000
WTNT41 KNHC 190233
TCDAT1
HURRICANE IGOR DISCUSSION NUMBER  44
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL112010
1100 PM AST SAT SEP 18 2010
 
THE CLOUD PATTERN IS NOT AS IMPRESSIVE AS IT WAS 12 HOURS AGO AND IT
APPEARS THAT IGOR COULD BE A LITTLE BIT WEAKER TONIGHT. THE AREA OF
DEEP CONVECTION HAS DECREASED AND THERE IS NO EYE OBSERVED ON
CONVENTIONAL SATELLITE IMAGERY. A MICROWAVE PASS A FEW HOURS AGO
SHOWS A PARTIAL RING OF CONVECTION ASSOCIATED WITH WHAT IS LEFT OF
THE EYEWALL. DVORAK T-NUMBERS HAVE DECREASED...BUT STILL SUPPORT AN
INITIAL INTENSITY OF 85 KNOTS. I WAS TEMPTED TO LOWER THE INTENSITY
JUST A LITTLE BIT GIVEN THE CURRENT SATELLITE PRESENTATION...BUT I
WOULD RATHER WAIT FOR DATA FROM THE RECONNAISSANCE AIRCRAFT...WHICH
WILL BE IN THE AREA SOON. FOR THE NEXT 24 HOURS...IGOR WILL BE
WITHIN AN ENVIRONMENT FAVORABLE TO MAINTAIN ITS CURRENT INTENSITY
AND IN FACT...THE INTENSITY CONSENSUS MODEL KEEPS IGOR WITH NO
CHANGE FOR THE NEXT 12 TO 24 HOURS. ALTHOUGH THE OFFICIAL FORECAST
SHOWS IGOR WITH 85 KNOTS AS IT PASSES NEAR OR OVER BERMUDA...THE
HURRICANE COULD EASILY EXPERIENCE SOME MINOR FLUCTUATIONS IN
INTENSITY. THEREAFTER...ONCE IGOR BECOMES EMBEDDED WITHIN THE
MID-LATITUDE WESTERLY FLOW WELL NORTHEAST OF BERMUDA...IT SHOULD
BEGIN TO BECOME POST-TROPICAL/EXTRATROPICAL.
 
THE STEERING FLOW HAS BEEN WELL ESTABLISHED AND WELL DEPICTED BY
GLOBAL MODELS SINCE IGOR FORMED MANY DAYS AGO...AND IT HAS BEEN
DESCRIBED IN DETAIL IN PREVIOUS DISCUSSIONS. IGOR IS NOW MOVING
TOWARD THE NORTH-NORTHWEST OR 330 DEGREES AT 11 KNOTS...AND A TURN
TO THE NORTH AROUND THE WESTERN EDGE OF THE SUBTROPICAL RIDGE
SHOULD BEGIN SOON. IN 36 HOUR...THE CYCLONE SHOULD BE MOVING
NORTHEASTWARD FULLY EMBEDDED WITHIN THE MID-LATITUDE FLOW AHEAD OF
A LARGE TROUGH. GIVEN THE WELL ESTABLISHED STEERING CURRENTS
FORECAST BY THE GLOBAL MODELS...TRACK GUIDANCE IS IN VERY GOOD
AGREEMENT FOR THE NEXT 12 TO 36 HOURS...INCREASING THE CONFIDENCE
IN THE FORECAST DURING THIS PERIOD. HOWEVER...THERE IS A LARGE
SPREAD IN MODELS BEYOND 48 HOURS AS IGOR BECOMES POST-TROPICAL/
EXTRATROPICAL AND MOVES RAPIDLY NORTHEASTWARD OVER THE NORTH
ATLANTIC.
 
IGOR CONTINUES TO HAVE A VERY LARGE WIND FIELD...AND CONDITIONS
SHOULD DETERIORATE ON BERMUDA SOON WELL IN ADVANCE OF THE
CENTER.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      19/0300Z 28.2N  64.7W    85 KT
 12HR VT     19/1200Z 29.7N  65.4W    85 KT
 24HR VT     20/0000Z 32.0N  65.1W    85 KT
 36HR VT     20/1200Z 35.0N  64.0W    80 KT
 48HR VT     21/0000Z 38.5N  60.5W    80 KT
 72HR VT     22/0000Z 46.0N  50.0W    70 KT...POST-TROP/EXTRATROP
 96HR VT     23/0000Z 49.5N  40.0W    60 KT...POST-TROP/EXTRATROP
120HR VT     24/0000Z 53.0N  35.5W    45 KT...POST-TROP/EXTRATROP
 
$$
FORECASTER AVILA