000
AXNT20 KNHC 171752
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
105 PM EST THU FEB 17 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM THE S 
CENTRAL COAST OF NIGERIA NEAR 05N05W TO 04N17W TO 00N26W TO 
02N36W TO THE COAST OF BRAZIL NEAR 00N48W. SCATTERED MODERATE 
AND ISOLATED STRONG CONVECTION IS NOTED WITHIN WITHIN 75 NM OF 
THE AXIS BETWEEN 10W AND 20W AND ALSO WITHIN 120 NM OF THE AXIS 
BETWEEN 20W AND 29W. SIMILAR CONVECTION IS NOTED WITHIN 90 NM N 
OF THE AXIS W OF 44W.

...DISCUSSION...

GULF OF MEXICO...
BROAD RIDGING ALOFT EXTENDS FROM CENTRAL MEXICO NE ACROSS E 
TEXAS AND INTO THE MID MISSISSIPPI VALLEY WITH VERY DRY AIR 
ACROSS THE GULF UNDER STRONG SUBSIDENCE. A SURFACE RIDGE EXTENDS 
FROM 1030 MB HIGH PRES IN THE W ATLANTIC TO ACROSS THE NORTHERN 
GULF COAST TO THE NE COAST OF MEXICO NEAR 24N98W WITH SOUTHERLY 
RETURN FLOW EVIDENT ACROSS THE MAJORITY OF THE GULF WATERS. THIS 
RETURN FLOW IS BANKING LOW LEVEL CLOUDS AND PATCHY FOG OVER THE 
FAR W GULF TO INLAND TEXAS. THE SURFACE RIDGE WILL REMAIN IN 
PLACE ACROSS THE N GULF THROUGH SUN.

CARIBBEAN SEA...
AN UPPER RIDGE EXTENDS FROM NEAR THE COLOMBIA AND PANAMA BORDER 
NW ACROSS CENTRAL AMERICA TO CENTRAL GUATEMALA RESULTING IN SW 
TO W FLOW ALOFT OVER THE CARIBBEAN. REMNANT SURFACE MOISTURE IN 
THE FORM OF SCATTERED SHOWERS AND ISOLATED TSTMS FROM A DECAYED 
FRONT REMAINS OVER THE NW CARIBBEAN EXTENDING FROM HAITI TO 
ACROSS JAMAICA TO THE NE COAST OF HONDURAS. FAIR WEATHER EXISTS 
ACROSS THE REMAINDER OF THE BASIN EXCEPT FOR ISOLATED SHOWERS 
WHICH ARE OVER THE NE AND N CENTRAL WATERS BEING USHERED IN FROM 
THE TROPICAL N ATLC BY EASTERLY TRADE WINDS. WEAK LOW PRES JUST 
W OF THE COAST OF COLOMBIA AND N OF THE ISTHMUS OF PANAMA WILL 
REMAIN NEARLY STATIONARY THROUGH SUN. TRADE WINDS WILL INCREASE 
LATE SUN AS HIGH PRES BUILDS DOWN FROM N OF CUBA AND HISPANIOLA.

ATLANTIC OCEAN...
IN THE FAR E ATLANTIC...AN UPPER RIDGE EXTENDS FROM AN 
ANTICYCLONE S OF THE EQUATOR THROUGH 00N18W TO 13N25W. A MID TO 
UPPER LEVEL TROUGH IS OVER W AFRICA NE OF THE RIDGE AXIS. 
CONVECTION IS BEING ENHANCED BETWEEN THE TWO WITH SCATTERED 
MODERATE TO STRONG CONVECTION FROM 00N TO 02N BETWEEN 04W AND 
14W. IN THE W ATLANTIC...A WEAK COASTAL TROUGH IS BEGINNING TO 
FORM JUST E OF THE N FLORIDA COAST OVER THE GULF STREAM 
GENERATING SCATTERED SHOWERS WITH DENSE FOG OVER THE 
JACKSONVILLE COASTAL WATERS UNDER MOIST ONSHORE FLOW. 1030 MB 
HIGH PRES IS JUST N OF THE AREA NEAR 33N66W. A SURFACE RIDGE 
EXTENDS SE FROM THE HIGH TO NEAR 27N47W. A COLD FRONT IS E OF 
THE RIDGE EXTENDING FROM 32N34W THROUGH 24N50W TO 23N57W. A 
FRONTAL TROUGH EXTENDS FROM THERE TO NEAR 21N67W. SCATTERED 
SHOWERS AND ISOLATED TSTMS ARE LAGGING WITHIN 180 NM BEHIND THE 
FRONT. RECENT ASCAT AND WINDSAT SCATTEROMETER PASSES INDICATED 
NORTHERLY WINDS OF 20 TO 25 KT BEHIND THE FRONT. THIS FRONT WILL 
SLOWLY DISSIPATE AS IT PUSHES E THROUGH SUN. THE HIGH AND RIDGE 
WILL WEAKEN AS A REINFORCING COLD FRONT ENTERS THE AREA SAT 
AFTERNOON THROUGH SUN WITH INCREASING NORTHERLY WINDS BEHIND THE 
FRONT AND INCREASING SW WINDS AHEAD OF THE FRONT AND SEAS 
BUILDING TO NEAR 26 FT N OF 31N. HIGH PRES BUILDS BACK IN FROM 
THE CAROLINAS BEHIND THE REINFORCING FRONT BY LATE SUN WITH 
SOUTHERLY RETURN FLOW SETTING UP OFF THE N FLORIDA COAST. 

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

$$
LEWITSKY