A surface area of high pressure over the Great Basin led to gusty Santa Ana winds across the mountains and foothills.
Every event with a place to put it; 2 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS SGX wrote it up.
A surface area of high pressure over the Great Basin led to gusty Santa Ana winds across the mountains and foothills.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS San Diego, CA wrote its last area forecast discussion before the first event at Oct 14, 8:34 PM PST, 3 hours 26 minutes earlier.
Area Forecast Discussion National Weather Service San Diego CA 934 PM PDT Thu Oct 14 2021 .SYNOPSIS... Fair and warmer weather will prevail through Saturday. Areas of Santa Ana winds in the foothills will boost the warmth and lower the humidity west of the mountains. Cooler weather returns next week with some coastal clouds and fog during nights and mornings. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Update: Weak Santa Ana winds have begun this evening with winds out of the northeast through the passes and canyons and along the coastal mountain slopes. Gusts in the most wind-prone areas in the San Diego County foothills are around 30 mph (except Sill Hill up to 39 mph) and further north below the San Gorgonio Pass and Cajon Pass gusts are in the 10-20 mph range. Winds will pick up and peak Friday morning. Relative humidity will plummet on Friday and it will get noticeably hotter due to the offshore, downsloping winds. This will create near critical fire weather conditions where the Santa Ana winds are blowing. No updates were needed to the forecast this evening. Previous Discussion (Issued at 212 PM PDT Thu Oct 14 2021): Clear skies continue across the region this afternoon, while a surface high settles into the Great Basin, and stirs the wind field around to an offshore pattern. The surface high builds on Friday to 1035 mb over the Great Basin and the Santa Ana winds will peak here in SoCal Friday morning with gusts as high as 35 to 45 mph immediately below the passes and in some of the coastal foothill areas. With the offshore flow comes very dry air as well, and RH values will plummet on Friday afternoon as low as 5% west of the mountains. Temperatures will also soar with temperatures into the 90s away from the coast and in the 80s close to the coast. The Santa Ana winds will relax Friday afternoon and evening, and then a secondary surge, not quite as strong, will come late Friday night into Saturday morning. As the surface high weakens on Sunday and a troughy pattern develops along the west coast, look for the synoptic pattern to shift back to marine influence dominated west of the mountains, with areas of fog and low clouds likely to develop Sunday through Monday. Inland areas will also cool off as the upper level temperatures moderate due to the troughy pattern and onshore flow sweeps through the passes each afternoon and evening. The weather pattern does not vary all that much next week, with onshore flow dominating the scene. A Pacific trough will remain the dominant west coast weather feature. The ensemble forecasts, especially the EC ensemble mean, show the Pacific Northwest upper level trough dropping south by next weekend, and bringing rainfall progressively further south. By next weekend, rainfall could be possible about halfway down California, and into the early part of the following week (after October 24th) we could eventually see the moisture fetch drop into SoCal. That is a long way off of course at this point, but the fact that the ensembles are increasing moisture parameters is promising for SoCal rain potential. && .AVIATION... 150245Z...Mostly clear with unrestricted vis through Friday afternoon across the region. NE-E winds with gusts 25-35 kt developing through/below the passes and canyons and along the coastal mountain slopes and foothills developing tonight through early Friday afternoon. Areas of LLWS and mod up/downdrafts possible over and SW/W of the mountains, including vcnty KONT and KSBD. && .MARINE... No hazardous marine conditions are expected through Sunday. Patchy fog, possibly dense, could develop over the coastal waters Saturday night into Sunday morning. && .FIRE WEATHER... Areas of Santa Ana winds will develop in the foothills and extend partially into valleys tonight through Saturday morning. Winds peak Friday morning with top gusts up to 45 mph in favored pockets of foothills and below the passes. These winds will boost the fire potential, becoming near critical for several hours during the late morning and afternoon Friday when humidity drops into the 5-10% range, while winds persist in these breezier pockets. Winds decrease late Friday afternoon, but it stays dry through Saturday, with another surge of Santa Ana winds Saturday morning. By Sunday, onshore flow will bring much higher humidity. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. && PUBLIC...Gregoria (Update)/Brotherton (Previous Discussion) AVIATION/MARINE...APR
The national radar mosaic for the moment the first event began.
2 high wind. Local standard time, as filed.
Highland Springs RAWS measures 59 MPH wind gust.
Gusty winds over 55 MPH across the region, including mesonet Sill Hill measuring wind gust of 70 MPH.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2021Every state in 2021This day in weather historyWarnings in California, October 2021
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 986850, 986854.