A 1018 MB HIGH IS OVER 
THE CENTRAL ATLANTIC NEAR 17N33W. IN THE UPPER LEVELS...AN UPPER 
LEVEL TROUGH IS OVER THE W ATLANTIC W OF 70W. ZONAL FLOW IS N OF 
20N FROM 70W TO THE AFRICAN COAST AT 15W. IN THE TROPICS AN 
UPPER LEVEL HIGH IS CENTERED E OF THE LESSER ANTILLES NEAR 
14N54W. A RIDGE AXIS EXTENDS E TO THE CAPE VERDE ISLANDS NEAR 
16N25W. EXPECT OVER THE NEXT 24 HOURS FOR THE COLD FRONTS TO 
MOVE E. ALSO EXPECT CONVECTION N OF THE LEEWARD ISLANDS FROM 
20N-27N BETWEEN 50W-65W DUE TO A NEW SURFACE LOW.  

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

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FORMOSA