000
AXNT20 KNHC 181120
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL  
705 AM EST SAT DEC 18 2010

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1115 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 7N13W 7N24W 6N30W 7N46W 5N53W. 
WIDELY SCATTERED MODERATE CONVECTION IS FROM 3N-8N BETWEEN 
18W-28W. A SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ EXTENDING 
FROM 12N47W TO 2N44W. CLUSTERS OF WIDELY SCATTERED MODERATE 
CONVECTION ARE FROM 7N-12N BETWEEN 41W-49W. 

...DISCUSSION...

GULF OF MEXICO...
A COLD FRONT EXTENDS FROM N FLORIDA TO THE BAY OF CAMPECHE ALONG 
30N83W 27N90W 26N95W 20N96W. SHOWERS AND RAIN ARE OVER THE E 
GULF OF MEXICO AND N FLORIDA E OF 86W. BROKEN TO OVERCAST LOW 
CLOUDS ARE N OF THE REMAINDER OF THE FRONT. 15 KT N WINDS ARE N 
OF THE FRONT WHILE 10-15 KT SE WINDS ARE S OF THE FRONT. 
TEMPERATURES ARE IN THE 40'S AND 50'S N OF THE FRONT ALONG THE N 
GULF COAST STATES. IN THE UPPER LEVELS... AN UPPER LEVEL TROUGH 
IS OVER THE W GULF WITH AXIS ALONG 97W SUPPORTING THE SURFACE 
FRONT. EXPECT THE FRONT TO EXTEND FROM S FLORIDA TO THE SRN BAY 
OF CAMPECHE IN 24 HOURS WITH ISOLATED SHOWERS AND A GOOD AMOUNT 
OF COLD AIR ADVECTION.   

CARIBBEAN SEA...
A SURFACE TROUGH IS OVER THE CENTRAL CARIBBEAN EXTENDING FROM 
CENTRAL CUBA TO S OF JAMAICA ALONG 22N80W 14N78W. ISOLATED 
MODERATE CONVECTION IS E OF JAMAICA FROM 16N-19N BETWEEN 
74W-76W. SCATTERED SHOWERS ARE ALSO FROM 17N-22N BETWEEN 
70W-81W. FURTHER E... ISOLATED SHOWERS ARE OVER THE LEEWARD 
ISLANDS... AND PUERTO RICO FROM 15N-20N BETWEEN 60W-70W. MOSTLY 
FAIR WEATHER IS OVER THE REMAINDER OF THE CARIBBEAN SEA AND 
CENTRAL AMERICA. IN THE UPPER LEVELS... A RIDGE IS PRODUCING SW 
UPPER LEVEL WINDS. CONSIDERABLE UPPER LEVEL MOISTURE IS OVER 
SOUTH AMERICA WHILE STRONG SUBSIDENCE IS OVER CENTRAL AMERICA 
AND THE W CARIBBEAN W OF 77W. EXPECT THE SURFACE TROUGH TO 
RETROGRADE E WITH CONVECTION OVER THE NEXT 24 HOURS.   

ATLANTIC OCEAN...
A 1014 MB LOW IS OFF THE COAST OF SOUTH CAROLINA NEAR 33N79W. A 
COLD FRONT EXTENDS S TO N FLORIDA AT 30N83W. A 1021 MB HIGH IS 
FURTHER E NEAR 27N67W PRODUCING FAIR WEATHER. A COLD FRONT IS 
OVER THE CENTRAL ATLANTIC ALONG 32N35W 28N36W 20N47W. WIDELY 
SCATTERED MODERATE CONVECTION IS E OF THE FRONT FROM 24N-32N 
BETWEEN 30W-37W. IN THE UPPER LEVELS...AN UPPER LEVEL RIDGE IS 
OVER THE W ATLANTIC W OF 45W. AN UPPER LEVEL TROUGH IS OVER THE 
E ATLANTIC E OF 45W. EXPECT IN 24 HOURS FOR THE SURFACE LOW TO 
BE OVER THE W ATLANTIC NEAR 33N73W WITH A COLD FRONT EXTENDING S 
TO S FLORIDA WITH CONVECTION.      

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

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FORMOSA