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Tropical Depression Fred Discussion Number  11
NWS National Hurricane Center Miami FL       AL062021
500 AM EDT Thu Aug 12 2021
 
The rugged terrain of Hispaniola has taken a toll on Fred.
Satellite images and surface observations indicate that the
circulation is stretched out and seems to resemble a trough at the
surface.  The system is now emerging back over water and is located
between Haiti, eastern Cuba, and the southeastern Bahamas.  Most of
the associated showers and thunderstorms are located to the east of
the estimated center, with heavy rains continuing over portions of
Hispaniola.  The initial intensity is estimated to be 30 kt, but
there is limited data to confirm this. Both the NOAA and Air Force
Hurricane Hunters will be investigating Fred later this morning, and
the data from both planes will be helpful in estimating Fred's
strength and structure.
 
Fred appears to be moving west-northwestward at about 14 kt.  The
track forecast reasoning has not changed much.  A subtropical
ridge currently situated to the north of Fred over the western
Atlantic should continue to steer the system west-northwestward for
the next 36 to 48 hours.  This motion should take the storm just
north of or across Cuba and the southeastern Bahamas during that
time period.  By the weekend, the models suggest that Fred will
be rounding the western periphery of the ridge, which will likely a
cause a slow down and a gradual turn to the northwest and then the
north across portions of the Florida Keys, the Florida peninsula,
and the eastern Gulf of Mexico.  There is uncertainty in exactly
where and when Fred will make that turn to the right, with models
currently spanning a region from over Florida to the east-central
Gulf of Mexico.  The NHC track forecast remains on the right side
of the guidance envelope, near the typically more skillful global
models and consensus aids.
 
Fred is currently in an environment of about 20 kt of westerly
vertical wind shear.  This shear is expected to persist during the
next day or so, and those unfavorable winds combined with some land
interaction with Cuba should prevent the system from strengthening
much, if at all, during that time period.  The shear could lessen on
Friday and since SSTs are very warm and there is abundant
environmental moisture, some strengthening seems likely when Fred is
approaching the Florida Keys and south Florida  Friday night and
Saturday.  After that time, the intensity forecast becomes more
complicated by how much land interaction there will be with Florida.
 Since the official forecast shows a track over the eastern Gulf,
additional strengthening is predicted before Fred makes its final
landfall along the Florida Big Bend region or Florida panhandle late
in the weekend or early next week.  However, that part of the
intensity forecast, since it will be very track dependent, is more
uncertain.
 
KEY MESSAGES:
 
1. Continued heavy rainfall today could lead to flash, urban, and
small stream flooding, along with possible rapid river rises and
potential mudslides in the Dominican Republic and Haiti.
 
2. Tropical storm conditions are possible in northern Haiti
and the southeastern Bahamas this morning, and in portions of Cuba
later today.
 
3. Beginning Friday, heavy rainfall could lead to areal, urban, and
small stream flooding, and possible rapid river rises across
southern Florida. Heavy rainfall associated with Fred will impact
the remainder of Florida and parts of the Southeast this weekend
and into next week.
 
4. There is a risk of tropical storm conditions beginning early
Saturday in the Florida Keys and south Florida.  These conditions
are expected to spread northward along portions of the Florida
west coast and the Florida Panhandle through Monday.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  12/0900Z 20.2N  73.5W   30 KT  35 MPH
 12H  12/1800Z 21.0N  75.1W   30 KT  35 MPH
 24H  13/0600Z 22.0N  77.2W   30 KT  35 MPH
 36H  13/1800Z 23.0N  79.1W   35 KT  40 MPH
 48H  14/0600Z 23.8N  80.3W   35 KT  40 MPH
 60H  14/1800Z 25.1N  81.4W   40 KT  45 MPH
 72H  15/0600Z 26.6N  82.6W   45 KT  50 MPH
 96H  16/0600Z 29.5N  84.4W   50 KT  60 MPH
120H  17/0600Z 32.2N  84.7W   35 KT  40 MPH...INLAND
 
$$
Forecaster Cangialosi
 
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