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#58321 (Received by flhurricane at: 3:40 PM 24.Nov.2005) TCDAT3 TROPICAL STORM DELTA DISCUSSION NUMBER 5 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 4 PM EST THU NOV 24 2005 THE EYE FEATURE MENTIONED IN THE PREVIOUS ADVISORY HAS BECOME RAGGED AND LESS DISTINCT DURING THE PAST FEW HOURS. WHILE IT IS POSSIBLE THAT DELTA MAY HAVE BRIEFLY REACHED HURRICANE STRENGTH BETWEEN 14-16Z WHEN THE EYE WAS BEST DEFINED...THE INITIAL INTENSITY WILL REMAIN AT 60 KT FOR THIS ADVISORY BASED ON A SATELLITE INTENSITY ESTIMATE OF T3.5/55 KT FROM TAFB/SAB AND A 1638Z UW-CIMSS INTENSITY ESTIMATE OF 978 MB AND 72 KT. WHILE THE AMSU WIND ESTIMATE IS PROBABLY TOO HIGH FOR A HYBRID-TYPE TROPICAL CYCLONE LIKE DELTA... THE CENTRAL PRESSURE HAS ESSENTIALLY REMAINED UNCHANGED SINCE 0519Z... SUGGESTING THAT DELTA HAS NOT STRENGTHENED MUCH... IF ANY... SINCE THEN. A QUIKSCAT OVERPASS AT 2048Z MAY PROVIDE SOME QUANTITATIVE WIND INFORMATION TO HELP SETTLE THIS QUESTION. THE INITIAL MOTION ESTIMATE IS STATIONARY...ALTHOUGH THE CYCLONE MAY BE DRIFTING SLOWLY SOUTHWARD AT LESS AT 1 KT. THERE REMAINS ESSENTIALLY NO CHANGE TO THE PREVIOUS FORECAST TRACK OR REASONING. ALL OF THE NHC MODELS...EXCEPT FOR THE UKMET MODEL... NOW DRIFT DELTA SLOWLY SOUTH OR EASTWARD... BEFORE TURING THE CYCLONE NORTHWARD IN 36-72 HOURS. AFTER THAT... ALL OF THE MODELS EXCEPT NOGAPS AND THE GFDN TAKE DELTA NORTH-NORTHEAST OR NORTHEASTWARD THROUGH 72 HOURS. NOGAPS SHOWS SOME BINARY INTERACTION OCCURRING WITH AN EXTRATROPICAL LOW THAT IS FORECAST TO DEVELOP TO THE WEST OF DELTA BY 96 HOURS. THE OFFICIAL FORECAST TRACK REFLECTS THIS INTERACTION BY A SLOW TURN TOWARD THE NORTHWEST IN 96-120 HOURS. DELTA HAS REMAINED BENEATH AN UPPER-LEVEL SHEAR AXIS WHERE THE VERTICAL SHEAR IS THE LEAST. HOWEVER... CIRRUS CLOUD MOTIONS SUGGEST THAT A SMALL UPPER-LEVEL LOW MAY HAVE SLID OVER THE TOP OF DELTA... WHICH HAS HELPED TO SUPPRESS THE ANTICYCLONIC OUTFLOW. WHILE THE EYE FEATURE IS LESS DISTINCT THAN EARLIER... CONVECTION HAS ACTUALLY INCREASED SLIGHTLY AROUND THE CENTER... SO THERE IS STILL SOME OPPORTUNITY FOR DELTA TO BRIEFLY STRENGTHEN BEFORE SIGNIFICANT WESTERLY SHEAR INDUCES SLOW WEAKENING BY 36-48 HOURS. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 24/2100Z 24.6N 38.9W 60 KT 12HR VT 25/0600Z 25.0N 38.7W 65 KT 24HR VT 25/1800Z 25.5N 38.8W 60 KT 36HR VT 26/0600Z 26.2N 38.9W 60 KT 48HR VT 26/1800Z 27.1N 39.0W 55 KT 72HR VT 27/1800Z 29.5N 39.5W 55 KT...BECOMING EXTRATROPICAL 96HR VT 28/1800Z 32.0N 40.0W 50 KT...EXTRATROPICAL 120HR VT 29/1800Z 34.0N 41.5W 50 KT...EXTRATROPICAL |