A trough of low pressure north of Southern California brought gusty winds to the mountains and deserts.
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The episode as NWS SGX wrote it up.
A trough of low pressure north of Southern California brought gusty winds to the mountains and deserts.
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 May 21, 7:21 PM PST, 1 hour 39 minutes earlier.
AREA FORECAST DISCUSSION National Weather Service San Diego CA 821 PM PDT SAT MAY 21 2016 .UPDATE... A LONGWAVE TROUGH OVER THE WESTERN STATES CONTINUES TO KEEP TEMPERATURES ACROSS THE AREA RUNNING COOLER THAN AVERAGE. THE HIGHEST TEMP DEPARTURES TODAY WERE OVER THE MOUNTAINS AND LOWER DESERTS. HIGHS ACROSS OUR SERVICE AREA TODAY RANGED FROM 48F AT BIG BEAR LAKE TO 85F AT THERMAL. THE AVERAGE HIGH FOR TODAY IS 68F AT BIG BEAR LAKE AND 97F AT THERMAL! TONIGHT WILL BE TRANQUIL AND COOL WITH JUST SOME CLOUDINESS DEVELOPING WEST OF THE MOUNTAINS, BUT NO PRECIP IS EXPECTED. GUSTY WINDS ARE IMPACTING PORTIONS OF THE MOUNTAINS AND DESERTS WITH THE LOWER DESERTS AVERAGING GUSTS OF 30-35 MPH. WIND GUSTS IN PORTIONS OF THE SAN GORGONIO PASS/WHITEWATER AT AROUND 2500 FT/ ARE AVERAGING 50 MPH THIS EVENING...BUT THIS IS A TYPICALLY EXPOSED LOCATION. WINDS AT LOWER ELEVATION IN THE PASS ARE GUSTING AT 30-40 MPH. WINDS ARE FORECAST TO GRADUALLY RELAX ACROSS THESE AREAS THROUGH SUNDAY AS THE PRESSURE GRADIENT CONTINUES TO LESSEN. SUNDAY LOOKS VERY SIMILAR TO WHAT WAS EXPERIENCED TODAY ACROSS SOUTHERN CALIFORNIA. NO SIGNIFICANT CHANGES WERE MADE TO THE FORECAST THIS EVENING. SEE PREVIOUS DISCUSSION BELOW FOR FURTHER FORECAST DETAILS. /GREGORIA && .SYNOPSIS... A trough of low pressure over the western United States will bring below normal temperatures most of the next week. There will be occasional low clouds from the coast to the mountains, with patchy fog in the mountains. A few showers could occur mainly from late Monday night through Wednesday morning. There will continue to be periods of gusty west winds in the mountains and deserts, strongest during the late afternoon and evening each day. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... The upper low is currently over SE Oregon and will continue to move NE. However, another wave will move down the west side of the low into central California, and subsequent waves will move down the back side of the trough to maintain it through at least midweek. Even though temperatures should be a few degrees higher Sunday due to a warmer profile and higher pressure levels, temperatures will remain below normal through next week with greatest departures from normal for daytime temperatures occurring in the valleys and mountains, at times 20 or more deg F below normal for highs when colder air aloft with waves moves through. Stratus will be variable and will cover most areas from the coast to the mountain slopes, though the cold air aloft will keep the inversion strength relatively weak, so the stratus will mostly be broken versus overcast. Local WRF does indicate some lowering of the stratus by Sunday night, so the mountains may get a little reprieve then before more waves deepen the marine layer again on following days. Some of the models show measurable precipitation Tuesday and Wednesday early mornings when waves go through, but precipitation should be only a few hundredths of an inch. The upper trough should temporarily weaken around Thursday before another trough moves down from the N/NW and brings more cool weather and occasional cloudiness. Onshore flow and continued valley-desert thermal gradients will keep the mountains and deserts breezy most of next week, though most likely below wind advisory criteria. && .AVIATION... 220300Z...Coast/Valleys...Sct/bkn low clouds with bases 2500-3500 ft and tops 4000 ft msl will continue to push over the coastal and valley areas through tonight. Vis will lower to 3-5 sm where these low clouds near terrain on the coastal slopes, otherwise P6SM. This stratus deck will scatter out by 21/1800z Sunday morning. Low clouds with slightly lower bases and tops are forecast to return to the coast and valleys aft 22/0300z Sunday evening. Mountains/Deserts...Partly cloudy skies and unrestricted vis will prevail through Saturday afternoon. Westerly winds will strengthen by Saturday morning, gusting to 20 to 25 kt at times. && .MARINE... 800 PM...Wind gusts over the outer waters will briefly reach 20 knots through late this evening, and again late Sunday afternoon and evening. Otherwise, no hazardous marine weather is expected through Wednesday. .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 AVIATION/MARINE...JT
The national radar mosaic for the moment the first event began.
1 dust storm. Local standard time, as filed.
A spotter reported blowing dust with visibility of 1/4 to 1/8 of a mile, sustained winds to 39 mph and gusts to 50 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2016Every state in 2016This day in weather historyWarnings in California, May 2016
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: 640200.