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Hurricane Rosa Forecast Discussion Number 15
2018-09-28 22:55:45| National Hurricane Center (East Pacific)
Issued at 200 PM PDT Fri Sep 28 2018 259 WTPZ45 KNHC 282055 TCDEP5 Hurricane Rosa Discussion Number 15 NWS National Hurricane Center Miami FL EP202018 200 PM PDT Fri Sep 28 2018 Rosa's appearance has rapidly deteriorated since this morning. There is still evidence of an ongoing eyewall replacement cycle, and an apparent moat region has occasionally been apparent in conventional satellite data during the past several hours. The slow motion of the hurricane since last night could also be causing upwelling that would lead to further weakening. Satellite intensity estimates from all agencies have dropped substantially accordingly, and the initial intensity has been lowered to 105 kt, based on a blend of Final-T and CI numbers from TAFB and SAB. Rosa is still moving northwestward, with an initial motion of 325/5 kt. The model spread has increased a little, with the GFS and its associated regional models showing a slightly right (southeast) track, compared to earlier cycles, while the ECMWF has shifted an equal amount to the left (northwest). The consensus models have not changed much as a result of these offsetting model trends, so almost no change was made to the NHC track forecast. Rosa is still expected to turn northward, and then north-northeastward ahead of a mid- to upper-level trough approaching from the northwest. The cyclone should then accelerate a little as it approaches the northern coast of the Baja California peninsula early next week. At this point, the structure of Rosa has degraded to the point that substantial restrengthening appears unlikely. Since the hurricane still has about 24-36 hours before it reaches much cooler SSTs, only gradual weakening is forecast, though most of the intensity guidance shows more rapid weakening than currently indicated. After that time, a more rapid rate of weakening could occur due to cooler SSTs and an increase in wind shear associated with an upper-level trough approaching from the west. By early next week, Rosa is forecast to move inland over northern Baja California, and its surface circulation will likely dissipate shortly thereafter. However, moisture associated with Rosa is expected to spread northeastward through parts of the southwest United States. For more information about potential rainfall in that area, please see products from the Weather Prediction Center and your local NWS forecast office. Key Messages: 1. Rosa could bring tropical storm conditions to portions of the central and northern Baja California peninsula in a few days. Interests in those locations should monitor the progress of Rosa. 2. Heavy rainfall associated with Rosa or its remnants is expected to affect parts of the southwest United States by early next week, which could cause flooding in this region. For more information about potential rainfall and flooding, please see products from the Weather Prediction Center and your local NWS forecast office. FORECAST POSITIONS AND MAX WINDS INIT 28/2100Z 17.7N 117.8W 105 KT 120 MPH 12H 29/0600Z 18.6N 118.3W 95 KT 110 MPH 24H 29/1800Z 20.3N 118.8W 85 KT 100 MPH 36H 30/0600Z 22.1N 118.9W 75 KT 85 MPH 48H 30/1800Z 24.0N 118.4W 65 KT 75 MPH 72H 01/1800Z 27.7N 116.8W 45 KT 50 MPH 96H 02/1800Z 32.3N 114.5W 30 KT 35 MPH...INLAND 120H 03/1800Z...DISSIPATED $$ Forecaster Zelinsky
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Category:Transportation and Logistics