An upper high set up over the Great Basin, ushering in gusty Santa Ana winds to Southern California. The highest wind gust was 91 mph at Hellhole Canyon, a wind prone location in the San Diego Mountains.
Every event with a place to put it; 11 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.
An upper high set up over the Great Basin, ushering in gusty Santa Ana winds to Southern California. The highest wind gust was 91 mph at Hellhole Canyon, a wind prone location in the San Diego Mountains. Many other locations had wind gusts in excess of 70 mph. A few tractor trailers were blown over on I-8 in San Diego County. Valley locations also had some gusty winds, with gusts of 25-45 mph, with locally higher gusts.
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 Dec 16, 8:54 PM PST, 6 hours 6 minutes earlier.
Area Forecast Discussion
National Weather Service San Diego CA
854 PM PST Mon Dec 16 2019
.SYNOPSIS...
Moderate to locally strong Santa Ana winds will impact the
mountains, foothills, and inland valleys through Tuesday evening.
On Wednesday and Thursday a weak trough will bring a brief period
of onshore flow. This will be followed by dry, warmer weather
Friday and Saturday under weak high pressure. Showers are looking
more likely next week as a slow moving Pacific trough moves inland
across the West.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
UPDATE...
A few high clouds were over the region this evening. Surface
pressure gradients continue to trend stronger offshore, currently
around -10 mb SAN-TPH. This will increase further overnight as the
surface high strengthens over the eastern Great Basin and northern
Rockies. Isolated gusts to 70 mph still looking likely on some of
the coastal mountain slopes. In fact, Sill Hill has already hit 69
mph. Winds will peak early to mid morning Tuesday, followed by a
gradual weakening through the afternoon. The forecast remains on
track and no significant changes were made this evening.
PREVIOUS DISCUSSION...
The Santa Ana event ends Tuesday night, followed by weak onshore
flow Wednesday, and somewhat stronger onshore flow Thursday as a low
pressure trough moves inland across central California. Most of the
precipitation will remain to the north of our area, but a marine
layer will reform Wednesday night with patchy low clouds in the
coastal and western valley zones.
Weak high pressure aloft on Friday and Saturday will bring warmer
days and sunny skies. Sunday will turn a little cooler as a
deepening trough over the eastern Pacific moves toward the coast.
The early look at Christmas week shows a period of cool, unsettled
weather as both the GFS and ECMWF ensembles show a quasi-stationary
high amplitude longwave trough over the West. Showers will accompany
any passing shortwaves rounding the base of the trough. Timing
issues have yet to be resolved, but the chances of a white Christmas
in the mountains and a wet Christmas in the lower elevations are
above average.
&&
.AVIATION...
170310Z...VFR conditions will prevail at all terminals through
Wednesday, with only a few high clouds AOA 20,000 ft MSL at times.
Primary concern will be gusty E to NE winds through Tuesday night.
Winds will be strongest on west-facing mtn slopes, foothills, and
adjacent valleys, with gusts 25 to 40 kt at times. Peak gusts at
KONT near 35 kt, and 25 kt at KSNA. Lighter winds anticipated at the
other terminals. Generally light, alternating E-W winds likely at
KSAN through much of the period.
Expect periods of LLWS and MOD-STG UDDFTS over and west of the mtns,
mainly through 03Z Wednesday.
&&
.MARINE...
Offshore flow with easterly winds will produce occasional and
isolated gusts to exceed 20 kts through early Wednesday. Otherwise,
no hazardous marine weather is expected through Saturday.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...High Wind Warning until 10 PM PST Tuesday for Riverside County
Mountains-San Bernardino County Mountains-San Diego County
Mountains-San Gorgonio Pass Near Banning-Santa Ana
Mountains and Foothills.
Wind Advisory until 10 PM PST Tuesday for Orange County Inland
Areas-San Bernardino and Riverside County Valleys-The
Inland Empire-San Diego County Valleys.
PZ...NONE.
&&
PUBLIC...SS
AVIATION/MARINE...RodriguezThe national radar mosaic for the moment the first event began.
11 high wind. Local standard time, as filed.
Fremont Canyon reported a peak wind gust of 76 knots at 0351 AM PST on 12/17.
Lytle Creek Rd. mesonet reported a peak wind gust of 60 knots at 0550 AM PST on 12/17.
Pauma Valley reported a peak wind gust of 59 knots at 0612 AM PST on 12/17.
Highland Springs reported a peak wind gust of 63 knots at 0716 AM PST on 12/17.
Devil Canyon reported a peak wind gust of 61 knots at 0720 AM PST on 12/17.
East Willows Rd. mesonet reported a peak wind gust of 58 knots at 0730 AM PST on 12/17. At least 1 tractor trailer was blown over on its side by the wind on Interstate 8, causing major traffic disruptions.
Hellhole Canyon mesonet reported a peak wind gust of 79 knots at 0850 AM PST on 12/17.
Sill Hill reported a peak wind gust of 67 knots at 0810 AM PST on 12/17.
Alpine RAWS reported a peak wind gust of 62 knots at 0852 AM PST on 12/17.
Poppet Flats RAWS reported a peak wind gust of 55 knots at 0914 AM PST on 12/17.
Potrero mesonet reported a peak wind gust of 54 knots at 0920 AM PST on 12/17.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2019Every state in 2019This day in weather historyWarnings in California, December 2019
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: 870063, 870068, 870069, 870065, 870067, 870070, 870062, 870064, 870066, 870071, 870072.