000 WTNT44 KNHC 302051 TCDAT4 HURRICANE MATTHEW DISCUSSION NUMBER 11 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142016 500 PM EDT FRI SEP 30 2016 Matthew has continued to rapidly strengthen at a remarkable rate today. A NOAA Hurricane Hunter aircraft recently reported a peak SFMR wind of 116 kt and flight-level winds of 121 kt. A recent dropsonde from the aircraft indicated that surface winds are around 120 kt. Based on all of these data, the initial intensity is set to 120 kt, an increase of 55 kt in the last 24 hours. The latest pressure estimate from the aircraft is 949 mb, a drop of 44 mb since this time yesterday. Some additional strengthening is possible in the next 12 hours or so, and the NHC forecast reflects that possibility, showing 125 kt at that time. Given the lack of skill of the intensity guidance thus far, this remains a low confidence forecast, and its possible this could be conservative. Since Matthew has now become a major hurricane, eyewall replacement cycles could occur that would lead to some fluctuations in intensity not shown here. After 12 hours, a gradual weakening is shown, following the trend of, but above nearly all of the intensity guidance. Land interaction with Cuba should lead to additional weakening by day 4, but Matthew is expected to remain a strong hurricane through the forecast period. The initial motion is still toward the west-southwest, but the forward speed has slowed a bit, to around 8 kt. The track forecast reasoning has not changed, with Matthew expected to turn westward by 12 hours and then gradually turn toward the north in the next 3 to 4 days as the cyclone moves into a weakness in the subtropical ridge. The track model guidance is in slightly better agreement this cycle through 3 days, although the ECMWF remains right of and slower than the rest of the guidance at days 4 and 5. The GFS, HWRF, and COAMPS-TC are faster and to the left late in the period, although the GFS has trended slower this cycle. The new NHC track has again been adjusted a little to the left through 72 hours given the initial position and motion, and after that time is along the previous official forecast but slower, following the slower trend in the guidance this cycle. The NHC forecast is near the middle of the guidance envelope and is a little to the east of the multi-model consensus at days 4 and 5. It is important to remind users that average NHC track forecast errors are around 175 miles at day 4 and 230 miles at day 5. Therefore, it is too soon to rule out possible hurricane impacts from Matthew in Florida. FORECAST POSITIONS AND MAX WINDS INIT 30/2100Z 13.5N 71.6W 120 KT 140 MPH 12H 01/0600Z 13.3N 72.8W 125 KT 145 MPH 24H 01/1800Z 13.5N 73.9W 120 KT 140 MPH 36H 02/0600Z 14.1N 74.8W 115 KT 130 MPH 48H 02/1800Z 15.2N 75.6W 110 KT 125 MPH 72H 03/1800Z 18.2N 76.2W 105 KT 120 MPH 96H 04/1800Z 22.0N 76.0W 90 KT 105 MPH 120H 05/1800Z 25.0N 76.0W 90 KT 105 MPH $$ Forecaster Brennan