WTPA44 PHFO 140852

TCDCP4



TROPICAL DEPRESSION NORA DISCUSSION NUMBER  20

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP182015

1100 PM HST TUE OCT 13 2015



THE SATELLITE PRESENTATION OF NORA CONTINUES TO LOOK VERY RAGGED

THIS EVENING...WITH THE LOW LEVEL CIRCULATION CENTER /LLCC/

COMPLETELY EXPOSED. OVER THE PAST COUPLE OF HOURS...CONVECTION HAS

MANAGED TO RE-DEVELOP NORTHEAST OF LLCC...BUT IT IS BATTLING STRONG

SOUTHWESTERLY VERTICAL WIND SHEAR. THE LATEST UW-CIMSS VERTICAL

WIND SHEAR ANALYSIS SHOWS 40 KNOTS OF SHEAR FROM THE SOUTHWEST AND

SHIPS GUIDANCE SHOWS 32 KNOTS OF SHEAR FROM THE SOUTHWEST. THE

LATEST FIXES FROM PHFO AND JTWC CAME IN AT 1.5/25 KNOTS...SAB

2.0/30 KNOTS...WHILE THE UW-CIMSS ADVANCED DVORAK TECHNIQUE /ADT/

CAME IN AT 2.0/30 KNOTS. ADDITIONALLY...A 0708Z ASCAT PASS SHOWED A

LARGE SWATH OF 25 KNOT WINDS IN THE NORTHERN SEMI-CIRCLE OF NORA.

BASED ON THE FIXES AND RECENT ASCAT PASS...THE INTENSITY FOR THIS

ADVISORY HAS BEEN LOWERED TO 30 KNOTS...MAKING NORA A TROPICAL

DEPRESSION. THE INITIAL MOTION WILL BE SET AT 280 DEGREES AT 5

KNOTS.



DUE TO THE LOSS OF DEEP CONVECTION...NORA IS CURRENTLY BEING

STEERED OFF TO THE WEST BY THE LOW LEVEL TRADE WIND FLOW. THIS

MOTION IS EXPECTED TO BE TEMPORARY AS THE APPROACH OF A LARGE UPPER

LEVEL TROUGH AND FORCING FROM THE RIGHT REAR QUAD OF AN UPPER LEVEL

JET WILL LIKELY ALLOW CONVECTION TO PULSE OVER THE SYSTEM THROUGH

THURSDAY MORNING...AND STEER NORA ON A MORE NORTHWESTWARD TRACK.

ONCE THE INFLUENCE OF THE UPPER DYNAMICS IS LOST...NORA IS EXPECTED

TO GET CAUGHT UP WITHIN THE TRADE WIND FLOW ONCE AGAIN...TRACKING

GENERALLY WESTWARD THROUGH DISSIPATION FRIDAY NIGHT OR SATURDAY.

THE OFFICIAL CPHC FORECAST TRACK IS TO THE LEFT OF THE GUIDANCE

ENVELOPE AND THE PREVIOUS OFFICIAL FORECAST THROUGH 36 HOURS DUE TO

THE INITIAL WESTWARD MOTION. THE TRACK THEN CLOSELY FOLLOWS THE

PREVIOUS OFFICIAL FORECAST FROM HOURS 36 THROUGH 72.



NORA IS EXPECTED TO SLOWLY AND STEADILY WEAKEN OVER THE NEXT

SEVERAL DAYS AS PERSISTENT VERTICAL WIND SHEAR OF 30 TO 35 KNOTS AS

INDICATED BY SHIPS GUIDANCE...WILL LIKELY KEEP THE LLCC DEVOID OF

DEEP CONVECTION. THIS IN COMBINATION WITH THE MID-LEVEL DRY AIR

EVIDENT IN WATER VAPOR IMAGERY WILL NEGATE ANY POSITIVE

CONTRIBUTION FROM WARM SEA SURFACE TEMPERATURES /SSTS/ OF AROUND 28

DEGREES C. AS A RESULT...NORA IS EXPECTED TO BECOME A POST-TROPICAL

REMNANT LOW ON WEDNESDAY...WITH THE SYSTEM DISSIPATING FRIDAY NIGHT

OR SATURDAY IF NOT SOONER.













FORECAST POSITIONS AND MAX WINDS



INIT  14/0900Z 14.8N 150.6W   30 KT  35 MPH

 12H  14/1800Z 15.2N 151.3W   30 KT  35 MPH

 24H  15/0600Z 16.0N 152.0W   25 KT  30 MPH...POST-TROP/REMNT LOW

 36H  15/1800Z 16.4N 152.5W   25 KT  30 MPH...POST-TROP/REMNT LOW

 48H  16/0600Z 16.6N 153.6W   20 KT  25 MPH...POST-TROP/REMNT LOW

 72H  17/0600Z 16.5N 155.0W   20 KT  25 MPH...POST-TROP/REMNT LOW

 96H  18/0600Z...DISSIPATED



$$

FORECASTER JELSEMA/WROE