ZCZC MIATCDAT5 ALL TTAA00 KNHC DDHHMM TROPICAL STORM NICOLE DISCUSSION NUMBER 24 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152016 1100 PM AST SUN OCT 09 2016 Depp convection associated with Nicole has decreased since the last advisory, with the primary convection now confined to an area south of the center. It is unclear whether this is due to the normal diurnal convective minimum, entrainment of dry air seen near the center in water vapor imagery, or the result of cooling sea surface temperatures under the stationary storm. Satellite intensity estimates from TAFB and SAB remain 55 kt, while the latest satellite consensus estimate from CIMSS is 51 kt. Based on these data, the initial intensity remains 55 kt. Nicole is now drifting northward, and this motion should continue for the next 12-24 hours as a blocking ridge of high pressure north of the cyclone weakens. A deep-layer trough associated with former Hurricane Matthew is forecast to pass north of Nicole, with a second ridge passing north of the storm after 24 hours. This should cause a northwestward turn, and the guidance during this stage of the forecast has shifted left since the previous advisory. After 72 hours, a new trough moving eastward from the United States should cause Nicole to recurve northeastward into the westerlies. The new forecast track is shifted to the left between 24-72 hours, but still lies to the east of the various consensus models. After 72 hours, the track lies a little north of the previous track. A combination of the above mentioned dry air, possible cooler waters, and continuing strong northerly shear should limit intensification for the next 12 hours or so. After that, the shear should gradually subside and allow Nicole to intensify if the cyclone does not entrain too much low-level dry air brought southward due to Matthew. The environment is most favorable at about 72 hours, and the new intensity forecast calls for a slightly increased peak intensity of 85 kt in best agreement with the SHIPS model. After that time, the cyclone is expected to encounter the mid-latitude westerlies with increased shear partly compensated for by increased upper-level divergence. This environment should lead to gradual weakening with extratropical transition beginning near 120 hours. FORECAST POSITIONS AND MAX WINDS INIT 10/0300Z 24.4N 65.3W 55 KT 65 MPH 12H 10/1200Z 25.1N 65.3W 55 KT 65 MPH 24H 11/0000Z 26.0N 65.5W 60 KT 70 MPH 36H 11/1200Z 26.6N 65.9W 65 KT 75 MPH 48H 12/0000Z 27.1N 66.4W 70 KT 80 MPH 72H 13/0000Z 28.5N 66.5W 85 KT 100 MPH 96H 14/0000Z 32.0N 64.0W 85 KT 100 MPH 120H 15/0000Z 37.0N 58.0W 70 KT 80 MPH $$ Forecaster Beven NNNN