WTPA42 PHFO 220859

TCDCP2



TROPICAL STORM LOKE DISCUSSION NUMBER   6

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   CP042015

1100 PM HST FRI AUG 21 2015



CONVECTION AROUND THE LOW-LEVEL CIRCULATION CENTER /LLCC/ OF

TROPICAL STORM LOKE WEAKENED CONSIDERABLY DURING THE LATE

AFTERNOON AND EARLY EVENING HOURS...BUT RECENTLY A SMALL AREA OF

VERY COLD CLOUD TOPS HAS DEVELOPED JUST TO THE SOUTH AND EAST OF

THE LLCC. DVORAK CURRENT INTENSITY ESTIMATES CAME IN AT 2.5/35 KT

FROM ALL THREE AGENCIES...WHILE THE LATEST CIMSS SATCON CONSENSUS

INTENSITY ESTIMATE IS 42 KT. HAVE HELD THE INITIAL INTENSITY AT 40

KT FOR THIS ADVISORY.



LOKE HAS CONTINUED TO DRIFT SLOWLY NORTHWARD...AND THE INITIAL

MOTION ESTIMATE IS 360/04. A MID-LEVEL RIDGE TO THE EAST AND

A WEAK MID/UPPER LEVEL TROUGH TO THE WEST SHOULD DRIVE A SLOW

NORTH-NORTHWEST MOTION DURING THE NEXT 36 HOURS...AS SHOWN BY

THE TIGHTLY CLUSTERED MODEL GUIDANCE. LOKE SHOULD ROUND THE WESTERN

END OF THE RIDGE BETWEEN TAU 36 AND TAU 48...AND THEREAFTER MOVE

SOMEWHAT MORE QUICKLY TO THE NORTH-NORTHEAST AS IT COMES UNDER

INCREASING INFLUENCE FROM A LARGE MID-LATITUDE TROUGH WHICH IS

FORECAST TO DEEPEN ALONG THE INTERNATIONAL DATE LINE. THE NEW

OFFICIAL FORECAST SHOWS LITTLE CHANGE FROM THE PREVIOUS FORECAST

THROUGH 48 HOURS...AND IS IN VERY GOOD AGREEMENT WITH THE TVCN

MODEL CONSENSUS. AT TAU 72 AND TAU 96...THE NEW FORECAST TRACK

REFLECTS A SOMEWHAT FASTER NORTH-NORTHEAST MOTION AS SHOWN BY

THE MAJORITY OF THE RELIABLE MODEL GUIDANCE AND THE TVCN CONSENSUS.

FINALLY AT TAU 120...THE NEW FORECAST TRACK INTRODUCES A TURN BACK

TO THE NORTH-NORTHWEST...AS THE MODEL SUITE MAINTAINS FAIRLY

GOOD CLUSTERING EVEN AT THAT TIME RANGE WITH THE CYCLONE BECOMING

CAPTURED WITHIN THE MUCH LARGER EXTRATROPICAL CIRCULATION

ASSOCIATED WITH BY THEN FORMER WEST PACIFIC TYPHOON ATSANI.



THE INTENSITY FORECAST REMAINS PROBLEMATIC. DESPITE VERY LOW

VERTICAL WIND SHEAR...WITH THE LATEST CIMSS ANALYSIS INDICATING

A SHEAR MAGNITUDE OF ONLY 4 KT...AND WARM SEA SURFACE

TEMPERATURES ALONG WITH AMPLE OCEANIC HEAT CONTENT...LOKE HAS THUS

FAR STRUGGLED TO MAINTAIN ANY CONSISTENT STRENGTHENING TREND. THE

OUTFLOW DOES APPEAR TO BE RESTRICTED TO THE NORTHWEST...AND THERE

ARE CONTINUED INDICATIONS THAT DRY MID-LEVEL AIR NORTH AND WEST OF

THE CYCLONE IS WRAPPING AROUND THE SOUTH SIDE OF THE CIRCULATION.

SHIPS AND LGEM GUIDANCE CONTINUE TO SHOW A SLOW STRENGTHENING TREND

THROUGH THE NEXT 72 HOURS...AND THE NEW INTENSITY FORECAST HAS

CHANGED VERY LITTLE FROM THE PREVIOUS FORECAST. UNCERTAINTY

INCREASES FOR TAU 72 THROUGH 120...WHEN THE CYCLONE MAY BE IMPACTED

BY INCREASING WESTERLY WIND SHEAR AND WILL ALSO BE MOVING ACROSS

COOLER WATERS. THE SHIPS GUIDANCE ACTUALLY STRENGTHENS THE SYSTEM AT

TAU 120 DESPITE THESE FACTORS...BUT THE OFFICIAL FORECAST WILL

FOLLOW MOST OF THE OTHER GUIDANCE AND THE PREVIOUS FORECAST WITH A

SLOW WEAKENING TREND.



INTERESTS IN THE WESTERN PAPAHANAUMOKUAKEA MARINE NATIONAL MONUMENT

SHOULD CONTINUE TO MONITOR THE PROGRESS OF LOKE DURING THE NEXT

SEVERAL DAYS.





FORECAST POSITIONS AND MAX WINDS



INIT  22/0900Z 17.1N 177.2W   40 KT  45 MPH

 12H  22/1800Z 17.9N 177.8W   40 KT  45 MPH

 24H  23/0600Z 19.1N 178.7W   45 KT  50 MPH

 36H  23/1800Z 20.5N 179.1W   50 KT  60 MPH

 48H  24/0600Z 22.0N 179.0W   50 KT  60 MPH

 72H  25/0600Z 25.0N 177.0W   55 KT  65 MPH

 96H  26/0600Z 29.0N 175.0W   55 KT  65 MPH

120H  27/0600Z 33.0N 176.0W   50 KT  60 MPH



$$

FORECASTER JACOBSON/HOUSTON