Hurricane Genevieve

362 
WTPZ42 KNHC 270848
TCDEP2
 
Hurricane Genevieve Discussion Number  12
NWS National Hurricane Center Miami FL       EP072026
200 AM MST Mon Jul 27 2026
 
Genevieve has maintained a clear and well-defined eye for the last
12 to 18 h.  During that time, eye temperatures have warmed and the
area of cold cloud tops surrounding the eye has expanded, leading to
continually increasing satellite intensity estimates.  The D-PRINT,
D-MINT, SATCON, and ADT satellite intensity estimates have all
reached the 137-142 kt range over the past several hours, especially
during the 03Z to 05Z time-frame, when Genevieve's satellite
presentation looked most impressive.  The latest TAFB estimate is
7.0/140 kt.  Based on these numbers, Genevieve is upgraded to a
140-kt category 5 hurricane on the Saffir-Simpson Hurricane Wind
Scale.  Genevieve is the first category 5 hurricane in the East
Pacific since Kristy of 2024.
 
Genevieve has been moving toward the northwest, or 310 degrees at 11
kt.  The track forecast reasoning hasn't changed.  The hurricane has
been moving along the periphery of a mid- to upper-level ridge
centered over northwestern Mexico.  Genevieve is expected to
continue moving west-northwestward to northwestward through the
forecast period, as it rounds the southwestern portion of the ridge.
The latest NHC track forecast is very similar to the previous
advisory and lies near the HCCA corrected consensus and Google
DeepMind ensemble mean.
 
Sea surface temperatures (SSTs) are forecast to gradually decrease
from 30C right now to 28C in 48 h, and Genevieve should cross the
26C isotherm just beyond 72 h.  During the same time period,
mid-level relative humidity should gradually decrease and stability
gradually increase, while vertical wind shear remains low to
moderate.  These environmental conditions might be favorable enough
for Genevieve to either maintain its intensity or fluctuate in
intensity during the next day or so, depending on whether it
undergoes an eyewall replacement cycle.  Microwave-based Probability
of Eyewall Replacement Cycle (MPERC) guidance indicates a 50/50
chance of an eyewall replacement cycle occurring within the next 24
h.  Beyond 24 h, the decreasing SSTs and humidity values should be
enough to commence steady weakening, with more substantial weakening
after 72 h when the cyclone crosses the 26C SST isotherm.  The new
NHC intensity forecast is similar to the previous one, perhaps
showing a slightly faster rate of weakening beyond 24 h.  The
intensity forecast lies near the middle of the typically reliable
intensity model solutions.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  27/0900Z 15.5N 112.2W  140 KT 160 MPH
 12H  27/1800Z 16.3N 113.4W  135 KT 155 MPH
 24H  28/0600Z 17.3N 115.0W  125 KT 145 MPH
 36H  28/1800Z 17.9N 116.4W  110 KT 125 MPH
 48H  29/0600Z 18.5N 117.9W  100 KT 115 MPH
 60H  29/1800Z 19.2N 119.6W   90 KT 105 MPH
 72H  30/0600Z 20.0N 121.5W   80 KT  90 MPH
 96H  31/0600Z 21.6N 126.2W   60 KT  70 MPH
120H  01/0600Z 23.3N 131.5W   45 KT  50 MPH
 
$$
Forecaster Hagen