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Tropical Storm Estelle Discussion Number 3
NWS National Hurricane Center Miami FL EP062022
1000 PM CDT Fri Jul 15 2022
A series of microwave images since the last advisory show that the
depression's low-level structure has become better defined, with
the center nearly surrounded by a cyan ring in the 37-GHz channel.
In addition, a tight band of deep convection with cloud tops colder
than -80 degrees Celsius has been persisting near the center.
Dvorak estimates from TAFB and SAB are a consensus T2.5, so the
depression is upgraded to Tropical Storm Estelle with 35-kt winds.
However, this could be a conservative estimate given the improved
structure, and objective intensity estimates are running slightly
higher.
The initial motion is a little faster toward the northwest, or
310/9 kt, but satellite location fixes suggest the storm is
beginning to turn toward the west-northwest as expected. Mid-level
ridging is forecast to be entrenched over the southwestern United
States for the next 5 days, which should steer Estelle on a general
west-northwestward heading for the entirety of the forecast period.
There is not much spread among the track guidance, at least
cross-track wise, but it is notable that the GFS solution is a bit
slower than the other reliable guidance. The NHC track forecast is
just a little slower than the consensus aids to account for that
slower scenario, and this update is not too different from the
previous forecast.
Despite Estelle's improved structure, a sharp edge on the eastern
side of the deep convection in infrared imagery suggests there is
still some shear affecting the cyclone, and SHIPS is showing 10-15
kt of deep-layer shear out of the northeast. The GFS and ECMWF
versions of SHIPS differ a bit on when that shear will decrease,
although both versions show Estelle benefiting from high values of
upper-level divergence for the next 24-48 hours. Combined with
high oceanic heat content and the cyclone's well-defined low-level
structure, rapid intensification (RI) is a realistic possibility,
and some guidance is showing a 50/50 chance of RI during the next
24 hours. The NHC official intensity forecast hedges on the high
side of the guidance but stops just short of showing explicit RI
given the uncertainties on how much vertical shear will decrease.
Continued strengthening could occur through day 3, but colder
waters are likely to induce weakening on days 4 and 5.
FORECAST POSITIONS AND MAX WINDS
INIT 16/0300Z 13.2N 102.0W 35 KT 40 MPH
12H 16/1200Z 13.9N 103.1W 50 KT 60 MPH
24H 17/0000Z 14.6N 104.7W 60 KT 70 MPH
36H 17/1200Z 15.2N 106.2W 75 KT 85 MPH
48H 18/0000Z 16.0N 107.9W 85 KT 100 MPH
60H 18/1200Z 16.7N 109.9W 85 KT 100 MPH
72H 19/0000Z 17.2N 112.1W 85 KT 100 MPH
96H 20/0000Z 18.8N 116.8W 80 KT 90 MPH
120H 21/0000Z 20.8N 121.1W 65 KT 75 MPH
$$
Forecaster Berg
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