000
AXNT20 KNHC 251037
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI SEP 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.

...TROPICAL WAVES...

TROPICAL WAVE IS FROM 19N29W THROUGH A 1012 MB LOW NEAR 14N30W 
TO 10N31W MOVING W NEAR 15 KT. WAVE IS ALONG THE LEADING EDGE OF 
A MOISTURE MAXIMUM AS INDICATED BY THE TOTAL PRECIPITABLE WATER 
IMAGERY WITH SAHARAN DUST BEING DRAWN INTO THE SURFACE LOW. 
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE 
FROM 13N-19N BETWEEN 27W-32W WITH CLUSTERS OF SCATTERED MODERATE 
CONVECTION FROM 9N-14N BETWEEN 26W-35W. 

TROPICAL WAVE IS ALONG 59W S OF 16N MOVING W NEAR 10 KT. WAVE IS 
UNDER AN UPPER RIDGE PROVIDING DIFFLUENCE ALOFT TO GENERATE 
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 
10N-14N BETWEEN 53W AND THE WAVE AXIS. 

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 14N15W 12N23W 13N32W 9N44W 
9N62W. NUMEROUS STRONG CONVECTION IS WITHIN A 75 NM RADIUS OF 
8.5N15.5W WITH SCATTERED MODERATE/STRONG CONVECTION COVERING THE 
REMAINDER OF THE AREA FROM 5N-10N BETWEEN 14W-19W. SCATTERED 
MODERATE/STRONG CONVECTION IS FROM 12N-16N E OF 19W TO INLAND 
OVER SENEGAL AFRICA. SMALL CLUSTERS OF SCATTERED MODERATE 
CONVECTION ARE FROM 7N-10N BETWEEN 46W-50W. 

...DISCUSSION...

GULF OF MEXICO...
A STATIONARY FRONT ENTERS THE GULF OVER LOUISIANA NEAR VERMILION 
BAY CONTINUING S ALONG 28N94W INTO THE BAY OF CAMPECHE AND S 
MEXICO TO NEAR 18N95W. SCATTERED SHOWERS/THUNDERSTORMS ARE S OF 
27N W OF THE FRONT TO INLAND OVER MEXICO AND TO THE COAST OF 
TEXAS WITH CLUSTERS OF SIMILAR ACTIVITY OVER THE REMAINDER OF 
THE W GULF S OF 27N W OF 92W. BROAD UPPER RIDGE ANCHORED OVER 
THE NE GULF JUST OFF SHORE OF PENSACOLA FLORIDA EXTENDS AN AXIS 
SW TO BETWEEN TAMPICO MEXICO AND BROWNSVILLE TEXAS. ISOLATED 
SHOWERS/THUNDERSTORMS ARE IN THE SE GULF S OF 24N INTO THE 
CARIBBEAN BETWEEN 83W-88W WITH ISOLATED SHOWERS DOTTING THE 
REMAINDER OF THE GULF THIS MORNING. 

CARIBBEAN SEA...
AN UPPER RIDGE IS OVER THE W CARIBBEAN EXTENDING THE AXIS FROM 
PANAMA TO THE YUCATAN PENINSULA NEAR BELIZE PROVIDING DIFFLUENCE 
ALOFT TO GENERATE SCATTERED SHOWERS/THUNDERSTORMS OVER THE SW 
CARIBBEAN S OF 11N BETWEEN COLOMBIA AND CENTRAL AMERICA WITH 
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS OVER THE 
REMAINDER OF THE W CARIBBEAN W OF 80W. BROAD UPPER TROUGH OVER 
THE W/CENTRAL ATLC EXTENDS OVER THE NE CARIBBEAN N OF 16N FROM 
THE VIRGIN ISLANDS TO CENTRAL CUBA PRODUCING ISOLATED SHOWERS 
OVER THE ISLANDS OF PUERTO RICO AND HISPANIOLA. FRESH TO STRONG 
EASTERLY TRADE WINDS CONTINUE ACROSS THE AREA BUT THE E 
CARIBBEAN REMAINS RATHER CLEAR THIS MORNING INCLUDING THE LESSER 
ANTILLES. A TROPICAL WAVE IS JUST E OF THE LESSER ANTILLES AND 
WILL OVER THE ISLANDS LATER THIS MORNING BRINGING SHOWERS AND 
POSSIBLE THUNDERSTORMS MAINLY TO THE WINDWARD ISLANDS. 

ATLANTIC OCEAN...
BROAD UPPER RIDGE ANCHORED IN THE NE GULF OF MEXICO COVERS THE W 
ATLC AND COMBINED WITH AN UPPER TROUGH OVER THE W/CENTRAL ATLC 
CENTERED NEAR 28N64W IS PRODUCING STRONG NE UPPER WINDS OVER THE 
W ATLC W OF 67W. THE UPPER TROUGH IS SUPPORTING A SURFACE TROUGH 
THAT EXTENDS THROUGH BERMUDA AND A 1013 MB LOW NEAR 28N66W TO 
24N70W. THE UPPER LOW IS ALSO PRODUCING SCATTERED SHOWERS/ 
ISOLATED THUNDERSTORMS FROM 19N-24N BETWEEN 61W-71W AND N OF 30N 
BETWEEN 57W-60W. A WEAK SURFACE TROUGH EXTENDS FROM 27N49W TO 
23N56W GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED 
THUNDERSTORMS BETWEEN FROM 22N-28N BETWEEN 47W-53W. THE FAR W 
ATLC IS DOMINATED BY A WEAK SURFACE RIDGE MAINLY N OF 28N W OF 
70W TO OVER THE SE U.S. WHILE THE E ATLC IS DOMINATED BY A 
SURFACE RIDGE N OF 20N E OF 50W. THE FIRST VISIBLE SATELLITE 
IMAGES SHOW A SWATH OF SAHARAN DUST WITHIN 200/225 NM OF LINE 
FROM WESTERN SAHARA SW TO THE W OF THE TROPICAL WAVE/LOW TO NEAR 
50W AND BEING DRAWN BACK INTO THE LOW ASSOCIATED WITH THE 
TROPICAL WAVE. 

$$
WALLACE