000
WTPZ42 KNHC 011459
TCDEP2
HURRICANE BORIS DISCUSSION NUMBER  19
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP022008
800 AM PDT TUE JUL 01 2008
 
THE EYE FEATURE HAS BECOME OBSCURED IN SHORTWAVE INFRARED IMAGERY
DURING THE PAST FEW HOURS...DISAPPEARING SHORTLY AFTER 0900 UTC
WHEN A TRMM OVERPASS REVEALED ABOUT HALF OF AN EYEWALL IN THE
SOUTHWESTERN SEMICIRCLE.  DVORAK ESTIMATES FROM TAFB AND SAB WERE
STILL 65 KT AT 1200 UTC...AND EVEN THOUGH CLOUD TOP TEMPERATURES
HAVE WARMED SLIGHTLY SINCE THEN...THE ADVISORY INTENSITY WILL
REMAIN 65 KT.  BORIS MIGHT HOLD ON TO HURRICANE STATUS A LITTLE
WHILE LONGER...BUT A WEAKENING TREND SHOULD NOT BE FAR BEHIND. 
SEA-SURFACE TEMPERATURES ALONG THE FORECAST TRACK WILL SLOWLY COOL
DURING THE NEXT 36 HOURS OR SO...THEN DECREASE FASTER AFTER THE
CYCLONE CROSSES THE 26C ISOTHERM.  GIVEN LITTLE CHANGE IN VERTICAL
WIND SHEAR FORECAST BY THE DYNAMICAL MODELS DURING THE NEXT COUPLE
OF DAYS...THE OFFICIAL INTENSITY FORECAST CALLS FOR ONLY SLOW
WEAKENING THROUGH 48 HOURS.  A MORE RAPID DECLINE IS FORECAST AT 3
TO 5 DAYS DUE TO THE COOLER WATERS AND AN EXPECTED SLIGHT INCREASE
IN THE WIND SHEAR BY THAT TIME...AND BORIS COULD DEGENERATE INTO A
REMNANT LOW IN LESS THAN FIVE DAYS.  THE NEW INTENSITY FORECAST
GENERALLY CALLS FOR FASTER WEAKENING THAN THE PREVIOUS ONE.

BORIS APPEARS TO BE SLOWING DOWN.  THE INITIAL MOTION ESTIMATE IS
270/10...WITH STEERING PROVIDED BY A NARROW MID-LEVEL RIDGE TO THE
NORTH OF THE CYCLONE.  THAT RIDGE IS FORECAST BY MOST OF THE MODELS
TO ERODE SOMEWHAT IN RESPONSE TO AN EASTWARD-MOVING DEEP-LAYER LOW
SEVERAL HUNDRED MILES WEST OF CALIFORNIA.  AS A RESULT THE OFFICIAL
TRACK FORECAST INDICATES A DECELERATION AND A SLIGHT BEND TO THE
RIGHT DURING THE NEXT COUPLE OF DAYS...FOLLOWED BY A MOTION
SLIGHTLY SOUTH OF WEST AFTER THE WEAKENING CYCLONE PROCEEDS WITHIN
THE LOWER-LEVEL FLOW.  THIS NEW FORECAST IS VERY SIMILAR TO THE
PREVIOUS ADVISORY AND REMAINS GENERALLY ON THE SOUTHERN SIDE OF THE
GUIDANCE ENVELOPE.

 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      01/1500Z 14.6N 125.0W    65 KT
 12HR VT     02/0000Z 14.7N 126.3W    60 KT
 24HR VT     02/1200Z 15.0N 127.7W    55 KT
 36HR VT     03/0000Z 15.3N 129.1W    50 KT
 48HR VT     03/1200Z 15.5N 130.3W    45 KT
 72HR VT     04/1200Z 15.5N 132.5W    30 KT
 96HR VT     05/1200Z 15.2N 134.5W    25 KT...REMNANT LOW
120HR VT     06/1200Z 14.8N 137.0W    25 KT...REMNANT LOW
 
$$
FORECASTER KNABB