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Tropical Depression Fred Discussion Number  15
NWS National Hurricane Center Miami FL       AL062021
500 AM EDT Fri Aug 13 2021
 
Fred continues to produce heavy rains across eastern Cuba and 
portions of the southeastern Bahamas this morning.  However, despite 
the areas of heavy rain, the system remains poorly organized. Most 
of the deep convection is located to the east of the center and 
there is little evidence of banding features.  The last pass by the 
Air Force Hurricane Hunters several hours ago and earlier ASCAT-A 
data indicated that maximum winds were around 30 kt. Since the storm 
has changed little in appearance since that time, the initial 
intensity is held at that value.  The NOAA and Air Force Hurricane 
Hunters will be investigating Fred later this morning, and the data 
both planes collect will be helpful in assessing Fred's intensity 
and structure.
 
Fred continues to move west-northwestward at about 9 kt.  This 
motion should persist for about another day as the storm continues 
to move in the flow on the southwest side of a subtropical ridge.  
After that time, a turn to the northwest and then the north is 
predicted as Fred moves around the western side of the ridge.  Based 
on this expected motion, the storm should track just north of 
eastern and central Cuba through tonight and near or across the 
Florida Keys on Saturday.  After that time, there is more spread in 
the models due to the uncertainty in exactly where and when Fred 
makes the northwest and north turns.  The range in the model 
solutions this cycle span from over the Florida peninsula to the 
east-central Gulf of Mexico.  Since the typically best-performing 
models ended up almost on top of the previous prediction, very 
little change to the track was required.
 
The system is still battling about 20 kt of westerly vertical wind 
shear, which is part of the reason why the convective pattern is 
disheveled.  The shear is only expected to lessen slightly during 
the next couple of days, but since the environmental moisture is 
abundant and SSTs are very warm, gradual strengthening seems likely 
as Fred moves across the Florida Keys and then near or offshore of 
the west coast of Florida this weekend.  The shear is expected to 
increase again before Fred makes its final landfall along the 
Florida panhandle in a few days, and that will likely prevent 
additional intensification.  Steady weakening is expected after the 
storm moves inland.  The intensity guidance is in very good 
agreement, and this forecast lies near the high end of the models.
 
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
and strongest winds will be.
 
KEY MESSAGES:
 
1. From today into 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.
 
2. Tropical storm conditions are expected in the Florida Keys on
Saturday, where a Tropical Storm Warning has been issued.
 
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  13/0900Z 22.0N  76.7W   30 KT  35 MPH
 12H  13/1800Z 22.6N  78.4W   35 KT  40 MPH
 24H  14/0600Z 23.6N  80.2W   35 KT  40 MPH
 36H  14/1800Z 24.8N  81.5W   40 KT  45 MPH
 48H  15/0600Z 26.4N  82.5W   40 KT  45 MPH
 60H  15/1800Z 28.1N  83.7W   45 KT  50 MPH
 72H  16/0600Z 29.6N  84.6W   45 KT  50 MPH
 96H  17/0600Z 32.5N  85.8W   25 KT  30 MPH...INLAND
120H  18/0600Z 35.5N  85.7W   20 KT  25 MPH...INLAND
 
$$
Forecaster Cangialosi
 
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