WTPA44 PHFO 042052

TCDCP4



HURRICANE JIMENA DISCUSSION NUMBER  37

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP132015

1100 AM HST FRI SEP 04 2015



THE SATELLITE PRESENTATION OF JIMENA HAS DEGRADED SLIGHTLY DURING

THE PAST SIX HOURS. WESTERLY VERTICAL WIND SHEAR IS UP TO 19 KT

ACCORDING TO THE 1800 UTC CIMSS ANALYSIS...CAUSING OUTFLOW TO

BECOME DISRUPTED IN THE WEST AND SOUTHWEST QUADRANTS. THE AREA OF

DEEP CONVECTION NEAR THE CENTER DECREASED SLIGHTLY IN SIZE WITH

CLOUD TOPS SHOWING SOME WARMING. DVORAK CURRENT INTENSITY ESTIMATES

FROM HFO AND SAB CAME IN AT 4.0/65 KT...WHILE JTWC HAD 4.5/77 KT.

CIMSS ADT SUPPORTED 65 KT...AND CIMSS SATCON FROM 1630 UTC WAS AT 67

KT. BASED ON A BLEND OF THESE ESTIMATES AND A CONTINUATION OF THE

WEAKENING TREND...THE INITIAL INTENSITY HAS BEEN LOWERED TO 70 KT

FOR THIS ADVISORY.



JIMENA REMAINS WITHIN A WEAK STEERING ENVIRONMENT WITH A SLOW

FORWARD MOTION. ALTHOUGH THE LOW LEVEL CENTER WAS DIFFICULT TO

LOCATE WITH GEOSTATIONARY IMAGERY...A WINDSAT PASS AT 1618 UTC AND

SSMIS PASSES AT 1629 AND 1643 UTC CONFIRMED THAT JIMENA WAS MOVING

CLOSE TO THE PRIOR FORECAST TRACK...AND THE INITIAL MOTION IS SET

TOWARD THE NORTHWEST...OR 320 DEGREES...AT 4 KT. JIMENA WILL

CONTINUE ON A SIMILAR TRACK WITH A RATHER SLOW FORWARD MOTION OVER

THE NEXT THREE DAYS. THIS MOTION WILL BE INDUCED BY A MID TO UPPER

LEVEL TROUGH PARKED JUST WEST OF HAWAII THAT WILL PRODUCE A

WEAKNESS IN THE LOW LEVEL RIDGE CENTERED OVER 1000 MILES NORTH OF

THE CYCLONE. THE GUIDANCE IS TIGHTLY CLUSTERED DURING THIS TIME BUT

DIVERGES SIGNIFICANTLY ON DAYS FOUR AND FIVE. THE OFFICIAL FORECAST

HAS BEEN NUDGED SLIGHTLY SOUTHWARD WITH AN INCREASE IN FORWARD

SPEED ON DAYS FOUR AND FIVE IN ANTICIPATION OF A BUILDING UPPER

LEVEL RIDGE PRODUCING NORTHWESTERLY FLOW ALOFT AND A WEAKER JIMENA

BECOMING INCREASINGLY STEERED BY THE LOW LEVEL RIDGE TO THE NORTH.

THE OFFICIAL FORECAST CLOSELY FOLLOWS THE TVCN TRACK...THOUGH IT

HAS A SLOWER FORWARD MOTION ON DAY FIVE. THE NOTABLE SOUTHERN

OUTLIER IS THE ECMWF...AND THE OFFICIAL FORECAST FALLS BETWEEN THE

OPERATIONAL GFS TO THE SOUTH AND THE GFS ENSEMBLE MEAN TO THE NORTH.



GRADUAL WEAKENING IS EXPECTED THROUGH THE NEXT FIVE DAYS. WESTERLY

VERTICAL WIND SHEAR IS FORECAST TO HOLD AT 15 TO 20 KT DURING THE

NEXT THREE DAYS THEN SHIFT OUT OF THE NORTHWEST ON DAYS FOUR AND

FIVE. THIS SHOULD CONTINUE TO DISRUPT THE OUTFLOW AND IS EXPECTED

TO LEAD TO CONTINUED SLOW WEAKENING. THE INTENSITY FORECAST CLOSELY

FOLLOWS THE PRIOR FORECAST AND IS IN GOOD AGREEMENT WITH ICON.

THERE ARE NOTABLE DIFFERENCES IN THE GUIDANCE. THE GFS AND THE

ECMWF MAINTAIN A STRONGER CYCLONE...WHILE THE GFDL AND HWRF SUGGEST

A RAPID WEAKENING LATE DAY FOUR AND DAY FIVE. MEANWHILE...SHIPS AND

LGEM WEAKEN JIMENA AT A MUCH FASTER RATE THAN THE OFFICIAL FORECAST.







FORECAST POSITIONS AND MAX WINDS



INIT  04/2100Z 20.0N 145.3W   70 KT  80 MPH

 12H  05/0600Z 20.5N 145.7W   65 KT  75 MPH

 24H  05/1800Z 21.4N 146.2W   60 KT  70 MPH

 36H  06/0600Z 22.5N 146.8W   60 KT  70 MPH

 48H  06/1800Z 23.6N 147.7W   55 KT  65 MPH

 72H  07/1800Z 24.9N 150.0W   50 KT  60 MPH

 96H  08/1800Z 24.9N 152.0W   45 KT  50 MPH

120H  09/1800Z 24.7N 155.0W   35 KT  40 MPH



$$

FORECASTER WROE