A low pressure system moved into Central California on the afternoon of the 16th then stalled over the area on the 17th before moving out on the 18th. A cold front associated with this system brought scattered thunderstorms on the afternoon of the 18th.
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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 HNX wrote it up.
A low pressure system moved into Central California on the afternoon of the 16th then stalled over the area on the 17th before moving out on the 18th. A cold front associated with this system brought scattered thunderstorms on the afternoon of the 18th. Snow was mainly confined to elevations above 8000 feet, but several locations in the Southern Sierra Nevada and adjacent foothills reported 48 hour rainfall totals between 1 and 2.5 inches. Several inches of new snowfall fell at elevations above 9000 feet. Most of the San Joaquin Valley and Kern County Mountains received between a quarter and half an inch of rain from this event.
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 Hanford, CA wrote its last area forecast discussion before the first event at Apr 17, 2:27 PM PST, 9 hours 28 minutes earlier.
Area Forecast Discussion National Weather Service San Joaquin Valley - Hanford CA 327 PM PDT Mon Apr 17 2017 .SYNOPSIS... Some showers moving into the Yosemite Merced area today ahead of another weather system which will bring more wet weather tonight and Tuesday. The next storm system will then brush the area Thursday, bringing gusty winds but little chance for precipitation. Dry and warming conditions then prevail through next weekend as high pressure builds over the region. && .DISCUSSION... Some light rain fell across much of the district today. however amounts were light. Stronger shower activity moving through the Yosemite Merced area this afternoon ahead of the next weather system. Moist plume with precipitable water values 1-1.5 inch will move onshore tonight. Models indicate a couple of upper level disturbances will interact with the moisture resulting in widespread precipitation with the heavier precipitation amount progged overnight tonight into tuesday morning. Rain amounts in the San Joaquin Valley could range from a tenth in the South to around half inch in the North. SW flow will result in good orographic lift over the Sierra Nevada with up to 1.5 inches of precipitation possible in the favorable slopes of the sierra and foothills. System will be mild with relatively high snow levels and snow accumulation may remain above 8kft. Model indicate some moderate instability with capes of 400-800 j/kg Tuesday afternoon especially on the East side of the valley and Sierra foothills. Thus have added a slight risk of thunderstorms mainly North of the Kern county line. Wednesday will be dry and warming ahead of another low pressure system which is progged to slide across the Pac NW Thursday and clip the northern Sierra locales near Yosemite with a slight chance for precipitation. This will mainly bring an increase in gusty winds for us Thursday, as onshore surface pressure gradients tighten up. Beyond Thursday, models are in general agreement in building a significant ridge over the west coast. This will bring dry and warm conditions into the first part of next week. Temperatures will climb to as much as 6-12 degrees above climo during the period. && .AVIATION... Local MVFR cigs and vsbys in the San Joaquin Valley in scattered showers. Widespread MVFR and areas of terrain obscuring IFR/LIFR conditions in the mountains and foothills. VFR conditions can be expected elsewhere in the central California interior during the next 24 hours. && .AIR QUALITY ISSUES... None. && .CERTAINTY... The level of certainty for days 1 and 2 is medium. The level of certainty for days 3 through 7 is medium. Certainty levels include low...medium...and high. Please visit www.weather.gov/hnx/certainty.php for additional information an/or to provide feedback. && .HNX Watches/Warnings/Advisories... NONE. && public...MV avn/fw...JDB prev discussion...JEB synopsis...MV weather.gov/hanford
The national radar mosaic for the moment the first event began.
1 heavy rain. Local standard time, as filed.
A trained spotter reported heavy rainfall in Ponderosa Basin on the morning of April 18th.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2017Every state in 2017This day in weather historyWarnings in California, April 2017
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: 693036.