000 WTPZ41 KNHC 300244 TCDEP1 HURRICANE ANDRES DISCUSSION NUMBER 8 NWS NATIONAL HURRICANE CENTER MIAMI FL EP012015 800 PM PDT FRI MAY 29 2015 Andres is gradually intensifying. The cyclone is maintaining a symmetric central dense overcast, consisting of plenty of cold-topped deep convection. A 2256 UTC GPM microwave pass showed numerous, well organized convective bands and a closed low-level ring of convection; in addition, a warm spot has recently become evident in infrared satellite imagery. Satellite intensity estimates at 0000 UTC were 4.0/65 kt and 4.5/75 kt from SAB and TAFB, respectively, and the latest ADT value from UW-CIMSS is 4.3/72 kt. Since that time, Andres' cloud pattern has increased further in organization, and the initial intensity is raised to 75 kt. Andres' motion has shifted toward the right or northwest, 320/06, in response to a weakness in the subtropical ridge along 115w caused by a shortwave trough near the Baja California peninsula. After this feature moves eastward tomorrow, the ridge is forecast to rebuild which should result in the track's bending toward the west- northwest and west by 36 to 48 hours. For this forecast cycle, there has been a notable shift in the guidance to the left through 48 hours, and the track has generally been shifted in that direction but not as far left as the ECMWF and GFS solutions. After 48 hours, the spread in the guidance increases, with the GFS depicting a stronger cyclone on the northern end of the guidance envelope and the ECMWF a weaker one on the southern edge. The official NHC forecast track lies nearly between the two extremes, close to the multi-model consensus (TVCE). The intensity forecast is challenging. Despite moderate northerly shear, the cyclone has slowly strengthened during the past 24 hours. Although this shear is forecast to persist through tomorrow, the cyclone's inner-core structure suggests that further intensification should occur. The official forecast exceeds the statistical-dynamical guidance through 36 hours on the basis of current trends and the hurricane's well organized inner core. Although the shear should lessen in a day or two, weakening should commence as thermodynamics in the near-storm environment gradually become less conducive for intensification. The official NHC intensity forecast shows steady weakening after 36 hours, very similar to the multi-model consensus (ICON). FORECAST POSITIONS AND MAX WINDS INIT 30/0300Z 13.4N 115.2W 75 KT 85 MPH 12H 30/1200Z 14.2N 116.0W 85 KT 100 MPH 24H 31/0000Z 15.1N 117.1W 85 KT 100 MPH 36H 31/1200Z 15.7N 118.4W 80 KT 90 MPH 48H 01/0000Z 16.2N 119.6W 75 KT 85 MPH 72H 02/0000Z 17.4N 122.3W 60 KT 70 MPH 96H 03/0000Z 18.6N 125.7W 50 KT 60 MPH 120H 04/0000Z 19.1N 128.8W 35 KT 40 MPH $$ Forecaster Kimberlain