WTPA45 PHFO 201457

TCDCP5



TROPICAL DEPRESSION FIVE-C DISCUSSION NUMBER   7

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   CP052015

500 AM HST SUN SEP 20 2015



THE SATELLITE PRESENTATION OF FIVE-C HAS CHANGED LITTLE DURING

THE NIGHT. 11-3.9 MICRON FOG PRODUCT IMAGERY CONTINUES TO DEPICT

A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER /LLCC/ DISPLACED

TO THE SOUTH AND WEST OF THE DEEP CONVECTION. STRONG

WEST-SOUTHWESTERLY VERTICAL WIND SHEAR CONTINUES TO IMPACT THE

SYSTEM...WITH GOES UPPER-LEVEL SATELLITE WIND RETRIEVALS AND THE

LATEST SHIPS/UW-CIMSS SHEAR ESTIMATES ALL INDICATING SHEAR

MAGNITUDES OF 25 TO 30 KT. SUBJECTIVE DVORAK CURRENT INTENSITY

ESTIMATES CAME IN AT 2.0/30 KT FROM JTWC...AND 1.5/25 KT FROM

PHFO/SAB...WHILE THE LATEST UW-CIMSS ADT INTENSITY ESTIMATE IS ALSO

1.5/25 KT. CONSIDERING THAT THE SATURDAY MORNING ASCAT PASS FOUND

SIGNIFICANT AREAS OF 30 KT WINDS IN THE EASTERN SEMICIRCLE...AND THE

OVERNIGHT ASCAT PASS DID NOT SAMPLE THAT AREA OF THE SYSTEM...THE

INITIAL INTENSITY WILL BE CONSERVATIVELY HELD AT 30 KT FOR THIS

ADVISORY.



TRACKING OF THE LLCC VIA FOG PRODUCT IMAGERY YIELDS AN INITIAL

MOTION ESTIMATE OF 015/08 KT. THE DEPRESSION CONTINUES TO MOVE

TOWARD THE NORTH-NORTHEAST BETWEEN A BROAD AND DEEP TROUGH CENTERED

WEST OF THE INTERNATIONAL DATE LINE AND A LOW TO MID LEVEL RIDGE

LOCATED FAR TO THE NORTHEAST. THE CYCLONE IS EXPECTED TO CONTINUE ON

THIS SAME GENERAL TRACK WITH SOME INCREASE IN FORWARD SPEED TODAY

AND TONIGHT...AS STEERING FLOW AROUND THE DEEP TROUGH STRENGTHENS.

A TURN TOWARD THE NORTH AND THEN THE NORTH-NORTHWEST IS EXPECTED

FOR MONDAY AND BEYOND...AS THE SYSTEM BECOMES DRAWN INTO THE DEEP

TROUGH. MOST OF THE RELIABLE DYNAMICAL GUIDANCE REMAIN REASONABLY

WELL CLUSTERED ABOUT THE FORECAST TRACK DIRECTION THROUGH THE NEXT

48 HOURS...ALTHOUGH AS WITH PREVIOUS FORECAST CYCLES THERE ARE STILL

SIGNIFICANT DIFFERENCES IN THE SPEED OF MOTION ALONG THIS TRACK. AS

NOTED PREVIOUSLY...THE 00Z ECMWF DEPICTS A MORE WESTERLY AND SLOWER

TRACK THAN DOES MOST OF THE OTHER GUIDANCE. THE NEW OFFICIAL TRACK

IS VERY SIMILAR TO THE PREVIOUS TRACK AND CLOSE TO THE TVCN

CONSENSUS THROUGH 48 HOURS...THEN IS ADJUSTED MODESTLY AT 72 AND 96

HOURS TO INCORPORATE INPUT FROM THE OCEAN PREDICTION CENTER.



THE INTENSITY FORECAST REMAINS PROBLEMATIC. SHIPS AND GLOBAL

MODEL GUIDANCE INDICATE THAT THE CURRENT SHEAR WILL REMAIN NEAR

THE CURRENT LEVELS FOR ANOTHER 24 HOURS...THEN INCREASE FURTHER

AS THE CYCLONE MOVES CLOSER TO THE DEEP MID-LATITUDE TROUGH.

DESPITE THIS...THE LATEST SHIPS STILL SHOWS SOME SLIGHT

INTENSIFICATION BY 24 HOURS...BRINGING THE SYSTEM TO MINIMAL

TROPICAL STORM STRENGTH. THE GFS ALSO DEPICTS SOME MODEST

INTENSIFICATION DURING THE NEXT COUPLE OF DAYS. THE NEW

INTENSITY FORECAST FOLLOWS THE PREVIOUS ONE...BRINGING THE CYCLONE

TO 35 KT AT 24 HOURS AND THEN HOLDING INTENSITY STEADY THEREAFTER

THROUGH 48 HOURS. THIS IS GENERALLY SIMILAR TO THE SHIPS AND

HWRF...BUT WELL BELOW THE GFDL. THE SYSTEM IS EXPECTED TO BEGIN

EXTRATROPICAL TRANSITION BY 48 HOURS...AND SHOULD HAVE COMPLETED

THIS TRANSITION BEFORE 72 HOURS. THE 72 AND 96 HOUR INTENSITY AND

72 HOUR WIND RADII FORECASTS WERE ALSO COORDINATED WITH THE OCEAN

PREDICTION CENTER.



THERE ARE NO CHANGES TO THE EXISTING TROPICAL STORM WATCHES AND

WARNINGS POSTED FOR PORTIONS OF THE PAPAHANAUMOKUAKEA MARINE

NATIONAL MONUMENT. IF CURRENT TRENDS CONTINUE...WE MAY BE ABLE

TO DISCONTINUE THE TROPICAL STORM WATCH FROM LISIANSKI TO PEARL AND

HERMES LATER TODAY.





FORECAST POSITIONS AND MAX WINDS



INIT  20/1500Z 21.1N 173.7W   30 KT  35 MPH

 12H  21/0000Z 22.7N 173.2W   30 KT  35 MPH

 24H  21/1200Z 25.5N 172.3W   35 KT  40 MPH

 36H  22/0000Z 27.9N 172.1W   35 KT  40 MPH

 48H  22/1200Z 30.4N 172.4W   35 KT  40 MPH...BECOMING EXTRATROPICAL

 72H  23/1200Z 35.0N 174.5W   40 KT  45 MPH...POST-TROP/EXTRATROP

 96H  24/1200Z 41.0N 179.0W   35 KT  40 MPH...POST-TROP/EXTRATROP

120H  25/1200Z...DISSIPATED



$$

FORECASTER JACOBSON