000
AXNT20 KNHC 210005
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
805 PM EDT TUE SEP 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 2345 UTC.

...SPECIAL FEATURES...

A 1007 MB LOW PRESSURE IS CENTERED NEAR 12N38W. ACCORDING TO THE 
TOTAL PRECIPITABLE WATER IMAGERY THIS LOW IS EMBEDDED IN A 
REGION OF HIGH MOISTURE. SCATTERED MODERATE CONVECTIVE 
PRECIPITATION IS FROM 9N-14N BETWEEN 36W-43W. THE SYSTEM DOES 
NOT HAVE A WELL-DEFINED CENTER OF CIRCULATION AT THE TIME. 
HOWEVER...CONDITIONS REMAIN CONDUCIVE FOR A TROPICAL DEPRESSION 
TO FORM IN THIS AREA LATER TODAY OR ON WEDNESDAY. PRESENT 
MOVEMENT IS WESTWARD AT 5 TO 10 MPH.


...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 19W. THE TOTAL PRECIPITABLE WATER 
IMAGERY SHOW A REGION OF HIGH MOISTURE IN THE NORTHERN PART OF 
THE WAVE AXIS FROM 15N-18N BETWEEN 18W-20W. THERE IS NOT A 
WELL-DEFINED LOW LEVEL CIRCULATION AT THE TIME ASSOCIATED WITH 
THIS SYSTEM. ISOLATED MODERATE RAINSHOWERS LIES IN THE REGION OF 
HIGH MOISTURE PREVIOUSLY MENTIONED.    

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

THE MONSOON TROUGH AXIS STARTS SW OF THE TROPICAL WAVE NEAR 
11N24W...CONTINUES TO THE 1007 MB LOW NEAR 12N38W THE SW TO 
10N48W. ISOLATED SHOWERS ARE WITHIN 200 NM EITHER SIDE OF THE 
MONSOON TROUGH AXIS EAST OF 32W. CONVECTIVE RAIN ALONG THE 
TROUGH ASSOCIATED TO THE 1007 MB LOW IS AS DESCRIBED IN THE 
SPECIAL FEATURES SECTION.  

...DISCUSSION...

THE GULF OF MEXICO...
WATER VAPOR IMAGERY SHOW THAT THE GULF IS BEING DOMINATED BY DRY 
AIR SUBSIDENCE FROM AN UPPER LEVEL RIDGE THAT CROSSES THE 
FLORIDA PENINSULA SW TO THE YUCATAN PENINSULA. THIS IS 
PRODUCING FAIR WEATHER CONDITIONS TO THE REGION. IN GENERAL 
WINDS ARE LIGHT FROM 5-10 KT AND FROM THE SE N 0F 25N E OF 
89W...FROM THE NE W OF 89W. EXPECT SIMILAR WEATHER CONDITIONS 
FOR THE NEXT 24 HOURS. 

THE CARIBBEAN SEA...
A SURFACE TROUGH IS IN THE WESTERN CARIBBEAN FROM 14N82W TO 
22N82W. SCATTERED SHOWERS ARE WITHIN 120 NM EITHER SIDE OF IT 
82W AXIS. THE AREA OF CONVECTION THAT WAS OVER PUERTO RICO 
YESTERDAY HAS MOVED WEST TO HISPANIOLA. SCATTERED MODERATE TO 
ISOLATED STRONG CONVECTION IS FROM 18N-20N BETWEEN 68W-73W. 
ALONG THE COASTS OF COLOMBIA...PANAMA AND COSTA RICA SCATTERED 
SHOWERS ARE OCCURRING DUE TO THE MONSOON TROUGH. LIGHT TRADE 
WINDS OF 5-10 KT PREVAILS IN THE ENTIRE REGION. EXPECT A SIMILAR 
WEATHER PATTERN IN THE NEXT 24 HOURS.     

THE ATLANTIC OCEAN...
IN THE CENTRAL ATLANTIC A SMALL AREA OF LOW PRESSURE IS LOCATED 
NEAR 17N56W OR ABOUT 300 MILES EAST OF THE NORTHERN LEEWARD 
ISLANDS PRODUCING DISORGANIZED SHOWER AND THUNDERSTORM ACTIVITY. 
UPPER-LEVEL WINDS ARE NOT FAVORABLE FOR DEVELOPMENT OF THIS 
SYSTEM. A SECOND LOW PRESSURE SYSTEM OF 1007 MB IS BEING 
ANALYZED...SEE THE SPECIAL FEATURES ABOVE. A TROPICAL WAVE IS IN 
THE EASTERN ATLANTIC WITH AXIS ALONG 18W...SEE THE TROPICAL 
WAVES SECTION ABOVE.


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

$$
RAMOS