Tornado and Hail in California, September 28 to 30, 2019

Name: Tornado and Hail in California, September 28 to 30, 2019
Start: 2019-09-28T15:25
End: 2019-09-30T09:40
Location: California

September 28 to 30, 2019 · NWS STO · 5 events in 2 counties and zones

An unseasonably cold upper level low pressure system brought showers and thunderstorms to the Valley, which brought accumulating and damaging hail and a weak tornado to the Davis. High elevation snow was observed as well.

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: $10,000
Events: 5

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.

What happened

The episode as NWS STO wrote it up.

What forecasters said that day

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 Sacramento, CA wrote its last area forecast discussion before the first event at Sep 28, 1:58 PM PST, 1 hour 27 minutes earlier.

Area forecast discussion, Sep 28, 1:58 PM PST, 1 hour 27 minutes before

Area Forecast Discussion
National Weather Service Sacramento CA
258 PM PDT Sat Sep 28 2019

.SYNOPSIS...
Much cooler weather along with a chance of showers and high
elevation snow over the weekend into Monday. Below normal
temperatures continue through next week.

&&

.DISCUSSION...
Latest radar imagery shows a frontal boundary progressing
southward this afternoon, with light snow been observed from about
Soda Springs to Donner summit. Observed precipitation amounts
over the last six hours have ranged from around 0.10 to 0.40
inches, locally higher across portions of the northern Sierra.
Afternoon temperatures are currently trending 2 to 10 degrees
cooler compared to yesterday's across the Valley, and as much as
15 to 25 degrees cooler over the mountains. An isolated
thunderstorm or two could be possible this afternoon over the
Sierra and adjacent foothills.

Shower activity will continue into Monday, mainly over the
southern Cascades, northern Sierra and the foothills. A few
showers will be possible in the valley as well. Additional precip
amounts in the 0.20-0.50 inch range, could be possible over
higher terrain. Forecast soundings and ensemble probabilities
indicate the potential for isolated afternoon thunderstorms over
the foothills and mountains on Sunday.

Early season high-elevation snowfall will be possible across the
higher elevations of the northern Sierra Nevada and southern
Cascade Range this weekend into Monday. Snow accumulations in the
2-6 inch range will be possible at pass levels; up to a foot will
be possible over the highest mountain peaks including Lassen
National Park. This could result in travel impacts over Sierra
passes. A Winter Weather Advisory remains in effect for elevations
above 6000 feet until 5 PM Monday. Snow will be showery in nature
with several hours of breaks in snow activity. Precipitation
activity will end late Monday as the upper low lifts to the
northeast.

With the large upper trough over the West, significantly cooler
temperatures will continue across interior NorCal. Forecast highs
will remain much as 15-30 degrees below normal through Monday.
Valley daytime temperatures will range from the mid 60s to low 70s
over the weekend, with mainly low 40s to mid 50s over the
mountains. Overnight lows in the mountains may reach below freezing
each night through Tuesday as this system moves across the area.
Valley overnight lows will be in the 40s, so we could see some
some record lows tonight.

&&

.EXTENDED DISCUSSION (Wednesday THROUGH Saturday)...
Upper ridging will move over the region by mid-week, resulting in
dry and warm conditions. Forecast highs in the Valley will be in
the upper 70s to low 80s on Wednesday. However, these readings
will remain below seasonal normals. Guidance shows an upper-level
trough pushing into the PacNW around Thursday. At this point, it
appears that precipitation activity will remain north of the
forecast area. Warmer temperatures are expected next Saturday as
high pressure slides across the north state.

&&

.AVIATION...
The low level clouds from this morning have dissipated with
satellite imagery showing cumulus clouds scattered over the
region. Isolated to scattered showers are expected mainly for the
foothills and mountains, with the potential of some straying into
the Valley. Expect VFR conditions with the occasional MVFR
ceilings next 24 hours as upper low drops southward through the
Pacific Northwest. North to northwest winds 10 to 20 mph through
about 06z Sunday then variable to 10 mph.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 5 PM PDT Monday for West Slope
Northern Sierra Nevada-Western Plumas County/Lassen Park.

&&

The radar

The Sacramento radar (KDAX), 17 km away, was scanning. The volume nearest the first event began at 23:23 UTC.

Open the radar archive at this moment

Event by event

2 hail, 1 tornado, 1 funnel cloud, 1 winter weather. Local standard time, as filed.

Hail, Yolo

When: September 28, 3:25 PM PST to 3:40 PM PST
Where: Yolo County, 0.78 mi WSW of Merritt
Measured: 1 in hail
Crop damage: $10,000
Reported by: Public
Coordinates: 38.627, -121.784

A member of the public called to inform us about hail damage to their pistachio crop. They estimated that the hail stone sizes were generally around 0.75-1.0 inch stones but that they also varied greatly in size as it fell. After the hail ended they went to check on their pistachio crop and found out that they lost all of it. These trees were about 30 years old and sustained damaged.

Hail, Yolo

When: September 28, 4:25 PM PST to 4:30 PM PST
Where: Yolo County, 4 mi S of Woodland
Measured: 1 in hail
Reported by: Trained Spotter
Coordinates: 38.622, -121.770

A spotter SO47, located on highway 113 north of Davis, reported one inch hail stones.

Tornado, Yolo

When: September 28, 4:37 PM PST to 4:50 PM PST
Where: Yolo County, 2 mi N of Davis
Rating: EF0
Path length: 1.7 mi
Path width: 1 yd
Reported by: Public
Coordinates: 38.579, -121.750

A tornado was reported by a University of California Davis atmospheric science student. The student was reported to be east of highway 101a and highway 29 around 5:41 pm pst and filmed the tornado.

Funnel Cloud, Yolo

When: September 28, 5:00 PM PST
Where: Yolo County, 1.41 mi N of Swingle
Reported by: Public
Coordinates: 38.550, -121.632

A member of the public reported a funnel cloud about 2 miles east of El Macero Country Club.

Winter Weather, Mt Shasta/Western Plumas County

When: September 28, 10:00 PM PST to September 30, 9:40 AM PST
Where: Mt Shasta/Western Plumas County forecast zone
Reported by: Park/Forest Service

At the Lassen National Park Visitor Center, which is at an elevation of 6700 feet, 6 to 8 inches of snow fell overnight. the park ranger noted that at about 7000 feet there were higher amounts but it was still snowing pretty heavily up there at the time of report.They also noted that prior to last night, each day they may have received a trace amount of snow.

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Tornado: A violently rotating column of air in contact with the ground and extending from a thunderstorm, filed with its path, width and Fujita or Enhanced Fujita rating from the damage survey.
Funnel Cloud: A rotating column of cloud extending from a thunderstorm that did not reach the ground.
Winter Weather: Snow, sleet or freezing rain below warning levels that still caused disruption, damage or casualties.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in California in 2019 Every state in 2019 This day in weather history The tornado archive for California, 2019 Warnings in California, September 2019

Sources

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: 860478, 860466, 860470, 860474, 860493.