WTPZ43 KNHC 262048 RRA

TCDEP3



TROPICAL STORM ROSLYN DISCUSSION NUMBER   6...CORRECTED

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP182016

200 PM PDT MON SEP 26 2016



CORRECTED STATUS AT 72H



ALTHOUGH THE CENTER OF ROSLYN HAS BECOME FARTHER SEPARATED

FROM THE DEEP CONVECTION THIS AFTERNOON DUE TO STRONG

SOUTHWESTERLY SHEAR, RECENT ASCAT DATA INDICATE THAT THE

TROPICAL CYCLONE IS STRONGER THAN PREVIOUSLY ESTIMATED.  THE

1756 UTC ASCAT OVERPASS REVEALED 40-45 KT WINDS, AND A MUCH

LARGER AREA OF 34-KT WINDS THAN ANALYZED EARLIER.  BASED ON

THESE DATA, THE INITIAL INTENSITY HAS BEEN SET AT 45 KT, AND

THE 34-KT WIND RADII HAVE BEEN EXPANDED ACCORDINGLY.



INCREASING SOUTHWESTERLY VERTICAL WIND SHEAR AND GRADUALLY

DECREASING SSTS SHOULD CAUSE WEAKENING, BUT GIVEN THE LARGE SIZE OF

THE SYSTEM THE SPINDOWN PROCESS IS LIKELY TO BE MORE GRADUAL THAN

AVERAGE.  IN 24 TO 36 HOURS, MUCH COOLER WATERS AND A MORE STABLE

AIRMASS ARE EXPECTED TO CAUSE ROSLYN TO DEGENERATE INTO A REMNANT

LOW AND TO DISSIPATE IN 3 TO 4 DAYS.  THE NHC INTENSITY FORECAST HAS

BEEN ADJUSTED UPWARD IN THE EARLY PORTION OF THE FORECAST TO ACCOUNT

FOR THE HIGHER INITIAL INTENSITY, BUT IS UNCHANGED THEREAFTER.  THE

OFFICIAL FORECAST SHOWS A SLOWER RATE OF DECAY THAN THE SHIPS

GUIDANCE, BUT IT IS GENERAL AGREEMENT WITH THE TREND IN THE GLOBAL

MODELS.



ROSLYN HAS NOT MOVED MUCH DURING THE PAST 24 HOURS, AND THE BEST

ESTIMATE OF THE INITIAL MOTION IS 035/2 KT.  THE MODELS INSIST THAT

ROSLYN WILL BEGIN MOVING NORTHEASTWARD WITHIN DEEP LAYER

SOUTHWESTERLY FLOW BETWEEN A MID-LEVEL RIDGE TO THE SOUTHEAST AND A

LARGE UPPER-LEVEL LOW OVER BAJA CALIFORNIA.  IN A COUPLE OF DAYS,=