AXNT20 KNHC 300545 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT FRI JUL 30 2010 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0500 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS OFF THE W AFRICAN COAST EXTENDING FROM 16N20W TO 7N17W MOVING W 10-15 KT. UPPER AIR SOUNDINGS FROM DAKAR SENEGAL INDICATE THE WAVE PASSED THE STATION ABOUT 24 HOURS AGO. THE WAVE LIES AHEAD OF A MOISTURE SURGE NOTED OFF THE COAST OF AFRICA EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/STRONG CONVECTION IS FROM 9N-12N BETWEEN 17W-22W. TROPICAL WAVE IS ADDED IN THE CENTRAL ATLC ASSOCIATED WITH AN AREA OF DISTURBED WEATHER. THE WAVE EXTENDS FROM 16N28W TO 5N32W MOVING W NEAR 10 KT. LOW-LEVEL CYCLONIC FLOW IS ABOUT THE WAVE AXIS NEAR A 1010 MB LOW CENTER ALONG THE WAVE NEAR 8N. THE WAVE LIES EMBEDDED IN A LARGE AREA OF DEEP LAYER MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 4N-6N BETWEEN 32W-35W...AND FROM 8N-10N BETWEEN 32W-34W. TROPICAL WAVE IS MOVING ACROSS THE LESSER ANTILLES ALONG 16N58W TO 6N64W MOVING W 20-25 KT. THE WAVE LIES W OF A MAXIMUM IN DEEP LAYER MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. UPPER AIR SOUNDINGS FROM BARBADOS INDICATE THAT THE WAVE JUST PASSED THE STATION WITH A SURGE OF MOISTURE AND A WIND SHIFT FROM NE TO E. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 12N-16N BETWEEN 58W-62W. TROPICAL WAVE IS MOVING INTO THE W CARIBBEAN EXTENDING FROM 20N79W TO 11N77W MOVING W 15-20 KT. THE WAVE COINCIDES WITH AN AREA OF DEEP LAYER MOISTURE COVERING THE CENTRAL CARIBBEAN EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 12N-18N BETWEEN 75W-80W. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 13N17W 10N25W 7N39W 13N52W 13N59W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 1N-3N BETWEEN 36W-39W. SIMILAR ACTIVITY IS FROM 5N-9N BETWEEN 39-43W...AND FROM 11N-13N BETWEEN 37W-40W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 12N-15N BETWEEN 43W-53W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL INVERTED TROUGH IS OVER THE TEXAS COAST CONNECTING TO AN UPPER LEVEL LOW CENTERED OVER THE FAR SE BAY OF CAMPECHE NEAR 18N92W. THIS TROUGH IS SUPPORTING A SURFACE TROUGH PARALLELING THE SE MEXICAN COASTLINE ALONG 23N96W TO 19N94W. SCATTERED SHOWERS/THUNDERSTORMS ARE ALONG THE COAST FROM 18N-19N BETWEEN 91W-93W. A SECOND SURFACE TROUGH EXTENDS OFF THE NW COAST OF FLORIDA ALONG 31N84W TO 29N87W. AN AREA OF SCATTERED SHOWERS/THUNDERSTORMS ARE S OF THE TROUGH FROM 25N-27N BETWEEN 84W-86W. THE REMAINDER OF THE BASIN IS DOMINATED BY SURFACE RIDGING ANCHORED BY A 1019 MB HIGH S OF LOUISIANA NEAR 28N92W MAINTAINING FAIR CONDITIONS AND MOSTLY CLEAR SKIES. ALOFT...AN UPPER LEVEL RIDGE COVERS THE MAJORITY OF THE BASIN CENTERED OVER SRN ALABAMA/MISSISSIPPI. EXPECT THE SURFACE RIDGE TO GRADUALLY SHIFT SW SUPPORTING GENERALLY FAIR WEATHER ACROSS THE BASIN WITH SHOWERS/THUNDERSTORMS CONTINUING OVER THE NW AREA AS THE SURFACE TROUGH DIGS SOUTHWARD. CARIBBEAN SEA... THE PRESSURE GRADIENT BETWEEN SURFACE RIDING ACROSS THE ATLC AND LOWER PRESSURES ACROSS NRN SOUTH AMERICA IS MAINTAINING MODERATE TO FRESH TRADEWINDS ACROSS MUCH OF THE BASIN. UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL TROUGH COVERING THE NW CARIBBEAN AROUND AN UPPER LEVEL LOW CENTERED OVER THE SRN BAY OF CAMPECHE AND BROAD UPPER RIDGING COVERING THE REMAINDER OF THE CARIBBEAN IS ENHANCING CONVECTION NEAR A TROPICAL WAVE JUST W OF JAMAICA. SEE TROPICAL WAVE SECTION ABOVE. A FEW SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO ALONG THE COAST OF NICARAGUA AND PANAMA. SIMILAR ACTIVITY IS ALSO ACROSS SRN HAITI FROM 18N-19N BETWEEN 71W-73W. SHOWERS/THUNDERSTORMS ARE IMPACTING THE WINDWARD ISLANDS ASSOCIATED WITH A SECOND TROPICAL WAVE JUST E OF THE ISLANDS. EXPECT CONTINUED SHOWER ACTIVITY ACROSS THE WRN AND ERN CARIBBEAN AS THE TWO TROPICAL WAVES PROGRESS W. ATLANTIC OCEAN... A FRONTAL BOUNDARY N OF THE DISCUSSION AREA ALONG WITH DIFFLUENCE ALOFT BETWEEN UPPER RIDGING EXTENDING FROM THE GULF OF MEXICO AND A SHORTWAVE UPPER LEVEL TROUGH EXTENDING FROM 33N63W TO 25N69W ARE ENHANCING ISOLATED SHOWERS/THUNDERSTORMS N OF 29N BETWEEN 64W-76W. THE REMAINDER OF THE BASIN IS DOMINATED BY SURFACE RIDGING ANCHORED BY A PAIR OF 1025 MB HIGHS NEAR 32N48W AND 37N31W MAINTAINING FAIR CONDITIONS ACROSS THE CENTRAL AND ERN ATLC. ALOFT...A NARROW UPPER LEVEL TROUGH EXTENDS FROM NEAR 32N55W TO E OF THE LEEWARD ISLANDS NEAR 18N58W. AN UPPER LEVEL RIDGE IS CENTERED TO THE E NEAR 24N40W WITH AN UPPER LEVEL TROUGH TO ITS E ALONG 35W. ANOTHER UPPER LEVEL RIDGE COVERS THE FAR E ATLC CENTERED NEAR THE CANARY ISLANDS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON