000
AXNT20 KNHC 131723
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST TUE JAN 13 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 1715 UTC.

...THE ITCZ...

THE ITCZ IS CENTERED ALONG 8N12W 5N16W 4N30W 3N40W...CROSSING 
THE EQUATOR ALONG 46W...INTO NORTHEASTERN BRAZIL NEAR 2S50W. 
SCATTERED MODERATE CONVECTION IS FROM 3N-5N BETWEEN 10W-12W... 
AND FROM 1N-3N BETWEEN 25W-28W. WIDELY SCATTERED MODERATE 
CONVECTION IS FROM 3N-7N BETWEEN 28W-34W.  

...DISCUSSION...

THE GULF OF MEXICO...
AS OF 1500 UTC...A COLD FRONT EXTENDS FROM CENTRAL FLORIDA TO 
THE YUCATAN PENINSULA ALONG 29N80W 26N86W 20N89W. SCATTERED 
SHOWERS EXTEND 120 NM N OF THIS FRONT. A NEW COLD FRONT EXTENDS 
S FROM CENTRAL LOUISIANA NEAR 29N91W TO 26N93W TO THE NORTHERN 
BAY OF CAMPECHE AT 22N94W. NO CONVECTION IS ALONG THIS FRONT. 
BOTH FRONTS ARE MOVING SE HOWEVER THE NEW FRONT IS MOVING FASTER 
AND WILL EVENTUALLY MERGE WITH THE ORIGINAL FRONT. 20-25 KT 
WINDS ARE PREDOMINATELY N OF THE NEW FRONT WITH GALE FORCE WINDS 
OVER THE WESTERN BAY OF CAMPECHE S OF 20N W OF 94W. TEMPERATURES 
ARE IN THE 40'S AND 50'S OVER THE N GULF STATES WHILE 
TEMPERATURES S OF THE ORIGINAL FRONT REMAIN IN THE 70'S. 
ADDITIONALLY...STRONG N TO NE SURFACE WINDS ARE BLOWING THROUGH 
THE ISTHMUS OF TEHUANTEPEC RESULTING IN GALE FORCE WINDS IN THE 
E PACIFIC REGION. IN THE UPPER LEVELS...SOUTHWESTERLY FLOW WITH 
SIGNIFICANT UPPER LEVEL MOISTURE COVERS THE ENTIRE GULF OF 
MEXICO. EXPECT BOTH FRONTS TO MERGE WITHIN 12 HOURS AND BE OUT 
OF THE GULF OF MEXICO IN 24 HOURS. NORTHERLY WINDS AND A 
SIGNIFICANTLY COLDER AIR MASS WILL REMAIN OVER THE ENTIRE GULF 
TOMORROW.  

THE CARIBBEAN SEA...
A TIGHT SURFACE PRESSURE GRADIENT IS PRODUCING FRESH TO STRONG 
TRADEWINDS OVER THE CARIBBEAN SEA AND CENTRAL AMERICA. AREAS OF 
BROKEN LOW CLOUDS WITH SCATTERED SHOWERS DOTS THE W CARIBBEAN 
AND CENTRAL AMERICA W OF 70W. IN THE UPPER LEVELS...A RIDGE IS 
OVER THE AREA WITH AXIS ALONG 70W. CONSIDERABLE UPPER LEVEL 
MOISTURE AND BROKEN HIGH CLOUDS ARE OVER THE W CARIBBEAN W OF 
80W WHILE STRONG SUBSIDENCE IS OVER THE E CARIBBEAN. EXPECT 
FRONTAL CONVECTION OVER THE YUCATAN PENINSULA AND THE NW 
CARIBBEAN IN 24 HOURS. ALSO EXPECT MORE SHOWERS OVER THE SW 
CARIBBEAN AND CENTRAL AMERICA.    

THE ATLANTIC OCEAN...
A COLD FRONT IS OVER THE W ATLANTIC FROM 32N77W TO CENTRAL 
FLORIDA NEAR 29N80W. BROKEN TO OVERCAST LOW CLOUDS WITH 20 KT 
NORTHERLY WINDS ARE N OF THE FRONT. A 1028 MB HIGH IS OVER THE 
CENTRAL ATLANTIC NEAR 29N54W. ANOTHER 1030 MB HIGH IS OVER THE E 
ATLANTIC NEAR 33N22W. A RIDGE AXIS EXTENDS FROM ONE HIGH CENTER 
TO THE OTHER WITH MOSTLY FAIR. IN THE UPPER LEVELS... A RIDGE IS 
OVER THE W ATLANTIC W OF 60W. AN UPPER LEVEL TROUGH IS OVER THE 
CENTRAL ATLANTIC N OF 10N BETWEEN 30W-60W. ANOTHER UPPER LEVEL 
RIDGE IS OVER THE E ATLANTIC AND W AFRICA BETWEEN 10W-30W. 
CONSIDERABLE UPPER LEVEL MOISTURE AND BROKEN HIGH CLOUDS ARE 
OVER THE E ATLANTIC E OF 40W.    

$$
FORMOSA