000
AXNT20 KNHC 182354
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
705 PM EST TUE JAN 18 2011

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.

...ITCZ...

THE ITCZ AXIS EXTENDS SW FROM THE COAST OF SENEGAL NEAR 13N17W 
TO 3N30W. THEN IT CONTINUES WEST TO THE COAST OF BRAZIL ALONG 
1N40W 2N51W. SCATTERED SHOWERS ARE WITHIN 70 NM EITHER SIDE OF 
THE AXIS BETWEEN 20W-42W. AN AREA OF SCATTERED MODERATE TO HEAVY 
SHOWERS IS FROM 5S TO THE EQUATOR BETWEEN 26W-35W.

...DISCUSSION...

GULF OF MEXICO...
A NARROW LINE OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS 
MOVES ACROSS THE N CENTRAL BASIN...ANALYZED AS A FORMING COLD 
FRONT...ENTERING THE BASIN THROUGH MARSH ISLAND LOUISIANA AND 
CONTINUING SW TO OFF THE COAST OF SOUTH PADRE ISLAND TEXAS ALONG 
27N94W. THIS BOUNDARY IS TRACKING EAST AT ABOUT 17 KT AND IT IS 
EXPECTED TO CONTINUE THIS TREND...BRINGING SCATTERED CONVECTION 
TO THE COASTAL WATERS OF LOUISIANA...MISSISSIPPI...ALABAMA...AND 
THE FLORIDA PANHANDLE OVER THE NEXT 24 HOURS. NW WINDS UP TO 20 
KT ARE OBSERVED BEHIND THE FRONT WHILE SSW WINDS 5-15 KT ARE 
AHEAD OF THE FRONT. THIS SYSTEM IS SUPPORTED BY A SHORTWAVE 
UPPER LEVEL TROUGH MOVING ACROSS THE SOUTHERN STATES. OTHERWISE 
FAIR WEATHER CONDITIONS ARE ELSEWHERE ACROSS THE BASIN THIS 
AFTERNOON...PROVIDED BY A DRY STABLE ZONAL FLOW ALOFT. 
 
CARIBBEAN SEA...
AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER THE SE CARIBBEAN 
NEAR 12N68W AND CONTINUES TO PROVIDE AN OVERALL DRY AND STABLE 
ATMOSPHERE ALOFT FOR THE CARIBBEAN SEA BASIN. MARINE OBS ACROSS 
THE BASIN INDICATED TRADE WINDS IN THE 10 TO 20 KT RANGE E OF 
80W...WITH HIGHER WINDS ALONG THE COAST OF COLOMBIA. LOW-LEVEL 
MOISTURE CONTINUES TO ADVECT FROM THE TROPICAL ATLC TO OVER THE 
EASTERN CARIBBEAN GENERATING SCATTERED SHOWERS WITHIN 75 NM ON 
EITHER SIDE OF A LINE FROM NORTH-CENTRAL VENEZUELA NEAR 11N65W 
TO EASTERN JAMAICA NEAR 18N76W. OTHERWISE...RELATIVELY FAIR 
WEATHER IS ACROSS THE BASIN TODAY...WITH NO SIGNIFICANT CHANGES 
EXPECTED OVER THE NEXT 24 HOURS. 

ATLANTIC OCEAN...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE N OF 28N 
BETWEEN 56W-68W...SUPPORTED BY AN UPPER LEVEL SHORTWAVE TROUGH 
LOCATED OVER THE W ATLC. WEST OF THIS AREA OF CONVECTION...A 
SURFACE TROUGH IS ANALYZED FROM 31N70W TO 27N72W INDICATING A 
LINE OF SURFACE CONVERGENCE ASSOCIATED WITH THE LARGER SCALE 
ENVIRONMENT. FARTHER EAST...THE TAIL END OF A COLD FRONT ACROSS 
THE CENTRAL NORTH ATLC IS ANALYZED TO 31N53W WITH A SURFACE 
TROUGH EXTENDING SW TO 28N60W. ISOLATED SHOWERS ARE OCCURRING 
WITHIN 40 NM EITHER SIDE OF THE BOUNDARY. A BROAD UPPER RIDGE 
COVERS MUCH OF THE ATLC E OF 52W...ANCHORED BY A 1026 MB HIGH 
NEAR 31N40W PROVIDING FAIR WEATHER CONDITIONS ACROSS THE CENTRAL 
AND MOST OF THE EASTERN ATLANTIC. THIS BROAD RIDGE CONTINUES TO 
HINDER A WEAK SURFACE TROUGH THAT ENTERS THE FAR EAST ATLANTIC 
ALONG 32N17W TO 29N21W. THEREFORE...JUST A FEW ISOLATED SHOWERS 
ARE NOTED IN THE VICINITY OF THE SURFACE TROUGH. THIS BOUNDARY 
IS EXPECTED TO DISSIPATE OVER THE NEXT 12 TO 24 HOURS.

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

$$

GARCIA