217 WTNT42 KNHC 232032 TCDAT2 Tropical Storm Kirk Discussion Number 6 NWS National Hurricane Center Miami FL AL122018 500 PM AST Sun Sep 23 2018 Deep convection has diminished near the estimated center of Kirk, and the main thunderstorm activity is occurring over the northwestern and western peripheries of the circulation. This has the appearance of an arc cloud, suggesting that some drier mid-level air has been entrained into the tropical cyclone. Since the system should be moving over warmer waters and through low vertical shear for the next day or so, some strengthening is anticipated into early this weak. Later in the forecast period, Kirk should be encountering increasing shear associated with strong upper-level westerlies over the Caribbean, and this will likely cause weakening. The official forecast is close to the latest Florida State University Superensemble prediction and is the same as the previous NHC forecast. Based on the latest center fixes, the motion continues swiftly toward the west, or about 280/20 kt. A mid-level subtropical ridge to the north of Kirk should steer the tropical cyclone westward at a fairly fast clip for the next couple of days. By days 3-4, the ridge weakens a bit and Kirk should slow its forward motion somewhat. The official track forecast has not changed much from the previous advisory and is close to the latest corrected consensus model, HCCA, prediction. FORECAST POSITIONS AND MAX WINDS INIT 23/2100Z 9.5N 32.3W 35 KT 40 MPH 12H 24/0600Z 9.9N 35.3W 40 KT 45 MPH 24H 24/1800Z 10.2N 39.5W 45 KT 50 MPH 36H 25/0600Z 10.4N 43.4W 50 KT 60 MPH 48H 25/1800Z 10.6N 47.1W 50 KT 60 MPH 72H 26/1800Z 11.6N 53.4W 45 KT 50 MPH 96H 27/1800Z 12.9N 58.1W 40 KT 45 MPH 120H 28/1800Z 14.0N 63.0W 35 KT 40 MPH $$ Forecaster Pasch