Caribbean-On-Line's Caribbean Hurricane Blog



HURRICANE IKE DISCUSSION NUMBER 17

Published on September 5, 2008 9:56 AM | Comments

The models are not all in agreement about the strength and track, but Ike is a hurricane and will most likely come through the Bahamas as a hurricane:

HURRICANE IKE DISCUSSION NUMBER 17 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL092008 500 AM EDT FRI SEP 05 2008

THE EYE OF IKE HAS LOST A LITTLE OF ITS DEFINITION...AND CLOUD TOPS OF THE EYEWALL HAVE WARMED SOMEWHAT. DVORAK T-NUMBERS HAVE COME DOWN SLIGHTLY AND THE INITIAL INTENSITY IS SET TO 110 KT. MICROWAVE IMAGERY JUST RECEIVED FROM THE AMSR-E DOES NOT REVEAL ANY SIGNIFICANT DETERIORATION OF THE INNER CORE STRUCTURE...NOR DOES IT DEPICT CONCENTRIC EYEWALLS...SO RAPID WEAKENING DOES NOT APPEAR TO BE ABOUT TO OCCUR. THAT IMAGERY DOES SHOW SOME EROSION OF THE NORTHWESTERN EYEWALL...AND GIVEN THE NORTHEASTERLY SHEAR...THE OFFICIAL FORECAST CALLS FOR SOME WEAKENING IN THE SHORT TERM. GLOBAL MODELS FORECAST THE SHEAR TO LESSEN BEYOND 24 HOURS...AS IKE REMAINS OVER WATERS NEAR 29 CELSIUS...SO RESTRENGTHENING IS THEN FORECAST. THE HWRF FORECASTS IKE TO BE A MAJOR HURRICANE AT DAYS 3-5...BUT THE GFDL DOES NOT SINCE ITS TRACK GOES OVER CUBA. MEANWHILE THE SHIPS AND LGEM FORECAST A WEAKER HURRICANE...ALTHOUGH THE LGEM PREDICTION APPEARS MORE REALISTIC SINCE IT DOES A BETTER JOB OF TAKING INTO ACCOUNT THE EVENTUAL LESSENING OF THE SHEAR. SINCE THE OFFICIAL FORECAST TRACK REMAINS OVER WATER THROUGH 96 HOURS...A BLEND OF THE HWRF AND LGEM SEEMS TO BE REASONABLE...AND IKE IS FORECAST TO BE A MAJOR HURRICANE AT LONGER RANGES. THE ONLY REASON FOR THE WEAKENING AT THE END IS THAT THE FIVE-DAY POINT IS OVER LAND...WHICH IS NOT A CERTAINTY.

THE MID-LEVEL RIDGE HAS SETTLED IN DIRECTLY NORTH OF IKE...AS THE HIGH-LATITUDE TROUGH DEPARTS ATLANTIC CANADA...AND THE HURRICANE IS NOW HEADED DUE WESTWARD OR 270/13. NEXT TO DEPART THE WESTERN ATLANTIC SCENE WILL BE HANNA...AND ALL DYNAMICAL MODELS SAY THAT IN ITS PLACE THE RIDGE WILL EXTEND SOUTHWESTWARD TO FLORIDA IN A COUPLE OF DAYS. A KEY UNKNOWN FOR THE 3-5 DAY FORECAST IS HOW STRONG THAT RIDGE WILL BE AND HOW LONG IT WILL REMAIN INTACT. IN GENERAL DURING THE LAST DAY OR TWO THE MODELS HAVE BEEN TRENDING TOWARD THE RIDGE STAYING IN PLACE LONGER...RESULTING IN TRACKS MAINTAINING THE GENERALLY WESTWARD MOTION LONGER AND DELAYING ANY POTENTIAL TURN TO THE NORTH. THAT TREND HAS CONTINUED SOMEWHAT ON THIS CYCLE...BUT THE CONSENSUS HAS ONLY SHIFTED WEST SLIGHTLY AT DAYS 4 AND 5. THE NEW OFFICIAL TRACK FORECAST IS ALMOST IDENTICAL TO THE PREVIOUS ONE THROUGH 72 HOURS...IS JUST NUDGED TOWARD THE CONSENSUS BEYOND THAT TIME...AND GIVES THE MOST WEIGHT TO THE GFS AND HWRF. IT CANNOT BE SAID ENOUGH THAT FIVE-DAY TRACK FORECASTS CAN HAVE SIGNIFICANT ERRORS...AND COMBINED WITH THE FACT THAT THE MODEL SPREAD IS STILL NOTABLE BEYOND 72 HOURS...ONE SHOULD NOT FOCUS ON THE EXACT TRACK.



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