000 AXNT20 KNHC 200607 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT MON JUL 20 2015 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH WWWW UTC. ...TROPICAL WAVES... TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC EXTENDS ALONG 41W/42W FROM 5N-17N MOVING W NEAR 20 KT OVER THE PAST 24 HOURS. WAVE COINCIDES WITH A 700 MB TROUGH BETWEEN 38W-45W. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS EMBEDDED WITHIN AN SURGE OF MODERATE TO DEEP MOISTURE. HOWEVER THE NOAA/NESDIS AEROSOL PRODUCT AND THE LAST VISIBLE SATELLITE IMAGERY INDICATES THAT THE WAVE IS ALSO EMBEDDED WITHIN A PLUMB OF AEROSOLS OR SAHARAN DUST LIMITING ANY ASSOCIATED CONVECTION. TROPICAL WAVE IN THE W TROPICAL ATLC EXTENDS ALONG 53W/54W FROM 7N-22N MOVING W 15-20 KT OVER THE PAST 24 HOURS. WAVE COINCIDES WITH A LOW AMPLITUDE 700 MB TROUGH BETWEEN 51W-55W S OF 14N. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS EMBEDDED WITHIN AN SURGE OF DEEP MOISTURE THAT EXTENDS N OF 26N. THE NOAA/NESDIS AEROSOL PRODUCT AND THE LAST VISIBLE SATELLITE IMAGERY INDICATES THAT THE WAVE IS ALONG THE LEADING EDGE OF A PLUMB OF AEROSOLS OR SAHARAN DUST. HOWEVER S OF THE AEROSOLS OR SAHARAN DUST IS A NARROW BAND OF CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ALONG A LINE FROM 9N48W TO 11N54W. TROPICAL WAVE IS MOVING OVER THE LESSER ANTILLES INTO THE E CARIBBEAN EXTENDING ALONG 60W-61W FROM 9N-20N MOVING W NEAR 15 KT OVER THE PAST 24 HOURS. WAVE COINCIDES WITH A 700 MB TROUGH THAT COVERS THE FAR E CARIBBEAN BETWEEN 60W-65W AND EXTENDS INTO THE CENTRAL ATLC. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS EMBEDDED WITHIN AN AREA OF MODERATELY DRY AIR. THE NOAA/NESDIS AEROSOL PRODUCT AND THE LAST VISIBLE SATELLITE IMAGERY INDICATES THAT THE WAVE IS ALSO EMBEDDED WITHIN A PREVIOUS PLUMB OF AEROSOLS OR SAHARAN DUST AGAIN LIMITING ANY ASSOCIATED CONVECTION. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 11N15W ALONG 8N21W TO 8N28W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 9N33W TO E OF THE EASTERN MOST TROPICAL WAVE NEAR 9N39W THEN RESUMES W OF THE WAVE NEAR 9N43W TO SOUTH AMERICA NEAR 5N53W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 6N-10N BETWEEN 23W-28W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER RIDGE COVERS THE N GULF AND INTO THE W ATLC ANCHORED OVER N LOUISIANA WHILE AN INVERTED UPPER TROUGH EXTENDS FROM THE W CARIBBEAN GIVING THE S GULF E TO SE FLOW ALOFT. THE UPPER RIDGE IS ADVECTING UPPER MOISTURE INTO THE NE GULF BRINGING WITH IT SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS N OF 27N E OF 90W. THE DIURNAL SURFACE TROUGH OVER THE W COAST OF THE YUCATAN PENINSULA IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 20N E OF 93W. THE REMAINDER OF THE GULF IS DOMINATED BY A SURFACE RIDGE THAT EXTENDS FROM THE W ATLC ACROSS S FLORIDA TO SE TEXAS WITH A 1018 MB HIGH NEAR 24N85W. SURFACE RIDGE WILL SHIFT TO THE E GULF MON THEN CHANGE LITTLE THROUGH THE WEEK. CARIBBEAN SEA... AN INVERTED UPPER TROUGH EXTENDS FROM GUATEMALA INTO THE GULF OF HONDURAS TO E CUBA COVERING THE W CARIBBEAN W OF 78W. AN UPPER RIDGE ANCHORED IN THE TROPICAL ATLC EXTENDS AN UPPER RIDGE AXIS ACROSS THE LESSER ANTILLES NEAR MARTINIQUE TO 13N78W. THE SOUTHERLY FLOW ALOFT ACROSS THE CARIBBEAN IS ADVECTING UPPER MOISTURE OVER THE S CARIBBEAN BRINGING SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS S OF LINE FROM COLOMBIA NEAR 11N74W TO NICARAGUA NEAR 13N84W. AFTERNOON/EVENING SHOWERS/THUNDERSTORMS THAT DEVELOPED OVER CUBA HAVE DIMINISH TO SOME ISOLATED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 19N-21N BETWEEN 76W- 79W. ISOLATED SHOWERS REMAIN ACROSS PORTIONS OF HISPANIOLA. THIS IS LEAVING THE REMAINDER OF THE CARIBBEAN WITH MOSTLY CLEAR SKIES TONIGHT. ATLC SURFACE RIDGE WILL MAINTAIN FRESH TO OCCASIONALLY STRONG TRADE WINDS ACROSS THE S/CENTRAL CARIBBEAN THROUGH THE WEEK. TROPICAL WAVE OVER THE LESSER ANTILLES WILL MOVE ACROSS THE E CARIBBEAN THROUGH MON NIGHT THEN ACROSS THE CENTRAL CARIBBEAN TUE THROUGH WED NIGHT AND ACROSS THE W CARIBBEAN THU THROUGH FRI NIGHT. THE NEXT TROPICAL WAVE WILL ENTER THE E CARIBBEAN EARLY TUE THROUGH WED NIGHT THEN THE CENTRAL CARIBBEAN THU AND THU NIGHT AND THE W CARIBBEAN FRI AND FRI NIGHT. THE THIRD TROPICAL WAVE WILL MOVE INTO THE E CARIBBEAN THU THROUGH FRI. ...HISPANIOLA... CURRENTLY...ISOLATED SHOWERS REMAIN ACROSS THE SW PORTION OF THE ISLAND TONIGHT. AN UPPER TROUGH OVER THE CENTRAL ATLC DIPS S OVER THE N PORTION OF THE ISLAND. THIS UPPER TROUGH WILL ENCOMPASS THE ISLAND BY MON NIGHT AND WILL PERSIST THROUGH THU. MOISTURE WILL INCREASE LATE MON AHEAD OF A SERIES OF TROPICAL WAVES THAT MOVE ACROSS THE ISLAND TUE THROUGH THE END OF THE WEEK. THIS WILL INCREASE THE CHANCE OF SHOWERS AND POSSIBLE THUNDERSTORMS STARTING TUE AFTERNOON. ATLANTIC OCEAN... AN UPPER RIDGE COVERS THE W ATLC N OF 24N W OF 70W. AN UPPER LOW IS IN THE N/CENTRAL ATLC NEAR 29N55W EXTENDING AN UPPER TROUGH SW ALONG 25N65W TO OVER THE N PORTION OS HISPANIOLA. AN UPPER RIDGE IS TO THE S ANCHORED NEAR 15N53W COVERING THE TROPICAL ATLC. BETWEEN THESE UPPER FEATURES IS AN AREA OF DIFFLUNCE ALOFT THAT IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 75 NM OF LINE FROM 27N47W TO 23N55W. THE ATLC BASIN IS DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1025 MB HIGH NEAR 29N45W WITH A RIDGE AXIS EXTENDING THROUGH A 1020 MB HIGH NEAR 27N72W INTO THE GULF OF MEXICO OVER S FLORIDA. SURFACE RIDGE WILL SHIFT SLIGHTLY S TUE NIGHT THE CHANGE LITTLE THROUGH THE REST OF THE WEEK. THE N PORTION OF THE TROPICAL WAVE ALONG 53W/54W WILL MOVE ACROSS THE SW ATLC MON THROUGH WED. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW