[Tropical] Tropical Cyclone Discussion

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WTNT44 KNHC 051454
TCDAT4

HURRICANE MATTHEW DISCUSSION NUMBER  30
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142016
1100 AM EDT WED OCT 05 2016

Both NOAA and Air Force Hurricane Hunter planes have been in the eye
of Matthew during the past several hours.  Data from those planes
indicate that the hurricane is gradually recovering from the
passage over the mountains of eastern Cuba and Haiti. The eye is
becoming better defined on satellite. Based on SFMR winds of
103 kt and a flight-level peak wind of 118 kt, the initial
intensity is 105 kt.

The environment between the Bahamas and Florida is favorable for
Matthew to restrengthen some during the next couple of days.
After that time, the shear is forecast to increase, resulting in
gradual weakening.

Fixes from the planes indicate that Matthew is moving toward the
northwest or 325 degrees at about 8 to 10 kt. The subtropical ridge
over the western Atlantic is amplifying as anticipated by the
global models.  The flow pattern around this ridge should continue
to steer the hurricane toward the northwest during the next day or
two with no significant change in forward speed. After that time
the ridge will move east allowing Matthew to move northward very
near or over the Florida east coast and then near or to the east of
the Georgia and South Carolina coasts. By the end of the forecast
period, models have changed significantly since yesterday.
Some track models keep the hurricane moving eastward across the
Atlantic while the GFS and the ECMWF reduce the hurricane's forward
speed with a southward turn. This change in these two valuable
models is reflected in the current NHC forecast.

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 hurricane warning areas in Cuba and the Bahamas.
Please consult statements from the meteorological services and other
government officials in those countries.

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.
However, a small deviation to the right could keep the hurricane-
force winds offshore.

3.  Tropical storm or hurricane conditions could affect 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
determine what, if any, land areas might be directly affected by
Matthew next week.  At a minimum, dangerous beach and boating
conditions are likely along much of the U.S. east coast during the
next several days.

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.

FORECAST POSITIONS AND MAX WINDS

INIT  05/1500Z 21.8N  75.2W  105 KT 120 MPH
 12H  06/0000Z 23.1N  76.0W  110 KT 125 MPH
 24H  06/1200Z 24.8N  77.5W  115 KT 130 MPH
 36H  07/0000Z 26.6N  79.0W  115 KT 130 MPH
 48H  07/1200Z 28.2N  80.1W  115 KT 130 MPH
 72H  08/1200Z 31.5N  80.0W   95 KT 110 MPH
 96H  09/1200Z 32.5N  76.0W   85 KT 100 MPH
120H  10/1200Z 32.0N  74.0W   70 KT  80 MPH

$$
Forecaster Avila
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