000 WTNT43 KNHC 160838 TCDAT3 HURRICANE GONZALO DISCUSSION NUMBER 16 NWS NATIONAL HURRICANE CENTER MIAMI FL AL082014 500 AM AST THU OCT 16 2014 The satellite presentation of Gonzalo has improved during the past few hours, with the eye warming and becoming more distinct since the last advisory. The 0600 UTC Dvorak estimate from TAFB was T6.0/115 kt and the 0715 UTC ADT was T6.2/120 kt. The initial intensity is set to 120 kt for this advisory based on the improving satellite appearance. The next Hurricane Hunter aircraft will be investigating Gonzalo around 1200 UTC to provide more information on the storm's intensity. Given the recent satellite trends, it seems that Gonzalo has completed the earlier eyewall replacement cycle. Some additional fluctuations in intensity are possible during the next 12 hours while Gonzalo remains over SSTs around 29C. Gradual weakening is forecast through 36 hours while SSTs slowly cool along the track and the shear begins to increase, and Gonzalo is expected to remain a dangerous hurricane as it passes near Bermuda on Friday. After 36 hours, faster weakening is shown as Gonzalo becomes post-tropical and then gradually decays as an extratropical cyclone late in the period. The new NHC intensity forecast is a little above most of the guidance in the short term and then trends toward the LGEM model while Gonzalo remains a tropical cyclone. The initial motion estimate is 360/08, as Gonzalo is moving northward to the west of a subtropical ridge. The model guidance is in very good agreement on the track forecast scenario, with Gonzalo expected to recurve ahead of a mid-latitude trough moving off the east coast of North America. The guidance this cycle has trended a little to the right through 48 hours and the NHC track has been adjusted 20-30 miles in that direction. This forecast is now a little to the left of the multi-model consensus and brings the center of Gonzalo very close to Bermuda in about 36 hours. Late in the period, post-tropical Gonzalo is expected to pass south of Newfoundland and then accelerate northeastward and eastward across the north Atlantic. At days 3 through 5, the new NHC forecast is largely an update of the previous one. The post-tropical portion of the forecast has been coordinated with the NOAA Ocean Prediction Center. FORECAST POSITIONS AND MAX WINDS INIT 16/0900Z 25.3N 68.7W 120 KT 140 MPH 12H 16/1800Z 26.8N 68.4W 115 KT 130 MPH 24H 17/0600Z 29.2N 67.1W 110 KT 125 MPH 36H 17/1800Z 31.9N 65.4W 100 KT 115 MPH 48H 18/0600Z 35.3N 63.4W 90 KT 105 MPH 72H 19/0600Z 45.5N 53.5W 70 KT 80 MPH...POST-TROPICAL 96H 20/0600Z 52.0N 33.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 21/0600Z 55.0N 10.0W 40 KT 45 MPH...POST-TROP/EXTRATROP $$ Forecaster Brennan