|
Show Selection: |
| #9077 (Received by flhurricane at: 11:00 PM 17.Sep.2004) TCDAT1 TROPICAL STORM JEANNE DISCUSSION NUMBER 18 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 PM EDT FRI SEP 17 2004 A USAF RESERVE UNIT AIRCRAFT LOCATED THE CENTER JUST OFFSHORE FROM HISPANIOLA WITH A 1000 MB CENTRAL PRESSURE AND A MAXIMUM 1500 FOOT FLIGHT LEVEL WIND OF 55 KT ABOUT 10 NMI NORTH OF THE CENTER. INFRARED SATELLITE IMAGES SHOW THE VERY SMALL AND EXPOSED LOW LEVEL CIRCULATION CENTER WITH THE DEEP CONVECTION ON THE EAST SIDE. THE WESTERLY SHEAR APPEARS TO BE AROUND 5 TO 10 KTS BASED UPON THE LATEST UW CIMSS ANALYSIS. BASED ON THIS...AND SATELLITE INTENSITY ESTIMATES OF 55 KTS...JEANNE IS UPGRADED BACK TO A TROPICAL STORM WITH A 40 KT WIND MAXIMUM. JEANNE IS VERY SMALL AND THE 34 KT SURFACE WINDS EXTEND OUT ONLY ABOUT 15 NMI FROM THE CENTER IN THE NORTHERN SEMI-CIRCLE. THE INITIAL MOTION ESTIMATE IS 315/05...BUT THE SPEED MAY BE GENEROUS...AS THE LATEST SATELLITE IMAGES SHOW THAT THE SYSTEM MAY BE SLOWING DOWN AGAIN. THE GUIDANCE IS REASONABLY CLUSTERED OUT TO ABOUT 48 HOURS...EXCEPT FOR THE GFS WHICH TAKES THE SYSTEM TOWARD THE NORTHEAST AND THEN...AFTER 3 DAYS...DOES A GRAND LOOP TO THE RIGHT DOWN TO THE SOUTH. THE GFDL FOLLOWS THE GFS SCENARIO BUT ON A MORE MODEST SCALE. ON THE LEFT SIDE WE HAVE THE UKMET AND NOGAPS GOING OFF TO THE WEST OR SOUTHWEST. SINCE THERE IS SO MUCH UNCERTAINTY AT THE LONGER RANGES I HAVE DONE WHAT THE PREVIOUS FORECASTER DID AND MOVED ALONG GUIDANCE CONSENSUS TO THE 3 DAY POSITION AND LEFT IT THERE FOR DAY 4 AND 5. EXACTLY WHAT HAPPENS IS DEPENDENT ON THE EVOLUTION OF THE REMAINS OF IVAN AND THERE IS DISAGREEMENT ON THIS. THE MODEL SPREAD INDICATES INCREASED UNCERTAINTY ASSOCIATED WITH THIS PARTICULAR FORECAST. SURPRISINGLY...THE SHIPS FORECASTS DECREASING SHEAR THROUGH 36 HOURS BUT DOES NOT STRENGTHEN THE SYSTEM. THE OFFICIAL FORECAST FOLLOWS THE SHIPS GUIDANCE AND GRADUALLY INCREASES THE SYSTEM TO 60 KTS IN 4 DAYS. FORECASTER JARVINEN FORECAST POSITIONS AND MAX WINDS INITIAL 18/0300Z 20.4N 72.2W 40 KT 12HR VT 18/1200Z 20.9N 72.9W 40 KT 24HR VT 19/0000Z 22.2N 73.5W 40 KT 36HR VT 19/1200Z 24.3N 73.9W 40 KT 48HR VT 20/0000Z 26.3N 74.0W 45 KT 72HR VT 21/0000Z 29.0N 74.0W 50 KT 96HR VT 22/0000Z 29.0N 74.0W 60 KT 120HR VT 23/0000Z 29.0N 74.0W 60 KT |
