ZCZC MIATCDAT1 ALL TTAA00 KNHC DDHHMM HURRICANE OPHELIA DISCUSSION NUMBER 39 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 PM EDT THU SEP 15 2005 OPHELIA HAS CONTINUED TO BECOME MORE RAGGED LOOKING IN RADAR AND SATELLITE IMAGERY. AN AIR FORCE RESERVE UNIT RECONNAISSANCE AIRCRAFT HAS RECENTLY MEASURED 850 MB FLIGHT-LEVEL WINDS OF 84 KT IN THE NORTHEAST QUADRANT AND 79 KT IN THE SOUTHEAST QUADRANT. THESE WIND VALUES ROUGHLY EQUAL 67 AND 63 KT...RESPECTIVELY. THE CENTRAL PRESSURE HAS ALSO INCREASED TO 987 MB. THEREFORE...THE INITIAL INTENSITY HAS BEEN DECREASED TO 65 KT...JUST ENOUGH TO KEEP OPHELIA AS A HURRICANE. THE INITIAL MOTION ESTIMATE IS AN UNCERTAIN 060/03. DURING THE PAST 6 HOURS...OPHELIA HAS BRIEFLY STALLED...MADE A SMALL CLOCKWISE LOOP...AND NOW APPEARS TO BE DRIFTING EASTWARD. HOWEVER...WITH RIDGING PERSISTING TO THE SOUTH AND EAST OF OPHELIA...THE HURRICANE SHOULD MOVE MORE NORTHWARD THAN EASTWARD DURING THE NEXT 12 HOURS. BEYOND THAT...THE MODELS ARE IN GENERAL AGREEMENT ON A SHORTWAVE TROUGH OVER THE CENTRAL U.S. TO CONTINUE MOVING EASTWARD AND GRADUALLY LIFT OUT OPHELIA TO THE NORTHEAST. THE 12Z GFDL...UKMET ...NOGAPS... AND CANADIAN MODELS HAVE MADE A SLIGHT WESTWARD SHIFT OVER OR NEAR SOUTHEASTERN MASSACHUSETTS...WHILE THE GFS MODEL DID NOT CHANGE AT ALL AND KEEPS OPHELIA WELL OFFSHORE OF THE NORTHEASTERN U.S. COAST. A CLOSER LOOK AT ALL OF THE MODEL FIELDS INDICATES THE MID-LEVEL CIRCULATION CENTERS ALSO REMAIN OFFSHORE SIMILAR TO THE GFS SURFACE AND UPPER-LEVEL CIRCULATIONS. GIVEN THAT OPHELIA IS A LARGE CIRCULATION AND SHOULD...THEREFORE... REMAIN MORE VERTICALLY STACKED...THE OFFICIAL FORECAST TRACK IS NEAR THE EASTERN PORTION OF THE NHC MODEL GUIDANCE ENVELOPE AND CLOSE TO THE GFS MODEL AND THE PREVIOUS FORECAST TRACK. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO REMAIN UNFAVORABLE FOR ANY INTENSIFICATION TO OCCUR. THE BIG QUESTIONS ARE HOW FAST WILL OPHELIA WEAKEN AND WHEN WILL EXTRATROPICAL TRANSITION OCCUR. OPHELIA IS EXPECTED TO REMAIN CLOSE ENOUGH TO THE WARMER GULFSTREAM TO AT LEAST KEEP SOME DEEP CONVECTION GOING IN THE EASTERN SEMICIRCLE FOR THE NEXT 24 HOURS. HOWEVER...ONCE OPHELIA REACHES ABOUT 40N LATITUDE WHERE THE OCEAN TEMPERATURES DECREASE SIGNIFICANTLY...THEN TRANSITION OVER TO A FORMIDABLE EXTRATROPICAL LOW PRESSURE SYSTEM SHOULD BEGIN. HOWEVER...DUE TO THE UNCERTAINTY ON EXACTLY WHEN THIS PHASE CHANGE WILL OCCUR...A TROPICAL STORM WATCH HAS BEEN ISSUED FOR SOUTHEASTERN MASSACHUSETTS. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 15/2100Z 34.8N 75.6W 65 KT 12HR VT 16/0600Z 35.1N 75.1W 65 KT 24HR VT 16/1800Z 36.4N 74.1W 65 KT 36HR VT 17/0600Z 38.7N 71.6W 60 KT...BECOMING EXTRATROPICAL 48HR VT 17/1800Z 41.7N 67.7W 55 KT...EXTRATROPICAL 72HR VT 18/1800Z 46.5N 58.0W 50 KT...EXTRATROPICAL 96HR VT 19/1800Z 49.5N 47.0W 45 KT...EXTRATROPICAL 120HR VT 20/1800Z 53.0N 27.0W 45 KT...EXTRATROPICAL $$ 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, 15-Sep-2005 21:10:09 UTC