| WTNT45 KNHC 130301 TCDAT5 HURRICANE NICOLE DISCUSSION NUMBER 36 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152016 1100 PM AST WED OCT 12 2016 Nicole's satellite presentation has improved, with a warm, distinct, 30 n mi wide eye surrounded by cloud tops of -70C. The large eye is also now visible on the Bermuda radar. An Air Force Reserve Hurricane Hunter aircraft just measured a 700-mb wind of 119 kt and a peak SFMR wind of 118 kt. Based on these data, the initial intensity is set to 115 kt for this advisory. The latest extrapolated minimum pressure from the aircraft is around 950 mb, a decrease of 20 mb since this morning. The aircraft data also showed an expansion of the hurricane force wind field in the northwest and southeast quadrants. The shear is expected to increase quickly, reaching 25-30 kt by 12 h and 45-50 kt by 36 hours. This increase in shear and a gradual decrease in SSTs should result in some weakening in the first 36 to 48 hours, but baroclinic forcing from a mid-latitude shortwave trough should maintain Nicole as a powerful cyclone through the forecast period. The amount of tropical characteristics Nicole will have late in the forecast period remains uncertain, as the cyclone will not undergo a classical extratropical transition. Post-tropical status is shown at days 3 through 5, but confidence in this part of the forecast remains low. The NHC intensity forecast is close to the latest intensity consensus through 48 hours and is based on global models after that time. The initial motion estimate is 020/10, as Nicole is beginning to recurve into the mid-latitude flow ahead of a broad longwave trough moving offshore of the U.S. east coast. This synoptic pattern should result in Nicole accelerating northeastward and then east-northwestward in the next 24 to 48 hours. After 72 hours, the trough moves away from Nicole, and leaves the cyclone meandering in a region of weak steering currents to the south of a high-latitude ridge, and only a a slow eastward to northeastward drift is expected at days 4 and 5. The new NHC track forecast is an update of the previous one through 24 hours, and continues to take the core of Nicole near or over Bermuda on Thursday. After 24 hours, the new NHC track has been shifted a bit to the right, and lies to the right of the multi-model consensus, favoring a blend of the global models and their ensemble means. The forecast at days 3 through 5 has been coordinated with the NOAA Ocean Prediction Center. Note that while hurricanes often affect Bermuda, a hurricane this strong is rare. There have only been seven major hurricanes that have passed within 40 n mi of Bermuda in the Atlantic hurricane database, which goes back to 1851. FORECAST POSITIONS AND MAX WINDS INIT 13/0300Z 30.1N 66.4W 115 KT 130 MPH 12H 13/1200Z 31.6N 65.3W 105 KT 120 MPH 24H 14/0000Z 33.8N 62.7W 90 KT 105 MPH 36H 14/1200Z 35.7N 59.0W 80 KT 90 MPH 48H 15/0000Z 37.3N 55.0W 75 KT 85 MPH 72H 16/0000Z 38.5N 50.5W 75 KT 85 MPH...POST-TROPICAL 96H 17/0000Z 38.5N 50.0W 65 KT 75 MPH...POST-TROPICAL 120H 18/0000Z 40.0N 49.0W 65 KT 75 MPH...POST-TROPICAL $$ Forecaster Brennan |