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Hurricane Linda Discussion Number 23
NWS National Hurricane Center Miami FL EP122021
1100 AM HST Sun Aug 15 2021
Linda now has the classic truck tire or doughnut appearance of an
annular hurricane in infrared satellite imagery. The large eye is
about 35 n mi in diameter, and the surrounding cold cloud tops are
uniformly 70-90 n mi thick in all quadrants. The initial intensity
is lowered slightly to 95 kt based on Dvorak estimates of T5.0/90 kt
from TAFB and T5.5/102 kt from SAB, and this value also matches the
latest objective ADT and SATCON estimates.
Linda has almost turned toward the west-southwest with an initial
motion of 260/10 kt, a result of a strong mid-level high centered
over California and Nevada. This feature should push Linda toward
the west-southwest during the next 24 hours, but a repositioning of
the high over the North Pacific in a few days will allow the
hurricane to turn back toward the west by 36 hours and then the
west-northwest by day 3. The track models remain in good agreement
on this scenario. The NHC track forecast lies near the southern
edge of the guidance envelope, leaning towards the HCCA consensus
aid, and it essentially lies right on top of the previous official
forecast.
With little to no shear expected during the next 5 days, Linda's
intensity will be driven by thermodynamic factors. The hurricane's
west-southwestward motion has it paralleling the sea surface
temperature gradient, keeping it over waters around 26 degrees
Celsius for the next 3 days or so. Since annular hurricanes
typically weaken only gradually with these types of environmental
conditions, the NHC intensity forecast is above the various
intensity consensus aids and leans toward the SHIPS model, which is
at the upper end of the guidance envelope. Linda is likely to
weaken below hurricane intensity after day 3 once it moves over
much colder waters. Although not explicitly shown here, it is
possible that Linda could lose organized deep convection and become
a post-tropical gale by day 5.
FORECAST POSITIONS AND MAX WINDS
INIT 15/2100Z 18.8N 121.2W 95 KT 110 MPH
12H 16/0600Z 18.4N 122.5W 90 KT 105 MPH
24H 16/1800Z 17.8N 124.3W 85 KT 100 MPH
36H 17/0600Z 17.6N 126.0W 80 KT 90 MPH
48H 17/1800Z 17.7N 127.7W 75 KT 85 MPH
60H 18/0600Z 18.1N 129.7W 70 KT 80 MPH
72H 18/1800Z 18.9N 132.0W 65 KT 75 MPH
96H 19/1800Z 20.7N 136.7W 55 KT 65 MPH
120H 20/1800Z 22.5N 140.9W 40 KT 45 MPH
$$
Forecaster Berg
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