WTPA43 PHFO 031458

TCDCP3



TROPICAL DEPRESSION EIGHT-C DISCUSSION NUMBER   1

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   CP082015

500 AM HST SAT OCT 03 2015



SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THE AREA OF LOW PRESSURE

LOCATED ABOUT 1100 MILES SOUTHWEST OF HONOLULU HAVE PERSISTED DURING

THE NIGHT...WITH A LARGE AREA OF VERY COLD CLOUD TOPS TO THE NORTH

AND NORTHEAST OF THE APPARENT LOW LEVEL CIRCULATION CENTER /LLCC/.

AN 0820Z ASCAT PASS LOCATED A REASONABLY WELL-DEFINED LLCC NEAR THE

SOUTHWESTERN EDGE OF THE DEEP CONVECTION...AND RECENT 11-3.9 MICRON

FOG PRODUCT IMAGERY SHOWS SOME INDICATION OF THE LLCC IN THE SAME

AREA. SUBJECTIVE DVORAK INTENSITY ESTIMATES CAME IN AT 2.0/30 KT

FROM PHFO AND SAB...AND 1.5/25 KT FROM JTWC...AND THE ASCAT PASS

DEPICTED A SUBSTANTIAL AREA OF 30 KT WINDS WITHIN THE DEEP

CONVECTION NORTH OF THE LLCC. BASED ON THE ABOVE DATA...THIS SYSTEM

IS CLASSIFIED AS TROPICAL DEPRESSION EIGHT-C. THIS MARKS THE

THIRTEENTH TROPICAL CYCLONE TO EXIST WITHIN THE BASIN SO FAR DURING

THE 2015 CENTRAL NORTH PACIFIC SEASON.



DATA FROM THE ASCAT PASS INDICATES THAT THE SYSTEM HAS APPARENTLY

BEEN DRIFTING SLOWLY TO THE EAST-SOUTHEAST DURING THE PAST 24

HOURS...BUT THIS MOTION APPEARS TO HAVE STOPPED RECENTLY...WITH THE

LAST FEW FOG PRODUCT IMAGES SHOWING AN APPARENT SLOW WEST-SOUTHWEST

DRIFT. INITIAL MOTION IS AN UNCERTAIN 245/03 KT. THE DEPRESSION IS

FORECAST TO REMAIN IN AN AREA OF VERY WEAK STEERING FLOW DURING THE

NEXT 36 TO 48 HOURS...WITH MODEL CONSENSUS DEPICTING A SLOW WEST-

SOUTHWEST TO WESTWARD DRIFT DURING THIS TIME. A DEEP LAYERED

ANTICYCLONE BUILDING WELL TO THE NORTH OF THE CYCLONE NEAR THE

INTERNATIONAL DATE LINE SHOULD INDUCE A QUICKER WEST-NORTHWEST

MOTION BEYOND 48 HOURS...WITH THE SYSTEM THEN FORECAST TO CONTINUE

MOVING TO THE WEST-NORTHWEST ALONG THE SOUTHERN FLANK OF THE RIDGE

THROUGH 120 HOURS. THE OFFICIAL FORECAST TRACK REPRESENTS A

COMPROMISE BETWEEN THE GFS AND ECMWF...AND IS SLIGHTLY NORTH OF THE

TVCN CONSENSUS.



THE SATELLITE PRESENTATION AND SHIPS DIAGNOSIS INDICATE MODERATE

SOUTHERLY VERTICAL WIND SHEAR OVER THE DEPRESSION AT THIS TIME. THIS

SHEAR IS BEING PRODUCED BY A WEAK UPPER LEVEL TROUGH WHICH WATER

VAPOR IMAGERY CLEARLY DEPICTS JUST TO THE WEST OF THE CYCLONE.

GLOBAL MODELS FORECAST THIS TROUGH TO WEAKEN...BUT ANOTHER UPPER

LEVEL TROUGH DROPS SOUTHWESTWARD ACROSS THE INTERNATIONAL DATE LINE

DURING THE NEXT 48 HOURS...AND MAINTAINS MODERATE SOUTHERLY WIND

SHEAR ALONG THE FORECAST TRACK. THE CYCLONE MAY MOVE INTO A MORE

FAVORABLE ENVIRONMENT AFTER ABOUT 72 HOURS...WHEN THE UPPER RIDGE IS

FORECAST TO BUILD TO ITS NORTH...BUT EVEN AT THE LATER TIME PERIODS

MOST OF THE MODELS SHOW LITTLE INTENSITY CHANGE. THE OFFICIAL

FORECAST WILL MAINTAIN EIGHT-C AS A 30 KT DEPRESSION THROUGH 120

HOURS...IN GOOD AGREEMENT WITH THE ICON CONSENSUS.





FORECAST POSITIONS AND MAX WINDS



INIT  03/1500Z 12.0N 171.4W   30 KT  35 MPH

 12H  04/0000Z 11.8N 171.8W   30 KT  35 MPH

 24H  04/1200Z 11.5N 172.8W   30 KT  35 MPH

 36H  05/0000Z 11.5N 173.7W   30 KT  35 MPH

 48H  05/1200Z 11.8N 174.6W   30 KT  35 MPH

 72H  06/1200Z 13.0N 178.5W   30 KT  35 MPH

 96H  07/1200Z 14.0N 177.0E   30 KT  35 MPH

120H  08/1200Z 15.5N 171.0E   30 KT  35 MPH



$$

FORECASTER JACOBSON