WTPZ43 KNHC 260835 RRA

TCDEP3



TROPICAL STORM ROSLYN DISCUSSION NUMBER   4

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP182016

200 AM PDT MON SEP 26 2016



THE SHEARED CLOUD PATTERN IN INFRARED SATELLITE IMAGERY HAS CHANGED

LITTLE SINCE THE PREVIOUS ADVISORY. HOWEVER, A 0304Z SSMI/S PASS

INDICATED THE LOW-LEVEL STRUCTURE HAD IMPROVED MARKEDLY, WITH A

SHARP HOOKED BAND WRAPPING MORE THAN HALF AROUND THE NOW

WELL-DEFINED LOW-LEVEL CIRCULATION CENTER. THE INITIAL INTENSITY HAS

BEEN INCREASED TO 35 KT BASED ON A DVORAK CLASSIFICATION OF T2.5/35

KT FROM TAFB AND THE IMPROVED LOW-LEVEL STRUCTURE INDICATED IN

SSMI/S 37 GHZ DATA. THIS MAKES ROSLYN THE SEVENTEENTH NAMED STORM OF

THE 2016 EASTERN NORTH PACIFIC HURRICANE SEASON.



THE INITIAL MOTION ESTIMATE IS 020/4 KT. THE ADVISORY POSITION HAD

TO BE ADJUSTED MORE THAN 30 NMI TO THE EAST OF THE PREVIOUS ADVISORY

TRACK BASED ON RECENT SSMI/S AND AMSU MICROWAVE CENTER FIXES.

OTHERWISE, THE PREVIOUS TRACK FORECAST RATIONALE REMAINS UNCHANGED.

A LARGE MID- TO UPPER-LEVEL LOW CURRENTLY LOCATED OVER THE CENTRAL

BAJA CALIFORNIA PENINSULA IS EXPECTED TO CONTINUE MOVING WESTWARD TO

WEST-SOUTHWESTWARD DURING THE NEXT DAY OR TWO. THE COMBINED

SOUTHWESTERLY FLOW BETWEEN THAT LOW AND A DEEP-LAYER RIDGE LOCATED

TO THE EAST AND SOUTHEAST OF ROSLYN SHOULD KEEP THE TROPICAL CYCLONE

MOVING SLOWLY NORTH-NORTHEASTWARD TO NORTHEASTWARD FOR THE NEXT 48

HOURS. AFTER THAT, ROSLYN IS EXPECTED TO WEAKEN INTO A SHALLOW

REMNANT LOW, TURNING NORTHWARD ON DAY 3 AND THEN NORTHWESTWARD ON

DAY 4. THE NEW NHC TRACK FORECAST IS TO THE RIGHT OF THE PREVIOUS

ADVISORY TRACK, MAINLY DUE TO THE MORE EASTWARD INITIAL POSITION,=