000
AXNT20 KNHC 302330
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED JUL 30 2008

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2245 UTC.

...SPECIAL FEATURES...
TROPICAL WAVE IS ALONG 20W/21W S OF 22N MOVING NW AT 10-15 KT 
WITH A 1008 MB LOW ALONG THE WAVE NEAR 16N. ALTHOUGH THIS SYSTEM 
REMAINS UN-ORGANIZED...THE LOW HAS THE POTENTIAL TO BECOME A 
TROPICAL DEPRESSION BEFORE MOVING OVER COOLER WATERS ON THU. 
REGARDLESS OF DEVELOPMENT...HEAVY RAIN AND GUSTY WINDS ARE 
POSSIBLE OVER THE CAPE VERDE ISLANDS FOR THE REMAINDER OF THE 
DAY THROUGH TOMORROW. SCATTERED SHOWERS COVER THE AREA FROM 
14N-21N BETWEEN 18W-23W. 

...TROPICAL WAVES...
TROPICAL WAVE APPROACHING THE LESSER ANTILLES REMAINS TILTED 
FROM 19N55W TO 8N60W MOVING W NEAR 20 KT. HIGH AMPLITUDE WAVE 
WITH WELL DEFINED INVERTED-V CURVATURE IN THE LOW CLOUDS. 
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS COVER THE AREA WITHIN 
350 NM W OF THE WAVE AXIS ENHANCED BY UPPER LEVEL FEATURES.  

TROPICAL WAVE IS IN THE CARIBBEAN ALONG 76W/77W S OF 18N MOVING 
W NEAR 20 KT. WAVE REMAINS AT THE LEADING EDGE OF LARGE SURGE OF 
AFRICAN DUST THAT CONTINUES TO MOVE W ACROSS THE THE CARIBBEAN. 
WAVE ALSO REMAINS EMBEDDED WITHIN SOME DRY AIR...THUS LIMITING 
SHOWER ACTIVITY. 

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 11N22W 8N31W 8N44W 11N56W. CLUSTERS 
OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 
120/150 NM OF THE ITCZ FROM 21W-32W AND FROM 41W-54W. 

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER RIDGE REMAINS OVER THE GULF ANCHORED OVER ALABAMA 
GIVING THE ENTIRE GULF E UPPER FLOW. THE SURFACE RIDGE EXTENDING 
FROM THE W ATLC REMAINS ACROSS THE E GULF. DIFFLUENCE ALOFT IS 
ENHANCING CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N 
OF 25N E OF 95W INCLUDING THE FLORIDA PENINSULA. THE REMAINDER 
OF THE GULF REMAINS RATHER CLEAR THIS EVENING. 

CARIBBEAN SEA...
NARROW UPPER TROUGH EXTENDS FROM AN UPPER LOW OVER THE TURKS AND 
CAICOS THROUGH THE FLORIDA STRAITS ACROSS THE W HALF OF CUBA 
INTO THE GULF OF HONDURAS ALONG THE E COAST OF THE YUCATAN 
PENINSULA. A BROAD UPPER RIDGE COVERS THE REMAINDER OF THE 
CARIBBEAN W OF 65W WITH AN INDUCED UPPER TROUGH COVERING THE 
LESSER ANTILLES BY A SECOND UPPER RIDGE OVER THE TROPICAL ATLC. 
THIS SCENARIO IS PROVIDING DIFFLUENCE ALOFT OVER THE W CARIBBEAN 
TO GENERATE AN AREA OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS 
S OF 17N W OF 80W TO INLAND OVER CENTRAL AMERICA...AND OVER THE 
FAR E CARIBBEAN ENHANCING THE ACTIVITY ASSOCIATED WITH THE 
TROPICAL WAVE THAT IS JUST E OF THE LESSER ANTILLES. AFRICAN 
DUST CONTINUES TO PUSH W OVER THE E HALF OF THE CARIBBEAN. 
MODERATE/STRONG EASTERLY TRADE WINDS CONTINUE TO DOMINATE MUCH 
OF THE CARIBBEAN DUE TO THE SURFACE RIDGE OVER THE ATLC WATERS. 

ATLANTIC OCEAN...
NARROW UPPER TROUGH EXTENDS FROM AN UPPER LOW OVER THE TURKS AND 
CAICOS THROUGH THE FLORIDA STRAITS ACROSS THE W HALF OF CUBA 
INTO THE FAR W CARIBBEAN AND GULF OF HONDURAS. THE UPPER RIDGE 
THAT IS GIVING THE GULF OF MEXICO E UPPER FLOW EXTENDS ACROSS 
THE W ATLC ALONG 33N TO 65W. A NARROW UPPER TROUGH ENTERS THE 
REGION NEAR 32N53W EXTENDING TO 25N57W. THESE UPPER LEVEL 
FEATURES ARE GENERATING ISOLATED CLUSTERS OF SCATTERED SHOWERS/ 
ISOLATED THUNDERSTORMS ACROSS THE W ATLC N OF 25N BETWEEN 
55W-75W AND OVER THE N BAHAMA ISLANDS N OF 23N W OF 75W TO THE 
FLORIDA COAST. LARGE UPPER HIGH IS ANCHORED IN THE CENTRAL ATLC 
NEAR 17N43W WHILE A SECOND UPPER RIDGE OVER W AFRICA IS 
ENHANCING THE SHOWERS ASSOCIATED WITH THE TROPICAL WAVE ALONG 
20W/21W. PATCHES OF AFRICAN DUST REMAIN OVER THE TROPICAL ATLC 
INTO THE E CARIBBEAN S OF 26N...BUT IS BEGINNING TO THIN. A 
SURFACE RIDGE DOMINATES THE ATLC ANCHORED BY A 1023 MB HIGH N OF 
THE REGION AND A 1020 MB HIGH S OF BERMUDA NEAR 26N65W WITH THE 
RIDGE CONTINUING W TO OVER THE E GULF OF MEXICO. 

$$
WALLACE