Eastern Pacific Basin Tropical Cyclones

Tropical Storm Kay Forecast Discussion


000
WTPZ42 KNHC 050252
TCDEP2

Tropical Storm Kay Discussion Number   3
NWS National Hurricane Center Miami FL       EP122022
1000 PM CDT Sun Sep 04 2022

The structure of Kay has slightly improved in satellite imagery
this evening. Deep convection has increased near the center, with a
more defined curved band over the southern and western portions
of the circulation. Earlier ASCAT data showed several 35-kt wind
vectors in the northeastern quadrant of the storm, and objective
satellite estimates have increased since TAFB provided a T2.5/35 kt
Dvorak classification at 00 UTC. Therefore, the initial intensity
is raised slightly to 40 kt for this advisory.

Kay has moved a bit right of the previous forecast track, but its
initial motion is still west-northwestward, or 295/12 kt. This
general motion is expected to continue for the next day or two as
the core of the cyclone passes well south of the coast of
southwestern Mexico. By Tuesday, the tightly clustered guidance
agrees that Kay will turn toward the northwest and then the
north-northwest, moving in the general direction of the Baja
California peninsula. The official NHC forecast track is virtually
unchanged from the previous one beyond 36 h, and closely follows the
HCCA and TVCE consensus aids. There is increased spread in the GFS
and ECMWF ensemble members later this week as Kay moves northward.
Users are reminded not to focus on the exact details of the
long-range forecast, as track errors on average increase with time.

The environmental conditions appear favorable for strengthening
during the next few days. Although Kay is currently contending with
some moderate northeasterly wind shear, a moist and unstable
atmosphere over very warm sea-surface temperatures (> 29C) should
allow the storm to intensify through the middle of the week. The
northeasterly shear is forecast to weaken beyond 48 h, which would
be even more conducive for significant strengthening as suggested by
some of the intensity guidance. The NHC intensity forecast generally
lies between the IVCN and HCCA aids, and it shows Kay becoming a
hurricane by early Tuesday and continuing to intensify into
Wednesday. Beyond 72 h, cooler SSTs are expected to induce a
weakening trend through the rest of the forecast period.

Tropical Storm or Hurricane Watches could be required tonight or on
Monday for portions of the Baja California peninsula, and interests
there should closely monitor the latest forecast updates.


KEY MESSAGES:

1. Although the center of Kay is expected to stay offshore, heavy
rainfall could lead to localized flash flooding in portions of
southwestern Mexico over the next few days.

2. Kay is forecast to strengthen into a hurricane while it moves
northward toward the Baja California peninsula later this week.
While the details of the long-range track and intensity forecasts
are uncertain, there is a risk of wind and rainfall impacts in the
Baja California peninsula during the middle and latter parts of the
week. Interests there should closely monitor updates to the forecast
as tropical storm or hurricane watches could be required tonight or
on Monday.


FORECAST POSITIONS AND MAX WINDS

INIT  05/0300Z 15.6N 103.8W   40 KT  45 MPH
 12H  05/1200Z 16.0N 105.4W   50 KT  60 MPH
 24H  06/0000Z 16.5N 107.2W   60 KT  70 MPH
 36H  06/1200Z 17.5N 109.0W   70 KT  80 MPH
 48H  07/0000Z 18.9N 110.5W   80 KT  90 MPH
 60H  07/1200Z 20.7N 111.8W   85 KT 100 MPH
 72H  08/0000Z 22.5N 112.7W   85 KT 100 MPH
 96H  09/0000Z 26.2N 114.3W   70 KT  80 MPH
120H  10/0000Z 29.3N 116.5W   50 KT  60 MPH

$$
Forecaster Reinhart



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