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| #39146 (Received by flhurricane at: 4:43 PM 12.Aug.2005) TCDAT4 TROPICAL STORM IRENE DISCUSSION NUMBER 33 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 PM EDT FRI AUG 12 2005 AN AIR FORCE PLANE INVESTIGATING IRENE CONFIRMED EARLIER SATELLITE INTENSITY ESTIMATES AT 1800 UTC. THE RECON MEASURED 64 KNOTS AT FLIGHT LEVEL AND A MINIMUM PRESSURE OF 997 MB. IT ALSO REPORTED A WELL-DEFINED CIRCULATION WITH GOOD RADAR PRESENTATION. BOTH SHEAR AND SST ARE FAVORABLE FOR STRENGTHENING BUT SINCE NO GUIDANCE BRINGS IRENE ABOVE A CATEGORY ONE HURRICANE...ONLY SLIGHT INTENSIFICATION IS INDICATED. IRENE HAS DECREASED ITS FORWARD SPEED AND IS MOVING TOWARD THE NORTHWEST OR 310 DEGREES AT 9 KNOTS. THE CYCLONE HAS BEEN STEERED BY THE FLOW AROUND A STRONG MID-LEVEL SUBTROPICAL RIDGE. AS THE RIDGE MOVES EASTWARD...IRENE SHOULD TURN MORE TOWARD THE NORTH-NORTHWEST AND NORTH AROUND THE RIDGE INTO AN AREA OF LIGHT STEERING CURRENTS. THIS WOULD RESULT IN A SIGNIFICANT DECREASE IN FORWARD SPEED DURING THE NEXT 2 TO 4 DAYS. IN FACT...IRENE COULD BEGIN TO MEANDER FOR A WHILE. THEREAFTER...THE WESTERLIES ARE EXPECTED TO BECOME ESTABLISHED AND THIS FLOW SHOULD TAKE IRENE NORTHEASTWARD AWAY FROM THE U.S. COAST. THE OFFICIAL TRACK FORECAST HAS BEEN GRADUALLY SHIFTING EASTWARD IN AGREEMENT WITH GUIDANCE. THIS LESSENS THE POTENTIAL THREAT TO THE UNITED STATES EAST COAST. A HIGH ALTITUDE NOAA JET IS CURRENTLY SAMPLING THE ENVIRONMENT. THE DATA WILL GO INTO TONIGHT'S MODEL RUNS. NOTE: JUST AFTER THE COORDINATION CALL THE PLANE REPORTED A PEAK WIND OF 75 KNOTS AT 850 MB. THE INITIAL INTENSITY HAS BEEN ADJUSTED TO 60 KNOTS. FORECASTER AVILA FORECAST POSITIONS AND MAX WINDS INITIAL 12/2100Z 28.7N 67.5W 60 KT 12HR VT 13/0600Z 29.4N 68.8W 65 KT 24HR VT 13/1800Z 30.8N 70.0W 75 KT 36HR VT 14/0600Z 32.5N 70.5W 75 KT 48HR VT 14/1800Z 34.0N 70.5W 75 KT 72HR VT 15/1800Z 36.0N 70.4W 75 KT 96HR VT 16/1800Z 37.1N 70.0W 75 KT 120HR VT 17/1800Z 39.0N 64.0W 75 KT |
