By PDC’s Senior Weather
Specialist Glenn James
The Pacific Disaster Center’s (PDC Global) Friday, August 18, 2023, Tropical Cyclone Activity Report…for the Pacific Ocean, the Indian Ocean, and adjacent Seas
Current Tropical Cyclones:
Tropical Cyclone 09E (Hilary)…is located about 285 miles southwest of the southern tip of Baja California
Northeast Pacific Ocean:
Tropical Cyclone 09E (Hilary)
LIFE-THREATENING AND POTENTIALLY CATASTROPHIC FLOODING LIKELY OVER MUCH OF BAJA CALIFORNIA AND THE SOUTHWESTERN UNITED STATES THIS WEEKEND AND EARLY NEXT WEEK…TROPICAL STORM WARNINGS EXTENDED NORTHWARD INTO SOUTHERN CALIFORNIA
According to the NHC advisory number 11…
Hilary is moving toward the north-northwest near 13 mph (20 km/h), and this motion is expected to continue through Saturday. A faster motion toward the north-northwest and north is expected Saturday night and Sunday. On the forecast track, the center of Hilary will move close to the west-central coast of the Baja California peninsula on Sunday and reach southern California by Sunday night.
Maximum sustained winds are near 130 mph (215 km/h) with higher gusts. Hilary is a category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale. Weakening is expected to begin by Saturday, but Hilary will still be a hurricane when it approaches the west coast of the Baja California peninsula Saturday night and Sunday. Hilary is expected to weaken to a tropical storm by late Sunday before it reaches southern California.
Hurricane-force winds extend outward up to 50 miles (85 km) from the
center and tropical-storm-force winds extend outward up to 255 miles
HAZARDS AFFECTING LAND
RAINFALL: Hilary is expected to produce rainfall amounts of 3 to 6 inches, with isolated maximum amounts up to 10 inches, across portions of the Baja California Peninsula through Sunday night. Flash flooding, locally significant, will be possible.
Heavy rainfall in association with Hilary is expected to impact the Southwestern United States through next Wednesday, peaking on Sunday and Monday. Rainfall amounts of 3 to 6 inches, with isolated amounts of 10 inches, are expected across portions of southern California and southern Nevada. Rare and dangerous flooding will be possible. Elsewhere across portions of the Western United States, rainfall totals of 1 to 3 inches are expected.
WIND: Hurricane conditions are expected within the hurricane warning area Saturday night and are possible within the hurricane watch by early Sunday. Tropical storm conditions are expected within the warning area by late today, and are possible within the watch area in Mexico on Saturday and in southern California beginning Sunday.
STORM SURGE: A dangerous storm surge is likely to produce coastal flooding along the western Baja California peninsula of Mexico near where the center passes the coast in areas of onshore winds, or east of the center if Hilary makes landfall. The surge will be accompanied by large and destructive waves.
SURF: Large swells generated by Hilary will affect portions of the coast of southwestern Mexico and the Baja California peninsula over the next few days. These swells are likely to cause life-threatening surf and rip current conditions.
>>> South of Southern Mexico…
A broad area of low pressure could form offshore of the coast of southern Mexico during the early or middle part of next week. Development of this system, if any, should be slow to occur while it moves toward the west-northwest or northwest.
* Formation chance through 48 hours…low…near 0 percent
* Formation chance through 7 days…low…20 percent
Western Pacific, Indian Ocean and adjacent Seas:
There are no active tropical cyclones…nor are there any areas of disturbed weather being investigated by the Joint Typhoon Warning Center (JTWC)