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#983749 (Received by flhurricane at: 4:54 PM 23.Sep.2019) TCDAT2 Tropical Depression Karen Discussion Number 7 NWS National Hurricane Center Miami FL AL122019 500 PM AST Mon Sep 23 2019 Karen has become increasingly disorganized today. Visible satellite imagery and surface observations suggest that there is a broad low-level circulation, but the aircraft struggled to find a well-defined center. Based on the current lack of organization, the initial wind speed has been lowered to 30 kt. The environment ahead of Karen is forecast to remain quite hostile, with dry mid-level air and strong northeasterly shear continuing overnight. After Karen moves north of Puerto Rico over the western Atlantic, it may find itself in a more favorable upper-level environment, but given the current structure of the cyclone it should take some time for any potential re-strengthening to occur. As a result, the long-range intensity forecast is a little lower than the previous advisory and remains of very low confidence. Karen is moving northwestward or 335/11 kt. Karen should turn northward later tonight or early Tuesday toward a weakness in the subtropical ridge over the western Atlantic caused by Jerry. A northward to north-northeast motion should then take the storm over the western Atlantic well to the east of the Bahamas around mid- week. After that time, a deep-layer ridge is forecast to build over the southeastern United States and far western Atlantic, which should cause Karen to slow down and become nearly stationary at days 4 and 5. The track guidance has trended toward Karen gaining more latitude before slowing, and the new NHC track forecast as been adjusted accordingly. The latter portion of the track forecast is still quite uncertain as the dynamical model guidance and their ensembles still exhibit large spread. Although Karen in shown to remain a tropical depression as it passed Puerto Rico and the Virgin Islands, the tropical storm warning is begin maintained since only a small increase in the wind speed would make Karen a tropical storm again. In addition, windward facing areas at high elevation on the islands could experience winds higher than those shown in the official forecast. 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 23/2100Z 15.9N 65.6W 30 KT 35 MPH 12H 24/0600Z 17.2N 66.2W 30 KT 35 MPH 24H 24/1800Z 18.9N 66.6W 30 KT 35 MPH 36H 25/0600Z 21.3N 66.3W 30 KT 35 MPH 48H 25/1800Z 23.3N 65.9W 35 KT 40 MPH 72H 26/1800Z 26.5N 65.0W 45 KT 50 MPH 96H 27/1800Z 27.5N 65.5W 50 KT 60 MPH 120H 28/1800Z 27.5N 67.0W 55 KT 65 MPH $$ Forecaster Brown |