A low that settled into the west coast the first few days of May brought showers and an increased chance (20-30%) of thunderstorms that also lowered rain-snow lines to 5500-7000 feet by early morning 3 May. Stronger showers and storms produced a mix of rain, snow, and ice pellets which lead to runoff issues in the lower elevations.
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.
A low that settled into the west coast the first few days of May brought showers and an increased chance (20-30%) of thunderstorms that also lowered rain-snow lines to 5500-7000 feet by early morning 3 May. Stronger showers and storms produced a mix of rain, snow, and ice pellets which lead to runoff issues in the lower elevations. High end chances (10-20%) of rainfall totals were expected to reach 0.50-1.00 inch. Although snow was projected to fall in the Sierra, the combination of warm road temperatures and the early May sun angle limited accumulations on paved surfaces. But bursts of convective heavy snow showers and/or snow occurring during the overnight hours were expected to bring overnight travel impacts to mountain passes. Tightening thermal and pressure gradients with the incoming low produced gusty south-southeast winds and travel impacts for portions of Churchill, Mineral, Lyon, and Mono Counties along US-395 and US-95.
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 May 1, 2:12 AM PST, 4 hours 48 minutes earlier.
Area Forecast Discussion National Weather Service Reno NV 312 AM PDT Mon May 1 2023 .SYNOPSIS... A much cooler weather system will drop into the west coast and stall over the California central coast this week. This lingering system will bring periods of rain, snow, pellet showers, as well as a few thunderstorms. The cooler temps will also slow the snowmelt leading to a slight reduction in flows on creeks, stream, and rivers. && .DISCUSSION... A much cooler early spring-like low pressure system will continue southward before settling over the central California coast. This system will be the focal point for a broader area of low pressure that will deepen across the western US through the week. The main upper low center will rotate energy and moisture over the region through mid-week with periods of mountain snow and valley rain showers. The First Wave: An initial thrust of upper wave driven divergence and modest mixed-layer CAPE will initiate a few thunderstorms (15-30% chance) that brings the occasional clap of thunder and pellet showers to some areas across the Sierra front, as well as parts of the Basin and Range this afternoon. Hi-Res CAM simulations also show showers and occasional thunder extending into northeast CA later in the evening through Tuesday along this first upper wave where is a moderate chance (20-30%) of a couple inches of higher elevation snow will fall west of US-395 above 6000-7500’. An inch or two of slushy nuisance snow could fall over some Sierra locations, including the Lake Tahoe Basin. The Second Wave: A stronger upper short-wave lifting east and north over the Sierra (Lake Tahoe Basin-Eastern Sierra-Mono County) across western NV will bring another round of mid-upper level divergent forcing and moisture over the region Tuesday and Wednesday. This second wave will bring a stronger surge of moisture with a better chance (30-50%) of a few inches of impactful snowfall across Sierra passes Tuesday afternoon into Wednesday morning. Travel impacts are not out of the question, so be sure to check with CalTrans and/or NDOT for the latest on road conditions. To add to the “MEH” feeling, higher elevation areas across the Sierra crest could see up to a foot of snow through Wednesday morning. Breezy afternoon and evening conditions with gusts 15-25 mph for most areas across the Sierra into western NV will return today and Tuesday. More enhanced breezes with gusts as high as 40 mph will followup across eastern areas of the Basin and Range (Mineral- Churchill-Pershing counties) Tuesday-Wednesday afternoon and evening that could make travel difficult over portions of US-395, US-50 east of Fallon, and US-95 in and around Walker lake into Hawthorne, NV. Subsequent upper short waves lifting through the broader area of low pressure will bring more higher elevation Sierra snow, as well as rain and pellet showers across western Nevada through the remainder of the week. Ensemble guidance does give a more generalized projection of the overall track of his system, but uncertainty abounds as precipitation amounts remain contingent upon the actual track of additional weather systems dropping into the trough along the west coast. Temperatures across the region will continue on a path that will swing between near to 5-10 degrees below normal through the rest of the week as the upper low pulls in cooler air into California and Nevada. -Amanda && .AVIATION... * Although clouds will continue to lower through the morning, VFR conditions will persist for main terminals through today. As showers begin to form and move into the region, terminals will see brief periods of MVFR conditions in occasional thunder, ice pellet and/or rain and snow showers this evening. Going into the overnight hours, convective bands of light snow could bring brief IFR conditions to Sierra terminals as well as periods lowered CIGs/VIS and mountain obscurations into Tuesday. * Since snow levels will remain mostly above 7000’ throughout the day, little to no snow accumulations are expected for runways areas. Overnight into early Tuesday morning, however, snow levels will gradually lower to 5500-6500’, bringing a good chance (40- 60%) for an inch or two of slushy snow on runway areas for Sierra terminals before 18Z Tuesday morning. * Southerly upper flow will increase winds to 20-35 kts above FL100 along with periods of mountain wave turbulence and LLWS across the Sierra and east into western Nevada Monday through Wednesday. Breezy afternoon and evening winds will gust to 15-25 kts today and Tuesday across Sierra and western NV terminals. There is an increased potential Tuesday for gusts 25-40 kts for terminals in the Basin and Range/west-central Nevada. -Amanda && .REV Watches/Warnings/Advisories... NV...None. CA...None. &&
The national radar mosaic for the moment the first event began.
2 heavy rain, 1 heavy snow. Local standard time, as filed.
The public located at the Heavenly Ski Base reported 24-hour snowfall totals of 7.0 inches.
Mesonet station (DLCC1) located 7.9 mi ESE of Antelope Lake, CA, and mesonet station (FHDC1) located 2.7 mi SSE of Frenchman Lake, CA, reported 0.65 inches, and 0.88 inches respectively.
A COCORAHS (NV-WH-47 Truckee) located 1.0 mi NW of Glenshire-Devonshire, CA, and a CO-OP Observer (FARC1) located 2.0 mi NNW of Floriston, CA, reported 24 hour rainfall totals of 0.43, and 0.48 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, May 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: 1102003, 1102010, 1102004.