000 WTPZ43 KNHC 300852 TCDEP3 HURRICANE LESTER DISCUSSION NUMBER 23 NWS NATIONAL HURRICANE CENTER MIAMI FL EP132016 200 AM PDT TUE AUG 30 2016 Lester has begun to weaken. The areal extent of deep convection within the hurricane's central dense overcast (CDO) has decreased substantially, and the CDO has lost much of its axisymmetry since late yesterday. In addition, the eye has warmed and become a little less defined. The recent weakening could be associated with an increase in easterly shear over the cyclone as analyzed by UW-CIMSS and SHIPS model output. Dvorak T-numbers have responded by suddenly decreasing. A blend of the latest TAFB Final T- and CI-numbers, including the UW-CIMSS ADT values, is used to lower the initial intensity estimate to 110 kt. The initial motion estimate is 275/12. A strong mid-level ridge over the east-central subtropical Pacific should continue to steer Lester just north of due west for the next couple of days. A probable binary interaction with Madeline should cause Lester's heading to turn west-northwestward as the hurricane approaches the Hawaiian Islands in 3-5 days. The NHC track forecast is barely adjusted relative to the previous one, and is closest to a blend of the GFS and ECMWF solutions. The intensity forecast is, again, quite challenging. The delicate balance of environmental factors leading to Lester's annular structure yesterday may have been disrupted by the recent uptick in easterly shear. With the shear forecast to diminish over the next day or so while the cyclone continues to move over nearly constant SSTs, Lester could regain its annular characteristics. This would allow Lester to sustain a higher intensity during the next 2-3 days than what the intensity guidance indicates. After that time, the ECMWF shows a less conducive environment than the GFS, which could result in a more decided weakening. Given the greater than normal uncertainty, the NHC forecast stays close to the multi-model consensus throughout the period. Lester's wind radii have been adjusted based on a partial ASCAT overpass. FORECAST POSITIONS AND MAX WINDS INIT 30/0900Z 18.2N 133.2W 110 KT 125 MPH 12H 30/1800Z 18.3N 135.1W 100 KT 115 MPH 24H 31/0600Z 18.4N 137.5W 90 KT 105 MPH 36H 31/1800Z 18.4N 139.7W 90 KT 105 MPH 48H 01/0600Z 18.5N 141.9W 85 KT 100 MPH 72H 02/0600Z 19.3N 146.4W 80 KT 90 MPH 96H 03/0600Z 20.8N 151.2W 70 KT 80 MPH 120H 04/0600Z 22.7N 156.4W 60 KT 70 MPH $$ Forecaster Kimberlain