000
AXNT20 KNHC 202316
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
805 PM EDT THU OCT 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC.

...TROPICAL WAVES...

NONE.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS SW TO 9N20W TO 5N28W. SCATTERED 
MODERATE TO ISOLATED STRONG CONVECTION FROM 2N-11N BETWEEN 
15N-30W. THE ITCZ IS DISRUPTED BY THE PRESENCE OF A TROPICAL 
WAVE AND SURFACE TROUGH DISCUSSED ABOVE.

...DISCUSSION...

THE GULF OF MEXICO...
AS OF 2100 UTC...A COOL AND DRY AIRMASS IS IN PLACE ACROSS THE 
GULF OF MEXICO. A 1020 MB HIGH IS CENTERED OVER THE NORTH 
CENTRAL GULF NEAR 28N91W. 5-10 KT ANTICYCLONIC SURFACE WINDS ARE 
NOTED AROUND THE HIGH. SOME LINGERING STRATOCUMULUS CLOUDS ARE 
OVER THE SE GULF. THE REMAINDER OF THE GULF HAS FAIR SKIES. IN 
THE UPPER LEVELS...AN UPPER LEVEL TROUGH WITH STRONG SUBSIDENCE 
COVERS THE ENTIRE GULF. EXPECT LITTLE CHANGE OVER THE NEXT 24 
HOURS.  

THE CARIBBEAN SEA...
AS OF 2100 UTC...A SURFACE TROUGH EXTENDS FROM CENTRAL CUBA NEAR 
21N78W TO THE SW CARIBBEAN NEAR 11N80W. A 1009 MB LOW IS 
EMBEDDED ON THE TROUGH AXIS NEAR 15N79W. WIDELY SCATTERED 
MODERATE CONVECTION IS OVER E CUBA FROM 20N-22N BETWEEN 75W-79W. 
SCATTERED MODERATE TO STRONG CONVECTION IS OVER THE W CARIBBEAN 
W OF JAMAICA FROM 15N-19N BETWEEN 81W-85W...AND E OF NICARAGUA 
FROM 11N-14N BETWEEN 80W-84W. WIDELY SCATTERED MODERATE 
CONVECTION IS ALSO OVER INLAND COSTA RICA. SCATTERED SHOWERS ARE 
THE REMAINDER OF CENTRAL AMERICA FROM PANAMA TO GUATEMALA. RADAR 
IMAGERY SHOWS ISOLATED SHOWERS AROUND PUERTO RICO. SIMILAR 
SHOWERS ARE NOTED OVER HISPANIOLA. EXPECT OVER THE NEXT 24 HOURS 
FOR THE SURFACE LOW TO DEEPEN AND MOVE S TO THE SW CARIBBEAN 
WITH CONTINUED CONVECTION.   

THE ATLANTIC OCEAN...
AS OF 2100 UTC...A COLD FRONT IS OVER THE W ATLANTIC FROM 30N71W 
TO CENTRAL CUBA AT 22N77W. SCATTERED SHOWERS ARE WITHIN 120 NM 
OF THE FRONT TO INCLUDE THE N BAHAMAS. A 1031 MB HIGH IS OVER 
THE CENTRAL ATLANTIC NEAR 39N40W WITH A SURFACE RIDGE EXTENDING 
SW TO 27N65W. IN THE TROPICS...TWO TROPICAL WAVES HAVE 
DISSIPATED AND ARE NOW DEPICTED AS SURFACE TROUGHS. ONE TROUGH 
EXTENDS FROM 17N39W TO AN EMBEDDED 1007 MB LOW AT 12N46W TO 
9N48W. SCATTERED MODERATE CONVECTION IS NEAR THE LOW FROM 
11N-14N BETWEEN 45W-48W. SCATTERED SHOWERS ARE WITHIN 90 NM OF 
THE REMAINDER OF THE TROUGH AXIS. THE OTHER TROUGH IS FURTHER W 
FROM 12N55W TO 8N53W. THIS TROUGH IS MOSTLY VOID OF CONVECTION.  
IN THE UPPER LEVELS...AN UPPER LEVEL LOW IS CENTERED NEAR 22N55W 
MOVING SW. WIDELY SCATTERED SHOWERS ARE FROM 20N-27N BETWEEN 
50W-57W. EXPECT OVER THE NEXT 24 HOURS FOR THE FRONT OVER THE W 
ATLANTIC TO BECOME STATIONARY WITH CONTINUES SHOWERS. ALSO 
EXPECT THE TROPICAL LOW TO MOVE NE TO 15N44W AND DEEPEN WITH 
CONTINUED CONVECTION.

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

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FORMOSA