ZCZC MIATCDEP1 ALL TTAA00 KNHC DDHHMM TROPICAL STORM MARTY DISCUSSION NUMBER 8 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP162009 800 PM PDT THU SEP 17 2009 ANALYSES FROM CIMSS AT THE UNIVERSITY OF WISCONSIN INDICATE THAT MARTY IS EXPERIENCING 10-15 KT OF SOUTHERLY VERTICAL WIND SHEAR THIS EVENING. THIS IS CAUSING THE CYCLONE TO HAVE A SOMEWHAT RAGGED APPEARANCE EVEN THOUGH THE CLOUD TOPS OF THE CENTRAL CONVECTION ARE COLDER THAN -80C. THE INITIAL INTENSITY REMAINS 40 KT FOR THIS ADVISORY...WHICH IS IN AGREEMENT WITH AN AMSU INTENSITY ESTIMATE AT 17/2031 UTC AND SLIGHTLY ABOVE THE SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB. THE FORECAST TRACK TAKES MARTY OVER GRADUALLY DECREASING SEA SURFACE TEMPERATURES AND INTO AN AREA OF STRONG SOUTHWESTERLY SHEAR. IN ADDITION...TOTAL PRECIPITABLE WATER DATA SHOWS VERY DRY AIR NOT FAR TO THE WEST OF THE STORM. THIS COMBINATION SHOULD CAUSE MARTY TO WEAKEN DURING THE PERIOD...AND THE INTENSITY FORECAST CALLS FOR IT TO DECAY TO A REMNANT LOW IN ABOUT 48 HR IN AGREEMENT WITH THE PREVIOUS FORECAST. MOST OF THE GLOBAL MODELS SHOW THE REMNANT LOW BREAKING OPEN INTO A TROUGH BEFORE 96 HR...SO THE NEW 96 HR FORECAST CALLS FOR DISSIPATION. MARTY IS CURRENTLY IN AN AREA OF LIGHT STEERING CURRENTS BETWEEN A MID/UPPER-LEVEL RIDGE OVER MEXICO AND A SECOND MID/UPPER-LEVEL RIDGE WEST OF THE CYCLONE. THE DYNAMICAL MODELS FORECAST THE RIDGE OVER MEXICO TO STEER MARTY SLOWLY TOWARD THE NORTHWEST FOR THE NEXT 24-36 HR. AFTER THAT TIME...MARTY SHOULD GRADUALLY TURN WESTWARD AS THE SYSTEM WEAKENS AND A LOW-LEVEL RIDGE TO THE NORTHWEST BECOMES THE MAIN INFLUENCE ON THE MOTION. THE NEW FORECAST TRACK IS AN UPDATE OF THE PREVIOUS TRACK. FORECAST POSITIONS AND MAX WINDS INITIAL 18/0300Z 20.0N 113.6W 40 KT 12HR VT 18/1200Z 20.5N 114.2W 35 KT 24HR VT 19/0000Z 21.4N 115.2W 35 KT 36HR VT 19/1200Z 22.2N 116.2W 30 KT 48HR VT 20/0000Z 22.6N 117.4W 25 KT...REMNANT LOW 72HR VT 21/0000Z 22.5N 119.5W 20 KT...REMNANT LOW 96HR VT 22/0000Z...DISSIPATED $$ FORECASTER BEVEN 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: Thursday, 31-Dec-2009 12:09:28 UTC