000 WTPZ42 KNHC 010819 TCDEP2 HURRICANE BORIS DISCUSSION NUMBER 18 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP022008 200 AM PDT TUE JUL 01 2008 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. IN A COUPLE DAYS...THE SSTS SHOULD COOL A LITTLE QUICKER AND HELP ACCELERATE THE WEAKENING OF THE CYCLONE. THIS SOLUTION IS REFLECTED IN THE OFFICIAL INTENSITY FORECAST AND IS IN REASONABLE AGREEMENT WITH A CONSENSUS OF HWRF/GFS/LGEM/SHIPS GUIDANCE. THE INITIAL MOTION IS 270/12... A LITTLE FASTER THAN BEFORE. BORIS HAS BEEN IGNORING THE MODELS SUGGESTING A SLOWDOWN AND IS CONTINUING A RELATIVELY STEADY FORWARD MOTION. OVERALL...THE COMPUTER MODELS HAVE BEEN TOO SLOW WITH THE HURRICANE...PERHAPS BECAUSE OF THE MODELS OVERESTIMATING THE AMOUNT OF INTERACTION WITH A DISTURBANCE TO THE EAST. THE BIGGEST CHANGE IN THE LARGE-SCALE GUIDANCE FROM EARLIER IS THAT A RIDGE TO THE NORTH OF THE HURRICANE IS FORECAST TO WEAKEN IN A DAY OR SO. ALL MODELS RESPOND BY TURNING BORIS TO THE WEST-NORTHWEST AND SHOWING SOME DECELERATION. THE RIDGE THEN RESTRENGTHENS BEYOND DAY 3...CAUSING A WEST- SOUTHWESTWARD MOTION OF BORIS. THE OFFICIAL FORECAST CONTINUES THE TREND OF SPEEDING THE SYSTEM UP FROM THE PREVIOUS FORECAST AND LIES ON THE EXTREME SOUTHERN EDGE OF THE GUIDANCE ENVELOPE...NOT TOO FAR AWAY FROM THE UKMET AND FLORIDA STATE SUPERENSEMBLE FORECASTS. FORECAST POSITIONS AND MAX WINDS INITIAL 01/0900Z 14.6N 124.2W 65 KT 12HR VT 01/1800Z 14.6N 125.7W 65 KT 24HR VT 02/0600Z 14.7N 127.1W 60 KT 36HR VT 02/1800Z 15.0N 128.5W 60 KT 48HR VT 03/0600Z 15.3N 129.8W 55 KT 72HR VT 04/0600Z 15.5N 131.5W 45 KT 96HR VT 05/0600Z 15.0N 133.5W 35 KT 120HR VT 06/0600Z 14.3N 136.0W 30 KT $$ FORECASTER BLAKE