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Tropical Storm Erick Forecast Discussion Number 4
2019-07-28 10:33:37| National Hurricane Center (East Pacific)
Issued at 1100 PM HST Sat Jul 27 2019 000 WTPZ41 KNHC 280833 TCDEP1 Tropical Storm Erick Discussion Number 4 NWS National Hurricane Center Miami FL EP062019 1100 PM HST Sat Jul 27 2019 Erick's cloud pattern has not changed much in organization over the past several hours, although there is slight evidence of increased convective banding over the southern semicircle of the circulation. Dvorak intensity estimates from both TAFB and SAB remain at 35 kt, so the advisory intensity is held at 35 kt for now. An upper-level anticyclone is established over the storm, and water temperatures are sufficiently warm for intensification. Apparently, Erick has not yet acquired a well-defined inner core but that is expected to occur rather soon. Therefore, steady strengthening is likely to begin within the next 12 hours. Some of the dynamical intensity models along with the simple and corrected consensus aids show the system becoming a hurricane within 36 hours, so the official forecast has been increased from the earlier NHC predictions and is near or below the consensus through 72 hours. By days 4 to 5, increased shear and some drier air is likely to cause weakening. The motion continues to be only slightly north of due west, or 280/14 kt. The steering scenario is fairly straightforward. A fairly well-defined mid-level ridge is forecast by the global models to remain established to the north of Erick throughout most of the forecast period. By the end of the forecast period, this ridge is likely to weaken, and this could cause a more northward motion to develop. By that time however, the weakening cyclone should be steered more by the low-level easterly flow which should keep the motion on a generally westward or just north of westward heading. The official track forecast is similar to the previous one, and close to the corrected dynamical model consensus. FORECAST POSITIONS AND MAX WINDS INIT 28/0900Z 12.1N 128.1W 35 KT 40 MPH 12H 28/1800Z 12.4N 130.2W 45 KT 50 MPH 24H 29/0600Z 12.8N 133.0W 55 KT 65 MPH 36H 29/1800Z 13.4N 135.9W 65 KT 75 MPH 48H 30/0600Z 14.0N 138.5W 75 KT 85 MPH 72H 31/0600Z 15.4N 143.3W 85 KT 100 MPH 96H 01/0600Z 16.6N 148.0W 65 KT 75 MPH 120H 02/0600Z 17.0N 153.0W 50 KT 60 MPH $$ Forecaster Pasch
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