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#983789 (Received by flhurricane at: 11:03 PM 23.Sep.2019) TCDAT2 Tropical Depression Karen Discussion Number 8 NWS National Hurricane Center Miami FL AL122019 1100 PM AST Mon Sep 23 2019 Deep convection associated with Karen has increased during the past few hours, but the thunderstorm activity remains confined to the south of the center due to north-northeasterly shear. The Air Force Hurricane Hunters have been investigating the depression this evening, and a combination of the flight-level and SFMR data indicate that winds are just below tropical-storm-force. The aircraft measured a minimum pressure of about 1008 mb. Karen is currently situated near the western periphery of a subtropical ridge, and it is forecast to turn northward on Tuesday as it passes Puerto Rico and the Virgin Islands. After that time, a northward to north-northeastward motion seems likely as the cyclone moves into a weakness left behind by Tropical Storm Jerry. However, the models indicate that the trough will not capture Karen, and instead the cyclone could come to a stop or drift westward by the weekend as a ridge builds to the north of the system. Although the models agree on the overall scenario, the details are quite uncertain and there remains a large spread in the guidance at days 4 and 5. The new NHC track forecast is adjusted a little to the right of the previous one to be in better agreement with the latest consensus models. The environment is still quite hostile around Karen with north-northeasterly shear of about 20 kt currently impacting the cyclone. However, the upper-level wind pattern is expected to become more favorable during the next few days, and that could give it an opportunity to strengthen. The NHC intensity forecast shows a slow increase in winds through the forecast period. This forecast is similar to the previous one, and lies roughly between the aggressive SHIPS/LGEM models and the HWRF/HMON models which show little change in intensity during the next several days. Key Messages: 1. Regardless of Karen`s status and intensity, the system is expected to bring heavy rainfall, flash floods and mudslides to Puerto Rico and the U.S. and British Virgin Islands on Tuesday, where a tropical storm warning is in effect. The rainfall and potential flooding will likely continue on Wednesday even as the center of Karen moves away from Puerto Rico and the Virgin Islands. FORECAST POSITIONS AND MAX WINDS INIT 24/0300Z 16.1N 65.8W 30 KT 35 MPH 12H 24/1200Z 17.5N 66.2W 35 KT 40 MPH 24H 25/0000Z 19.6N 66.2W 35 KT 40 MPH 36H 25/1200Z 22.0N 65.8W 35 KT 40 MPH 48H 26/0000Z 23.9N 65.2W 40 KT 45 MPH 72H 27/0000Z 26.8N 64.1W 45 KT 50 MPH 96H 28/0000Z 28.0N 64.0W 50 KT 60 MPH 120H 29/0000Z 28.0N 66.5W 55 KT 65 MPH $$ Forecaster Cangialosi |