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Tropical Storm Genevieve Discussion Number 18
NWS National Hurricane Center Miami FL EP122020
300 PM MDT Thu Aug 20 2020
Dry and stable air continues to be drawn into Genevieve's
circulation. This is noted by a slow erosion of convection over
the southwestern semicircle, and warming cloud tops over
the past several hours, indicating weakening. An Air Force Reserve
Hurricane Hunter aircraft investigating the system this afternoon
measured peak 700 mb flight-level winds of 71 kt, which reduce to
64 kt at the surface, with peak SFMR winds of 57 kt. A blend of
these values supports lowering the initial intensity to 60 kt.
Genevieve should continue to gradually weaken as it moves over
progressively lower oceanic temperatures. By Friday, the cyclone is
expected to cross the 26 C SST isotherm, and it will reach waters
cooler than 24 C by early Saturday. These much cooler waters should
cause the cyclone to degenerate to a remnant low by late Saturday.
The latest NHC intensity forecast is little changed from the
previous one, and is near the HFIP corrected consensus HCCA.
Genevieve continues to move northwestward at 10 kt, paralleling the
coast of the southern Baja California Peninsula. This general motion
is expected to continue until the cyclone dissipates later in the
forecast period. On this track, Genevieve will begin to move away
from the peninsula tonight. The NHC forecast track is very little
changed from the previous one and is in the middle of the tightly
clustered track guidance.
1. The center of Genevieve is forecast to pass just west of the Baja
California peninsula through this evening, with tropical storm
conditions expected to continue over portions of this area during
2. Rainfall from Genevieve will continue to decrease in intensity
over southern Baja California Sur, although some instances of flash
flooding and mudslides remain possible through this evening.
3. Large swells generated by Genevieve will affect portions of
the west-central coast of Mexico and the coast of the southern Baja
California peninsula through Friday.
FORECAST POSITIONS AND MAX WINDS
INIT 20/2100Z 23.9N 112.4W 60 KT 70 MPH
12H 21/0600Z 24.8N 113.7W 50 KT 60 MPH
24H 21/1800Z 26.1N 115.3W 40 KT 45 MPH
36H 22/0600Z 27.4N 117.2W 30 KT 35 MPH
48H 22/1800Z 28.6N 119.3W 25 KT 30 MPH...POST-TROP/REMNT LOW
60H 23/0600Z 29.4N 120.9W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 23/1800Z 30.3N 122.0W 20 KT 25 MPH...POST-TROP/REMNT LOW