|
Show Selection: |
| #376669 (Received by flhurricane at: 4:35 AM 17.Sep.2010) TCDAT1 HURRICANE IGOR DISCUSSION NUMBER 37 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL112010 500 AM AST FRI SEP 17 2010 THE CLOUD PATTERN OF IGOR HAS BECOME A LITTLE LESS ORGANIZED OVERNIGHT WITH WEAKER EYEWALL CONVECTION NOTED. SATELLITE CLASSIFICATIONS RANGE FROM 102 KT FROM TAFB AND SAB...TO UW-CIMSS ADT NUMBERS NEAR 125 KT. A BLEND OF THESE DATA SUGGEST THAT KEEPING THE INITIAL INTENSITY AT 110 KT IS REASONABLE. DATA FROM NOAA BUOY 41044 SUGGESTED THAT THE PRESSURE WAS SEVERAL MB LOWER THAN THE LAST AIRCRAFT FIX FROM THIS AFTERNOON...WHEN THE INTENSITY WAS ALSO NEAR 110 KT. IGOR IS LIKELY TO REMAIN A MAJOR HURRICANE FOR THE NEXT TWO TO THREE DAYS WHILE IT STAYS IN A WARM WATER AND MOSTLY LIGHT SHEAR ENVIRONMENT. THEREAFTER...WATERS GRADUALLY COOL...WHILE SOUTHWESTERLY SHEAR IS FORECAST TO INCREASE. MODEL GUIDANCE IS IN RELATIVELY GOOD AGREEMENT ON THIS SCENARIO...AND THE NHC FORECAST IS CLOSE TO THE PREVIOUS ONE. REGARDLESS OF THE EXACT INTENSITY... IGOR IS EXPECTED TO BE A VERY LARGE AND DANGEROUS HURRICANE WHEN IT PASSES CLOSE TO BERMUDA. IN THE LONG RANGE... EXTRATROPICAL TRANSITION SHOULD BE COMPLETED AROUND 120 HOURS...AND GLOBAL MODELS ARE SHOWING A RATHER INTENSE CYCLONE AT THAT TIME. THE INITIAL MOTION HAS SHIFTED A LITTLE TO THE LEFT OR 305 DEGREES AT 8 KT. THE SYNOPTIC STEERING HAS BEEN RELATIVELY WELL DEFINED FOR THE LAST SEVERAL DAYS AS IGOR TRAVELS AROUND THE SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE. A TURN TO THE NORTH SHOULD OCCUR IN ABOUT TWO DAYS...WITH ALMOST ALL OF THE MODEL GUIDANCE VERY CLOSE TO BERMUDA IN ABOUT 3 DAYS TIME. THE NEW NHC FORECAST IS BASICALLY AN UPDATE OF THE PREVIOUS ONE FOR THE FIRST FEW DAYS. AFTER PASSING BERMUDA...IGOR SHOULD ACCELERATE AS IT BEGINS TO GET CAUGHT UP INTO THE MID-LATITUDE SOUTHWESTERLIES. MOST OF THE GUIDANCE IS A LITTLE FASTER IN THE LONG RANGE...AND THE OFFICIAL FORECAST GOES ALONG WITH THAT IDEA. FORECAST POSITIONS AND MAX WINDS INITIAL 17/0900Z 22.4N 59.4W 110 KT 12HR VT 17/1800Z 23.2N 60.8W 110 KT 24HR VT 18/0600Z 24.5N 62.5W 110 KT 36HR VT 18/1800Z 26.1N 64.0W 105 KT 48HR VT 19/0600Z 27.8N 64.9W 105 KT 72HR VT 20/0600Z 32.5N 64.5W 95 KT 96HR VT 21/0600Z 40.0N 56.0W 80 KT 120HR VT 22/0600Z 50.0N 45.0W 70 KT...POST-TROP/EXTRATROP $$ FORECASTER BLAKE/BRENNAN |
