ZCZC MIATCDAT3 ALL
TTAA00 KNHC DDHHMM
 
Tropical Storm Henri Discussion Number   7
NWS National Hurricane Center Miami FL       AL082021
1100 AM AST Tue Aug 17 2021
 
Henri remains a sheared tropical storm.  Geostationary satellite 
images and microwave data show a relatively large area of deep 
convection (~200 miles across), but the center of the storm is 
located near the western edge of the thunderstorms due to ongoing 
northwesterly vertical wind shear.  The latest Dvorak estimates have 
been steady at 3.0/45 kt from TAFB and SAB, and based on that data, 
the initial intensity is held at 45 kt.  The center of Henri is 
located roughly 130 miles south-southeast of Bermuda currently, and 
this will likely be as close as the storm gets to the island.
 
The tropical storm is gradually turning to the west, as expected, 
and the initial motion is estimated to be 255/5 kt.  A subtropical 
ridge over the western Atlantic is building eastward to the north of 
Henri, and this feature should steer the storm westward at a 
slightly faster pace during the next two or three days.  After that 
time, the ridge is expected to weaken and shift farther east as a 
cut off low or negatively-tilted trough develops over the northeast 
U.S.  This change in the steering pattern should cause Henri to turn 
northeastward between Bermuda and the east coast of the U.S in the 
72-120 h period.  The NHC track forecast is a little faster than the 
previous one in the short term and farther west than the previous 
one from days 3-5, trending toward the latest consensus models.

The northwesterly shear currently affecting Henri is expected to 
subside later today, and that should allow the storm to gain 
strength during the next 12-24 hours.  However, a round of moderate 
northerly shear is expected to setup over Henri during the 24-96 
hour period.  Although this shear would typically cause some 
weakening, the combination of warm SSTs and increasing mid-level 
moisture could offset the negative influences of the shear.  
Therefore, no change in strength is predicted beyond the 24 h 
period.  Some of the models suggest that the shear could lessen 
again this weekend, so although not explicitly forecast, some 
strengthening is possible then.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  17/1500Z 30.4N  64.3W   45 KT  50 MPH
 12H  18/0000Z 30.4N  65.1W   50 KT  60 MPH
 24H  18/1200Z 30.3N  66.5W   55 KT  65 MPH
 36H  19/0000Z 30.3N  68.2W   55 KT  65 MPH
 48H  19/1200Z 30.4N  69.7W   55 KT  65 MPH
 60H  20/0000Z 30.7N  70.6W   55 KT  65 MPH
 72H  20/1200Z 31.6N  71.3W   55 KT  65 MPH
 96H  21/1200Z 34.1N  69.6W   55 KT  65 MPH
120H  22/1200Z 37.4N  66.0W   55 KT  65 MPH
 
$$
Forecaster Cangialosi
 
NNNN