000
AXNT20 KNHC 171738
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
205 PM EDT THU MAR 17 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL 
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION 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 AXIS IS ANALYZED FROM THE BORDER OF LIBERIA AND THE 
IVORY COAST NEAR 4N8W TO ACROSS THE EQUATOR NEAR 15N CONTINUING 
W ALONG 1S AND INLAND INTO NORTHERN BRAZIL NEAR 3N44W. SCATTERED 
MODERATE TO STRONG CONVECTION IS FROM THE EQUATOR TO 7N BETWEEN 
12W AND 16W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS 
FROM 1S-3N BETWEEN 16W AND 20W...FROM 1N-3N BETWEEN 32W AND 
36W... AND FROM THE EQUATOR TO 3N BETWEEN 42W AND 50W. SCATTERED 
MODERATE CONVECTION IS FROM THE EQUATOR TO 4N BETWEEN 20W AND 
26W. 
 
...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE OVER THE E-CENTRAL CONUS SUPPORTING A 1027 
MB HIGH OVER SW GEORGIA WHICH IS PROVIDING SURFACE RIDGING OVER 
THE GULF OF MEXICO. 10-15 KT ANTICYCLONIC FLOW COVERS THE GULF 
WITH MOSTLY CLEAR SKIES. SURFACE RIDGING WILL CONTINUE ACROSS 
THE REGION AS THE SURFACE HIGH MOVE TO THE SE OVER THE NEXT 24 
HOURS.

CARIBBEAN SEA...
AN UPPER RIDGE SPANS MUCH OF THE CARIBBEAN PROVIDING DRY AIR AND 
SUBSIDENCE ALOFT. AT THE SURFACE...SHOWERS DOT THE CARIBBEAN... 
WITH THE MOST SIGNIFICANT AREAS SW OF HAITI FROM 16N-18N BETWEEN 
73W AND 75W AND . FRESH TRADE WINDS ARE BANKING MOISTURE ALONG 
THE COAST OF CENTRAL AMERICA GENERATING ISOLATED SHOWERS FOR 
HONDURAS... NICARAGUA... COSTA RICA AND WESTERN PANAMA. THE 
SURFACE RIDGE OVER THE W ATLC CONTINUES TO MAINTAIN FRESH ENE 
TRADE WINDS ACROSS THE BASIN WITH STRONGER WINDS ALONG THE COAST 
OF COLOMBIA. A LOW LEVEL MOISTURE MAXIMA IS FOUND NEAR THE COAST 
OF VENEZUELA ALLOWING SCATTERED SHOWERS WITHIN 190 NM OF THE 
COAST OF VENEZUELA BETWEEN 64W AND 70W. THE SURFACE RIDGE OVER 
THE W ATLC WILL MAINTAIN THE TRADE WINDS THROUGH FRI. 
     
ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH IS MOVING OFF THE E CONUS SUPPORTING A 
COLD FRONT THAT ENTERS THE AREA...AS OF 1500 UTC... NEAR 32N71W 
EXTENDING TO 29N76W WHERE IT BECOMES DISSIPATING TO THE COAST OF 
FLORIDA NEAR 28N80W. SCATTERED SHOWER AND ISOLATED THUNDERSTORMS 
ARE WITHIN 45 NM E OF THE COLD FRONT. A SURFACE TROUGH EXTENDS 
FROM THE DISSIPATING COLD FRONT NEAR 28N79W TO 26N80W. A TIGHT 
UPPER TROUGH IN THE CENTRAL ATLANTIC SUPPORTS ANOTHER COLD 
FRONT THAT ENTERS THE AREA NEAR 32N33W EXTENDING ALONG 27N37W TO 
25N45W WHERE IT BECOMES DISSIPATING TO 25N54W. A PREFRONTAL 
SURFACE TROUGH EXTENDS FROM 27N36W TO 22N45W. SCATTERED SHOWERS 
ARE WITHIN 105 NM E OF THE FRONT AND 60 NM W OF THE FRONT E OF 
37W... WITHIN 90 NM EITHER SIDE OF THE COMBINED FRONT AND TROUGH 
BETWEEN 37W AND 40W. ISOLATED SHOWERS ARE WITHIN 45 NM EITHER 
SIDE OF THE FRONT W OF 40W. ANOTHER SURFACE TROUGH IS ANALYZED S 
OF THE DISSIPATING COLD FRONT EXTENDING ALONG 22N50W 20N49W 
16N50W WITH SCATTERED SHOWERS WITHIN 120 NM E OF THE TROUGH. THE 
REMAINDER OF THE AREA E 30W IS UNDER SURFACE RIDGING FROM A 1027 
MB HIGH N OF THE AREA. DRY UPPER LEVEL AIR ON WATER VAPOR 
IMAGERY DENOTES SUBSIDENCE OVER THE ATLC TROPICS FROM 10N-24N E 
OF BAHAMAS TO OVER AFRICA. 

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

$$
MONTALVO/GARCIA