000 WTNT44 KNHC 011453 TCDAT4 HURRICANE MATTHEW DISCUSSION NUMBER 14 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142016 1100 AM EDT SAT OCT 01 2016 The eye of Matthew has shrunk and become less distinct in geostationary imagery during the past few hours. Data from an Air Force Reserve Hurricane Hunter aircraft show a very sharp wind profile near the center and a radius of maximum winds of 7 n mi. The central pressure has risen a little, to 947 mb on the last center fix. The highest SFMR wind sampled by the aircraft was 118 kt, so the initial intensity is conservatively lowered to 125 kt for this advisory. Its possible that an eyewall replacement cycle has begun, but there is not much evidence of a secondary wind maximum in the aircraft data yet, and we haven't had any recent microwave imagery to look at the inner-core structure. Gradual weakening is expected in the next 24 hours, in agreement with all of the guidance, but Matthew is expected to remain a powerful hurricane until it until interacts with the land masses of Jamaica, Hispaniola, and Cuba in 2-3 days. After that time, conditions appear conducive for restrengthening once Matthew moves into the Bahamas late in the forecast period. Note that there will likely be short-term fluctuations in intensity due to possible eyewall replacement cycles that are not shown here. Matthew has been moving westward at around 5 kt under the influence of a mid-level ridge centered near Bermuda. This ridge is forecast to gradually weaken and shift eastward, which should allow Matthew to turn northward while it moves into a weakness in the ridge during the forecast period. The track model guidance is in generally good agreement on this scenario through 48 hours, and during that time the new NHC forecast has been shifted a little to the right toward the latest consensus aids, but remains to their left and lies near the latest GFS track. Late in the period the track model spread increases, with the ECMWF on the right and the GFS well to the left. The evolution of the western Atlantic subtropical ridge late in the period appears to be sensitive to the track and strength of the mid/upper-level low currently centered over the Ohio Valley. The ECMWF shows a weaker ridge, which allows Matthew to move farther east, while the GFS has a stronger ridge and takes Matthew more north-northwestward. Given the uncertainty and variability seen in the handling of these features from cycle to cycle, the NHC forecast continues to lie in between the two scenarios, and maintains continuity with the previous official forecast. The new NHC track is well east of the latest GFS by day 5, but lies west of the consensus aids. Needless to say, confidence in the details of the track forecast at days 4 and 5 is quite low. 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 01/1500Z 13.4N 73.4W 125 KT 145 MPH 12H 02/0000Z 13.6N 73.9W 120 KT 140 MPH 24H 02/1200Z 14.5N 74.6W 115 KT 130 MPH 36H 03/0000Z 15.7N 75.2W 110 KT 125 MPH 48H 03/1200Z 17.1N 75.5W 110 KT 125 MPH 72H 04/1200Z 20.5N 75.5W 95 KT 110 MPH...INLAND 96H 05/1200Z 24.0N 76.0W 95 KT 110 MPH...OVER WATER 120H 06/1200Z 26.5N 76.5W 100 KT 115 MPH $$ Forecaster Brennan