000
AXNT20 KNHC 201716
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
205 PM EDT FRI MAY 20 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...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1715 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 65W/66W TO THE SOUTH OF 14N MOVING W AT 
10 KT. THE WAVE EXTENDS OVER VENEZUELA TO 4N. IT IS EMBEDDED IN 
A BROAD AREA OF MOISTURE N OF THE ITCZ AS DEPICTED ON THE SSMI 
TOTAL PRECIPITABLE WATER IMAGERY. ISOLATED MODERATE CONVECTION 
IS WITHIN 90 NM OF THE AXIS.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 7N12W 3N30W 3N40W EQ50W. 
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS ON THE COAST 
OF W AFRICA FROM 2N-7N BETWEEN 10W-18W. WIDELY SCATTERED 
MODERATE CONVECTION IS FROM EQ-6N BETWEEN 23W-33W

...DISCUSSION...

GULF OF MEXICO...
10-15 KT SE FLOW IS OVER THE EASTERN GULF OF MEXICO. 15-20 KT SE 
FLOW IS OVER THE WESTERN GULF CAUSED BY A TIGHTER SURFACE 
GRADIENT BETWEEN A 1021 MB HIGH CENTERED OVER KENTUCKY NEAR 
37N85W AND A 1002 MB LOW CENTERED OVER NE MEXICO NEAR 28N100W. 
BROKEN TO OVERCAST LOW CLOUDS ARE INLAND OVER TEXAS. VISIBLE 
SATELLITE IMAGERY SHOWS SMOKE OVER S MEXICO...THE YUCATAN 
PENINSULA...AND THE WESTERN GULF N OF 16N BETWEEN 90W-98W. FAIR 
SKIES ARE OVER THE GULF. IN THE UPPER LEVELS...NW FLOW IS OVER 
THE GULF WITH STRONG SUBSIDENCE...THUS THE AREA IS VOID OF ANY 
HIGH CLOUD. EXPECT IN 24 HOURS FOR A COLD FRONT TO APPROACH THE 
TEXAS COAST.

CARIBBEAN SEA...
A TROPICAL WAVE IS OVER THE EASTERN CARIBBEAN...SEE ABOVE. A 
1010 MB LOW IS OVER LAKE MARACAIBO. A SURFACE TROUGH EXTENDS N 
FROM THE LOW TO HISPANIOLA NEAR 18N70W. ISOLATED MODERATE 
CONVECTION IS WITHIN 120 NM OF THE TROUGH AXIS. RADAR IMAGERY 
FROM PUERTO RICO SHOWS EXTENSIVE SHOWERS FROM 15N-21N BETWEEN 
63W-69W. SIMILAR SHOWERS ARE NOTED OVER THE EASTERN CARIBBEAN E 
OF 70W. FAIR WEATHER IS NOTED OVER THE WESTERN CARIBBEAN W OF 
75W. IN THE UPPER LEVELS...W-SW UPPER LEVEL FLOW DOMINATES THE 
CARIBBEAN WITH UPPER LEVEL MOISTURE E OF 72W...AND STRONG 
SUBSIDENCE W OF 72W. EXPECT OVER THE NEXT 24 HOURS FOR THE 
TROPICAL WAVE AND TROUGH TO MOVE SLOWLY W WITH CONTINUED SHOWERS.

ATLANTIC OCEAN...
A SURFACE TROUGH EXTENDS FROM 29N59W TO 22N61W. ISOLATED 
MODERATE CONVECTION IS WITHIN 120 NM OF THE TROUGH AXIS. ANOTHER 
SURFACE TROUGH IS OVER THE CENTRAL ATLC FROM 32N47W TO 27N50W 
WITH SCATTERED SHOWERS WITHIN 30 NM OF THE AXIS. A SURFACE RIDGE 
AXIS IS OVER THE E ATLC N OF 10N E OF 42W. VISIBLE SATELLITE 
IMAGERY SHOWS DUST OVER THE E ATLC FROM 6N-22N E OF 34W. IN THE 
UPPER LEVELS...DIFFLUENCE ON THE WESTERN HALF OF AN UPPER RIDGE 
WITH AN AXIS ALONG 55W IS SUPPORTING THE W ATLC SURFACE TROUGH. 
EXPECT OVER THE NEXT 24 HOURS FOR...LITTLE CHANGE.

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

$$
FORMOSA/MONTALVO