CoconutCandy
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Reged: Fri
Posts: 245
Loc: Beautiful Honolulu Hawaii
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Boris has won the struggle against the persistent 15-20 Kts. NNE shear over the last few days. And now that the shear has weakened further, it's allowed the convection to wrap completely around and Boris was sporting a nice eyewall feature for a while there.
From the 03Z Advisory discussion ...
Quote:
"AS IT DID AROUND THIS TIME LAST NIGHT...BORIS IS SHOWING EVIDENCE OF AN EYE IN BOTH CONVENTIONAL AND MICROWAVE IMAGERY ... INDICATING THAT BORIS HAS A STRONG UPPER WARM CORE SIGNATURE. WHILE THE CONVECTION IS NOW SHOWING EXCELLENT BANDING ... THE ADVISORY INTENSITY IS INCREASED TO 60 KT.
THERE IS LITTLE EVIDENCE OF VERTICAL WIND SHEAR ... ALL OF THE INTENSITY GUIDANCE EXCEPT THE HWRF NOW MAINTAINS BORIS AS A TROPICAL STORM THROUGHOUT THE FIVE-DAY PERIOD...AND THE OFFICIAL FORECAST DOES NOT INDICATE AS RAPID A DECLINE AS THE PREVIOUS ADVISORY."
and from the most recent, 09Z, discussion ...
Quote:
"NIGHTTIME VISIBLE SATELLITE IMAGES INDICATE THAT THE EYE FEATURE OF BORIS HAS BECOME A LITTLE BETTER-DEFINED DURING THE PAST SIX HOURS. IN ADDITION MICROWAVE IMAGES HAVE SHOWN AN EYEWALL, ALTHOUGH BROKEN, TO NORTH.
THE PERSISTENCE OF THE EYE SUGGESTS THAT THE FEATURE IS REAL, AND THAT BORIS HAS FINALLY ATTAINED HURRICANE STRENGTH. THE INITIAL INTENSITY IS SET TO 65 KT, IN GOOD AGREEMENT WITH THE LATEST SATELLITE CLASSIFICATIONS FROM SAB/TAFB.
NONE OF THE MODELS ARE FORECASTING ANY SIGNIFICANT WIND SHEAR ACROSS BORIS DURING THE NEXT FEW DAYS ... AND THE SYSTEM IS VIRTUALLY PARALLELING THE 26C SST ISOTHERM, SUGGESTING THAT ANY WEAKENING OF BORIS SHOULD BE SLOW TO OCCUR.
IT IS EVEN POSSIBLE THE SYSTEM COULD ENTER AN ANNULAR STATE DUE TO THE ABOVE ENVIRONMENTAL CONDITIONS WHICH WOULD ALSO FAVOR LITTLE CHANGE IN STRENGTH IN THE SHORT-TERM.
Sorry to quote so much of it here, but it really says it very well and saves me a lot of 'rambling', which I am wont to do. 
The system still *looks* sheared to me, with much of the convection pushed south of the alleged eyewall feature. In fact, the eye seems to have collapsed in the last few hours.
We'll have to wait for an upcoming microwave overpass to really tell if Boris is hanging onto hurricane status. One must be very careful about making 'assumptions' based on nighttime IR loops. They can be very 'deceiving' in this regard.
It would be VERY interesting of Boris becomes an annular, steady-state hurricane. Is it even possible to have a minimal Cat 1 Annular ?? 
I thought that only occurred with much stronger cyclones ?!? ( Like Cat 3/4 Hurricane Flossie last year, which went annular for many days in the Central Pacific, all the while making a bee-line for Hawaii. ) Please enlighten.
Any thoughts on Boris becoming the first hurricane of 2008 when it was written off a few days ago, the forecasters' poor intensity estimates and the potential and/or likelihood of Boris going into annular mode ??
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