WTPA44 PHFO 050900

TCDCP4



HURRICANE JIMENA DISCUSSION NUMBER  39

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP132015

1100 PM HST FRI SEP 04 2015



LATEST SATELLITE IMAGERY SHOWS THAT THE OUTFLOW ALOFT ASSOCIATED

WITH JIMENA HAS RECENTLY IMPROVED...ESPECIALLY IN THE SOUTHWEST

SEMICIRCLE...AND IT APPEARS THAT JIMENA HAS INTENSIFIED SOMEWHAT

SINCE THE PREVIOUS ADVISORY. A SERIES OF MICROWAVE OVERPASSES

BETWEEN 0301Z AND 0343Z WERE HELPFUL IN LOCATING THE CENTER...BEFORE

THE RE-APPEARANCE OF AN EYE IN CONVENTIONAL IMAGERY AROUND 0600Z.

TEMPERATURES IN THE EYE WARMED SIGNIFICANTLY AT 0600Z...WHILE DVORAK

DATA-T VALUES BASED ON 0530Z IMAGERY YIELDED T3.5/55 KT FROM

SAB...T4.0/65 KT FROM PGTW...AND T4.5/77 KT FROM PHFO. WHILE THE

CLOUD-FILLED EYE HAS WARMED SOMEWHAT IN THE LAST COUPLE OF SATELLITE

IMAGES...THE IMPROVED SATELLITE APPEARANCE OF THE CYCLONE LED TO AN

INCREASE IN THE INITIAL INTENSITY TO 75 KT FOR THIS ADVISORY.



BASED ON A 0343Z SSMI PASS THAT INDICATED A NORTHEASTWARD TILT

WITH HEIGHT DUE TO THE ONGOING SOUTHWESTERLY SHEAR...THE LOW-LEVEL

CIRCULATION CENTER WAS ESTIMATED TO BE ON THE SOUTHWEST SIDE OF THE

WARMER TEMPERATURES ASSOCIATED WITH THE EYE...THUS YIELDING

A CURRENT MOTION VECTOR OF 330/06 KT. JIMENA IS EMBEDDED WITHIN A

COMPLEX STEERING PATTERN...WITH DEEP LAYER RIDGES CENTERED NEARBY

TO SOUTHEAST...AND TO THE DISTANT NORTH. OVER THE NEXT 48 HOURS...

THE RIDGE TO THE SOUTHEAST WILL BUILD TO THE SOUTH OF JIMENA...

WHILE THE RIDGE TO THE NORTH MOVES LITTLE. THIS IS EXPECTED TO

RESULT IN A SLIGHT INCREASE IN FORWARD SPEED...AND A GRADUAL TURN

TOWARD THE NORTHWEST. AFTER THIS TIME...THE RIDGE TO THE NORTH IS

EXPECTED TO BUILD TO THE NORTHWEST OF JIMENA...THEREBY IMPARTING AN

INCREASINGLY WESTWARD MOTION ON THE CYCLONE. THE UPDATED TRACK

FORECAST IS FASTER AND TO THE RIGHT OF THE PREVIOUS THROUGH 72

HOURS...AND THEN IS VERY CLOSE TO THE PREVIOUS ON DAYS 4 AND 5. THE

0000Z RUN OF THE ECMWF SHIFTED NORTHWARD FROM THE PREVIOUS CYCLE...

AND IS VERY CLOSE TO THE PREVIOUS FORECAST...WHILE THE OPERATIONAL

GFS CONTINUES TO REPRESENT THE SOUTHERNMOST RELIABLE GUIDANCE

MEMBER. THE UPDATED FORECAST TRACK NOW LIES NEAR THE MIDDLE OF A

GUIDANCE ENVELOPE THAT EXPANDS IN THE LATER PERIODS...AND LIES IN

BETWEEN GFEX CONSENSUS AND THE FLORIDA STATE SUPER ENSEMBLE.



DESPITE THE RECENT INCREASE IN INTENSITY...WEAKENING IS STILL

EXPECTED THROUGH THE FORECAST PERIOD. WEST TO SOUTHWEST VERTICAL

WIND SHEAR OF 20 KT OR MORE WILL PERSIST THROUGH THE NEXT THREE

DAYS...THEN SHIFT OUT OF THE NORTHWEST ON DAYS FOUR AND FIVE. THIS

SHOULD LEAD TO A DISRUPTION OF THE OUTFLOW...RESULTING IN SLOW

WEAKENING. AFTER THE INITIAL INCREASE IN INTENSITY...THE UPDATED

OFFICIAL FORECAST CLOSELY FOLLOWS THE PRIOR FORECAST TREND. THE

INTENSITY FORECAST IS THE SAME AS THE PREVIOUS AFTER 36 HOURS...IN

GOOD AGREEMENT WITH IVCN CONSENSUS AND HWRF. NOTABLE DIFFERENCES

REMAIN IN THE GUIDANCE...AS THE GFS AND THE ECMWF MAINTAIN A STRONGER

CYCLONE...WHILE SHIPS AND LGEM WEAKEN JIMENA AT A MUCH FASTER

RATE...WITH SHIPS FORECASTING DISSIPATION BY THE END OF THE

FORECAST PERIOD.





FORECAST POSITIONS AND MAX WINDS



INIT  05/0900Z 20.9N 145.9W   75 KT  85 MPH

 12H  05/1800Z 21.7N 146.4W   65 KT  75 MPH

 24H  06/0600Z 22.8N 147.2W   60 KT  70 MPH

 36H  06/1800Z 23.7N 148.0W   55 KT  65 MPH

 48H  07/0600Z 24.6N 149.2W   50 KT  60 MPH

 72H  08/0600Z 25.3N 151.6W   45 KT  50 MPH

 96H  09/0600Z 25.0N 154.5W   40 KT  45 MPH

120H  10/0600Z 24.5N 158.0W   30 KT  35 MPH



$$



FORECASTER BIRCHARD