August 16, 2023/pm
Summary: The tropical low we’ve been discussing the past few mornings has now been assigned a name. Tropical storm Hilary was located several hundred miles to the southwest Manzanilla, Mexico. Hilary will be off the extreme southern Baja coastline as a major hurricane then will move northward parallel to the Baja peninsula. By 8:00pm Saturday, it will be about halfway up the peninsula. By 8:00am Sunday, the center of circulation will be roughly 100 miles south of Tijuana then will move inland across the extreme northern Baja peninsula, possibly through San Diego County Monday morning.
It now appears heavy precipitation is likely in southern California and, at the very least, over the Kern County mountains and the southern Sierra Nevada, mainly north of Fresno County. This is shaping up to be a rare event as tropical storm force winds, generally 40 mph or less, may spread as far north as southern Orange County. It does look like we’ll have some precipitation, mainly from Sunday afternoon through early Tuesday, perhaps with totals of .10 or less.
The wild card in all of this is that the same upper low we’ve mentioned over the past week could head inland at this time, with the timing being critical for potential rainfall amounts. Worse case scenario shows moisture becoming entrained within this low, causing it to move over the southern half of the San Joaquin Valley, resulting in numerous showers and the potential for thunderstorms. Under this scenario, locations south of Fresno County could possibly pick up between .50 and 1.00. If heavy thunderstorms occur with this event, locations primarily in Kern and Tulare Counties could rack up more than an inch of precip. It’s the timing of that off shore low that makes for such a hazardous forecast.
This will be a rare event. This forecast will be updated in the morning.
Forecast Partly cloudy at times through Friday night with a slight chance of isolated thunderstorms near the foothills afternoons and evenings. Increasing clouds Saturday night. Mostly cloudy Sunday with a slight chance of showers Sunday morning with a chance of showers and thunderstorms Sunday night. Numerous showers and isolated thunderstorms Monday and Monday night. A chance of showers Tuesday morning. Becoming partly cloudy Tuesday afternoon through Wednesday with a slight chance of showers near the foothills.
Temperatures: Lows tonight will cool into the low to mid 70s, possibly the low 80s in Kern County. Highs Thursday will be near 105. Lows Thursday night will cool into the mid 60s to the lower 70s with highs Friday warming into the upper 90s.