000 AXNT20 KNHC 251804 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED JUL 25 2012 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1745 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS WEST OF CAPE VERDE ISLANDS ANALYZED FROM 18N17W TO A 1012 MB LOW EMBEDDED IN THE MONSOON TROUGH NEAR 11N17W. THIS SYSTEM IS EMBEDDED WITHIN A REGION OF DEEP LAYER OF MOISTURE DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY. CLUSTERS OF SCATTERED MODERATE TO STRONG CONVECTION COVER THE AREA FROM 10N-15N BETWEEN 20W-27W. THIS CONVECTION IS ALSO ASSOCIATED TO THE MONSOON TROUGH DISCUSSED BELOW. TROPICAL WAVE MOVES ACROSS THE CENTRAL TROPICAL ATLC WITH AXIS ANALYZED FROM 23N39W TO THE MONSOON TROUGH AXIS NEAR 12N40W MOVING W AT ABOUT 5-10 KT. THE WAVE REMAINS ALONG THE WRN EDGE OF A SURGE OF DEEP LAYER MOISTURE AS DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER...THIS SYSTEM IS EMBEDDED IN A DENSE REGION OF SAHARAN DUST LIMITING THE CONVECTIVE ACTIVITY AROUND THE WAVE TO NEAR ZERO. A TROPICAL WAVE MOVES ACROSS THE WESTERN CARIBBEAN WITH AXIS ANALYZED FROM 20N75W TO 12N78W. WAVE REMAINS ON THE WRN EDGE OF A SURGE OF DEEP MOISTURE NOTED ON TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER...THIS SYSTEM IS EMBEDDED IN REGION OF STRONG SUBSIDENCE ALOFT AND SAHARAN DUST LIMITING THE CONVECTIVE ACTIVITY AROUND THE WAVE TO JUST A FEW ISOLATED SHOWERS IN THE VICINITY OF THE WAVE AXIS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE TROPICAL ATLC THROUGH THE COAST OF MAURITANIA ALONG 18N16W TO THE TROPICAL WAVES 1012 MB LOW NEAR 11N17W CONTINUING WESTWARD ALONG 10N27W 12N40W TO 7N50W...WHERE A SHORT SECTION OF THE ITCZ CONTINUES TO THE COAST OF GUYANA NEAR 6N58W. CLUSTERS OF WEAK SCATTERED CONVECTION ARE FROM 4N-10N BETWEEN 46W-55W. CLUSTERS OF SCATTERED MODERATE TO STRONG CONVECTION ARE WITHIN 100-150 NM ON EITHER SIDE OF THE MONSOON TROUGH BETWEEN 20W-33W. ...DISCUSSION... GULF OF MEXICO... WEAK UPPER LEVEL CYCLONIC FLOW FLOW REMAINS OVER THE SE CONUS SUPPORTING A SURFACE TROUGH ANALYZED ALONG THE BIG BEND REGION OF FLORIDA NEAR 30N84W TO 25N86W. DOPPLER RADAR IMAGERY SHOWS SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS WITHIN 70 NM O NEITHER SIDE OF THE TROUGH AXIS FROM 26N-29N. THE ACTIVITY IN THIS REGION IS EXPECTED TO DECREASE AND SHIFT TO THE WSW OVER THE NEXT 24 HOURS. SIMILAR CONVECTION IS NOTED ON SATELLITE IMAGERY ACROSS THE GOLF COAST OF MEXICO AFFECTING THE COASTAL WATERS FROM VERACRUZ TO MATAMOROS. THE ACTIVITY IS SUPPORTED ALOFT BY AN ELONGATED UPPER LEVEL LOW NOTED OVER NE MEXICO. WHILE THE ACTIVITY IS EXPECTED TO DECREASE DURING THE NEXT 24 HOURS...THIS AREA OF SHOWERS IS EXPECTED TO REMAIN NEARLY STATIONARY DURING THE FORECAST PERIOD. CARIBBEAN SEA... AN UPPER LEVEL INVERTED TROUGH MOVES ACROSS CENTRAL AMERICA ON WATER VAPOR IMAGERY. ALTHOUGH THIS FEATURE IS EMBEDDED IN DRY AIR ALOFT...ITS MID-UPPER LEVEL LIFTING COMBINED WITH LOW LEVEL MOISTURE CONVERGENCE ALONG THE MONSOON TROUGH OVER THE FAR SW BASIN IS GENERATING AN AREA OF SCATTERED SHOWERS AND THUNDERSTORMS AFFECTING THE COASTAL WATERS OF NICARAGUA AND COSTA RICA WITHIN 100 NM S OF BLUEFIELDS. THIS AREA OF CONVECTION WILL CONTINUE TO MOVE INLAND DURING THE NEXT 24 HOURS. A TROPICAL WAVE MOVES ACROSS THE WESTERN CARIBBEAN BASIN WITH NO ASSOCIATED ACTIVITY DUE TO STRONG SUBSIDENCE AND DRY AIR ALOFT AROUND THIS SYSTEM. THE REMAINDER OF THE DISCUSSION AREA IS UNDER FAIR WEATHER CONDITIONS WITH A FEW ISOLATED SHOWERS EMBEDDED IN THE LIGHT TO MODERATE EASTERLY TRADEWIND FLOW. UPPER AIR SOUNDINGS AND SATELLITE DATA CONTINUE TO SAHARAN DUST ALOFT ACROSS MOST OF THE DISCUSSION AREA. ATLANTIC OCEAN... A BROAD UPPER LEVEL LONGWAVE TROUGH MOVES ACROSS THE WEST ATLANTIC SUPPORTING TWO SURFACE TROUGHS EXTENDING INTO THE AREA. THE LEADING SURFACE TROUGH EXTENDS FROM THE SAME LOW THROUGH 32N54W TO 28N59W. THE TRAILING SURFACE TROUGH EXTENDS THROUGH 32N63W TO 28N67W. THE COMBINATION OF THESE TWO FEATURES IS GENERATING AN AREA OF SCATTERED SHOWERS AND THUNDERSTORMS N OF 28N BETWEEN 55W-65W. THIS AREA OF CONVECTION IS FORECAST TO TRACK ESE DURING THE NEXT 24 HOURS. OTHERWISE...BROAD UPPER LEVEL RIDGING COVERS THE REMAINDER OF THE ATLC DISCUSSION AREA. THE FAIR WEATHER IS FURTHER ENHANCED BY SAHARAN DUST COVERING THE ENTIRE ATLC DISCUSSION AREA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA