|
Show Selection: |
| #5663 (Received by flhurricane at: 4:58 AM 19.Aug.2004) TCDAT4 TROPICAL STORM DANIELLE DISCUSSION NUMBER 24 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 AM EDT THU AUG 19 2004 DANIELLE REMAINS STRONGLY SHEARED...BUT THE CYCLONE HAS CONTINUED TO DEVELOP DEEP CONVECTION IN THE NORTHEAST QUADRANT. THE INITIAL INTENSITY IS A BLEND OF DVORAK T-NUMBERS OF T2.5...OR 35 KT AND A DVORAK CURRENT INTENSITY ESTIMATE OF T3.0...OR 45 KT...FROM ALL THREE SATELLITE AGENCIES. THIS IS ALSO CONSISTENT WITH AN EARLIER QUIKSCAT OVERPASS SHOWING 40 KT UNCONTAMINATED WINDS. THE INITIAL MOTION ESTIMATE IS 040/04. DANIELLE HAS MADE SOME LARGE WOBBLES IN THE TRACK OVER THE PAST 12 HOURS...BUT THE GENERAL MOTION HAS BEEN TOWARD THE NORTHEAST...ALBEIT AT A MUCH SLOWER FORWARD SPEED. DANIELLE IS EXPECTED TO REMAIN UNDER THE INFLUENCE OF MID- TO UPPER-LEVEL SOUTHWESTERLY OR EVEN WESTERLY SHEAR THROUGHOUT THE FORECAST PERIOD SINCE THE CYCLONE WILL BE PUSHING INTO A STRONG LOW-LEVEL RIDGE/SURFACE HIGH PRESSURE AREA LOCATED TO THE NORTHEAST. THE FORECAST TRACK HINGES UPON THE ASSUMPTION THAT DANIELLE WILL CONTINUE TO GENERATE INTERMITTENT DEEP CONVECTION TO MAINTAIN THE VERTICAL CIRCULATION. HOWEVER...IF THE CONVECTION WEAKENS SIGNIFICANTLY OR DISSIPATES...THEN DANIELLE WILL RAPIDLY SPIN DOWN AND POSSIBLY BECOME STATIONARY OR EVEN MOVE BACK TO THE WEST OR SOUTHWEST LIKE THE NOGAPS...GFS...AND GFDN MODELS ARE INDICATING. HOWEVER...IF THE LATTER SCENARIO SHOULD HAPPEN...THEN DANIELLE WOULD NOT REMAIN A TROPICAL CYCLONE FOR MORE THAN 24 HOURS ...IF THAT. THE FORECAST TRACK IS SIMILAR TO THE PREVIOUS TRACK. DANIELLE IS EXPECTED TO REMAIN OVER 25-26C SEA SURFACE TEMPERATURES THROUGH 48 HOURS OR SO...WHICH WOULD GENERALLY ALLOW FOR AT LEAST INTERMITTENT DEEP CONVECTION TO DEVELOP AND KEEP DANIELLE ALIVE. BY 72 HOURS...ASSUMING DANIELLE IS STILL A TROPICAL CYCLONE... INTERACTION WITH A FRONTAL SYSTEM AND A STRONG MID-LEVEL SHORTWAVE TROUGH APPROACHING FROM THE WEST AND NORTHWEST IS EXPECTED TO BRING ABOUT EXTRATROPICAL TRANSITION...OR POSSIBLY EVEN ABSORPTION INTO A LARGER EXTRATROPICAL CYCLONE. THE SHIPS MODEL WAS FOLLOWED CLOSELY. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 19/0900Z 30.0N 37.5W 40 KT 12HR VT 19/1800Z 30.4N 37.0W 35 KT 24HR VT 20/0600Z 31.1N 36.2W 30 KT 36HR VT 20/1800Z 32.0N 35.0W 25 KT 48HR VT 21/0600Z 32.9N 33.6W 25 KT...BECOMING EXTRATROPICAL 72HR VT 22/0600Z 34.5N 30.5W 25 KT...EXTRATROPICAL 96HR VT 23/0600Z 36.5N 28.0W 25 KT...EXTRATROPICAL 120HR VT 24/0600Z...ABSORBED BY EXTRATROPICAL LOW |
