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| #941506 (Received by flhurricane at: 4:50 AM 23.Sep.2018) TCDAT2 Tropical Storm Kirk Discussion Number 4 NWS National Hurricane Center Miami FL AL122018 500 AM AST Sun Sep 23 2018 Recent microwave data show that Kirk`s center is located near the eastern edge of the deep convection. There are a few curved bands trying to form, but overall the convective activity is oriented along an east-west line extending west of the center. Since Dvorak classifications from TAFB and SAB are T2.5, the initial intensity remains 35 kt. Kirk has been accelerating since yesterday, and the current motion is westward, or 280 degrees, at 16 kt. Low- to mid-level ridging over the eastern Atlantic is expected to cause Kirk to move even faster toward the west during the next couple of days, reaching speeds of at least 22 kt in 24-36 hours. A reduction in speed is likely after 48 hours once Kirk moves south of a large central Atlantic trough, but it should still be moving along at a pretty good clip. The forecast thinking is the same as in previous advisories, with the latest NHC track forecast still closely following a blend of the GFS, ECMWF, and HFIP Corrected Consensus model along the southern edge of the guidance envelope. This new prediction is a little faster than what was indicated in the previous advisory. Kirk will be moving over increasingly warmer waters and through a relatively low-shear environment for the next 2-3 days, which should allow for some strengthening. The biggest limiting factors for intensification would be the cyclone`s fast motion and possible entrainment of dry air. Like every other tropical cyclone which has approached the Lesser Antilles from the east this season, Kirk is expected to run into strong westerly shear in 4-5 days, resulting in weakening as the cyclone gets closer to the islands. The NHC official forecast is still not as high as the statistical-dynamical guidance and more closely follows the HCCA, Florida State Superensemble, and intensity consensus, as well as the trends in the GFS and ECMWF. Based on those global models, it is possible that Kirk may open up into a trough as it is approaching the Lesser Antilles and moving into the eastern Caribbean Sea, but for now the official forecast maintains Kirk as a tropical storm through day 5. FORECAST POSITIONS AND MAX WINDS INIT 23/0900Z 9.1N 28.0W 35 KT 40 MPH 12H 23/1800Z 9.5N 30.7W 40 KT 45 MPH 24H 24/0600Z 10.0N 35.1W 45 KT 50 MPH 36H 24/1800Z 10.2N 39.5W 50 KT 60 MPH 48H 25/0600Z 10.4N 43.7W 50 KT 60 MPH 72H 26/0600Z 10.9N 51.0W 45 KT 50 MPH 96H 27/0600Z 12.0N 57.0W 40 KT 45 MPH 120H 28/0600Z 13.0N 61.5W 35 KT 40 MPH $$ Forecaster Berg |
