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#941634 (Received by flhurricane at: 4:48 AM 24.Sep.2018) TCDAT2 Tropical Depression Kirk Discussion Number 8 NWS National Hurricane Center Miami FL AL122018 500 AM AST Mon Sep 24 2018 After having a minimal amount of deep convection late yesterday, Kirk is now producing some thunderstorm activity in fragmented bands around the estimated center. However, earlier ASCAT data and low cloud motion suggest that the circulation resembles a sharp trough instead of a closed low that is necessary for a tropical cyclone. Hopefully more visible satellite images and additional scatterometer data will help better assess the circulation and status of Kirk. For now, advisories are being maintained on the system, and the initial intensity is held at 30 kt based on the earlier ASCAT data and a blend of the Dvorak estimates. Kirk is moving very quickly to the west at about 21 kt, which is likely the reason why the system has been struggling. A continued westward motion but at a decreasing forward speed is expected during the next two to three days while the cyclone remains on the south side of a low- to mid-level ridge. After that time, a large deep-layer low pressure system over the central Atlantic should cause Kirk to gain more latitude. The NHC track forecast is largely an update of the previous one, and remains near the southern side of the guidance envelope near the GFS and ECMWF models. This forecast takes Kirk toward the Lesser Antilles in 3 to 4 days and interests there should monitor the progress of this system. Although Kirk will be moving over warmer SSTs and remain in relatively moist conditions, its fast forward speed will likely limit the system from strengthening significantly during the next few days, so only a little intensification is predicted. The global models show a notable increase in westerly shear when Kirk reaches the eastern Caribbean Sea in about 4 days, and that should cause weakening and possibly even dissipation by the end of the forecast period. The NHC intensity forecast lies near the lower side of the guidance envelope, in best agreement with the NOAA HCCA model. FORECAST POSITIONS AND MAX WINDS INIT 24/0900Z 9.5N 37.4W 30 KT 35 MPH 12H 24/1800Z 9.9N 40.5W 30 KT 35 MPH 24H 25/0600Z 10.2N 44.6W 35 KT 40 MPH 36H 25/1800Z 10.5N 48.4W 35 KT 40 MPH 48H 26/0600Z 10.9N 51.7W 40 KT 45 MPH 72H 27/0600Z 12.1N 57.1W 40 KT 45 MPH 96H 28/0600Z 13.2N 61.5W 35 KT 40 MPH 120H 29/0600Z 14.0N 66.0W 30 KT 35 MPH $$ Forecaster Cangialosi |