|
Show Selection: |
| #37600 (Received by flhurricane at: 5:03 AM 05.Aug.2005) TCDAT4 TROPICAL DEPRESSION NINE DISCUSSION NUMBER 3 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 AM EDT FRI AUG 05 2005 THE CENTER OF TD-9 REMAINS DIFFICULT TO LOCATE. THE BEST ESTIMATE OF THE POSITION IS ABOUT 60 NMI NORTH OF THE PREVIOUS POSITIONS AND FORECAST TRACKS BASED ON MICROWAVE AND NIGHTIME VISIBLE SATELLITE IMAGERY. A 05/0411Z AQUA OVERPASS CLEARLY INDICATED THE BROAD CIRCULATION WAS BETWEEN 14N AND 15N LATITUDE. A MORE SOUTHERLY POSITION CLOSER TO 14N WAS CHOSEN SINCE THIS WOULD BE CLOSER TO THE DEEP CONVECTION. HOWEVER...IT IS POSSIBLE THAT THE CENTER MAY HAVE TO BE ADJUSTED FARTHER NORTH ONCE VISIBLE IMAGERY IS AVAILABLE. THE INITIAL MOTION ESTIMATE IS AN UNCERTAIN 295/11...BASED ON THE OVERALL MOTION OF THE LARGE CIRCULATION ENVELOPE. TD-9 IS CURRENTLY MOVING TOWARD A WEAKNESS IN THE BERMUDA RIDGE THAT IS BEING CREATED BY AN UPPER-LEVEL LOW NEAR 29N 42W...AND AN ASSOCIATED TROUGH EXTENDING SOUTHWARD. MOST OF THE GLOBAL MODELS AGREE THAT THE WEAKNESS WILL SLOWLY FILL IN AS THE LOW WEAKENS... WHICH WILL ACT TO FORCE THE TROPICAL CYCLONE ON A MORE WESTWARD TRACK AFTER 36 HOURS. IN THE DAY 4 AND 5 TIME PERIODS...THE MODELS DIFFER SIGNIFICANTLY WITH THE UKMET...NOGAPS...CANADIAN...AND ECMWF MODELS TURNING THE CYCLONE NORTHWESTWARD TOWARD ANOTHER DEVELOPING WEAKNESS IN THE RIDGE...WHEREAS THE GFS AND GFDL MOVE THE STORM MORE WESTWARD. GIVEN THE HIGH ZONAL FLOW FORECAST TO PERSIST ACROSS THE U.S. AND NORTH ATLANTIC...THE OFFICIAL FORECAST LEANS MORE TOWARD THE GFS AND GFDL SOLUTIONS. ALTHOUGH THE VERTICAL SHEAR IS FORECAST TO REMAIN LOW...LESS THAN 5 KT...THE HIGHER LATITUDE INITIAL POSITION AND FORECAST TRACK KEEPS THE CYCLONE OVER COOLER SSTS UNTIL 72 HOURS. AFTERWARDS. GRADUALLY INCREASING SSTS ABOVE 28C SHOULD ALLOW FOR SOME SIGNIFICANT STRENGTHENING TO OCCUR.ON. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 05/0900Z 14.4N 36.1W 25 KT 12HR VT 05/1800Z 15.1N 37.5W 30 KT 24HR VT 06/0600Z 15.9N 39.5W 35 KT 36HR VT 06/1800Z 16.7N 41.6W 40 KT 48HR VT 07/0600Z 17.7N 44.4W 45 KT 72HR VT 08/0600Z 19.0N 48.6W 55 KT 96HR VT 09/0600Z 20.5N 53.5W 65 KT 120HR VT 10/0600Z 22.0N 58.5W 75 KT |
