000 AXNT20 KNHC 080541 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0445 UTC. ...SPECIAL FEATURES... AS OF 0300 UTC...TROPICAL STORM CHANTAL HAS FORMED IN THE TROPICAL ATLC. AT 0600 UTC...THE CENTER OF CHANTAL IS NEAR 10.1N 48.5W...OR ABOUT 675 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 SCATTERED MODERATE/STRONG CONVECTION IS FROM 7N-11N BETWEEN 45W- 48W WITH THE STRONGEST CONVECTION NEAR THE STORM CENTER. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 11N24W TO 4N24W MOVING WEST AT 10-15 KT. THE WAVE ALIGNS WITH A LOW-AMPLITUDE 700 MB TROUGH AXIS. ISOLATED MODERATE CONVECTION IS FROM 5N-9N BETWEEN 26W-29W. TROPICAL WAVE IS ALONG 25N71W TO 9N77W MOVING WEST NEAR 15 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 13N-17N. THE NORTHERN PORTION OF THE WAVE IS ALSO UNDER THE INFLUENCE OF AN UPPER LEVEL LOW CENTERED NEAR 24N73W. IT IS HARD TO DETERMINE WHICH FEATURE IS CONTRIBUTING TO CONVECTION IN THE AREA. REGARDLESS...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 19N-21N BETWEEN 64W- 70W. STRONG CONVECTION IS ALSO INLAND OVER NORTHERN COLOMBIA NEAR A 1005 MB LOW FROM 6N-10N BETWEEN 73W-77W. ...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/THUNDERSTORMS ARE IN THE NE GULF FROM 26N-30N BETWEEN 83W-85W..AND IN THE WESTERN GULF FROM 21N-24N BETWEEN 97W-99W. POSSIBLE ISOLATED SHOWERS ARE ACROSS MUCH OF THE REMAINING PORTION OF THE BASIN EXCEPT THE SE CORNER WHERE DRIER AIR ALOFT IS PROVIDING FAIRER CONDITIONS. ELSEWHERE ALOFT...MOIST AIR STREAMS AROUND AN UPPER LEVEL RIDGE WITH AXIS FROM LOUISIANA NEAR 30N92W TO 22N98W. AT THE SURFACE...EAST TO SOUTHEAST WINDS OF 10-15 KT SPREAD THROUGHOUT THE BASIN AROUND THE SURFACE RIDGE. LITTLE CHANGE IS EXPECTED SYNOPTICALLY 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 THE WINDWARD PASSAGE TO NORTHERN COLOMBIA. A FEW ISOLATED SHOWERS/THUNDERSTORMS ARE SOUTH OF WESTERN CUBA. SIMILAR ACTIVITY IS OVER THE FAR SW CARIBBEAN SOUTH OF 11N NEAR THE WAVE...AND THE MONSOON TROUGH THAT EXTENDS ALONG 8N TO A 1005 MB SURFACE LOW OVER NORTHERN COLOMBIA. STRONGER CONVECTION IS OVER NORTHERN COLOMBIA ASSOCIATED WITH THE LOW PRESSURE CENTER AND THE WAVE. OTHER ACTIVITY ASSOCIATED WITH THE WAVE IS NORTH OF THE CARIBBEAN AND IS ENHANCED BY AN UPPER LEVEL LOW NEAR 24N74W. THE ONLY OTHER ACTIVITY IN THE BASIN IS OVER THE LESSER ANTILLES WHERE SCATTERED SHOWERS ARE MOVING THROUGH EAST OF 62W. ALOFT...MOSTLY DRY AIR IS PRESENT AROUND AN UPPER LEVEL RIDGE CENTERED NEAR 13N67W. 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 TUESDAY MORNING. INTERESTS IN THE EASTERN CARIBBEAN SHOULD MONITOR THE PROGRESS OF CHANTAL. HISPANIOLA... HISPANIOLA IS FAIRLY DRY DESPITE SCATTERED SHOWERS/THUNDERSTORMS IMMEDIATELY NORTH OF THE ISLAND. MOISTURE EAST OF THE TROPICAL WAVE IN THE WINDWARD PASSAGE STILL LINGERS NEAR THE ISLAND...BUT IS MAINLY KEEPING TO THE NORTH. 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 1023 MB HIGH NEAR 33N72W. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE TO THE NORTH CENTERED NEAR 37N66W. HOWEVER...AN UPPER LEVEL LOW TO THE SOUTH OVER THE BAHAMAS NEAR 24N74W IS ENHANCING ACTIVITY NEAR A TROPICAL WAVE NEAR 72W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 19N-25N BETWEEN 65W-72W. ACROSS THE CENTRAL ATLC...A SURFACE TROUGH IS ANALYZED ALONG 22N55W TO 13N57W. NO SHOWERS ARE ASSOCIATED WITH THE TROUGH. A SECOND SURFACE TROUGH...REMNANTS OF A FRONTAL BOUNDARY ARE ALONG 32N40W 28N47W 26N54W. ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS ARE FROM 29N-31N BETWEEN 41W- 49W.AN UPPER TROUGH IS ALONG 37W NORTH OF 23N SUPPORTING THE SURFACE TROUGH. THE REMAINDER OF THE BASIN IS DOMINATED BY BROAD SURFACE RIDGING AROUND A 1026 MB HIGH NEAR 33N31W. 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