KEY MESSAGES: 1. Matthew is likely to produce devastating impacts from storm surge, extreme winds, and heavy rains in the central and northwestern Bahamas today, and along portions of the east coast of Florida tonight. 2. When a hurricane is forecast to take a track roughly parallel to a coastline, as Matthew is forecast to do from Florida through South Carolina, it becomes very difficult to specify impacts at any one location. For example, only a small deviation of the track to the left of the NHC forecast could bring the core of a major hurricane onshore within the hurricane warning area in Florida and Georgia. However, a small deviation to the right could keep the hurricane-force winds offshore. Similarly large variations in impacts are possible in the hurricane watch area in northeast Georgia and South Carolina. 3. Tropical storm or hurricane conditions could affect eastern North Carolina later this week or this weekend, even if the center of Matthew remains offshore. 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. In addition, because the Flooding Map is based on inputs that extend out only to about 72 hours, it best represents the flooding potential in those locations within the watch and warning areas in Florida and Georgia.