WTPZ41 KNHC 120248 RRA

TCDEP1



TROPICAL STORM ORLENE DISCUSSION NUMBER   5

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP162016

800 PM PDT SUN SEP 11 2016



VISIBLE, INFRARED, AND MICROWAVE SATELLITE IMAGERY INDICATE THAT THE

CYCLONE HAS CONTINUED TO BECOME MORE ORGANIZED, WITH A WELL-DEFINED

LOW- TO MID-LEVEL EYE NOTED IN A 2336Z SSMI/S OVERPASS. ORLENE NOW

HAS A LARGE, CIRCULAR CDO ALONG WITH A SYMMETRICAL AND EXPANDING

UPPER-LEVEL OUTFLOW PATTERN. DVORAK INTENSITY ESTIMATES FROM TAFB

AND SAB ARE A CONSENSUS T3.5/55 KT WHILE THE OBJECTIVE UW-CIMSS ADT

IS 60-65 KT. GIVEN THE RATHER LARGE AVERAGE EYE DIAMETER OF ABOUT 35

NMI, THE INITIAL INTENSITY IS SET BELOW THE ADT VALUES AND FOLLOWS

THE SUBJECTIVE ESTIMATE OF 55 KT.



THE INITIAL MOTION IS 305/08 KT BASED HEAVILY ON MICROWAVE EYE

POSITION ESTIMATES. ALTHOUGH THERE IS SOME DIVERGENCE IN THE MODELS,

THEY ARE GOOD AGREEMENT OVERALL ON ORLENE GRADUALLY SLOWING DOWN

AND MOVING NORTH-NORTHWESTWARD AND NORTHWARD INTO A BREAK IN THE

SUBTROPICAL RIDGE DURING THE NEXT 48 HOURS. AFTER THAT, THE BREAK IN

THE RIDGE ALONG 120W LONGITUDE IS FORECAST TO FILL BACK IN AS A

SHORTWAVE TROUGH LIFTS OUT QUICKLY TO THE NORTHEAST. THE

RE-STRENGTHENING RIDGE TO THE NORTH OF ORLENE IS THEN EXPECTED TO

ACCELERATE THE CYCLONE ON A WESTWARD TRACK ON DAYS 3-5. THE NEW NHC

FORECAST TRACK IS ESSENTIALLY JUST AN UPDATE AND EXTENSION OF THE

PREVIOUS ADVISORY TRACK, AND LIES CLOSE TO A CONSENSUS OF THE

GFS-ECMWF MODEL SOLUTIONS.



ORLENE IS EXPECTED TO REMAIN IN A VERY LOW-SHEAR ENVIRONMENT FOR THE

NEXT 72 HOURS, WHICH TYPICALLY FAVORS RAPID INTENSIFICATION.

HOWEVER, THE CYCLONE IS ALSO EXPECTED TO REMAIN EMBEDDED WITHIN A=