Eastern Pacific Basin Tropical Cyclones

Tropical Storm Kay Forecast Discussion


000
WTPZ42 KNHC 051438
TCDEP2

Tropical Storm Kay Discussion Number   5
NWS National Hurricane Center Miami FL       EP122022
900 AM MDT Mon Sep 05 2022

Kay continues to produce very deep convection, but the storm is 
asymmetric with its center estimated to be on the north side of the 
main area of thunderstorms.  The latest satellite intensity 
estimates range from 45 to 55 kt, and based on that data, the 
initial intensity is held at 50 kt for this advisory.  Kay is a 
sprawling tropical storm with its outer rain bands extending as far 
out as 300 n mi from the center.  The northern rain bands are 
affecting the coast of southwestern Mexico, where 
tropical-storm-force wind gusts are likely occurring.  An Air Force 
Hurricane Hunter aircraft is scheduled to investigate Kay later 
today.

The storm is moving westward at 13 kt and continues to be steered by 
a mid-level ridge to its north.  The model guidance remains in 
fairly good agreement that a turn to the west-northwest is likely to 
begin tonight followed by a northwestward motion by Tuesday night. 
Although this should take the core of Kay well to the west of the 
southern tip of the Baja California peninsula, tropical storm 
conditions are possible there by early Wednesday given its expansive 
wind field.  Kay will likely be very near the west-central portion 
of the peninsula on Thursday and Friday, and hurricane watches could 
be required for that region later today or tomorrow.  The spread in 
the GFS and ECMWF ensemble members is basically the same as it was 
yesterday and shows solutions spanning a region from over 
central Baja to a few hundred miles west of the peninsula.  A turn 
back to the left is expected by the end of the forecast period due 
to a mid-level ridge to its north.  Overall, the NHC track forecast 
has changed little this cycle and lies near the HCCA model and a 
consensus of the GFS and ECMWF.

Kay is still experiencing moderate north-northeasterly shear, which 
is causing its asymmetric cloud pattern.  This shear is expected to 
persist, which should prevent rapid intensification.  Nonetheless, 
given the warm SSTs and high mid-level moisture, continued steady 
strengthening is likely to continue during the next couple of days 
and Kay will likely become a hurricane tonight or on Tuesday. Beyond 
a couple of days, progressively cooler SSTs and a drier air mass 
should end the strengthening trend and induce steady weakening. The 
NHC intensity forecast is similar to the previous one and lies a 
little above the HCCA and IVCN guidance, but below the latest SHIPS 
output.

KEY MESSAGES:

1. Although the center of Kay is forecast to stay offshore of
southwest mainland Mexico, gusts to tropical-storm-force and
rough surf along the coast are expected through Tuesday.  In
addition, heavy rainfall could lead to flash flooding, including
landslides, across portions of the Mexican Riviera and western
Mexico through Wednesday night.

2. Tropical storm conditions are possible across the southern
Baja California peninsula by early Wednesday, where a Tropical
Storm Watch has been issued.

3. Kay is expected to be a hurricane when it nears the central
portion of the Baja California peninsula later this week. While the
details of the long-range track and intensity forecasts
remain uncertain, there is increasing risk of significant wind, 
surf, and rainfall impacts there, and a tropical storm or hurricane 
watch could be issued for that region later today or Tuesday.


FORECAST POSITIONS AND MAX WINDS

INIT  05/1500Z 15.8N 106.4W   50 KT  60 MPH
 12H  06/0000Z 16.2N 107.8W   60 KT  70 MPH
 24H  06/1200Z 17.3N 109.6W   70 KT  80 MPH
 36H  07/0000Z 18.7N 111.2W   80 KT  90 MPH
 48H  07/1200Z 20.2N 112.4W   90 KT 105 MPH
 60H  08/0000Z 22.0N 113.3W   90 KT 105 MPH
 72H  08/1200Z 24.0N 114.0W   80 KT  90 MPH
 96H  09/1200Z 27.5N 115.7W   60 KT  70 MPH
120H  10/1200Z 29.7N 119.1W   45 KT  50 MPH

$$
Forecaster Cangialosi



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