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Tropical Storm Jerry Forecast Discussion Number 4
2019-09-18 12:23:43| National Hurricane Center (Atlantic)
Issued at 500 AM AST Wed Sep 18 2019 000 WTNT45 KNHC 180901 TCDAT5 Tropical Storm Jerry Discussion Number 4 NWS National Hurricane Center Miami FL AL102019 500 AM AST Wed Sep 18 2019 Enhanced BD-curve infrared imagery and a 0431 UTC AMSR2 microwave pass indicate that the cyclone has become better organized during the pass several hours. Although the surface center is still situated near the northeastern edge of the convective mass, the deep convection has expanded in the form of curve bands in the south portion of the cyclone. Based on the increased subjective and objective satellite intensity estimates, and the improved microwave presentation, the initial intensity is raised to 40 kt making the system the tenth named storm of the season. Even though the shear is low and the sea surface temperatures are warm, GOES-16 sounder data and the GFS/ECMWF SHIPS intensity models indicate that the environment surrounding the cyclone is still a little dry and stable. Therefore, only gradual intensification is forecast. The shear is forecast to increase after 24 hours or so, to the point where it should slow, or halt development, and this is reflected in the official forecast. It should be noted that the forecast still calls for the cyclone to become a hurricane as it approaches the northern Leeward Islands. The initial motion is estimated to be west-northwestward, or 290/11 kt, within the low to mid-tropospheric steering flow produced by a subtropical ridge to the north of the tropical storm. This general motion is expected to continue during the next 3 to 4 days. Afterward, a northwest to north-northwestward turn, influenced by a growing weakness in the aforementioned ridge, is expected. The NHC track forecast is basically an update from the previous advisory and lies in the middle of the guidance suite, and hedged toward the HCCA multi-model consensus. Key Messages: 1. Jerry is expected to strengthen and be a hurricane when its moves near the northern Leeward Islands Friday, although it is too soon to determine if there will be any direct impacts in the islands. Interests there should ensure they have their hurricane plan in place and monitor the progress of this system. FORECAST POSITIONS AND MAX WINDS INIT 18/0900Z 14.1N 47.7W 40 KT 45 MPH 12H 18/1800Z 14.8N 49.4W 45 KT 50 MPH 24H 19/0600Z 15.7N 52.0W 55 KT 65 MPH 36H 19/1800Z 16.8N 54.9W 60 KT 70 MPH 48H 20/0600Z 17.9N 57.9W 65 KT 75 MPH 72H 21/0600Z 20.2N 64.2W 65 KT 75 MPH 96H 22/0600Z 22.8N 68.6W 65 KT 75 MPH 120H 23/0600Z 25.6N 70.2W 65 KT 75 MPH $$ Forecaster Roberts
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