Chantal has weakened overnight. Wind speed has reduced to 45mph. NHC forecasts a much weaker system heading towards the Bahamas and Florida.

WTNT43 KNHC 100837
TCDAT3

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