A cold front that was associated with a moist upper trough pushed across central California on December 17. This system brought moderate to locally heavy rainfall from Fresno County northward the late evening of December through the morning of December 17 where several stations reported a half inch to an inch and a quarter of rainfall, and there were several reports of mainly nuisance flooding…
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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 cold front that was associated with a moist upper trough pushed across central California on December 17. This system brought moderate to locally heavy rainfall from Fresno County northward the late evening of December through the morning of December 17 where several stations reported a half inch to an inch and a quarter of rainfall, and there were several reports of mainly nuisance flooding during this time period. The precipitation mainly fell as snow above 6500 feet where several stations in the Southern Sierra Nevada north of Fresno County picked up between 3 and 6 inches of new snow. Further south the rainfall was less plentiful with most locations receiving between a few hundredths of an inch to a quarter of an inch of rain by the time the precipitation ended by early afternoon on December 17.
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 Dec 16, 5:15 PM PST, 4 hours 27 minutes earlier.
Area Forecast Discussion National Weather Service San Joaquin Valley - Hanford CA 515 PM PST Sun Dec 16 2018 ...Updated Air Quality Section... .SYNOPSIS...A weather system will move into and across the Central California Interior tonight and Monday bringing rain and mountain snow to most areas. High pressure will then build over the West Coast through much of the upcoming week for dry and warmer weather. && .DISCUSSION...Satellite imagery shows a classic cloud signature over the area with thicker clouds over the northwest part of the forecast area and nearly cloud skies over most of Kern County. Regional radars show light precipitation moving into the Bay Area east to Stockton and Modesto but thus far nothing any farther south. As for movement of the incoming low pressure system, water vapor imagery shows the main frontal band aligned nearly north to south along the coast with clouds and precipitation moving southwest to northeast along this boundary. With the north to south orientation of the front, movement to the east will be slow initially and the latest high resolution rapid refresh model generates some rain in Western Merced County after 6 pm with the bulk of precipitation arriving after 8 pm and ending around sunrise. Same model drives the front southeast through the overnight hours with lingering showers noted through Monday morning. Instability will increase over Merced, Madera and Fresno Counties later tonight in the wake of the front as colder air aloft arrives and given convective parameters including negative lifted indices and in coordination with Storm Prediction Centers general thunderstorm risk for the area, a few thunderstorms seem and good bet over this area. Not much threat of thunder to the south and east as the instability will lift northeast pretty rapidly. As for winter weather, snow accumulations of 9-12 inches are generated by the latest qpf forecasts and this matches up really well with the Winter Weather Advisory. Snow levels look to fall to around 6000-6500 feet for the bulk of the precipitation evening with some areas seeing some minor accumulation down to around 5500 feet in Yosemite Park in the colder, more unstable air. All precipitation is expected to come to an end Monday night. Models then are in good agreement in building a high pressure ridge over the region Tuesday through Thursday for warming and drying weather. Based on how much additional rain falls in the fog prone San Joaquin Valley, low visibilities may become an issue as early as Tuesday morning Wednesday and Thursday the days most likely to have persistent dense fog. The ridge does weaken as a decaying trough of low pressure moves across far Northern California on Friday. This looks to be followed by a dry northwest flow pattern in the big travel pre Christmas weekend next week. Taking a quick look at any white Christmas possibilities, as of today the long range has some promise in the mountains of Northern California however for us down this far south...it looks dry for now. && .AVIATION... MVFR in showers/mist for the San Joaquin Valley along with mountain obscuring IFR conditions across the Sierra Nevada and Kern County Mountains becoming a possibility after 03Z Monday. Over the desert...VFR conditions will prevail over the next 24 hours. && .AIR QUALITY ISSUES... On Monday December 17 2018... Fireplace/Wood Stove Burning Status is: No Burning Unless Registered in Fresno... Kern... Kings... and Merced Counties. Further information is available at Valleyair.org && .CERTAINTY... The level of certainty for days 1 and 2 is high. 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.html for additional information an/or to provide feedback. && .HNX Watches/Warnings/Advisories... Winter Weather Advisory from 4 PM this afternoon to 4 PM PST Monday Caz093. && public...Dudley avn/fw...Molina synopsis...Dudley weather.gov/hanford
The national radar mosaic for the moment the first event began.
3 flood, 1 debris flow. Local standard time, as filed.
California Highway Patrol reported large rocks on on State Route 152 at Dinosaur Point.
California Highway Patrol reported flooding at the intersection of Shain Ave. and Brannon Ave. near Dos Palos.
California Highway Patrol reported flooding at the intersection of Indiana Rd. and Santa Rita Grade near Dos Palos.
California Highway Patrol reported moving water on Yaqui Gulch road at 4900 block just to the south of State Route 140.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2018Every state in 2018This day in weather historyWarnings in California, December 2018
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: 789825, 789822, 789823, 789824.