WTPA44 PHFO 040255

TCDCP4



HURRICANE JIMENA DISCUSSION NUMBER  34

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP132015

500 PM HST THU SEP 03 2015



THE CLOUD-FILLED EYE OF JIMENA HAS BEEN WOBBLING TOWARD THE

NORTHWEST AT A VERY SLOW RATE OF SPEED SINCE THE PREVIOUS ADVISORY.

THE OVERALL SATELLITE PRESENTATION OF THE HURRICANE HAS DEGRADED

SLIGHTLY OVER THE COURSE OF THE DAY...BUT IMPRESSIVE OUTFLOW ALOFT

CONTINUES...ESPECIALLY IN THE NORTHERN SEMICIRCLE. A 2342Z SSMI

OVERPASS INDICATED THAT THE EYE WALL ERODED IN THE SOUTHWEST

QUADRANT...WHILE COOLING EYE TEMPERATURES LED TO LOWER DVORAK

INTENSITY ESTIMATES. CURRENT INTENSITY ESTIMATES FROM PHFO/SAB/JTWC

ALL CAME IN AT 4.5/77 KT...WITH DATA-T VALUES OF T4.0/65 KT.

UW-CIMSS ADT CURRENT INTENSITY ESTIMATES CONTINUE NEAR 5.0/90 KT...

AND BASED ON A BLEND OF THIS DATA AND THE SATELLITE TRENDS...THE

INITIAL INTENSITY HAS BEEN LOWERED SLIGHTLY TO 85 KT. A 1930Z ASCAT

PASS WAS USED TO REFINE THE TROPICAL STORM FORCE RADII IN THE

EASTERN SEMICIRCLE.



JIMENA REMAINS EMBEDDED IN AN AREA OF NEARLY NON-EXISTENT STEERING

FLOW...AND IT REMAINS UNCLEAR AS TO WHAT SYNOPTIC SCALE FEATURE IS

DRIVING THE CURRENT MOTION OF 310/03 KT. WEAK DEEP-LAYER HIGHS ARE

CENTERED TO THE EAST AND TO THE DISTANT NORTH-NORTHWEST OF

JIMENA...AND GIVEN THE CURRENT OBSERVED MOTION...IT IS LIKELY

THAT BETA-DRIFT REMAINS THE PRIMARY STEERING MECHANISM THIS

AFTERNOON. WEAK STEERING WILL PERSIST FOR THE NEXT 24 HOURS OR SO...

AND A SLOW DRIFT TO THE NORTHWEST IS EXPECTED. FROM SATURDAY INTO

SUNDAY...THE COMPLEX STEERING PATTERN WILL PERSIST...AS THE HIGH TO

THE NORTH TEMPORARILY RECEDES NORTHWARD...WHILE THE RIDGE TO THE

EAST BUILDS TO THE SOUTHEAST AND SOUTH OF THE CYCLONE. THIS IS

EXPECTED TO RESULT IN A SLIGHTLY FASTER MOTION TOWARD THE NORTH-

NORTHWEST. ON MONDAY AND TUESDAY...THE RIDGE TO THE NORTH IS

FORECAST TO STRENGTHEN...AND JIMENA WILL RESPOND BY TURNING TOWARD

THE WEST. THE UPDATED OFFICIAL FORECAST IS A LITTLE SLOWER THAN THE

PREVIOUS THROUGH THE FIRST 36 HOURS...IS ESSENTIALLY UNCHANGED

FROM 48 THROUGH 96 HOURS...LIES SOUTH OF THE PREVIOUS AT DAY 5...AND

IS VERY CLOSE TO THE GFEX CONSENSUS.



THE INTENSITY FORECAST CONTINUES TO ANTICIPATE GRADUAL BUT STEADY

WEAKENING THROUGH THE FORECAST PERIOD...PRIMARILY DUE TO THE EFFECTS

OF SOUTHWESTERLY SHEAR. MODERATE SHEAR...NEAR 10 TO 15 KT...IS

EXPECTED TO PERSIST OVER THE NEXT 24 HOURS OR SO...AFTER WHICH

TIME IT STEADILY INCREASES TO NEAR 25 KT BY DAY 3. THE FORECAST

TRACK ALSO TAKES JIMENA OVER GRADUALLY DECREASING WATER TEMPERATURES

AND OCEAN HEAT CONTENT. THE UPDATED INTENSITY FORECAST IS SIMILAR TO

THE PREVIOUS AND IVCN INTENSITY CONSENSUS...BUT CONTINUES TO BE

HIGHER THAN THAT INDICATED BY SHIPS GUIDANCE.





FORECAST POSITIONS AND MAX WINDS



INIT  04/0300Z 19.2N 144.5W   85 KT 100 MPH

 12H  04/1200Z 19.7N 144.8W   80 KT  90 MPH

 24H  05/0000Z 20.3N 145.1W   75 KT  85 MPH

 36H  05/1200Z 21.0N 145.4W   70 KT  80 MPH

 48H  06/0000Z 22.2N 145.9W   60 KT  70 MPH

 72H  07/0000Z 24.2N 147.1W   55 KT  65 MPH

 96H  08/0000Z 25.5N 148.5W   50 KT  60 MPH

120H  09/0000Z 25.5N 150.0W   45 KT  50 MPH



$$



FORECASTER BIRCHARD