Colder air moving behind a low pressure system allowed an increase in instability across the San Joaquin Valley which created thunderstorms with heavy rains. Heavy rains coupled with already saturated soils caused some flooding of roads and low lying areas.
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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.
Colder air moving behind a low pressure system allowed an increase in instability across the San Joaquin Valley which created thunderstorms with heavy rains. Heavy rains coupled with already saturated soils caused some flooding of roads and low lying areas.
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 Jan 23, 4:30 AM PST, 1 hour 6 minutes earlier.
Area Forecast Discussion National Weather Service San Joaquin Valley - Hanford CA 430 AM PST Mon Jan 23 2017 .SYNOPSIS...A cold and unsettled airmass will prevail over the area today and provide for numerous showers and a chance of thunderstorms. A drying trend will begin on Tuesday although isolated showers will still be possible. High pressure will provide for dry conditions on Wednesday then a weak system will bring increased clouds and some light mountain showers to the area on Thursday. An upper ridge will then prevail over the area Friday through the weekend with dry weather and seasonal temperatures. && .DISCUSSION...A cooler and unstable post-frontal airmass now prevails over central CA with radar composites showing numerous showers over the southern Sierra Nevada and scattered showers over across much of the remainder of our area. A few lightning strikes were even noted in the Tulare County Mountains overnight. The strong winds that prevailed across our area on Sunday have diminished over the lower elevations while a few of the higher peaks in the Tehachapi Mountains have still have gusts between 35 and 50 mph. Meanwhile, a deep upper low center off the OR coast near 45N/130W continues to keep a moist southwest flow over central CA which is providing ample moisture for a continuation of showers across our area. The 06Z WRF is indicating the large upper low will drop southeast today to off the Norcal coast which will keep our area under a very unstable airmass today. WRF is indicating LI's of -4 to -2 Deg C and CAPES of 400 to 800 J/KG over the San Joaquin Valley this afternoon with CAPES between 200 and 400 J/KG across the remainder of our area. Have mentioned a chance of thunderstorms across the valley this afternoon and a slight chance across the rest of our area. Would not be surprised if some thunderstorms contain ice pellets and/or small hail as low freezing levels prevail. Webcams are already indicating snow falling as low as 2500 feet this morning over the southern Sierra foothills although by this afternoon enough diurnal warming should take place for the snow level to rise to 3000 to 3500 feet. A winter storm warning remains in effect for the Southern Sierra Nevada and the Kern County Mountains through 10 am PST this morning as the potential still exists for impacts to travel from heavier snow showers. The low is progged to move inland across Norcal tonight and Tuesday which will keep the potential for showers across our area through Tuesday afternoon. Snow levels are progged to drop to 2000 to 3000 feet tonight then rise to 3000 to 4000 feet by Tuesday afternoon. Shortwave ridging is then progged to build into central CA on Tuesday Night and provide our area with dry conditions on Wednesday along with with clearing skies. However, some patchy fog will be possible in the San Joaquin Valley with the lower levels remaining very saturated. The WRF is now showing a weak shortwave pushing through our area on Thursday which will delay then onset of any persistent fog as a keep the airmass from stabilizing and may provide for a few showers in in the Yosemite area. The medium range models and their ensemble means are in fairly good agreement with building a dry upper ridge over CA by the end of the week which will keep a dry and stable airmass over our regions through the upcoming weekend and into the early part of next week. This will result in mainly clear skies and a noticeable drying trend over the higher elevations while inversion conditions become more prevalent over the San Joaquin Valley providing for a return of night and morning fog from Friday onward. && .AVIATION... In the San Joaquin Valley, generally VFR through 17z then areas of of MVFR and local IFR in showers and thunderstorms In the southern Sierra Nevada and adjacent foothills, mountain obscuring IFR in low clouds and precipitation prevailing with areas of LIFR. Otherwise, VFR conditions will prevail 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... Flash Flood Watch until 10 AM PST this morning CAZ093>097. Winter Storm Warning until 10 AM PST this morning CAZ096-097. Winter Storm Warning until 10 AM PST this morning CAZ095. && public...DS avn/fw...Dudley synopsis...DS weather.gov/hanford
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HANFORD CA
1203 AM PST MON JAN 23 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0900 PM DEBRIS FLOW 8 WSW COALINGA 36.08N 120.48W
01/22/2017 FRESNO CA DEPT OF HIGHWAYS
HIGHWAY 198 BLOCKED BY LARGE ROCKS.
&&
NWS HANFORD CA
IRIS SYSTEMThe national radar mosaic for the moment the first event began.
9 flood, 2 heavy rain. Local standard time, as filed.
California Highway Patrol reported roadway flooding near Neurailia Road and Rogers Road just southwest of Cantil.
Trained spotteer report of measured 24 hour rainfall total of 0.45 inches in Chowchilla.
California Highway Patrol reported road flooding at the intersection of Panama Road and Velma Avenue in Lamont.
Trained spotter report of measured 24 hour rainfall total of 0.93 inches south of Yosemite Lakes.
California Highway Patrol reported water flowing off of field and onto Avenue 12 north of Rolling Hills.
California Highway Patrol reported roadway flooding on Avenue 364 near Road 200 intersection south of Elderwood.
California Highway Patrol reported roadway flooding with 1 to 2 feet of water at off ramp of State Route 198 near Avenue 296 in Cameron Creek Colony area.
California Highway Patrol reported roadway flooding near State Route 201 and Piedra Avenue west of Elderwood.
Public reported roadway flooding near Malaga Road and Mountain View Road intersection due to runoff from nearby farm fields near Lamont in Kern County.
California Highway Patrol reported mud in road from heavy rainfall near Road 256 and 7th Avenue east of Strathmore.
California Highway Patrol reported roadway flooding near Avenue O and Veneto Street in Delano.
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, January 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: 677717, 677756, 677724, 677758, 677728, 677734, 677740, 677745, 677749, 677752, 677760.