ZCZC MIATCDAT3 ALL TTAA00 KNHC DDHHMM TROPICAL STORM CHANTAL DISCUSSION NUMBER 10 NWS NATIONAL HURRICANE CENTER MIAMI FL AL032013 500 AM AST WED JUL 10 2013 OBSERVATIONS FROM A HURRICANE HUNTER MISSION AND NOAA DATA BUOY 42059 INDICATE THAT CHANTAL MAY NO LONGER HAVE A CLOSED CIRCULATION. THE SATELLITE PRESENTATION OF THE SYSTEM HAS ALSO DETERIORATED MARKEDLY THIS MORNING...AND IS BARELY CLASSIFIABLE BY THE DVORAK TECHNIQUE. FLIGHT-LEVEL AND SFMR SURFACE WINDS DO NOT SUPPORT AN INTENSITY OF MORE THAN 40 KT...AND THE CURRENT WIND SPEED IS SET AT THAT VALUE. EVEN IF CHANTAL DOES NOT CEASE ITS EXISTENCE AS A TROPICAL CYCLONE...DYNAMICAL GUIDANCE SHOWS STRONG WESTERLY SHEAR OVER THE SYSTEM FOR THE NEXT COUPLE OF DAYS. THE SHEAR...ALONG WITH LAND INTERACTION...SHOULD CAUSE FURTHER WEAKENING. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE STATISTICAL-DYNAMICAL LGEM GUIDANCE AND THE INTENSITY MODEL CONSENSUS. ALTHOUGH THE CENTER IS DIFFICULT TO TRACK...THE BEST ESTIMATE IS THAT CHANTAL MOVED VERY RAPIDLY WESTWARD...NEAR 28 KT...OVER THE PAST SEVERAL HOURS. A MORE CONSERVATIVE...LONGER-TERM...ESTIMATE OF INITIAL MOTION IS 285/25. A WELL-DEFINED MID-LEVEL RIDGE TO THE NORTH OF THE STORM HAS BEEN STEERING IT QUICKLY WESTWARD TO WEST-NORTHWESTWARD. A WEAKNESS IN THE RIDGE IN THE VICINITY OF THE EASTERN GULF OF MEXICO AND THE FLORIDA PENINSULA SHOULD RESULT IN CHANTAL...OR ITS REMNANT...TURNING TOWARD THE NORTHWEST AND NORTH OVER THE NEXT FEW DAYS. SINCE THE INITIAL POSITION HAS BEEN SHIFTED SUBSTANTIALLY WESTWARD IN COMPARISON TO THE PREVIOUS ADVISORY... THIS NECESSITATES A LARGE WESTWARD SHIFT TO THE NHC FORECAST TRACK. NONETHELESS...THE NEW OFFICIAL FORECAST IS STILL ON THE EASTERN SIDE OF THE TRACK MODEL GUIDANCE SUITE. SINCE THE CYCLONE MAY BE OPENING UP INTO A WAVE...ADVISORIES MAY BE DISCONTINUED LATER TODAY. FORECAST POSITIONS AND MAX WINDS INIT 10/0900Z 16.5N 69.5W 40 KT 45 MPH 12H 10/1800Z 17.8N 72.3W 35 KT 40 MPH 24H 11/0600Z 19.5N 75.7W 30 KT 35 MPH 36H 11/1800Z 21.5N 78.5W 30 KT 35 MPH...INLAND 48H 12/0600Z 23.8N 79.5W 30 KT 35 MPH 72H 13/0600Z 27.5N 80.0W 30 KT 35 MPH 96H 14/0600Z 31.0N 81.0W 35 KT 40 MPH 120H 15/0600Z 32.5N 82.0W 25 KT 30 MPH...INLAND $$ FORECASTER PASCH/BLAKE NNNN