ZCZC MIATCDAT1 ALL TTAA00 KNHC DDHHMM TROPICAL DEPRESSION SIX DISCUSSION NUMBER 8 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 AM EDT MON JUL 21 2003 THE LOW LEVEL CENTER IS NOT WELL DEFINED. THE INITIAL MOTION ESTIMATE IS 280/20 BASED MAINLY ON CONTINUITY. THE GFS AND OTHER DYNAMICAL MODELS SHOW A WEAKNESS IN THE SUBTROPICAL RIDGE IN THE VICINITY OF FLORIDA. A SHORT WAVE TROUGH IS FORECAST TO AMPLIFY THIS WEAKNESS AND SHIFT IT A LITTLE WESTWARD. THE UKMET HAS THE WEAKNESS MOVING MUCH FURTHER EAST THAN THE GFS AND THIS RESULTS IN THE UKMET MOVING THE SYSTEM NORTHWARD JUST EAST OF FLORIDA BY DAY 4. THE GFS LOSES THE CIRCULATION AFTER DAY 3 BUT SUGGESTS A TRACK MUCH FURTHER SOUTH AND WEST. THE NOGAPS IS IN BETWEEN WITH A TRACK TO THE NORTHEAST GULF OF MEXICO BY DAY 5. THE OFFICIAL FORECAST IS A COMPROMISE INTO THE EASTERN GULF BY DAY 5 AND IS SIMILAR TO THE PREVIOUS ADVISORY FORECAST. SO THERE IS A RATHER LARGE UNCERTAINTY ABOUT THE TRACK AFTER DAY 3. RECENT SATELLITE IMAGERY SHOWS A NOT VERY IMPRESSIVE CONVECTIVE PATTERN TO GO ALONG WITH THE POORLY DEFINED CENTER. AN AIRCRAFT WILL INVESTIGATE THIS AFTERNOON TO DETERMINE THE EXACT LOCATION AND INTENSITY. A RECENT QUIKSCAT SHOWS WINDS NEAR 45 KNOTS BUT THE INTENSITY WILL BE KEPT AT 30 KNOTS UNTIL RECONNAISSANCE DATA CONFIRMS THE WIND SPEED. MEANWHILE WATCHES AND WARNINGS ARE IN PLACE FOR MOST OF THE CENTRAL LESSER ANTILLES IN THE EVENT THAT THE WINDS ARE ACTUALLY ABOVE STORM STRENGTH. EXCEPT FOR THE PURE STATISTICAL SHIFOR MODEL WHICH HAS 80 KNOTS ON DAY 5...NONE OF THE OTHER GUIDANCE FORECASTS MORE THAN ABOUT 50 KNOTS WITH A FAIR AMOUNT OF VERTICAL SHEAR ANTICIPATED THROUGH DAY 5. THE OFFICIAL WIND SPEED FORECAST GOES TO 55 KNOTS AT DAY 3 THROUGH 5 WHICH IS A LITTLE LESS THAN THE PREVIOUS ADVISORY. FAST MOVING SYSTEMS SUCH AS THIS ONE ARE A CHALLENGE IN THAT THERE MAY NOT BE A CLOSED SURFACE CIRCULATION AND YET THE WINDS CAN BE TROPICAL STORM FORCE. THIS WAS THE CASE WITH CLAUDETTE MOVING THROUGH THE ISLANDS AND MAY BE THE CASE WITH THIS DEPRESSION. FORECASTER LAWRENCE FORECAST POSITIONS AND MAX WINDS INITIAL 21/1500Z 14.2N 58.8W 30 KT 12HR VT 22/0000Z 14.8N 62.0W 35 KT 24HR VT 22/1200Z 15.9N 66.4W 40 KT 36HR VT 23/0000Z 17.3N 70.1W 45 KT 48HR VT 23/1200Z 19.0N 74.0W 50 KT 72HR VT 24/1200Z 22.0N 80.0W 55 KT 96HR VT 25/1200Z 25.0N 84.0W 55 KT 120HR VT 26/1200Z 28.0N 86.0W 55 KT 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: Monday, 07-Feb-2005 16:49:56 UTC