An upper level low over northern California yielded a cooler, wetter, and breezy pattern across the region through Labor Day weekend. Periods of light to moderate precipitation intermingled with isolated thunderstorms produced brief periods of heavy rainfall across the Sierra into northwest Nevada that caused some flash flooding and flooding concerns through the Labor weekend.
Every event with a place to put it; 1 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 REV wrote it up.
An upper level low over northern California yielded a cooler, wetter, and breezy pattern across the region through Labor Day weekend. Periods of light to moderate precipitation intermingled with isolated thunderstorms produced brief periods of heavy rainfall across the Sierra into northwest Nevada that caused some flash flooding and flooding concerns through the Labor weekend. Of particular concern was flooding in the playa area of the Black Rock Desert during the Burning Man festival.
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 Reno, NV wrote its last area forecast discussion before the first event at Sep 1, 1:20 AM PST, 5 hours 40 minutes earlier.
Area Forecast Discussion
National Weather Service Reno NV
220 AM PDT Fri Sep 1 2023
.SYNOPSIS...
A breezy and cooler pattern will prevail across the Sierra and
western Nevada over Labor Day weekend as an upper level low remains
parked across N.California. This will also yield a wetter pattern
with daily chances for showers and thunderstorms each day this
weekend. Drier and warmer conditions will return next week.
&&
.DISCUSSION...
An upper level low over northern California will yield a cooler,
wetter, and breezy pattern through Labor Day weekend. Drier and
warmer conditions will return beginning on Labor Day and extending
through next week. Additional details below:
PRECIPITATION:
* Widespread chances for rain showers and thunderstorms are expected
region wide this weekend with the best potential expected from Fri-
Sun before things start to dry out beginning Labor Day (Monday).
* Areas from roughly the Tahoe Basin northward to the Oregon
border and west of Gerlach will be the main focus for rain as
enhanced instability and dynamic forcing will be in place as the
upper low sits atop of N.CA this weekend. Overall we are looking
at a 60-90% chance for widespread showers and a 20-30% chance
for thunderstorms this afternoon across these areas. Other areas
will see 25-50% chances for showers while Mono-Mineral remain on
the drier side with 10-20% chances for showers. Through
Saturday and Sunday, rain chances become more scattered with
30-60% chances for showers each day and locally up to 75% across
areas along the Sierra.
* Rainfall amounts through the weekend could yield upwards of 0.25-
0.50" across the Tahoe Basin with 0.75-1.5" across portions of
Plumas and Lassen counties. Areas across W.Nevada, generally from
Pyramid Lake southward will see lesser amounts of 0.10-0.25" with
generally less than 0.10" across Mono-Mineral. While rain will be
the main mode of precipitation this weekend, we can't ruled out a
skiff of snow across the tippiest of tops of the Sierra as snow
levels dip just below 10,000 feet.
WIND:
* Expect another breezy day out there today, but the strongest winds
will shift southward of US-50 where southwest wind gusts of 40-50
mph will be possible mainly across Mono and Mineral counties this
afternoon. Locally higher wind gusts are possible across wind
prone locations along US-395 and US-95 near Walker Lake. This
could produce crosswind hazards for high profile vehicles. A Wind
Advisory remains in effect for Friday in these areas as a result.
* Areas to the north will see wind ease up in comparison to
yesterday with wind gusts generally up to 30 mph. This may
result choppy conditions across area lakes along with areas of
blowing dust near desert sinks. However, this dust impact
should decrease as precipitation moves in today.
TEMPERATURES:
* Cooler weather will arrive today with highs cooling 10-15 degrees
over yesterday. Highs today will dip into the upper 70s across
western Nevada with warmer conditions (mid-80s) generally south of
US-50 through W.NV where the cooler airmass has yet to arrive.
Sierra valleys will only increase into the low 60s.
* Sunday will be the coolest day of the weekend with lower 70s
across western Nevada and upper 50s across the Sierra. Sunday
night into Monday morning will also see lows dip to near the
freezing mark across Sierra valleys.
* A warming trend returns beginning on Labor Day as highs rebound to
the upper 70s across western Nevada and upper 60s for Sierra
valleys. Steady warming persists through next week with
temperatures returning to near season averages by next weekend.
&&
.AVIATION...
A low pressure system positioned across N.CA will continue to
provide gusty winds today with strong Sierra ridgetop winds. Expect
mountain wave turbulence and LLWS through early morning as wind
gusts across the Sierra ridgetops (FL100) gust near 70-80kts.
Surface gusts through this afternoon will remain near 20-30kts
across Tahoe and Sierra Front terminals while KMMH and KHTH see
stronger gusts of 30-40kts as a surface cold front tracks south
across W.Nevada.
Shower and isolated thunderstorm chances will remain possible
through the balance of the weekend with generally 30-60% chances for
scattered showers each day along with a 15-25% probability for
thunderstorms. The increased moisture and cooler weather will lead
to increasing clouds and lowering CIGS this weekend which could
result in mountain top obscurations. Fuentes
&&
.FIRE WEATHER...
* Wind advisories are in effect this afternoon and evening for Mono
and Mineral counties. Fuels status remains non-critical in these
areas per the latest fuels analysis. Winds will remain strong
today, with the focus being mainly south of US-50. Lower elevation
sustained 20-30 mph winds with 45-50 mph gusts likely. Locally
higher wind gusts will be possible in wind-prone areas. Although
fuels are deemed non-critical in the areas of higher winds,
exercise caution and avoid activities that could start a fire.
* Rolling into the weekend, we'll see much cooler temperatures with
higher chances for wetting rains and isolated thunder across NE
California and Surprise Valley, extending southward tonight.
Across the northern Sierra and northeast California, wetting rain
probabilities are greater than 50%, with near 75-90% chances
across Plumas and Lassen counties. In western Nevada, wetting rain
chances are lower, but 20-40%. Farther south into Mono County,
wetting rain chances are lower than 20%. Expect much higher
humidities, especially Saturday night into Sunday across the
region.
-Johnston
&&
.REV Watches/Warnings/Advisories...
NV...Lake Wind Advisory from 10 AM this morning to 8 PM PDT this
evening for Lake Tahoe in NVZ002.
Wind Advisory from 10 AM this morning to 8 PM PDT this evening
NVZ001.
Lake Wind Advisory from 10 AM this morning to 8 PM PDT this
evening for Washoe Lake in NVZ003.
Lake Wind Advisory from 10 AM this morning to 8 PM PDT this
evening NVZ004.
CA...Lake Wind Advisory from 10 AM this morning to 8 PM PDT this
evening for Lake Tahoe in CAZ072.
Wind Advisory from 10 AM this morning to 8 PM PDT this evening
CAZ073.
&&The national radar mosaic for the moment the first event began.
5 heavy rain, 1 high wind. Local standard time, as filed.
A mesonet station (SNOTEL) located 3.6 mi N of Independence Lake reported a total rainfall amount of 0.90 inches.
A mesonet station (ECOC1-SNOTEL) located 3.5 mi NE of Twin Bridges, and ASOS station located at South Lake Tahoe Airport (KTVL) reported total rainfall amounts of 1.70 and 0.89 inches respectively.
A CoCoRaHS station (CA-NV-51) located 1.6 mi N of Truckee, CA, reported a total rainfall amount of 0.57 inches.
Mesonet station (MTH03) located 1.7 S of Mammoth Mountain, CA, reported a peak wind gust of 78 mph.
A trained spotter located 6.0 mi SSE Susanville, CA, reported a storm total rainfall amount of 1.45 inches.
A mesonet station (GW0802-Taylorsville) located 6.0 NW of Genesee, CA, a mesonet station (PIEC1-Pierce) located 5.0 mi NNW of Antelope Lake, CA, and mesonet station (QCSC1-Carman Saddle) located 4.0 mi SSW of Portola, CA, reported total rainfall amounts of 1.14, 0.89 and 0.85 inches respectively.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2023Every state in 2023This day in weather historyWarnings in California, September 2023
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: 1143000, 1143002, 1143003, 1142998, 1143004, 1143007.