Eastern Pacific Basin Tropical Cyclones

Hurricane Rick Forecast Discussion


000
WTPZ42 KNHC 232054
TCDEP2

Hurricane Rick Discussion Number   6
NWS National Hurricane Center Miami FL       EP172021
400 PM CDT Sat Oct 23 2021

Rick continued to strengthen through the late morning, with a brief 
appearance of an eye in visible satellite images.  Over the past few 
hours the eye has become less apparent, and the Central Dense 
Overcast (CDO) has become a bit elongated.  An Air Force Reserve 
Hurricane Hunter Aircraft investigated the hurricane late this 
afternoon and was able to provide beneficial data regarding Rick's 
structure and intensity.  During the flight, the aircraft measured 
peak 700-mb flight-level winds of 80 kt (which reduce to 72 kt at 
the surface), and SFMR surface winds of 81 kt a little earlier in 
the flight.  A blend of these values suggests the initial advisory 
intensity is 75 kt, which agrees well with unanimous 77-kt Dvorak 
intensity estimates from TAFB, SAB, and the UW-CIMSS ADT. The 
aircraft also confirmed that the core of Rick is compact, with 
tropical-storm-force winds extending only about 50 n mi from the 
center.  However, earlier scatterometer data sampled winds to near 
tropical storm force in the large curved band that wraps around much 
of the hurricane's center at a distance of 100 to 150 n mi. 

Rick has jogged west-northwest over the past couple hours, but the 
12 h motion is about 335/05 kt.  There is no change to the forecast 
track reasoning.  Rick is expected to resume a motion between
north-northwest and north, through a weakness in the
mid-tropospheric subtropical ridge, during the next couple of days. 
The track model guidance has come into better agreement, and the 
only notable change to the NHC forecast track was during the first 
12 h to adjust for the recent left-of-track motion. 

The environment of sea-surface temperatures near 30 degrees C and 
very low shear should support a fast pace of strengthening over the 
next day or so.  The only factor that could inhibit the pace of 
intensification is the presence of a dry moat between the CDO and 
outer band, and some of this dry air could get drawn into the core 
of Rick.  However, based on the other favorable factors, the NHC 
intensity forecast calls for continued strengthening through Sunday 
morning.  As the hurricane nears the coast in 36 h, dry air and 
increasing southwesterly vertical wind shear may weaken the cyclone. 
The latest NHC intensity forecast still calls for Rick to reach 
major hurricane intensity on Sunday, despite the recent pause in 
strengthening. This forecast remains on the high end of the 
guidance.  

Key Messages:

1. Rick is forecast to be at or near major hurricane strength when
it reaches the coast of southern Mexico by Sunday night or Monday,
and life-threatening storm surge and dangerous hurricane-force
winds are expected within the Hurricane Warning area from Tecpan de
Galeana to Punta San Telmo.  Residents in this area should
follow any advice given by local officials and check updates
to the forecast.

2. Rick is expected to bring tropical storm conditions to
portions of the southern and southwestern coasts of Mexico as early
as Sunday from east of Tecpan de Galeana to Acapulco, and by Monday
morning from west of Punta San Telmo to Manzanillo, where a Tropical
Storm Warning is in effect.

3. Heavy rains associated with Rick are expected to move into the
Mexican states of Guerrero and Michoacan starting later today, and
could persist through Monday night.  This rainfall will likely
produce flash flooding and mudslides.


FORECAST POSITIONS AND MAX WINDS

INIT  23/2100Z 15.1N 101.8W   75 KT  85 MPH
 12H  24/0600Z 15.7N 102.1W   90 KT 105 MPH
 24H  24/1800Z 16.5N 102.1W  100 KT 115 MPH
 36H  25/0600Z 17.6N 102.3W   85 KT 100 MPH...NEAR COAST
 48H  25/1800Z 18.9N 102.7W   60 KT  70 MPH...INLAND
 60H  26/0600Z 20.3N 103.3W   30 KT  35 MPH...INLAND
 72H  26/1800Z...DISSIPATED

$$
Forecaster Latto/Pasch



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