000 AXNT20 KNHC 051204 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU SEP 05 2013 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...SPECIAL FEATURES... TROPICAL STORM GABRIELLE IS CENTERED NEAR 17.7N 67.4W AT 05/1200 UTC...OR ABOUT 57 NM W-SW OF PONCE PUERTO RICO AND ABOUT 73 NM SE OF PUNTA CANA DOMINICAN REPUBLIC MOVING NW AT 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. SEE THE LATEST INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT2/WTNT32 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. GABRIELLE IS EXPECTED TO PRODUCE TOTAL RAINFALL AMOUNTS OF 3 TO 6 INCHES OVER PORTIONS OF PUERTO RICO...THE U.S. VIRGIN ISLANDS...AND EASTERN PORTIONS OF THE DOMINICAN REPUBLIC WITH ISOLATED MAXIMUM AMOUNTS OF UP TO 12 INCHES POSSIBLE IN AREAS OF MOUNTAINOUS TERRAIN. THESE HEAVIER AMOUNTS COULD RESULT IN DANGEROUS FLASH FLOODS AND MUD SLIDES OVER MOUNTAINOUS TERRAIN. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 15N-20N BETWEEN 62W-68W INCLUDING PORTIONS OF THE LEEWARD ISLANDS...THE VIRGIN ISLANDS AND PUERTO RICO. BROAD SURFACE LOW PRESSURE COVERS THE SOUTHWESTERN CORNER OF THE GULF OF MEXICO. A SURFACE TROUGH EXTENDS FROM A 1012 MB LOW PRESSURE CENTER THAT IS NEAR 19N91W AT THE COAST OF MEXICO... TO 21N93W AND 24N94W. CONVECTIVE PRECIPITATION...NUMEROUS STRONG FROM 21N TO 24N BETWEEN 92W AND 95W. THE CLOUDINESS AND CONVECTIVE PRECIPITATION THAT ARE AND HAVE BEEN IN THE SOUTHWESTERN CORNER OF THE GULF OF MEXICO HAVE INCREASED COMPARATIVELY. FURTHER DEVELOPMENT OF THIS SYSTEM IS POSSIBLE BEFORE IT MOVES INLAND ALONG THE COAST OF MAINLAND MEXICO ON FRIDAY. THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS...AND A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 5 DAYS. ...TROPICAL WAVES... TROPICAL WAVE W OF THE CAPE VERDE ISLANDS EXTENDS FROM 18N29W THROUGH A 1012 MB LOW NEAR 14N31W TO 9N31W. WAVE HAS BEEN MOVING W NEAR 10-15 KT FOR THE PAST 24 HOURS. WAVE IS EMBEDDED WITHIN A BROAD SURGE OF DEEP MOISTURE AS DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY. WAVE IS WELL DEFINED IN THE SATELLITE WINDS WITH CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION WITHIN 75 NM OF LINE FROM 17N27W 15N32W TO 10N34W. TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC EXTENDS FROM 22N51W TO 12N49W. WAVE HAS BEEN MOVING W 15-20 KT FOR THE PAST 24 HOURS. WAVE IS EMBEDDED WITHIN A CUT-OFF AREA OF DEEP MOISTURE AS DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY. NO ASSOCIATED SHOWERS OR CONVECTION. TROPICAL WAVE ENTERING THE E CARIBBEAN EXTENDS FROM 18N62W TO 11N62W. WAVE HAS BEEN MOVING W NEAR 10 KT FOR THE PAST 24 HOURS. THE N PORTION OF THE WAVE HAS SPLIT AND IS NOW DEPICTED AS A SURFACE TROUGH NE OF THE LEEWARD ISLANDS. WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP MOISTURE AS DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY. SEE SPECIAL FEATURES ABOVE FOR ACTIVITY IN THE VICINITY. TROPICAL WAVE IN THE W CARIBBEAN EXTENDS FROM CUBA NEAR 21N79W TO 10N78W. WAVE HAS BEEN MOVING NEAR 10 KT FOR THE PAST 24 HOURS. WAVE IS EMBEDDED WITHIN AN AREA OF MODERATE TO DEEP MOISTURE THAT COVERS THE CARIBBEAN AS DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 75 NM OF LINE FROM 17N77W TO 13N83W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 17N16W AND CONTINUES ALONG 16N22W THROUGH THE LOW/TROPICAL WAVE NEAR 14N31W TO 10N40W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 8N51W TO 9N59W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 200 NM ALONG THE COAST OF AFRICA BETWEEN SIERRA LEONE THE S BORDER OF MAURITANIA. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER RIDGE IS ANCHORED OVER S/CENTRAL MEXICO AND EXTENDS AN AXIS THE GULF BETWEEN TUXPAN AND S FLORIDA. A SURFACE TROUGH EXTENDS FROM A 1012 MB LOW PRESSURE CENTER THAT IS NEAR 19N91W AT THE COAST OF MEXICO...TO 21N93W AND 24N94W. DEEP MOISTURE COVERS MOST OF THE GULF AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 22N-25N BETWEEN 87W-95W WITH ISOLATED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS DOTTING THE REMAINDER OF THE AREA S OF 28N FROM FLORIDA TO MEXICO. A BROAD UPPER TROUGH COVERS THE NE GULF AND INTO THE W ATLC SUPPORTING A STATIONARY BOUNDARY THAT REMAINS INLAND OVER THE SE CONUS. THE LOW/SURFACE TROUGH WILL PREVAIL ACROSS THE BAY OF CAMPECHE AND SW GULF THROUGH MON. TROPICAL WAVE WILL MOVE INTO THE SW GULF MON. CARIBBEAN SEA... PRIMARY CONCERN THIS MORNING IS TROPICAL STORM GABRIELLE AND THE ACCOMPANYING RAINFALL. SEE SPECIAL FEATURES ABOVE. THE UPPER RIDGE OVER THE GULF OF MEXICO COVERS THE NW CARIBBEAN N OF 15N W OF 82W. THE UPPER RIDGE ASSOCIATED WITH TROPICAL STORM GABRIELLE DOMINATES THE E CARIBBEAN E OF 77W. THIS IS INDUCING AN INVERTED TROUGH THAT EXTENDS FROM N COSTA RICA/SE NICARAGUA TO OVER CUBA NEAR 21N79W. CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS DOT THE N CARIBBEAN N OF 18N BETWEEN 75W-84W AND FROM 13N-18N BETWEEN 69W-75W. THE MONSOON TROUGH EXTENDS ACROSS THE SW CARIBBEAN FROM COLOMBIA NEAR 10N75W TO ACROSS PANAMA/ COSTA RICA NEAR 9N84W. CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 13N BETWEEN 75W-78W AND S OF 10N BETWEEN 78W-82W. THE ACTIVITY OVER THE E CARIBBEAN IS DUE TO TROPICAL STORM GABRIELLE. GABRIELLE IS EXPECTED TO MOVE THROUGH THE MONA PASSAGE LATE TODAY. THE W CARIBBEAN TROPICAL WAVE WILL CONTINUE W AND MOVE W OF THE AREA LATE FRI. THE E CARIBBEAN TROPICAL WAVE WILL CONTINUE W REACHING THE CENTRAL CARIBBEAN ON SAT AND SUN AND CONTINUE THROUGH THE W CARIBBEAN ON MON AND TUE. HISPANIOLA... SATELLITE IMAGERY INDICATES SOME POSSIBLE ISOLATED SHOWERS ARE ACROSS THE DOMINICAN REPUBLIC THIS MORNING. TROPICAL STORM GABRIELLE IS EXPECTED TO MOVE THROUGH THE MONA PASSAGE LATE TODAY. THIS WILL GIVE THE DOMINICAN REPUBLIC MOST OF THE HEAVY RAINFALL STARTING LATER THIS AFTERNOON. THE TROPICAL WAVE IN THE E CARIBBEAN WILL MOVE S OF THE ISLAND SAT AND SUN. GABRIELLE IS EXPECTED TO PRODUCE TOTAL RAINFALL AMOUNTS OF 3 TO 6 INCHES OVER THE EASTERN PORTIONS OF THE DOMINICAN REPUBLIC WITH ISOLATED MAXIMUM AMOUNTS OF UP TO 12 INCHES POSSIBLE IN AREAS OF MOUNTAINOUS TERRAIN. THESE HEAVIER AMOUNTS COULD RESULT IN DANGEROUS FLASH FLOODS AND MUD SLIDES OVER MOUNTAINOUS TERRAIN. ATLANTIC OCEAN... THE UPPER TROUGH OVER THE NE GULF OF MEXICO EXTENDS OVER THE FAR W ATLC N OF 27N W OF 68W SUPPORTING A FRONTAL BOUNDARY THAT IS N OF THE DISCUSSION AREA. ISOLATED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 60/75 NM OF LINE FROM ACROSS FLORIDA NEAR VERO BEACH TO BEYOND 30N72W AND SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 60 NM OF LINE FROM 30N72W TO BEYOND 32N67W. AN UPPER LOW COVERS THE REMAINDER OF THE W ATLC INTO THE CENTRAL ATLC N OF 24N CENTERED NEAR 28N60W. A SECOND WEAKER UPPER LOW IS CENTERED NEAR 26N43W. A SURFACE TROUGH...PREVIOUSLY THE N PORTION OF THE E CARIBBEAN TROPICAL WAVE...EXTENDS FROM 20N61W TO 26N57W WITH SCATTERED SHOWERS WITHIN 150 NM EITHER SIDE OF THE TROUGH. THE UPPER RIDGE ASSOCIATED WITH TROPICAL STORM GABRIELLE EXTENDS AN AXIS NE ALONG 20N58W ALONG 26N52W TO 31N52W WHICH IS PROVIDING DIFFLUENCE ALOFT TO GENERATE AN AREA OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 60/75 NM OF LINE FROM 26N51W ALONG 29N55W TO 30N62W. THE REMAINDER OF THE ATLC IS DOMINATED BY A SURFACE RIDGE ANCHORED BY A WEAK 1020 M B HIGH IN THE W ATLC NEAR 29N73W A 1025 MB HIGH IN THE CENTRAL ATLC NEAR 34N50W AND A 1026 MB HIGH IN THE E ATLC NEAR 36N302W. TROPICAL STORM GABRIELLE IS EXPECTED TO MOVE INTO THE W ATLC THROUGH THE MONA PASSAGE LATE THU CONTINUING TO MOVE NORTHWARD E OF THE TURKS AND CAICOS BEFORE NE ON SUN THEN N OF THE AREA ON TUE. A WEAK COLD FRONT WILL DIP INTO THE N/CENTRAL WATERS TODAY BEFORE WEAKENING TO A TROUGH ON FRI THEN SHIFT E AND STRENGTHEN OVER THE CENTRAL ATLC OVER THE WEEKEND. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW