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Tropical Depression Fred Discussion Number  16
NWS National Hurricane Center Miami FL       AL062021
1100 AM EDT Fri Aug 13 2021
 
Fred remains disorganized this morning.  The low-level center,
which is currently over the barrier islands of the north coast of
Cuba, is exposed to the northwest of the main convective mass due
to moderate southwesterly vertical shear.  Reports from Air Force
Reserve and NOAA Hurricane hunter aircraft show winds of 25-30 kt
to the northeast of the center, so the initial intensity remains 
30 kt.  The central pressure is 1013 mb based on a combination of
aircraft data and surface observations.
 
The center has jogged a bit to the left during the past several
hours, which has brought it to the Cuban coast.  The longer-term
initial motion is 295/10.  The cyclone should continue
west-northwestward for the next 12-24 h, followed by a turn toward
the northwest as Fred approaches the western periphery of the
subtropical ridge.  This motion should take the center along the
northern coast of Cuba today, near the Florida Keys and the
southwestern coast of Florida on Saturday, and near or over the
coast of the Florida Panhandle Sunday night or Monday.  After that,
a northward turn is expected as Fred moves into a weakness in the
ridge over the southeastern United States.  With both the initial
position and the track guidance shifting westward since the last
advisory, the new forecast track is also nudged a little to the
west.  The new track is east of the consensus models, especially
from 24-60 h, and thus some additional adjustments could occur
later today if the current model trends continue.
 
Fred is continuing to experience about 20 kt of westerly or 
southwesterly vertical wind shear, and these conditions should 
continue for at least another 24 hours.  Between that and land 
interaction, the intensity forecast calls for only modest 
strengthening during this time.  After that, there is still 
relatively poor agreement on how much shear Fred will experience as 
it crosses the eastern Gulf of Mexico, with the ECMWF and the UKMET 
forecasting less shear than the GFS and CMC global models.  Due to 
the uncertainty, the intensity forecast will keep the previous peak 
intensity of 45 kt.  However, the intensity guidance during this 
period has trended a little higher, and the 45 kt peak is now a 
little below the upper edge of the guidance. 
 
It should be noted that much of the Florida peninsula is expected
to be on the east side of Fred, which is where the heaviest rains,
strongest winds, and a chance of tornadoes will be.
 
KEY MESSAGES:
 
1. Today through Monday, heavy rainfall could lead to areal, urban, 
small stream, and exacerbated river flooding across southern and 
central Florida into the Big Bend.  From Sunday onward, heavy rain 
and flood impacts could extend into other portions of the Southeast 
and into the southern and central Appalachians and Piedmont as Fred 
interacts with a front in that area. 
 
2. Tropical storm conditions are expected in portions of the 
Florida Keys on Saturday, where a Tropical Storm Warning is in 
effect.
 
3. Tropical storm conditions are possible late Saturday and
early Sunday across portions of the west coast of Florida in the
Tropical Storm Watch area. The risk of tropical storm conditions
will spread northward along the Florida west coast and to the
Florida Panhandle Sunday and Monday.

FORECAST POSITIONS AND MAX WINDS
 
INIT  13/1500Z 22.3N  78.4W   30 KT  35 MPH...NEAR COAST OF CUBA
 12H  14/0000Z 23.0N  79.7W   30 KT  35 MPH
 24H  14/1200Z 24.2N  81.3W   35 KT  40 MPH
 36H  15/0000Z 25.6N  82.5W   35 KT  40 MPH
 48H  15/1200Z 27.2N  83.6W   40 KT  45 MPH
 60H  16/0000Z 28.7N  84.6W   45 KT  50 MPH
 72H  16/1200Z 30.2N  85.4W   35 KT  40 MPH...INLAND
 96H  17/1200Z 33.0N  86.5W   25 KT  30 MPH...INLAND
120H  18/1200Z 36.5N  86.5W   20 KT  25 MPH...POST-TROP/INLAND
 
$$
Forecaster Beven
 
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