000 WTNT44 KNHC 071459 TCDAT4 HURRICANE MATTHEW DISCUSSION NUMBER 38 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142016 1100 AM EDT FRI OCT 07 2016 The satellite presentation has degraded during the past several hours, and the eye is not very distinct. However, the SFMR and flight-level wind data from an Air Force reconnaissance plane indicate that the initial intensity is still 105 kt. Matthew is expected to change little in intensity during the next 6 to 12 hours, but it should begin to weaken at a faster pace in 24 hours while the shear increases, and by the end of the forecast period, Matthew is expected to become a tropical depression. Fixes from a reconnaissance plane indicate that Matthew is moving toward the north-northwest or 345 degrees at 10 kt. Matthew is reaching the northwestern edge of the subtropical ridge and encounter the mid-latitude westerlies. This flow pattern should steer the hurricane northward and then northeastward during the next 36 hours. After that time, the flow pattern is forecast to change again and a weakening Matthew should then turn southward and southwestward. The NHC forecast is a little bit to the north from the previous one during the first 24 to 36 hour period following the multi-model consensus. After 72 hours, models continue to vary the flow pattern and the confidence in the track forecast is low. KEY MESSAGES: 1. We have been very fortunate that Matthew's category 3 winds have remained a short distance offshore of the Florida Coast thus far, but this should not be a reason to let down our guard. Only a small deviation to the left of the forecast track could bring these winds onshore. The western eyewall of Matthew, which contains hurricane-force winds, is expected to move over or very near the coast of northeastern Florida and Georgia today. 2. Hurricane winds increase very rapidly with height, and occupants of high-rise buildings in the Jacksonville area are at particular risk of strong winds. Winds at the top of a 30-story building will average one Saffir-Simpson category higher than the winds near the surface. 3. The water hazards remain, even if the core of Matthew remains offshore. These include the danger of life-threatening inundation from storm surge, as well as inland flooding from heavy rains from Florida to North Carolina. 4. The National Hurricane Center is issuing Potential Storm Surge Flooding Maps, and Prototype Storm Surge Watch/Warning Graphics for Matthew. It is important to remember that the Potential Storm Surge Flooding Map does not represent a forecast of expected inundation, but rather depicts a reasonable worst-case scenario -- the amount of inundation that has a 10 percent chance of being exceeded. FORECAST POSITIONS AND MAX WINDS INIT 07/1500Z 29.4N 80.4W 105 KT 120 MPH 12H 08/0000Z 30.8N 80.7W 100 KT 115 MPH 24H 08/1200Z 32.5N 79.9W 85 KT 100 MPH 36H 09/0000Z 33.5N 78.1W 75 KT 85 MPH 48H 09/1200Z 33.5N 76.0W 60 KT 70 MPH 72H 10/1200Z 32.0N 74.0W 50 KT 60 MPH 96H 11/1200Z 28.0N 75.0W 35 KT 40 MPH 120H 12/1200Z 27.0N 76.0W 30 KT 35 MPH $$ Forecaster Avila