ZCZC MIATCDAT3 ALL TTAA00 KNHC DDHHMM TROPICAL STORM HANNA DISCUSSION NUMBER 24 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082008 500 PM EDT TUE SEP 02 2008 AN AIR FORCE RECONNAISSANCE AIRCRAFT CURRENTLY INVESTIGATING HANNA CONFIRMS THAT THE SYSTEM HAS WEAKENED. THE PEAK FLIGHT-LEVEL WIND AT 850 MB WAS 66 KT WHICH CORRESPONDS TO ABOUT 55 KT AT THE SURFACE. HANNA WILL CONTINUE TO ENCOUNTER STRONG SHEAR FOR ANOTHER 12-24 HOURS WHICH SHOULD LIMIT STRENGTHENING IN THE SHORT TERM. BY TOMORROW...GLOBAL MODELS FORECAST AN UPPER-LEVEL LOW TO CUT OFF JUST WEST OF HANNA AND THEN DROP SOUTHWARD DURING THE NEXT FEW DAYS. IF THIS EVOLUTION MATERIALIZES...AND ASSUMING HANNA IS ABLE TO FIGHT OFF THE SHEAR...THE ENVIRONMENT WOULD GRADUALLY BECOME MORE FAVORABLE FOR STRENGTHENING. THE OFFICIAL INTENSITY FORECAST CALLS FOR HANNA TO REGAIN HURRICANE STRENGTH IN A DAY OR SO...IN LINE WITH NEARLY ALL OF THE AVAILABLE INTENSITY MODELS. HOWEVER...THE EVOLUTION OF THE LARGE-SCALE ENVIRONMENT OVER THE NEXT DAY OR SO IS COMPLEX...WHICH RESULTS IN LOWER THAN NORMAL CONFIDENCE IN THE INTENSITY FORECAST. THE LAST FEW AIRCRAFT FIXES INDICATE THAT HANNA CONTINUES TO DRIFT SOUTHEASTWARD WITH AN INITIAL MOTION ESTIMATE OF 150/02. TRACK MODELS INSIST THAT HANNA WILL START ITS MUCH-ANTICIPATED TURN TOWARD THE NORTHWEST SOON...AS A LARGE MID-LATITUDE TROUGH OVER THE WESTERN ATLANTIC LIFTS NORTHWARD AND THE SUBTROPICAL RIDGE BUILDS BACK IN. SUCH A TRACK WOULD TAKE THE CYCLONE NORTHWESTWARD THROUGH THE CENTRAL AND NORTHWESTERN BAHAMAS DURING THE NEXT TWO DAYS. HANNA IS THEN EXPECTED TO ACCELERATE AS IT MAKES ITS APPROACH TO THE SOUTHEASTERN UNITED STATES. HOWEVER...UNTIL HANNA BEGINS A MORE DEFINITIVE MOTION...IT WILL BE DIFFICULT TO NARROW THE POTENTIAL IMPACT AREA. IN ADDITION...THE ANTICIPATED ANGLE OF APPROACH TO THE SOUTHEAST UNITED STATES COAST MEANS THAN ONLY A SMALL DEVIATION LEFT OR RIGHT OF THE TRACK WILL HAVE LARGE IMPLICATIONS IN BOTH TIME AND LOCATION OF LANDFALL. IN FACT...THE WIND SPEED PROBABILITY PRODUCT INCLUDED WITH THIS ADVISORY PACKAGE SHOWS THAT THE CHANCES OF HURRICANE-FORCE WINDS ARE ABOUT EQUAL AT EACH SPECIFIC LOCATION ALONG THE COAST FROM FLORIDA THROUGH THE CAROLINAS. FORECAST POSITIONS AND MAX WINDS INITIAL 02/2100Z 20.4N 72.7W 55 KT 12HR VT 03/0600Z 20.9N 73.1W 55 KT 24HR VT 03/1800Z 22.2N 74.0W 60 KT 36HR VT 04/0600Z 23.5N 75.5W 65 KT 48HR VT 04/1800Z 25.4N 77.2W 70 KT 72HR VT 05/1800Z 30.5N 80.5W 70 KT 96HR VT 06/1800Z 38.0N 78.0W 30 KT...INLAND 120HR VT 07/1800Z 47.0N 66.0W 25 KT...REMNANT LOW $$ FORECASTER RHOME/KNABB 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, 21-Apr-2009 12:09:17 UTC