000 AXNT20 KNHC 310538 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT WED JUL 31 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...TROPICAL WAVES... TROPICAL WAVE IN THE TROPICAL ATLC EXTENDS FROM 17N40W TO 7N34W MOVING W-SW NEAR 10 KT. WAVE IS EMBEDDED WITHIN A NARROW SURGE OF MODERATE MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. THE NOAA GOES R SATELLITE SHOWS THE WAVE AT THE LEADING EDGE OF A DENSE SAHARAN DUST LAYER WHICH IS LIMITING SHOWER ACTIVITY. TROPICAL WAVE OVER THE SW ATLC/CENTRAL CARIBBEAN EXTENDS FROM 23N76W TO 14N76W MOVING W NEAR 15 KT. THE N PORTION OF THE WAVE IS EMBEDDED WITHIN AN AREA OF DEEP MOISTURE THAT COVERS THE W ATLC. HOWEVER...THE S PORTION IS WITHIN AN AREA OF LIMITED MOISTURE...ALL AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY AND IN WATER VAPOR IMAGERY. WAVE IS MOVING W OF AN UPPER LOW THAT COVERS THE W ATLC WHICH IS ENHANCING ANY SHOWER ACTIVITY IN THE VICINITY NOT BY THE TROPICAL WAVE. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 21N16W AND CONTINUES THROUGH A WEAK 1012 MB LOW NEAR 14N25W THEN ALONG 8N31W TO 6N37W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 6N48W TO SOUTH AMERICA NEAR 5N52W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 5N-10N E OF 30W TO INLAND OVER SW AFRICA. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER RIDGE ANCHORED OVER W TEXAS EXTENDS E ACROSS THE SE CONUS ALONG THE N GULF COAST AND INTO THE W ATLC GIVING THE GULF NE TO E FLOW ALOFT. A RIDGE AXIS EXTENDS FROM THIS MAIN RIDGE E-SE OVER CUBA TO HAITI. A SECOND UPPER RIDGE EXTENDS ACROSS S MEXICO TO OVER CENTRAL AMERICA. ALTHOUGH WATER VAPOR IMAGERY SHOWS SOME DRY AIR ALOFT MAINLY OVER THE W GULF AFTERNOON SHOWERS/THUNDERSTORMS THAT DEVELOPED INLAND OVER FLORIDA HAVE MOVED INTO THE E GULF E OF 84W INCLUDING THE STRAITS OF FLORIDA AND THE FLORIDA KEYS. SIMILAR AFTERNOON ACTIVITY THAT GENERATED OVER THE YUCATAN PENINSULA HAVE MOVED INTO THE BAY OF CAMPECHE S OF 21N W OF 95W. A SURFACE RIDGE ANCHORED IN THE W/CENTRAL ATLC EXTENDS FROM THE W ATLC ACROSS FLORIDA TO TEXAS AND MEXICO WITH A WEAK 1021 MB HIGH NEAR 29N85W. THE GULF HIGH WILL WEAKEN AS IT SLIDES S THROUGH SUN. THE TROPICAL WAVE IN THE SW ATLC IS EXPECTED TO ENTER THE SE GULF WED NIGHT AND THU AND POSSIBLY REACH THE FAR SE PORTION OF THE CENTRAL GULF BY FRI. CARIBBEAN SEA... THE UPPER RIDGE ANCHORED IN THE E PACIFIC EXTENDS ACROSS CENTRAL AMERICA TO OVER THE THE GULF OF HONDURAS. THE MAIN UPPER RIDGE OVER THE GULF OF MEXICO EXTENDS A RIDGE AXIS E-SE OVER CUBA TO HAITI. AFTERNOON SHOWERS/THUNDERSTORMS THAT DEVELOPED OVER PUERTO RICO TO CUBA INCLUDING JAMAICA HAVE MOVED INTO THE CARIBBEAN WATERS DOTTING THE AREA N OF 17N BETWEEN 66W-80W. THE MONSOON TROUGH EXTENDS ALONG 9N FROM COLOMBIA TO COSTA RICA ARE GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 12N W OF 80W. W ATLC/CENTRAL CARIBBEAN TROPICAL WAVE WILL MOVE INTO THE W CARIBBEAN WED AND EXIT THE AREA INTO THE SE GULF OF MEXICO LATE WED NIGHT INTO THU. HISPANIOLA... AFTERNOON SCATTERED SHOWERS/ISOLATED THUNDERSTORMS HAVE MOVED OFF THE ISLAND INTO THE GULF OF GONAVE TONIGHT. THEY WILL FURTHER DIMINISH OVER BY MORNING. THE UPPER LOW N OF HISPANIOLA ENHANCED THE AFTERNOON ACTIVITY AND IS FORECAST TO MOVE W LATE WED THROUGH THE STRAITS OF FLORIDA BY SAT AS A SECOND UPPER LOW MOVES TOWARD THE DOMINICAN REPUBLIC BY THE WEEKEND. AFTERNOON SHOWERS AND THUNDERSTORMS WILL CONTINUE OVER THE NEXT FEW DAYS. ATLANTIC OCEAN... THE UPPER RIDGE OVER THE GULF OF MEXICO EXTENDS INTO THE W ATLC ALONG 30N TO 70W BUT IS IS BEING UNDERCUT E OF 75W BY AN ELONGATED UPPER LOW THAT IS CENTERED NEAR 24N71W. THIS UPPER LOW IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 24N TO THE COAST OF HISPANIOLA AND INLAND OVER CUBA W OF 68W INTO THE STRAITS OF FLORIDA. A SECOND LARGER UPPER LOW IS IN THE CENTRAL ATLC NEAR 24N52W SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 27N49W TO TO 20N50W AND GENERATING CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 24N-31N BETWEEN 49W-60W. THE REMAINDER OF THE ATLC IS DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1023 MB HIGH ABOUT 140 NM E OF BERMUDA AND A 1022 MB HIGH IN THE E ATLC NEAR 29N36W. THE HIGH E OF BERMUDA WILL CHANGE LITTLE THROUGH THU THEN SHIFT S TO NEAR 27N FRI THROUGH SUN. THE W ATLC/CENTRAL CARIBBEAN TROPICAL WAVE WILL MOVE W ACROSS SOUTHERN PORTION THROUGH WED AND REACH THE SE GULF WED NIGHT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW