Monsoonal moisture allowed for another round of thunderstorms to develop over the San Bernardino Mountains on August 1st. Slow-moving storms allowed for efficient rainfall production, which led to flash flooding in the town of Big Bear and also over portions of Highway 38.
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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.
Monsoonal moisture allowed for another round of thunderstorms to develop over the San Bernardino Mountains on August 1st. Slow-moving storms allowed for efficient rainfall production, which led to flash flooding in the town of Big Bear and also over portions of Highway 38.
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 Jul 31, 7:43 PM PST, 4 hours 17 minutes earlier.
Area Forecast Discussion
National Weather Service San Diego CA
843 PM PDT Sun Jul 31 2022
.SYNOPSIS...
Monsoonal moisture across the region will fuel shower and
thunderstorm development again on Monday with isolated showers
possible overnight. Local flash flooding will be possible near
the heavier thunderstorms again on Monday afternoon. The
atmosphere will dry out a bit, and become more stable through mid
week as high pressure builds aloft. This will be accompanied by
slight warming, but monsoonal flow is likely to return late in the
week as high pressure drifts east, and opens the door for more
clouds, showers, and thunderstorms across the region.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Update:
It was another active day of monsoonal thunderstorm activity
across especially the San Bernardinos and high desert region. See
local storm reports headlined on our webpage weather.gov/sandiego
for details on impacts today.
The activity has dissipated with just a few showers over the high
desert currently. A few showers could develop over Orange County
to the Inland Empire tonight. One lone shower had developed near
Perris but has dissipated. HRRR shows a few more showers
developing in this region overnight, but light rainfall amounts.
Another active monsoon day is forecast for Monday. See details
below from the previous discussion.
Previous Discussion:
Showers and thunderstorms were ongoing at 2 PM PDT, mainly over the
mountains and high deserts, although we have had a few showers over
Orange County as well. Please see the rainfall summary posted on our
webpage for the latest amounts we have been able to record. Very
heavy rainfall rates are possible, due to the high PW levels up to
two inches or more in some eastern portions of the forecast area. A
Flood Watch remains in effect for our northern mountains and high
deserts through 10 PM this evening.
Several more rounds of thunderstorms are possible over the mountains
and deserts this afternoon, and we could even see some scattered,
less intense shower/t-storm activity overnight into Monday morning,
even west of the mountains. Any marine layer clouds will likely be
patchy, if they develop at all tonight.
For Monday, not a whole lot of change is forecast as the monsoonal
flow continues, although some modest drying is indicated, and subtle
differences in the synoptic features aloft could affect how
widespread development is. The latest NAM12 has a weak easterly wave
moving north along the San Diego County coast late in the day. The
flow aloft from the S-SE could be a bit stronger as well, which
could decrease the flash flood potential a bit. All things
considered, there remains a significant flash flood threat on Monday.
Further stabilization of the atmosphere occurs after Monday though,
as the subtropical ridge strengthens along 35N. This position cuts
off the moist SE flow aloft into SoCal as well, further reducing any
shwr/tstm threat.
By Thursday, the ridge is on the move again, drifting NE and
settling over Colorado. The ridge also morphs back to a more
cellular form, guiding monsoonal moisture back up over SoCal,
renewing the chance for shwrs/tstms and increasing the humidity
levels. There is a wider spread of the ensemble solutions regarding
precipitation over SoCal with this next round, but a majority do
show some precipitation centered around next weekend and into early
the following week. Seasonal onshore flow is maintained as well, so
a shallow marine layer will likely persist, but could be disrupted
at times due to periods of convection. Daytime temperatures overall
should be near, or a bit below the seasonal average.
&&
.AVIATION...
010300Z...Coast/Valleys...SCT-BKN high clouds at/above 10,000 feet
MSL will continue through Monday morning. Patchy low clouds may
return to coastal areas after 10Z Monday. Most likely timing for
ceilings at coastal terminals is 11-15Z. Scatter out expected 15-
17Z. Very slight chances for SHRA and TSRA can be anticipated again
Monday afternoon, with a 20% chance of occurrence over the eastern
valleys and portions of the Inland Empire. Minimal precipitation
chances along/near the coast.
Mountains/Deserts...SCT-BKN high clouds at/above 10,000 feet MSL
through Monday morning. Scattered TSRA forming again over the
mountain and desert foothills generally after 18z Monday with most
activity diminishing by 03z Tue. Low confidence in any TSRA
impacting the terminals with PSP having the highest odds, albeit at
only a 20-30% chance. Downpours reducing VIS as well as gusty and
erratic winds will be possible with any TSRA.
&&
.MARINE...
An increasing southerly swell, up to 5 feet, from 180-200 degrees
and with a period of 12-14 seconds, is expected tonight through
Wednesday due to the remnants of Hurricane Frank.
&&
.BEACHES...
Hurricane Frank will generate hazardous surf conditions, including
strong rip currents, tonight through Wednesday. The 6 foot south
swell from 180-200 degrees at a period of 12-14 seconds will
generate surf of 4-7 feet, mainly along south-facing beaches.
Highest surf will be in northern Orange County.
&&
.SKYWARN...
Skywarn activation is requested for this afternoon, and may be
needed again on Monday.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through Wednesday afternoon for Orange
County Coastal Areas-San Diego County Coastal Areas.
PZ...NONE.
&&
PUBLIC...Gregoria (Update)/10 (Previous Discussion)
AVIATION/MARINE...AdamsThe Santa Ana Mts radar (KSOX), 73 km away, was scanning. The volume nearest the first event began at 07:57 UTC.
3 heavy rain, 3 flash flood. Local standard time, as filed.
Mesonet station Yucc1 Yucaipa Ridge reported 2.28 inch of heavy rain from July 30 - August 2.
Mesonet station FW9733 Fawnskin reported rainfall of 2.63 inch from July 30 to August 1.
County alert gauge north of Big Bear Lake reported 0.55 inch of rain in ten minutes between 11:39 and 11:49 AM PDT.
Car stalled in 4 feet of water at Highway 38 at Stanfield Cutoff. Parties trapped inside were rescued by Fire Department. Road was closed to clear debris.
Roadway flooding near 1509 Shay Rd in Big Bear City. North and south side of Shay Road was flooded. Storm survey by WCM showed several inches of water still flowing over Shay Road. Radar estimated 2 to 3 inches of rain in less than 3 hours. Water flowed around numerous homes, flowing into Baldwin Lake. Nearby Big Bear Yard reported 1.80 inches.
Two to three feet of water flooding across the roadway at SR18 and Johnson Road.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2022Every state in 2022This day in weather historyWarnings in California, August 2022
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: 1047144, 1047145, 1040810, 1040786, 1040803, 1040805.