000 AXNT20 KNHC 101157 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT WED JUL 10 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 CHANTAL IS CENTERED NEAR 16.5N 70.8W AT 10/1200 UTC OR ABOUT 132 NM SSW OF SANTO DOMINGO DOMINICAN REPUBLIC MOVING W AT 25 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1011 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. SCATTERED MODERATE CONVECTION IS FROM 15N-18N BETWEEN 67W-70W. SCATTERED SHOWERS AND TSTMS ARE ELSEWHERE FROM 12N-21N BETWEEN 60W-70W. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT3/WTNT33 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 10N23W TO 16N22W MOVING W AT 10-15 KT. THE WAVE REMAINS EMBEDDED WITHIN THE ITCZ AXIS AND COINCIDES WITH A GLOBAL MODEL INDICATED 700 MB TROUGH AND ASSOCIATED VORTICITY MAXIMUM IN THE VICINITY OF 12N23W. TOTAL PRECIPITABLE WATER IMAGERY SHOWS A RELATIVE MOISTURE MAXIMUM FROM 10N-15N BETWEEN 18W-25W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 08N-13N BETWEEN 20W-25W. TROPICAL WAVE EXTENDS FROM 07N37W TO 14N35W MOVING W AT 5-10 KT. THE WAVE REMAINS EMBEDDED WITHIN THE ITCZ AXIS WITH LOW-LEVEL STREAMLINE ANALYSIS INDICATING CYCLONIC TURNING OF THE LOW-LEVEL WIND FIELD VERTICALLY THROUGH 700 MB S OF 14N BETWEEN 30W-42W. A SAHARAN AIR LAYER REMAINS ON THE NORTHERN PERIPHERY OF THE WAVE AXIS AND THIS IS RESULTING IN VERY LIMITED CONVECTION AT THIS TIME. WIDELY SCATTERED MODERATE CONVECTION LARGELY REMAINS E OF 36W AND ASSOCIATED WITH CLOSE PROXIMITY TO THE ITCZ AXIS. TROPICAL WAVE EXTENDS FROM 12N94W TO 20N92W MOVING W AT 10-15 KT. THE WAVE...LARGELY INLAND ACROSS PORTIONS OF SOUTHERN MEXICO CONTINUES TO BECOME MORE DIFFUSE AND MORE DIFFICULT TO TRACK. EARLIER CONVECTION ASSOCIATED WITH THE WAVE HAS DIMINISHED. GLOBAL MODEL DATA INDICATES ANY REMNANTS OF THIS WAVE WILL LIKELY MOVE ACROSS PORTIONS OF SOUTHERN MEXICO AND THE NEAR COASTAL EASTERN PACIFIC WATERS THROUGH LATE WEDNESDAY. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 16N17W TO 15N20W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 15N20W TO 12N23W TO 08N37W TO THE EQUATOR NEAR 51W. SCATTERED MODERATE CONVECTION IS FROM 06N-12N BETWEEN 25W-36W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES NORTHERLY UPPER LEVEL FLOW DOMINATES OVER THE GULF BETWEEN A MIDDLE TO UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER EASTERN NEW MEXICO NEAR 35N104W AND AN UPPER LEVEL LOW CENTERED OVER THE FLORIDA STRAITS NEAR 25N81W. MOSTLY MODERATE DRY AIR ALOFT PREVAILS AND ALONG WITH A SURFACE RIDGE ANCHORED BY A 1020 MB HIGH CENTERED NEAR 29N87W THE BASIN REMAINS UNDER FAIRLY QUIET CONDITIONS THIS MORNING. AS THE UPPER LEVEL LOW DRIFTS W-NW...INCREASING CLOUDS AND MOISTURE ARE NOTED OVER THE SOUTHERN FLORIDA PENINSULA AND PORTIONS OF THE FAR EASTERN GULF WITH ISOLATED SHOWERS AND TSTMS OCCURRING S OF 28N E OF 85W. ISOLATED SHOWERS ARE ALSO OCCURRING OVER THE WESTERN GULF W OF 93W. SURFACE RIDGING IS FORECAST TO HOLD FAIRLY STATIONARY OVER THE BASIN THROUGH LATE THURSDAY AS TROPICAL STORM CHANTAL...CURRENTLY CENTERED OVER THE EASTERN CARIBBEAN SEA...IS EXPECTED TO BE POSITIONED ACROSS CENTRAL CUBA AND EMERGE INTO THE WATERS OF THE EASTERN FLORIDA STRAITS AND MOST LIKELY BE IMPACTING PORTIONS OF THE SE GULF AND SOUTHERN FLORIDA PENINSULA WITH PRECIPITATION INTO THE UPCOMING WEEKEND. CARIBBEAN SEA... THE PRIMARY FOCUS FOR THE CARIBBEAN IS TROPICAL STORM CHANTAL WHICH IS POSITIONED IN THE EASTERN CARIBBEAN AND PROVIDING SCATTERED SHOWERS AND WIDELY SCATTERED TSTMS N OF 14N E OF 71W...INCLUDING PUERTO RICO AND MANY OF THE LEEWARD ISLANDS. CHANTAL IS FORECAST TO TRACK W-NW OVER THE NEXT 24 HOURS AND CONTINUE IMPACTING HISPANIOLA THROUGH EARLY THURSDAY. OTHERWISE...AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER SOUTHERN GUATEMALA NEAR 14N91W AND IS PROVIDING MUCH OF THE WESTERN CARIBBEAN WITH NW TO NORTHERLY FLOW ALOFT. WHILE THE CENTRAL CARIBBEAN BETWEEN 70W-80W REMAINS FAIRLY TRANQUIL THIS MORNING...UPPER LEVEL DIFFLUENCE UNDER THE INFLUENCE OF THE UPPER LEVEL RIDGING IS GENERATING ISOLATED SHOWERS AND TSTMS S OF 20N W OF 80W...INCLUDING INLAND PORTIONS OF CENTRAL AMERICA. FARTHER SOUTH ACROSS THE SW CARIBBEAN...CLOSE PROXIMITY OF THE MONSOON TROUGH AXIS ALONG 09N IS GENERATING SCATTERED SHOWERS AND TSTMS S OF 11N BETWEEN 76W-84W. CHANTAL IS EXPECTED TO TRACK W-NW CLEARING THE BASIN BY LATE THURSDAY INTO EARLY FRIDAY WITH E-SE TRADES RE-ESTABLISHING ACROSS THE BASIN FOR THE UPCOMING WEEKEND. HISPANIOLA... CURRENTLY ISOLATED SHOWERS ARE OCCURRING ACROSS THE ISLAND AS MOISTURE AND CLOUDINESS IS EXPECTED TO INCREASE OVER THE NEXT 24 HOURS DUE TO TROPICAL STORM CHANTAL TRACKING TOWARDS THE SOUTH- CENTRAL COAST OF HISPANIOLA. CHANTAL IS EXPECTED TO PRODUCE PLENTY OF RAINFALL...LOCALLY HEAVY AT TIMES...THROUGH EARLY THURSDAY ON TOP OF OTHER IMPACTS SUCH AS WIND AND STORM SURGE. ONCE CHANTAL MAKES ITS WAY INTO THE EASTERN FLORIDA STRAITS BY LATE THURSDAY INTO FRIDAY...E-SE TRADES ARE EXPECTED TO RESUME WITH THE MORE TYPICAL AFTERNOON SHOWERS AND TSTMS OCCURRING ACROSS THE ISLAND DURING THE WEEKEND. ATLANTIC OCEAN... AN UPPER LEVEL LOW IS CENTERED OVER THE FLORIDA STRAITS NEAR 25N81W THAT IS PROVIDING THE SW NORTH ATLC S OF 30N W OF 75W WITH WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS THIS MORNING. THIS AREA INCLUDES WESTERN CUBA AND PORTIONS OF THE CENTRAL AND NW BAHAMAS. OTHERWISE...THE REMAINDER OF THE SW NORTH ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1026 MB HIGH CENTERED IN THE VICINITY OF BERMUDA NEAR 33N66W. THE HIGH IS EXPECTED TO REMAIN FAIRLY STATIONARY OVER THE NEXT 24 TO 36 HOURS AS TROPICAL STORM CHANTAL TRACKS ON ITS SOUTHERN AND SOUTHWESTERN PERIPHERY FOR THE REMAINDER OF THE WEEK. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED NEAR 32N55W THAT SUPPORTS A SURFACE TROUGH ANALYZED INTO THE DISCUSSION AREA ALONG 32N48W TO 30N50W TO 28N56W. ISOLATED SHOWERS ARE POSSIBLE WITHIN 90 NM EITHER SIDE OF THE BOUNDARY. ANOTHER UPPER LEVEL SHORTWAVE TROUGH IS NOTED ON WATER VAPOR IMAGERY IN THE VICINITY OF 37N33W THAT SUPPORTS A SURFACE TROUGH FROM 31N40W TO 26N45W. ISOLATED SHOWERS ARE OCCURRING WITHIN 120 NM EAST OF THE SURFACE TROUGH AXIS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN