ZCZC MIATCDAT4 ALL TTAA00 KNHC DDHHMM TROPICAL DEPRESSION NINE DISCUSSION NUMBER 6 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 PM EDT FRI AUG 05 2005 TROPICAL DEPRESSION NINE HAS A LARGE AND WELL-DEFINED SWIRL OF LOW CLOUDS THIS EVENING...BUT THERE IS NO ORGANIZED CONVECTION NEAR THE CENTER AT THIS TIME. THE CYCLONE IS OVER 26C-27C SEA SURFACE TEMPERATURES...AND THE WEST-NORTHWESTWARD MOTION HAS TAKEN IT INTO AN AREA OF WESTERLY VERTICAL SHEAR. THIS COMBINATION HAS INTERRUPTED DEVELOPMENT. THE INITIAL INTENSITY IS REMAINS 25 KT BASED ON SATELLITE INTENSITY ESTIMATES...ALONG WITH QUIKSCAT AND SSM/I WINDS. THE INITIAL MOTION IS 295/17. THE DEPRESSION IS SOUTH OF A LOW/ MID-LEVEL RIDGE OVER THE EASTERN ATLANTIC. OBSERVATIONS AND LARGE-SCALE MODEL ANALYSES SHOW A WEAKNESS IN THIS RIDGE BETWEEN 50W-60W PARTLY ASSOCIATED WITH TROPICAL STORM HARVEY...AND THIS WEAKNESS WILL NOT COMPLETELY FILL DURING THE NEXT FIVE DAYS. IN RESPONSE...THE CYCLONE SHOULD MOVE GENERALLY WEST-NORTHWESTWARD WITH SOME SLOWING FOR ABOUT 72 HR...AND THEN POSSIBLY TURN NORTHWESTWARD. THE TRACK FORECAST GUIDANCE AGREES ON THE FIRST 2-3 DAYS OF MOTION AND THEN DIVERGES. THE UKMET AND THE BAM MODELS CALL FOR A CONTINUED WEST-NORTHWESTWARD MOTION AT 96-120 HR...WHILE THE NOGAPS...LBAR...AND GFS ENSEMBLE MEAN CALL FOR A TURN TOWARD THE NORTH. THE OFFICIAL FORECAST WILL COMPROMISE BETWEEN THESE EXTREMES...CALLING FOR A GRADUAL NORTHWESTWARD TURN IN BEST AGREEMENT WITH THE CONSENSUS MODEL CONU. THE FORECAST AFTER 72 HR IS ALSO SLOWER THAN EARLIER IN LIGHT OF THE GUIDANCE SPREAD. WATER VAPOR IMAGERY SHOWS A STRONG UPPER-LEVEL LOW NEAR 27N42W WITH A TROUGH EXTENDING TO NEAR 19N44W. THIS SYSTEM HAS CREATED WESTERLY UPPER-LEVEL FLOW OVER THE DEPRESSION. LARGE-SCALE MODELS SUGGEST A SHEARING ENVIRONMENT COULD CONTINUE FOR 2-3 DAYS AS A SERIES OF UPPER-LEVEL SHORTWAVE TROUGHS PASS NEAR OR NORTH OF THE DEPRESSION. THE SHIPS MODEL SLOWLY STRENGTHENS THE SYSTEM DESPITE THE SHEAR AS IT MOVES GRADUALLY OVER WARMER SEA SURFACE TEMPERATURES...AND THE INTENSITY FORECAST FOLLOWS THAT GUIDANCE. HOWEVER...THERE IS A CHANCE THAT THE SYSTEM COULD DISSIPATE OR DEGENERATE INTO A LOW PRESSURE AREA BEFORE CONDITIONS BECOME MORE FAVORABLE....AS FORECAST BY THE GFDL AND GFS MODELS. FORECASTER BEVEN FORECAST POSITIONS AND MAX WINDS INITIAL 06/0300Z 17.6N 40.6W 25 KT 12HR VT 06/1200Z 18.5N 42.6W 25 KT 24HR VT 07/0000Z 19.6N 44.9W 25 KT 36HR VT 07/1200Z 20.6N 46.9W 30 KT 48HR VT 08/0000Z 21.7N 49.0W 30 KT 72HR VT 09/0000Z 23.5N 52.5W 35 KT 96HR VT 10/0000Z 25.0N 55.0W 40 KT 120HR VT 11/0000Z 27.5N 56.5W 45 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: Saturday, 06-Aug-2005 02:40:05 UTC