000 WTNT44 KNHC 032035 TCDAT4 HURRICANE MATTHEW DISCUSSION NUMBER 23 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142016 500 PM EDT MON OCT 03 2016 Matthew's structure has not changed much today. The most recent Air Force Hurricane Hunter aircraft mission found peak SFMR winds of 124 kt on their last pass through the northeastern eyewall, and a peak flight-level wind of 118 kt. Based on a blend of these data, the initial intensity is held at 120 kt for this advisory. The central pressure has been steady around 940 mb for much of the day. Matthew's satellite presentation remains impressive, with a 15 n mi wide eye surrounded by convective tops of -80C or colder and excellent outflow, especially poleward. Little change in intensity is expected during the next couple of days, with the exception of some possible weakening due to land interaction with Haiti and eastern Cuba. However, there could be fluctuations in intensity due to eyewall cycles that are difficult to predict. While Matthew is expected to be a little weaker once it moves into the Bahamas as the shear increases somewhat and the ocean heat content decreases a little, it is expected to remain a dangerous hurricane through the next 5 days, as shown by the global models. The new NHC intensity forecast is close to or a little above the latest intensity consensus through 4 days and is closest to the GFDL model at day 5. Matthew is now moving a little to the east of due north, or 010/06. The short term track forecast reasoning remains unchanged, as the hurricane will move generally northward for the next 24 to 36 hours around the western periphery of the Atlantic subtropical ridge. The new NHC track forecast during this time has been nudged eastward toward the latest multi-model consensus aids, and continues to show the core of the dangerous hurricane moving near or over the southwestern peninsula of Haiti tonight and near or over eastern Cuba on Tuesday. At 48 hours and beyond, the GFS has trended sharply westward, and now is in agreement with the UKMET and ECMWF in showing the western extent of the Atlantic subtropical ridge nosing north of Matthew across the Carolinas in 3-4 days. This results in Matthew taking a more northwesterly track across the Bahamas, and closer to the Florida peninsula during this time. The UKMET is farthest west, with a track over the east coast of Florida and into South Carolina in 4-5 days. The GFS, ECMWF, and the GFDL model are a little farther east and remain close to but offshore of Florida. The GFDL and GFS are close to southeastern North Carolina by day 5, while the ECMWF is slower. The new NHC track forecast has been adjusted significantly westward at days 3-5, and now lies near the middle of the guidance envelope and close to the ECMWF/GFS blend. While there remains significant uncertainty in the track of Matthew in the long range, the threat to Florida and the southeastern U.S. coast has increased. KEY MESSAGES: 1. Matthew is likely to produce devastating impacts from storm surge, extreme winds, heavy rains, flash floods, and/or mudslides in portions of the watch and warning areas in Haiti, Cuba, and the Bahamas. Please consult statements from the meteorological services and other government officials in those countries. 2. Direct hurricane impacts are possible in Florida later this week. Tropical storm and/or hurricane watches could be issued sometime tonight or early tomorrow for portions of the Florida peninsula and the Florida Keys. 3. Tropical storm or hurricane conditions could affect portions of Georgia, South Carolina, and North Carolina later this week or this weekend, even if the center of Matthew remains offshore. It is too soon to specify what, if any, direct impacts Matthew might have on the remainder of the U.S. east coast. At a minimum, very dangerous beach and boating conditions are likely along much of the U.S. east coast later this week and weekend. FORECAST POSITIONS AND MAX WINDS INIT 03/2100Z 16.3N 74.7W 120 KT 140 MPH 12H 04/0600Z 17.4N 74.6W 120 KT 140 MPH 24H 04/1800Z 19.2N 74.4W 120 KT 140 MPH 36H 05/0600Z 21.0N 74.7W 115 KT 130 MPH 48H 05/1800Z 22.8N 75.5W 110 KT 125 MPH 72H 06/1800Z 26.0N 78.0W 105 KT 120 MPH 96H 07/1800Z 29.5N 79.0W 100 KT 115 MPH 120H 08/1800Z 33.0N 78.0W 90 KT 105 MPH $$ Forecaster Brennan