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Hurricane Genevieve Discussion Number  13
NWS National Hurricane Center Miami FL       EP122020
900 AM MDT Wed Aug 19 2020
 
Genevieve continues to have a fairly well-defined eye in
geostationary satellite imagery, however a recent SSMIS microwave
overpass shows that the eyewall is open to the southwest and that
deep convection is generally lacking over the southwestern portion
of the circulation.  The various satellite intensity estimates range
from about 80-96 kt, which SATCON being at the higher end.  The
cloud tops over the northeastern portion of the circulation have
cooled within the past few hours, so the initial intensity is held
at a possibly generous 100 kt.  An Air Force Reserve hurricane
hunter aircraft is scheduled to investigate Genevieve this
afternoon, and should provide a better assessment of the
hurricane's intensity and size.
 
The hurricane has continued to move slightly right of track, and
the initial motion estimate is 335/8 kt. A north-northwestward
motion is expected to continue today, followed by a turn toward the
northwest tonight as mid-level ridging builds over northwestern
Mexico.  The new NHC forecast track has again been shifted slightly
east of the previous track at 12 and 24 hours, but it is essentially
unchanged thereafter.  This track adjustment brings the center a
little closer to the southern portion of the Baja California
peninsula tonight and early Thursday.  Only a slight deviation to
the right of the track would bring hurricane-force winds onshore, 
and the government of Mexico has issued a Hurricane Warning for a 
portion of the southern coast of Baja California.
 
Genevieve is forecast to move over gradually decreasing sea surface
temperatures over the next couple of days, which should result in
slow weakening during that time.  After 48 hours, the cyclone will
encounter much cooler waters and a more stable air mass. Therefore,
a more rapid rate of weakening is expected after that time, with
the system becoming a remnant low by 96 hours.  The NHC intensity
forecast is a blend of the statistical and dynamic model guidance.
 
 
Key Messages:
 
1. The center of Genevieve is forecast to pass near or just west of
the Baja California peninsula.  Tropical storm conditions are
expected to spread across southern Baja California Sur this
afternoon and continuing through Thursday.  Hurricane conditions
are expected within the Hurricane Warning area beginning tonight and 
continuing into Thursday.
 
2.  Heavy rainfall from Genevieve may lead to life-threatening
flash flooding and mudslides across portions of far southern Baja
California Sur through Thursday.
 
3. Large swells generated by Genevieve are affecting portions of the
coast of southern Mexico and will spread northward along the coast
of Mexico to the Baja California peninsula through Thursday.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  19/1500Z 20.9N 109.7W  100 KT 115 MPH
 12H  20/0000Z 21.7N 110.2W   90 KT 105 MPH
 24H  20/1200Z 22.6N 111.1W   85 KT 100 MPH
 36H  21/0000Z 23.4N 112.3W   80 KT  90 MPH
 48H  21/1200Z 24.3N 113.6W   75 KT  85 MPH
 60H  22/0000Z 25.5N 115.4W   60 KT  70 MPH
 72H  22/1200Z 26.6N 117.2W   50 KT  60 MPH
 96H  23/1200Z 28.9N 120.6W   30 KT  35 MPH...POST-TROP/REMNT LOW
120H  24/1200Z 30.5N 122.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
 
$$
Forecaster Brown
 
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