WTPA43 PHFO 032100

TCDCP3



TROPICAL DEPRESSION EIGHT-C DISCUSSION NUMBER   2

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   CP082015

1100 AM HST SAT OCT 03 2015



TROPICAL DEPRESSION 08C IS A STRONGLY SHEARED SYSTEM. AN EXPOSED

LOW LEVEL CIRCULATION CENTER...LLCC...DEFINED BY SPIRALING LOW

CLOUD LINES CAN BE SEEN ON VISIBLE SATELLITE IMAGERY. OVER THE PAST

6 HOURS A 350NM DIAMETER AREA OF VERY COLD HIGH CLOUDS HAS MOVED OFF

FAR TO THE NORTHEAST OF THE LLCC WITH ONLY ISOLATED CUMULONIMBUS

CLOUDS POPPING UP NORTH OF THE CENTER. SUBJECTIVE DVORAK INTENSITY

ESTIMATES AT 1730 UTC WERE 2.0/30 KT FROM PHFO...SAB...AND JTWC. ADT

FROM UW-CIMSS ALSO SHOWED 30 KT. I WILL KEEP THE INITIAL INTENSITY

AT 30 KT.



WITH HIGH CONFIDENCE IN THE CENTER LOCATION BASED ON THE EXPOSED

LLCC I HAVE RE-BESTED THE 1200 UTC POSITION A BIT FARTHER

SOUTH...BUT EVEN AFTER THE ADJUSTMENT THE SHORT-TERM MOTION HAS

SHIFTED FARTHER SOUTHWEST. FOR THE NEXT 24 HOURS...THE RELIABLE

TRACK MODELS SHOW EIGHT-C TRACKING WEST SOUTHWEST...THEN

WEST...ALONG THE SOUTH SIDE OF A DEEP LAYER RIDGE TO THE NORTH.

BEYOND THAT...THE MODELS SHOW EIGHT-C TRACKING TOWARD THE WEST

NORTHWEST WITH GRADUALLY INCREASING FORWARD SPEED AS THE RIDGE

SHIFTS SOUTHWEST AND A NORTH-SOUTH TROUGH DEEPENS SOUTH OF TROPICAL

STORM CHOI-WAN. THE CURRENT FORECAST TRACK REMAINS CLOSE TO THE

PREVIOUS TRACK AND NEAR THE MIDDLE OF THE CONSENSUS FROM THE TRUSTED

MODELS.



UW-CIMSS VERTICAL WIND SHEAR AT 1800 UTC WAS 21 KT FROM THE SOUTH

SOUTHWEST WHILE SHIPS SHOWED 20 KT FROM THE SOUTHEAST. BASED ON

SATELLITE IMAGERY...IT APPEARS THERE IS STRONG SHEAR FROM THE

SOUTHWEST OVER EIGHT-C DUE TO A LOW ALOFT ABOUT 900NM NORTH OF THE

DEPRESSION. EIGHT-C IS FORECAST TO CONTINUE MOVING OVER 29-30 DEGREE

CELSIUS WATER...BUT STRONG SHEAR IS FORECAST TO CONTINUE THROUGH 36

HOURS AS THE LOW ALOFT DIGS SOUTHWEST. WITH THIS SHEAR CONTINUING...

EIGHT-C IS UNLIKELY TO INTENSIFY. I HAVE KEPT THE INTENSITY AT

30KT. BEYOND 36 HOURS THE VERTICAL WIND SHEAR IS LIKELY TO RELAX AS

THE LOW ALOFT WEAKENS AND MOVES NORTHWEST. GRADUAL INTENSIFICATION

MAY OCCUR IF THE DEPRESSION SURVIVES THAT LONG.





FORECAST POSITIONS AND MAX WINDS



INIT  03/2100Z 11.5N 171.9W   30 KT  35 MPH

 12H  04/0600Z 11.5N 172.5W   30 KT  35 MPH

 24H  04/1800Z 11.5N 173.5W   30 KT  35 MPH

 36H  05/0600Z 11.7N 174.5W   30 KT  35 MPH

 48H  05/1800Z 12.2N 175.7W   30 KT  35 MPH

 72H  06/1800Z 13.3N 179.8W   30 KT  35 MPH

 96H  07/1800Z 14.5N 175.5E   35 KT  40 MPH

120H  08/1800Z 15.5N 170.0E   45 KT  50 MPH



$$

FORECASTER DONALDSON