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| #983501 (Received by flhurricane at: 5:11 AM 22.Sep.2019) TCDAT5 Tropical Storm Jerry Discussion Number 20 NWS National Hurricane Center Miami FL AL102019 500 AM AST Sun Sep 22 2019 A very large burst of deep convection has formed near Jerry, but there is no sign from recent microwave data that it is causing any significant change in structure. The center still appears to be on the northwestern edge of the deep convection, which is consistent with a tropical cyclone undergoing moderate-to-strong northwesterly shear. The initial wind speed is held at 55 kt, a bit above the ASCAT pass from several hours ago, but at that time the center was exposed, so it is reasonable to think the system is a bit stronger than shown in that pass. An Air Force Reserve Hurricane Hunter aircraft should investigate the system around 1200 UTC. Overall, there are a lot of mixed signals with the future strength of Jerry. While the storm should remain over very warm waters, any relaxation of the current shear isn`t expected to last very long, and the consensus of the models is that an expected mid-latitude trough interaction should lead to much weakening or strengthening. Thus, little change in strength is shown throughout the period, similar to the last forecast, and only slight weakening is shown at long range as Jerry undergoes the first stages of extratropical transition. The initial motion is slower to the north-northwest, 330/10 kt. The biggest change from the past advisory is shifting the forecast track westward about half a degree in about 48 hours, with more of the models showing that the aforementioned trough interaction will steer the storm more to the left. Jerry should then accelelerate to the northeast ahead of the next mid-latitude trough, and the forecast track is a little faster at long range. Key Messages: 1. The risk of tropical-storm-force winds on Bermuda is increasing, with Jerry forecast to pass near the island Tuesday and Wednesday. It is too soon to determine what impacts the system may have on Bermuda, but interests there should monitor the progress of Jerry. A Tropical Storm Watch could be issued later today for Bermuda. FORECAST POSITIONS AND MAX WINDS INIT 22/0900Z 25.0N 66.9W 55 KT 65 MPH 12H 22/1800Z 26.3N 67.6W 55 KT 65 MPH 24H 23/0600Z 27.6N 68.0W 60 KT 70 MPH 36H 23/1800Z 29.0N 68.3W 60 KT 70 MPH 48H 24/0600Z 30.4N 68.6W 55 KT 65 MPH 72H 25/0600Z 34.0N 65.5W 55 KT 65 MPH 96H 26/0600Z 39.0N 57.0W 50 KT 60 MPH 120H 27/0600Z 43.0N 47.0W 45 KT 50 MPH $$ Forecaster Blake |
