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#941441 (Received by flhurricane at: 4:48 PM 22.Sep.2018) TCDAT2 Tropical Storm Kirk Discussion Number 2 NWS National Hurricane Center Miami FL AL122018 500 PM AST Sat Sep 22 2018 The convection associated with Kirk is currently disorganized, with the majority of it in a cluster to the west of the center. Most of the subjective and objective satellite intensity estimates are in the 30-35 kt range, so the initial intensity remains 35 kt for this advisory. The forecast track takes Kirk over SSTs around 27C for the next 36 h or so with generally low shear, which appears favorable for gradual strengthening. However, there is a possibility that entrainment of dry air from an area of African dust present to the north of Kirk may allow less intensification than currently forecast. From 36-72 h, there is some divergence in the intensity guidance between the SHIPS and LGEM models, which forecast strengthening into a hurricane, and the dynamical models, which forecast little additional strengthening. The intensity forecast leans toward the dynamical models during that period. After 72 h, Kirk should encounter increasing westerly shear and gradually weaken. The intensity forecast, which is unchanged from the previous forecast, lies a little above the intensity consensus IVCN. The initial motion is now 290/13. The subtropical ridge to the north of the storm should steer Kirk quickly westward for the next 72 h or so, with forward speeds reaching 20-25 kt. Later in the forecast period, Kirk should turn west-northwestward with a decrease in forward speed as it nears a developing weakness in the ridge near and to the east of the Lesser Antilles. The new forecast track, which is closest to the HCCA consensus model, is shifted a little to the north of the previous track. However, it continues to lie on the south side of the guidance envelope. FORECAST POSITIONS AND MAX WINDS INIT 22/2100Z 8.6N 24.8W 35 KT 40 MPH 12H 23/0600Z 9.1N 27.1W 40 KT 45 MPH 24H 23/1800Z 9.5N 31.2W 45 KT 50 MPH 36H 24/0600Z 9.7N 35.7W 50 KT 60 MPH 48H 24/1800Z 9.8N 40.2W 50 KT 60 MPH 72H 25/1800Z 10.5N 48.0W 50 KT 60 MPH 96H 26/1800Z 11.5N 54.0W 45 KT 50 MPH 120H 27/1800Z 13.0N 59.0W 40 KT 45 MPH $$ Forecaster Beven |