440 
 WTNT44 KNHC 072046
 TCDAT4
 
 HURRICANE MATTHEW DISCUSSION NUMBER  39
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142016
 500 PM EDT FRI OCT 07 2016
 
 Data from a NOAA Hurricane Hunter plane and satellite intensity
 estimates indicate that Matthew has weakened a little bit and the
 maximum winds are 95 kt.  The hurricane is heading toward an area of
 increasing shear, and this should result in gradual weakening.  The
 shear is forecast to continue during the next 5 days, so additional
 weakening is anticipated and Matthew is expected to be a tropical
 depression by the end of the forecast period.
 
 Matthew has begun to move northward at about 10 kt. In about 12
 hours, the hurricane will encounter the mid-latitude westerlies, and
 this flow pattern should induce a northeastward and then eastward
 motion during the next 2 days. During that time the core of the
 hurricane is expected to hug the coast from Georgia through
 southeastern North Carolina.  The confidence in this portion of the
 track forecast is high.  After that time, the steering flow becomes
 very complex, and both the GFS and ECMWF models turn the cyclone
 southward and southwestward embedded within the flow on the west
 side of a mid-level trough. The NHC track follows these two models,
 but the confidence is portion of the forecast is low.
 
 
 KEY MESSAGES:
 
 1.  We have been very fortunate that Matthew's strongest 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 through tonight.
 
 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  07/2100Z 30.2N  80.7W   95 KT 110 MPH
  12H  08/0600Z 31.7N  80.7W   90 KT 105 MPH
  24H  08/1800Z 33.0N  79.0W   80 KT  90 MPH
  36H  09/0600Z 33.8N  76.7W   65 KT  75 MPH
  48H  09/1800Z 33.5N  75.0W   60 KT  70 MPH
  72H  10/1800Z 30.0N  74.5W   40 KT  45 MPH
  96H  11/1800Z 27.0N  76.0W   35 KT  40 MPH
 120H  12/1800Z 26.0N  77.0W   30 KT  35 MPH
 
 $$
 Forecaster Avila