WTPA43 PHFO 210246
TCDCP3

HURRICANE JOVA DISCUSSION NUMBER  37
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI
5 PM HST TUE SEP 20 2005
 
THE CURRENT FORECAST TRACK FOR HURRICANE JOVA HAS BEEN ADJUSTED TO 
THE RIGHT BEYOND 48 HOURS...YIELDING TO ENSEMBLE GUNS...GUNA AND 
CONU TRENDS OVER THE PAST TWO FORECAST CYCLES. THE FORECAST TRACK 
REMAINS SLIGHTLY LEFT OF THESE ENSEMBLES BUT TO THE RIGHT OF LATEST 
STAND-ALONE GFDL GUIDANCE. FORWARD MOVEMENT HAS ALSO BEEN INCREASED 
TO 12 AND 14 KT AT 96 AND 120 HOURS...RESPECTIVELY...FOR THE SAME 
REASON. THERE IS LITTLE OR NO CHANGE IN FORECAST TRACK UP TO 48 
HOURS FROM THE PREVIOUS FORECAST CYCLE. AS JOVA MOVES 
NORTHWESTWARD...IT SHOULD PASS ABOUT 350 MILES EAST OF THE MAIN 
HAWAIIAN ISLANDS. 

INITIAL JOVA STRENGTH REMAINS AT 100 KT...BASED ON CURRENT INTENSITY 
DVORAK NUMBERS OF 5.5 FROM CPHC...JTWC...SAB AND GWC. AS 
BEFORE...GFDL WANTS TO KEEP JOVA AT OR NEAR 100 KT EVEN AT 120 
HOURS...WHILE SHIP WEAKENS JOVA TO LESS THAN 30 KT BY 96 HOURS. 
GFS75 GUIDANCE FROM 18Z SHOWS UNFAVORABLY HIGH SHEAR BETWEEN 850 AND 
300 MB ALONG THE FORECAST TRACK BEYOND 72 HOURS. LATEST UW-CIMSS 
VERTICAL SHEAR OUTPUT ALSO SHOWS AN UNFAVORABLE SHEAR ENVIRONMENT 
OVER JOVA...AT LEAST THROUGH 24 HOURS. SEA SURFACE TEMPERATURE WILL 
LIKELY HAVE LITTLE OR NO EFFECT ON JOVA SINCE THE FORECAST TRACK 
CLOSELY PARALLELS THE 26C DEGREE ISOTHERM. IT SEEMS UNLIKELY THAT 
JOVA WILL BE ABLE TO MAINTAIN STRENGTH THROUGH SUCH A LONG FETCH OF 
UNFAVORABLE SHEAR...SO THE FORECAST IS FOR JOVA TO WEAKEN TO 
TROPICAL STORM STRENGTH BY 120 HOURS. 

IN SHORT...THE TRACK FORECAST HAS BEEN ADJUSTED TO THE RIGHT TO 
BETTER ALIGN WITH MODEL ENSEMBLES...WHILE THE INTENSITY FORECAST 
REMAINS THE SAME TO REFLECT THE FORECAST SHEAR ENVIRONMENT. 

A CHANGE IN THE FORECAST SHEAR ENVIRONMENT BEYOND 48 HOURS MAY ALTER 
THE FORECAST INTENSITY. IF JOVA WEAKENS FASTER THAN 
FORECAST...STEERING WILL BE SHALLOWER...CAUSING THE LONG RANGE TRACK 
TO VEER BACK TO THE LEFT.
 
FORECASTER POWELL
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      21/0300Z 17.1N 145.8W   100 KT
 12HR VT     21/1200Z 17.6N 146.5W    95 KT
 24HR VT     22/0000Z 18.4N 147.4W    95 KT
 36HR VT     22/1200Z 19.4N 148.3W    90 KT
 48HR VT     23/0000Z 20.5N 149.2W    90 KT
 72HR VT     24/0000Z 23.6N 151.3W    85 KT
 96HR VT     25/0000Z 27.9N 153.4W    70 KT
120HR VT     26/0000Z 33.1N 155.3W    60 KT
 
 
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