ZCZC MIATCDAT2 ALL TTAA00 KNHC DDHHMM TROPICAL DEPRESSION SEVENTEEN DISCUSSION NUMBER 2 NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011 1100 AM EDT SAT SEP 24 2011 AFTER AN EARLIER INCREASE IN DEEP CONVECTION AND BANDING FEATURES...THE CONVECTIVE ORGANIZATION OF THE DEPRESSION HAS DECREASED A LITTLE SINCE THE 12Z FIXES. INTENSITY ESTIMATES ARE T2.8/41 KT FROM UW-CIMSS ADT...T2.5/35 KT FROM TAFB...AND T1.5/25 KT FROM SAB. HOWEVER...THE CURVED BAND TO THE NORTH OF CENTER HAS FRACTURED AND DEGENERATED AND THE ADT ESTIMATES ARE BASED ON AN UNREPRESENTATIVE SHEAR PATTERN. AS A RESULT...THE INITIAL INTENSITY WILL REMAIN AT 30 KT FOR THIS ADVISORY...WHICH IS CONSISTENT WITH SEVERAL 30-KT WIND VECTORS NOTED IN A 1058Z ASCAT OVERPASS. THE INITIAL MOTION ESTIMATE IS 285/14. THE CYCLONE IS EXPECTED TO MOVE IN A GENERAL WEST-NORTHWESTWARD MOTION FOR THE NEXT 3 DAYS OR SO UNDER THE INFLUENCE OF A STRONG SUBTROPICAL RIDGE ORIENTED EAST-WEST ALONG 20N LATITUDE. HOWEVER...BY 72 HOURS A BREAK IN THE RIDGE IS FORECAST TO DEVELOP BETWEEN 40-45W LONGITUDE AS A BROAD LOW PRESSURE TROUGH DIGS SOUTHEASTWARD OVER THE EASTERN ATLANTIC. THIS SHOULD RESULT IN THE CYCLONE SLOWING DOWN AND TURNING TOWARD THE NORTHWEST INTO THE WEAKNESS. THE OFFICIAL FORECAST IS JUST AN EXTENSION OF THE PREVIOUS ADVISORY TRACK AND LIES CLOSE TO THE CONSENSUS MODELS TVCN AND TVCA. ENVIRONMENTAL CONDITIONS WILL BE MAXIMIZED DURING THE NEXT 48 HOURS OR SO FOR INTENSIFICATION TO OCCUR OVER THE NEXT COUPLE OF DAYS. AFTER THAT...VERTICAL SHEAR IS EXPECTED TO INCREASE...ALBEIT TO ONLY ABOUT 15 KT...FROM THE SOUTHWEST AHEAD OF THE AFOREMENTIONED MID/UPPER-LEVEL TROUGH. THIS IS EXPECTED TO RESULT IN A SLOWER RATE OF INTENSIFICATION. THE OFFICIAL INTENSITY FORECAST REMAINS ON THE CONSERVATIVE SIDE OF THE INTENSITY GUIDANCE ENVELOPE AND FOLLOWS A BLEND OF THE SHIPS AND LGEM MODELS. FORECAST POSITIONS AND MAX WINDS INIT 24/1500Z 11.0N 26.7W 30 KT 35 MPH 12H 25/0000Z 11.4N 28.3W 35 KT 40 MPH 24H 25/1200Z 12.2N 30.5W 40 KT 45 MPH 36H 26/0000Z 13.2N 32.3W 50 KT 60 MPH 48H 26/1200Z 14.2N 33.8W 60 KT 70 MPH 72H 27/1200Z 16.4N 36.1W 60 KT 70 MPH 96H 28/1200Z 18.4N 38.1W 55 KT 65 MPH 120H 29/1200Z 20.5N 39.5W 50 KT 60 MPH $$ FORECASTER STEWART NNNN
Alternate Formats
About Alternates -
E-Mail Advisories -
RSS Feeds
Cyclone Forecasts
Latest Advisory -
Past Advisories -
About Advisories
Marine Forecasts
Latest Products -
About Marine Products
Tools & Data
Satellite Imagery -
US Weather Radar -
Aircraft Recon -
Local Data Archive -
Forecast Verification -
Deadliest/Costliest/Most Intense
Learn About Hurricanes
Storm Names
Wind Scale -
Prepare -
Climatology -
NHC Glossary -
NHC Acronyms -
Frequently Asked Questions -
AOML Hurricane-Research Division
About Us
About NHC -
Mission/Vision -
Other NCEP Centers -
NHC Staff -
Visitor Information -
NHC Library
NOAA/
National Weather Service
National Centers for Environmental Prediction
National Hurricane Center
11691 SW 17th Street
Miami, Florida, 33165-2149 USA
nhcwebmaster@noaa.gov
Disclaimer
Privacy Policy
Credits
About Us
Glossary
Career Opportunities
Page last modified: Tuesday, 17-Jul-2012 13:44:08 UTC