Hurricane John Forecast Discussion

000
WTPZ45 KNHC 232049
TCDEP5

Hurricane John Discussion Number   6
NWS National Hurricane Center Miami FL       EP102024
300 PM CST Mon Sep 23 2024

John continues to rapidly strengthen.  The latest subjective Dvorak 
intensity estimates range from 65 to 77 kt, while the latest 
objective intensity estimates are a little higher, in the 79 to 90 
kt range.  On infrared satellite imagery, the area of cold cloud 
tops continues to grow, and the inner core is becoming more 
symmetric.  The latest visible images have shown hints of a small 
eye, that has become a little more apparent in the last few hours.  
Based on the above data and recent satellite trends, the initial 
intensity is increased to 85 kt, making John a category 2 hurricane.

Environmental parameters continue to be ripe for additional rapid 
intensification, with very warm ocean temperatures, weak vertical 
wind shear and a moist atmosphere.  The only potential limiting 
factor could be how John might interact with the mountainous 
topography of Mexico as the hurricane approaches the coastline.  The 
DSHIPS and LGEM statistical intensity models remain at the higher 
end of the guidance envelope and show John becoming a major 
hurricane as it approaches the coast.  The EC SHIPS Rapid Intensity 
Index is depicting a high likelihood of continued rapid 
intensification over next 12 hours.  The latest NHC forecast is near 
the high end of the intensity guidance and continues to show John 
strengthening to a 105-kt hurricane.  It is possible that John could 
peak even higher than shown below between the 12 h forecast point 
and when it reaches the coast.

John continues to move due northward, now at 5 kt.  The current 
motion and the latest model guidance has again necessitated a 
westward track shift to the NHC forecast. Given the updated track 
forecast, the government of Mexico has extended the hurricane 
warning westward.


KEY MESSAGES:

1. John is expected to continue rapidly intensifying, and is 
forecast to become a major hurricane before the center reaches the 
coast of southern Mexico within the Hurricane Warning area tonight 
or early Tuesday. Damaging hurricane-force winds and a 
life-threatening storm surge are expected within portions of the 
hurricane warning area.

2. John will bring very heavy rainfall to coastal portions of
southern Mexico through this week.  This heavy rainfall will likely
cause significant and possibly catastrophic, life-threatening flash
flooding and mudslides to the Mexican States of Chiapas, Oaxaca, and
southeast Guerrero, particularly in areas near the coast.


FORECAST POSITIONS AND MAX WINDS

INIT  23/2100Z 15.5N  98.5W   85 KT 100 MPH
 12H  24/0600Z 16.0N  98.3W  105 KT 120 MPH
 24H  24/1800Z 16.5N  98.3W   65 KT  75 MPH...INLAND
 36H  25/0600Z 16.7N  98.4W   30 KT  35 MPH...POST-TROP/INLAND
 48H  25/1800Z...DISSIPATED

$$
Forecaster Hagen