000
AXNT20 KNHC 251055
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE AUG 25 2009

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1015 UTC.

...SPECIAL FEATURES...
A TROPICAL WAVE IS ALONG 64W FROM 24N TO 13N MOVING WESTWARD 
ABOUT 20 KT. THIS WAVE IS MOVING THROUGH THE AREA OF AN 
ALREADY-EXISTING MIDDLE LEVEL TO UPPER LEVEL TROUGH. THE 
PRE-EXISTING TROUGH GOES FROM A CYCLONIC CENTER NEAR 35N54W 
32N62W 26N67W 20N68W INTO THE CARIBBEAN SEA TO 16N73W AND 
12N77W. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS FROM 19N TO 
24N BETWEEN 60W AND 65W IN PRECIPITATION THAT HAS FORMED IN 
UPPER LEVEL DIFFLUENT FLOW. SCATTERED MODERATE SHOWERS AND
ISOLATED STRONG THUNDERSTORMS ALSO COVER THE WATERS FROM 25N
TO 26N BETWEEN 68W AND 70W. ISOLATED AND DISORGANIZED SHOWERS 
COVER THE REST OF THE AREA FROM THE CARIBBEAN SEA NEAR 14N TO 
32N IN THE ATLANTIC OCEAN BETWEEN 58W AND 71W.

..TROPICAL WAVES...
AN EASTERN ATLANTIC OCEAN TROPICAL WAVE RUNS FROM 21N28W TO
A 1011 MB LOW PRESSURE CENTER NEAR 13N33W TO 11N33W. THIS WAVE 
WAS DRIFTING WESTWARD DURING THE LAST SIX HOURS. A MIDDLE 
LEVEL TO UPPER LEVEL TROUGH THAT IS ON TOP OF AND JUST TO THE 
WEST OF THIS WAVE GOES FROM 30N30W TO A 26N34W CYCLONIC 
CIRCULATION CENTER TO 17N36W 11N36W. ISOLATED MODERATE SHOWERS 
ARE WITHIN 120 NM TO 180 NM ON EITHER SIDE OF 25N27W 20N28W
17N30W 10N34W.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 81W/82W TO THE SOUTH OF 
18N MOVING WEST 15 TO 20 KT. THE 1006 MB LOW PRESSURE CENTER
FROM SIX HOURS AGO WAS NOT APPARENT FOR THIS MAP TIME. SCATTERED 
TO NUMEROUS STRONG SHOWERS AND THUNDERSTORMS HAVE MOVED OVER 
LAND AND COVER THE CARIBBEAN SEA AND LAND AREAS FROM 11N TO 15N
BETWEEN 80W AND 86W.

THE ITCZ...
FROM 14N17W TO 14N30W TO 10N37W TO 6N50W 10N62W. ISOLATED 
MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS FROM 7N TO 12N
BETWEEN 40W AND 60W. STRONG SHOWERS AND THUNDERSTORMS HAVE 
EMERGED OFF THE AFRICA COAST FROM 12N TO 16N BETWEEN LAND AND 
20W...POSSIBLY IN ADVANCE OF THE NEXT TROPICAL WAVE.

...DISCUSSION...

THE GULF OF MEXICO...
THE UPPER LEVEL TROUGH THAT HAS BEEN COVERING THE SOUTH CENTRAL 
GULF OF MEXICO HAS BEEN ERODED AWAY BY UPPER LEVEL SOUTHWESTERLY 
WIND FLOW. THE SAME TROUGH NOW PASSES THROUGH MISSISSIPPI TO 
NORTHEASTERN MEXICO JUST TO THE SOUTH OF THE DEEP SOUTH OF TEXAS 
INTO CENTRAL INTERIOR MEXICO. A STATIONARY FRONT LINGERS FROM
30N80W TO NORTH CENTRAL FLORIDA TO THE SOUTH CENTRAL GULF OF 
MEXICO INTO THE SOUTHWESTERN CORNER OF THE AREA NEAR 20N95W.
SURFACE HIGH PRESSURE HAS BUILT FROM THE NORTH CENTRAL GULF OF 
MEXICO SOUTHWARD. SCATTERED MODERATE SHOWERS TO ISOLATED STRONG 
THUNDERSTORMS COVER THE SOUTHWESTERN CORNER OF THE AREA TO THE 
SOUTH OF 23N TO THE WEST OF 90W.
 
THE CARIBBEAN SEA...
BROAD MIDDLE LEVEL TO UPPER LEVEL CYCLONIC FLOW COVERS THE AREA 
TO THE NORTH OF 15N TO THE EAST OF 80W. THIS CYCLONIC FLOW IS 
ASSOCIATED WITH THE TROUGH THAT IS ON TOP OF AND TO THE WEST OF 
THE 64W TROPICAL WAVE. STRONG SHOWERS AND THUNDERSTORMS ARE IN 
THE SOUTHWESTERN CORNER AND IN NICARAGUA WITH THE 81W/82W 
TROPICAL WAVE.

THE ATLANTIC OCEAN...
THE MIDDLE LEVEL TO UPPER LEVEL TROUGH GOES FROM A CYCLONIC 
CENTER NEAR 35N54W TO 32N62W 26N67W 20N68W...AND TO 16N73W AND 
12N77W IN THE CARIBBEAN SEA. THIS TROUGH IS NEAR THE 64W
TROPICAL WAVE. A SECOND TROUGH RUNS FROM 30N30W TO 11N36W.
THIS TROUGH IS NEAR THE 21N28W 11N33W TROPICAL WAVE.

$$
MT