000 WTPZ45 KNHC 060851 TCDEP5 HURRICANE JULIO DISCUSSION NUMBER 10 NWS NATIONAL HURRICANE CENTER MIAMI FL EP102014 200 AM PDT WED AUG 06 2014 A small burst of deep convection with cloud tops of -75C to -80C has developed over the low-level center, resulting in the formation of a central dense overcast feature. In addition, passive microwave satellite imagery has been indicating a 75-100 percent closed low- to mid-level eye feature since about 0100 UTC. Satellite intensity estimates are a consensus T4.0 from TAFB and SAB, so the initial intensity has been increased to 65 kt, making Julio the fifth hurricane of the 2014 eastern North Pacific season. The initial motion estimate is 285/15 kt based on a blend of conventional and microwave satellite fixes. The NHC model guidance remains in excellent agreement on Julio moving along the southern periphery of a deep-layer ridge to its north for the next 72 hours or so. After that, a break in the ridge is forecast to develop north of the Hawaiian Islands on Days 4 and 5, and Julio is expected to turn more northwestward, passing just north of the Islands. However, the new model runs, which have incorporated the 0000 UTC NOAA G-IV jet dropsonde data are not showing as much erosion of the ridge as in previous runs, and the response has been a slight southward shift of the track guidance at 96 and 120 hours. The official forecast track is just an update of the previous advisory track through 72 hours, and was shifted slightly southward after that, similar to the consensus model TVCE, but not as far south as the ECMWF model. The latter model brings Julio much closer to the Hawaiian Islands since it no longer develops a break in the ridge. The developing eye feature, low shear of less than 5 kt, and a moistening mid-troposphere argue for at least some modest strengthening for the next 36 hours or so as Julio moves from a SST cold pool and over a warmer oceanic ridge. These condition also typically favor rapid intensification, which would be a possibility, except for the occasional intrusions of cooler and more stable air from the north. However, it wouldn't be surprising if Julio reaches its peak intensity a little sooner than forecast while the upper-level outflow pattern continues to expand. By 48 hours, the cyclone will be moving over cooler waters and into a more stable air mass, which should induce gradual weakening. The official intensity forecast is a little higher than the previous advisory and the consensus model ICON. FORECAST POSITIONS AND MAX WINDS INIT 06/0900Z 14.8N 129.0W 65 KT 75 MPH 12H 06/1800Z 15.4N 131.4W 70 KT 80 MPH 24H 07/0600Z 16.1N 134.5W 75 KT 85 MPH 36H 07/1800Z 16.7N 137.5W 80 KT 90 MPH 48H 08/0600Z 17.3N 140.4W 75 KT 85 MPH 72H 09/0600Z 18.5N 145.9W 65 KT 75 MPH 96H 10/0600Z 20.4N 151.1W 55 KT 65 MPH 120H 11/0600Z 23.0N 156.0W 50 KT 60 MPH $$ Forecaster Stewart