ZCZC MIATCDAT5 ALL TTAA00 KNHC DDHHMM TROPICAL STORM NICOLE DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152016 500 PM AST WED OCT 05 2016 A 1846 UTC SSMI microwave pass showed that Nicole has a well-defined mid-level eye with the deepest convection to the southeast of the center. Nicole's visible satellite presentation has also improved, and there has been a recent burst of convection right over the center. Dvorak intensity estimates are now T3.0 from SAB and T3.5 from TAFB, so the initial intensity is raised to 50 kt. It's often difficult to estimate the strength of small cyclones like Nicole based on satellite alone, and it's possible that the intensity could be higher. As discussed this morning, Nicole is located beneath an upper-level shear axis, so the vertical shear directly over the cyclone is actually not that high. Since Nicole could stay in this type of environment for another 12-24 hours, and due to the cyclone's small size, the maximum winds could increase in the short term. The new NHC intensity forecast is higher than the previous forecast during the first 24 hours, and it is above all of the guidance during that period. In fact, it would not be surprising if Nicole was to become a hurricane some time soon, especially since it already has a eye in microwave imagery. After 24 hours, a larger area of strong upper-level winds should overspread Nicole, and the maximum winds should therefore decrease through the end of the forecast period. The initial motion remains 300/7 kt. Nicole's forward motion is expected to slow down to a crawl by 36 hours, and after that time, there is considerable spread in the guidance. For example, by day 5, the ECMWF pulls Nicole well northward, absorbed by Matthew and a nearby frontal zone, while the UKMET, HWRF, and GFDN models push Nicole southward or southwestward. Given this uncertainty, the NHC track forecast continues to show a slow meandering motion on days 2-5. FORECAST POSITIONS AND MAX WINDS INIT 05/2100Z 25.3N 63.5W 50 KT 60 MPH 12H 06/0600Z 26.3N 64.5W 60 KT 70 MPH 24H 06/1800Z 27.4N 65.2W 60 KT 70 MPH 36H 07/0600Z 27.9N 65.3W 55 KT 65 MPH 48H 07/1800Z 27.7N 64.8W 55 KT 65 MPH 72H 08/1800Z 27.0N 64.0W 55 KT 65 MPH 96H 09/1800Z 27.5N 65.0W 45 KT 50 MPH 120H 10/1800Z 29.5N 65.0W 35 KT 40 MPH $$ Forecaster Berg NNNN