Deadly floodwaters inundated streets across Mexico’s arid Baja California on Sunday as Tropical Storm Hilary moved ashore carrying torrential rain into Southern California, and concerns mounted that flash floods could strike in places as far north as Idaho that rarely get such heavy rain.
At least 9 million people were under flash-flood warnings as heavy rain fell across normally sunny Southern California ahead of the brunt of the storm. Desert areas were especially susceptible along with hillsides with wildfire burn scars, forecasters warned. CONTINUE READING
“Hilary” grew into a powerhouse “Cat-4” hurricane with 145 mph sustained winds between Wednesday and Thursday last week—then, moving up and over the much cooler waters off Baja California Saturday and Sunday—weakened to its current tropical storm status
The satellite “presentation” of “Hilary” in this multi-day sequence of image, frames of which you can “click through”and watch the progression on the series of true color GOES WEST satellite images I’m posting, is quite stunning.
The sequence begins with a 9:40am CDT Wed GOES WEST image, then progresses day by day through Thursday, Friday, Saturday–and finally 9:40am CDT this (Sunday) morning 8/20/2023.
Intensification over the warm waters off western Mexico was explosive between Wednesday and Thursday. Ocean temps there are running 3.6 to 7-deg F above typical August levels—and in the mid 80s F.
Equally impressive has been the storm’s weakening as it’s moved over cooler waters off Baja California—where despite above normal temps—actual water temps drop to the 60s. Tropical cyclones derive their energy from the evaporation and condensation of warm ocean waters. Deprive these systems of warm water—in particular, water temps below 78.8°F—and these systems weaken dramatically.
While Hilary has weakened, its potential to produce flooding rains HAS NOT! The NHC warns of potentially catastrophic flooding in sections of southern California, western Arizona and Nevada.