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Tropical Storm Kay Discussion Number 21
NWS National Hurricane Center Miami FL EP122022
800 AM PDT Fri Sep 09 2022
Kay is gradually becoming less organized. There is currently
minimal convection near its center of circulation, although there is
a complex of convective bands occurring about 75-150 n mi north of
the center. Doppler radar data from Yuma and San Diego has shown
winds as high as 60 kt aloft, although it is unclear how well these
winds are mixing down to the surface. Based on the radar and
satellite intensity estimates, the initial intensity is reduced to
45 kt, and this could be a bit generous. An Air Force Reserve
Hurricane Hunter aircraft is enroute to investigate Kay.
Kay should continue to weaken as it reaches sea surface
temperatures of 20-21C by 24 h, and the dynamical model suggest it
should stop producing convection near or just after that time. The
new intensity forecast shows the cyclone as a minimal tropical storm
in 24 h, followed by decay to a remnant low as the convection
dissipates and the winds drop below tropical-storm force. The
global models indicate that the remnant low should dissipate
between 96-120 h, and the new intensity forecast follows this.
The initial motion is now northwestward or 320/ 11 kt. A mid-level
ridge to the north of Kay is expected to cause the cyclone to
gradually turn west-northwestward away from land in the next 12 h,
followed by a westward turn between 12-24 h. After that time,
low-level ridging in the Eastern Pacific should steer the remnant
low slowly southward and then southeastward before the system
dissipates completely. There was little change in the track
forecast guidance since the last advisory, and the new forecast
track is similar to the previous track.
Although Kay's intensity has decreased, the tropical cyclone 34-kt
wind radii remain quite large on its eastern side. Wind, surf, and
rainfall impacts continue to extend far from the center so users
should not focus on the exact forecast track of Kay.
KEY MESSAGES:
1. As the center of Kay passes just offshore, heavy rainfall will
likely result in flash flooding, including possible landslides,
across the Baja California peninsula and portions of mainland
northwestern Mexico through Saturday morning. Flash, urban, and
small stream flooding is likely across Southern California beginning
today, especially in and near the peninsular ranges. Flash, urban,
and small stream flooding is possible beginning today in Arizona
and southern Nevada.
2. Tropical storm conditions are occurring over portions of the Baja
California peninsula, and these conditions extend all the way to the
northern Gulf of California coastline, where a Tropical Storm
Warning is in effect.
3. Strong winds not directly associated with Kay's core wind field
are occurring across portions of southern California and extreme
southwestern Arizona. For information on this wind hazard, users
should see High Wind Warnings and other products from their local
NWS Weather Forecast Office.
FORECAST POSITIONS AND MAX WINDS
INIT 09/1500Z 30.3N 116.7W 45 KT 50 MPH
12H 10/0000Z 31.1N 118.1W 40 KT 45 MPH
24H 10/1200Z 31.4N 119.5W 35 KT 40 MPH
36H 11/0000Z 31.4N 120.6W 30 KT 35 MPH...POST-TROP/REMNT LOW
48H 11/1200Z 31.0N 121.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
60H 12/0000Z 30.3N 121.7W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 12/1200Z 29.6N 121.4W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 13/1200Z 28.5N 120.0W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 14/1200Z...DISSIPATED
$$
Forecaster Beven
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