000 AXNT20 KNHC 081151 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT MON JUL 08 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... AS OF 1200 UTC...TROPICAL STORM CHANTAL IS CENTERED NEAR 10.6N 50.6W...OR ABOUT 545 NM ESE OF BARBADOS MOVING W NEAR 23 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. 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 STORM WATCHES AND WARNINGS HAVE BEEN ISSUED FOR PORTIONS OF THE LESSER ANTILLES. TOTAL RAIN ACCUMULATIONS OF 2-4 INCHES ARE EXPECTED WITH MAXIMUM OF 6 INCHES POSSIBLE. CURRENTLY NUMEROUS STRONG CONVECTION IS NEAR THE STORM CENTER FROM 9N-11N BETWEEN 48W-50W. SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM 8N-12N BETWEEN 47W-52W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 15N24W TO 7N25W MOVING WEST NEAR 10-15 KT. THE WAVE ALIGNS WITH A LOW-AMPLITUDE 700 MB TROUGH. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WEST OF THE WAVE NEAR THE MONSOON TROUGH FROM 5N-9N BETWEEN 26W-30W. TROPICAL WAVE IS ALONG 22N75W TO 9N80W MOVING WEST AT 15-20 KT. THE WAVE IS ON THE WEST SIDE OF A SURGE OF DEEP LAYER MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. SOME DRIER AIR APPEARS TO BE PRESENT FROM ABOUT 14N-17N. THE NORTHERN PORTION OF THE WAVE IS ALSO UNDER THE INFLUENCE OF AN UPPER LEVEL LOW CENTERED NEAR 24N74W. IT IS HARD TO DETERMINE WHICH FEATURE IS CONTRIBUTING TO CONVECTION IN THE AREA. REGARDLESS...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 22N-28N BETWEEN 68W- 77W. STRONG CONVECTION IS ALSO NEAR THE COAST OF PANAMA FROM 9N- 10N BETWEEN 79W-81W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF GUINEA NEAR 11N15W TO 8N23W 9N33W. THE ITCZ BEGINS NEAR 9N33W AND CONTINUES ALONG 12N42W WHERE IT BREAKS DUE TO TROPICAL STORM CHANTAL. A SMALL SECTION OF THE ITCZ CONTINUES WEST OF THE STORM ALONG 8N50W TO 5N53W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 7N- 11N BETWEEN 14W-20W. ...DISCUSSION... GULF OF MEXICO... WEAK SURFACE RIDGING IS PRESENT OVER THE GULF OF MEXICO EXTENDING FROM HIGH PRESSURE OVER THE EASTERN CONUS AND WEST ATLC. HOWEVER...DEEP LAYER MOISTURE REMAINS THROUGHOUT MUCH OF THE AREA. CURRENTLY...SCATTERED SHOWERS ARE MAINLY ALONG THE COASTLINE FROM 29N-30N BETWEEN 87W-92W...AND FROM 21N-29N BETWEEN 95W-100W. THE REMAINDER OF THE BASIN IS MOSTLY CLEAR AT THIS TIME...ESPECIALLY THE SE CORNER WHERE THERE IS DRIER AIR ALOFT. ELSEWHERE ALOFT...MOIST AIR STREAMS AROUND AN UPPER LEVEL RIDGE WITH AXIS FROM THE FLORIDA PANHANDLE NEAR 31N84W TO 27N96W. AT THE SURFACE...EAST TO SOUTHEAST WINDS OF 10-15 KT SPREAD THROUGHOUT THE BASIN AROUND THE SURFACE RIDGE WITH 20 KT WINDS OVER THE FAR WESTERN GULF. LITTLE SYNOPTIC CHANGE IS EXPECTED WITH SURFACE RIDGING DOMINATING THE AREA...AND MOIST AIR REMAINING OVER THE NW HALF OF THE BASIN. CARIBBEAN SEA... MUCH OF THE CARIBBEAN IS EXPERIENCING FAIR CONDITIONS DESPITE THE PRESENCE OF A TROPICAL WAVE EXTENDING FROM EASTERN CUBA TO PANAMA. A FEW ISOLATED SHOWERS/THUNDERSTORMS ARE OVER THE NW CARIBBEAN. STRONGER SHOWERS/THUNDERSTORMS ARE JUST NORTH OF PANAMA NEAR THE TROPICAL WAVE. THE MONSOON TROUGH MAY ALSO BE CONTRIBUTING TO THIS ACTIVITY WITH AXIS EXTENDING FROM COSTA RICA TO NORTHERN COLOMBIA. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ALSO MOVING THROUGH THE EASTERN CARIBBEAN EAST OF 67W ASSOCIATED WITH AN AREA OF INCREASED MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. ALOFT...MOSTLY DRY AIR IS PRESENT AROUND AN UPPER LEVEL RIDGE CENTERED NEAR 13N68W. UPPER LEVEL TROUGHING IS ONLY OVER THE NW CORNER...BUT IS ACCOMPANIED BY DRY AIR ALOFT. THE WAVE IS EXPECTED TO CONTINUE MOVING WEST. TROPICAL STORM CHANTAL IS EAST OF THE LESSER ANTILLES...BUT IS MOVING QUICKLY AND EXPECTED TO REACH THE ISLANDS BY LATE TONIGHT OR EARLY TUESDAY MORNING. INTERESTS IN THE EASTERN/CENTRAL CARIBBEAN SHOULD MONITOR THE PROGRESS OF CHANTAL. HISPANIOLA... HISPANIOLA IS RATHER DRY AT THIS TIME. MOISTURE EAST OF THE TROPICAL WAVE OVER EASTERN CUBA STILL LINGERS NEAR THE ISLAND...BUT IS MAINLY KEEPING TO THE NORTH AND EAST. TOTAL PRECIPITABLE WATER IMAGERY INDICATES MORE MOISTURE IS STILL FARTHER EAST AND COULD IMPACT HISPANIOLA OVER THE NEXT COUPLE OF DAYS. TROPICAL STORM CHANTAL MAY ALSO IMPACT THE ISLAND BY THE MIDDLE OF THE WEEK. ATLANTIC OCEAN... TROPICAL STORM CHANTAL IS IN THE TROPICAL ATLC. SEE SPECIAL FEATURES ABOVE. BROAD SURFACE RIDGING DOMINATES THE WEST ATLC AROUND A 1024 MB HIGH NEAR 34N71W. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE TO THE NORTH CENTERED NEAR 37N64W. HOWEVER...AN UPPER LEVEL LOW TO THE SOUTH OVER THE BAHAMAS NEAR 24N74W IS ENHANCING ACTIVITY NORTH OF A TROPICAL WAVE NEAR 75W. SCATTERED SHOWERS/THUNDERSTORMS ARE FROM 22N-28N BETWEEN 68W- 77W. ACROSS THE CENTRAL ATLC...A SURFACE TROUGH...REMNANTS OF A FRONTAL BOUNDARY ARE ALONG 32N40W 30N46W 27N52W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 29N-31N BETWEEN 41W-47W. AN UPPER TROUGH IS ALONG 35W NORTH OF 23N SUPPORTING THE SURFACE TROUGH. THE REMAINDER OF THE BASIN IS DOMINATED BY BROAD SURFACE RIDGING AROUND A 1026 MB HIGH NEAR 31N32W. ALOFT...UPPER RIDGING DOMINATES THE TROPICAL ATLC AND FAR EASTERN ATLC. VERY DRY AIR IS THROUGHOUT THE EAST ATLC DUE TO THE PRESENCE OF A BROAD SAHARAN AIR LAYER...WHICH IS KEEPING CONDITIONS FAIR ACROSS MUCH OF THE AREA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON