ZCZC MIATCDAT5 ALL TTAA00 KNHC DDHHMM TROPICAL STORM DANNY DISCUSSION NUMBER 6 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL052009 500 PM EDT THU AUG 27 2009 REPORTS FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATE THAT THE CIRCULATION OF DANNY HAS BECOME BETTER DEFINED TODAY... WITH STRONGER WINDS IN THE PREVIOUSLY WEAK SOUTHWESTERN QUADRANT. ASIDE FROM THAT...THE CYCLONE REMAINS VERY DISORGANIZED. THE MAIN CONVECTION IS IN A LINE 130-170 N MI EAST THROUGH SOUTH OF THE CENTER...AND THE STRONGEST WINDS ARE 100 N MI OR MORE FROM THE CENTER OVER THE NORTHERN SEMICIRCLE. THE AIRCRAFT DATA...AS WELL AS DATA FROM THE QUIKSCAT AND ASCAT SCATTEROMETERS...SUGGEST THAT THE MAXIMUM WINDS HAVE DECREASED TO 40-45 KT. THE INITIAL INTENSITY WILL BE REDUCED TO 45 KT. THE CENTER HAS MOVED SLOWLY WESTWARD SINCE SUNRISE...WITH THE INITIAL MOTION ESTIMATED AT 270/2. THE TRACK GUIDANCE MODELS REMAIN IN EXCELLENT AGREEMENT THAT DANNY SHOULD TURN NORTHWARD OVER THE NEXT 24-36 HR IN ADVANCE OF A COMPLEX DEEP-LAYER TROUGH MOVING INTO THE EASTERN UNITED STATES. AFTER THAT...THE STORM SHOULD ACCELERATE NORTHEASTWARD INTO THE WESTERLIES...PASSING NEAR OR OVER CAPE HATTERAS...SOUTHEASTERN NEW ENGLAND...AND THE CANADIAN MARITIMES ON ITS WAY INTO THE NORTH ATLANTIC. WITH THE MORE WESTERLY INITIAL POSITION...THE TRACK GUIDANCE ENVELOPE HAS SHIFTED SOMEWHAT WESTWARD DURING THE FIRST 48 HR...AND THE NEW FORECAST TRACK IS ADJUSTED WESTWARD AS WELL. WHILE THE TRACK IS STILL DOWN THE MIDDLE OF THE GUIDANCE ENVELOPE...THE GFS...UKMET...NOGAPS... AND CANADIAN MODELS ARE ALL TO THE LEFT OF THE NEW TRACK. SOME ADDITIONAL ADJUSTMENT TOWARD THE LEFT...TOWARD THE EAST COAST OF THE U. S....MAY BE REQUIRED IF THIS TREND CONTINUES. DANNY REMAINS IN AN AREA OF UPPER-LEVEL CONFLUENT FLOW ASSOCIATED WITH THE PERSISTENT CYCLONIC SHEAR AXIS SEEN IN WATER VAPOR IMAGERY. IN ADDITION...BOTH WATER VAPOR IMAGERY AND SSM/IS TOTAL PRECIPITABLE WATER IMAGERY SUGGEST THAT THE ENVIRONMENT NEAR DANNY IS DRY. THESE FACTORS...COMBINED WITH THE CURRENT LACK OF ORGANIZATION...SUGGESTS THAT STRENGTHENING WILL BE SLOW AT BEST DURING THE NEXT 24 HR. THERE IS A WINDOW OF OPPORTUNITY FOR DANNY TO STRENGTHEN FROM 24-36 HR AS IT IS FORECAST TO MOVE UNDER AN UPPER-LEVEL ANTICYCLONE. AFTER THAT...IT WILL ENCOUNTER STRONG SOUTHWESTERLY FLOW ASSOCIATED WITH THE DEEP-LAYER TROUGH...WHICH SHOULD CAUSE WEAKENING AND EXTRATROPICAL TRANSITION. THE NEW INTENSITY FORECAST CALLS FOR DANNY TO NOT REACH HURRICANE STRENGTH...WITH A PEAK INTENSITY OF 60 KT IN 48 HR. IT SHOULD BE NOTED THAT THE GFDL AND HWRF STILL FORECAST DANNY TO BECOME A HURRICANE BY 36 HR. FORECAST POSITIONS AND MAX WINDS INITIAL 27/2100Z 27.5N 73.5W 45 KT 12HR VT 28/0600Z 28.5N 74.7W 45 KT 24HR VT 28/1800Z 30.7N 75.0W 50 KT 36HR VT 29/0600Z 34.4N 74.1W 55 KT 48HR VT 29/1800Z 38.8N 71.6W 60 KT 72HR VT 30/1800Z 46.5N 61.5W 50 KT...EXTRATROPICAL 96HR VT 31/1800Z 50.0N 49.0W 40 KT...EXTRATROPICAL 120HR VT 01/1800Z 51.0N 32.0W 35 KT...EXTRATROPICAL $$ 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 12:09:08 UTC