Dense Fog, W Central S.J. Valley
- When
- February 3, 12:00 AM PST to 10:00 AM PST
- Where
- W Central S.J. Valley forecast zone
- Reported by
- Mesonet
Winter Storm and Dense Fog in California, February 3 to 7, 2010
February began with a weak upper-level ridge over the central California interior. The ridge kept a low-level inversion over the central and southern San Joaquin Valley, resulting in areas of Tule fog through the first four days of the month.
Where it happened
Every event with a place to put it. Tap one for its entry below.
- Tornadoes
- Tropical storms and surge
- Floods
- Wind
- Hail
- Winter weather
- Heat and drought
- Cold
- Fire, smoke and dust
- Marine and coastal
- Other
The toll
- Deaths
- 0
- Injuries
- 0
- Property damage
- $500
- Crop damage
- None recorded
- Events
- 9
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.
What happened
The episode as NWS HNX wrote it up.
February began with a weak upper-level ridge over the central California interior. The ridge kept a low-level inversion over the central and southern San Joaquin Valley, resulting in areas of Tule fog through the first four days of the month. The worst fog occurred during the morning of February 3rd, with a Dense Fog Advisory being issued.
An upper-level low-pressure trough moved into northern California on February 2nd. While the trough had a minimal impact on interior central California, it did provide enough dynamics to bring some very light rain to Naval Air Station Lemoore during the night of February 1st-2nd. The trough axis moved through central California late on February 2nd into the morning of the 3rd.
Computer forecast models on February 3rd began indicating that the storm forecast for the 6th-7th would be a cold system, with snow levels falling to around 4500 feet by the morning of the 7th. This prompted the issuance of a Winter Storm Watch for the Southern Sierra Nevada and the Tehachapi Mountains.
The Pacific storm moved into California during February 5th-7th, with the first rain actually occurring during the evening of the 4th in the warm sector ahead of the cold front. The storm brought up to an inch of rain to the central and southern San Joaquin Valley, and between 2 and 3 inches of rain to the Southern Sierra Nevada. A spotter at Hume Lake measured 1.08 inch of rain in an 18-hour period, from midnight to 6 PM on February 5th. For the 24-hour period from 10 PM on the 4th to 10 PM on the 5th, Wishon Dam recorded 1.53 inch of rain, and Oakhurst received 1.09 inch.|As the snow level dropped bottoming out between 4000-4500 feet during the night of February 6th-7th and the rain turned to snow, up to 2 feet of snow fell in the Southern Sierra Nevada above 6000 feet. Gusty winds also occurred in the Sierra Nevada and Tehachapi Mountains. At the CHP Weigh Station on I-5 at the base of the Grapevine, gusty winds around 60 mph were measured during the morning hours of Feb 5th.
What forecasters said that day
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 Feb 2, 9:16 PM PST, 2 hours 44 minutes earlier.
Area forecast discussion, Feb 2, 9:16 PM PST, 2 hours 44 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA 916 PM PST TUE FEB 2 2010 .SYNOPSIS... A VERY WEAK SYSTEM WILL MOVE THROUGH THE REGION TONIGHT AND WEDNESDAY. VERY LITTLE IN THE WAY OF PRECIPITATION IS EXPECTED. A PAIR OF STRONGER STORMS IS EXPECTED LATER IN THE WEEK BRINGING PERIODS OF RAIN AND MOUNTAIN SNOW FRIDAY AND SATURDAY. RAIN AND SNOW WILL TAPER OFF ON SUNDAY. && .DISCUSSION...BIG UPDATE THIS EVE TO REMOVE MOST POPS THRU WED...DECREASE CLOUDS CONSIDERABLY...AND SLIGHTLY LOWER MINS TONITE...AND NEAR PERSISTENT MAX/S WED. SAT PIX SAY IT ALL...CLEARING IS OCCURRING EXCEPT FOR SOME TYPICAL POST-TROF STUFF. DENSE FOG IN THE VALLEY MAY BE A PROBLEM TOWARD DAYBREAK SINCE SKIES ARE CLEARING. TONITES MODEL TRENDS STILL ON TAP FOR A ONE-TWO PUNCH FRI AND SAT. && .PREV DISCUSSION... /ISSUED 344 PM PST TUE FEB 2 2010/ DISCUSSION...THE WEAK OFFSHORE TROUGH CONTINUES TO PRODUCE SOME SHOWERS NORTH OF MERCED COUNTY WHILE STREAMING CLOUDS AND A FEW SPRINKLES ACROSS OUR FORECAST AREA. AS THE TROUGH PUSHES INLAND OVERNIGHT EXPECT A BETTER CHANCE FOR SOME SHOWERS ACROSS OUR AREA...ESPECIALLY IN THE MOUNTAINS AND IN THE VALLEY FROM FRESNO COUNTY NORTHWARD. SOME WEAK BRIEF RIDGING BEHIND THE TROUGH WILL PRODUCE GENERALLY DRY AND MILD CONDITIONS WEDNESDAY INTO THURSDAY. THE NEXT FRONTAL SYSTEM IS ON TRACK TO BEGIN IMPACTING INTERIOR CENTRAL CALIFORNIA BY THURSDAY NIGHT. INCREASING PRECIPITATION CHANCES WILL SPREAD SOUTHWARD ACROSS THE DISTRICT THROUGH FRIDAY AS THE INITIAL IMPULSE PUSHES INTO THE REGION. WET CONDITIONS SHOULD CONTINUE THROUGH SATURDAY AS ADDITIONAL SHORTWAVE ENERGY TRACKS INLAND. MODELS THEN INDICATE DRIER CONDITIONS FOR THE FIRST PART OF NEXT WEEK IN GENERALLY NORTHWEST FLOW AS ADDITIONAL SHORTWAVE ENERGY MAINTAINS A BROAD TROUGHINESS OVER THE REGION. SNOW LEVELS DURING THE PERIOD DO NOT LOOK TO FALL BELOW AROUND 4000 FEET IN THE NORTH AND 5000 FEET DOWN SOUTH AS NO PARTICULARLY COLD AIR IS PROGGED TO INVADE THE REGION. MAX AND MIN TEMPERATURES SHOULD NOT STRAY TOO FAR FROM CLIMO THROUGH THE PERIOD. && .AVIATION... IN THE SAN JOAQUIN VALLEY...WIDESPREAD MVFR IN HZ/BR THROUGH 08Z WEDNESDAY WITH CONDITIONS LOWERING TO AREAS OF IFR IN FG THROUGH 18Z WEDNESDAY. ISOLATED SHOWERS AROUND YOSEMITE RESULTING IN LOCALIZED MVFR CONDITIONS. IN THE KERN COUNTY DESERT...CONDITIONS REMAINING VFR THROUGH 06Z THURSDAY. && .AIR QUALITY ISSUES... NONE && .HNX WATCHES/WARNINGS/ADVISORIES... NONE. && PUBLIC...BINGHAM AVN/FW...DCH SYNOPSIS...BINGHAM WEATHER.GOV/HANFORD
The radar
The national radar mosaic for the moment the first event began.
Event by event
4 dense fog, 3 winter storm, 1 heavy rain, 1 strong wind. Local standard time, as filed.
Dense Fog, E Central S.J. Valley
- When
- February 3, 12:00 AM PST to 10:00 AM PST
- Where
- E Central S.J. Valley forecast zone
- Reported by
- Mesonet
Dense Fog, Sw S.J. Valley
- When
- February 3, 12:00 AM PST to 10:00 AM PST
- Where
- Sw S.J. Valley forecast zone
- Reported by
- Mesonet
Dense Fog, Se S.J. Valley
- When
- February 3, 12:00 AM PST to 10:00 AM PST
- Where
- Se S.J. Valley forecast zone
- Reported by
- Mesonet
Winter Storm, S Sierra Mtns
- When
- February 4, 6:00 PM PST to February 7, 4:00 AM PST
- Where
- S Sierra Mtns forecast zone
- Reported by
- Trained Spotter
Winter Storm, Tulare Cty Mtns
- When
- February 4, 6:00 PM PST to February 7, 4:00 AM PST
- Where
- Tulare Cty Mtns forecast zone
- Reported by
- Trained Spotter
Heavy Rain, Fresno
- When
- February 4, 10:00 PM PST to February 5, 10:00 PM PST
- Where
- Fresno County, 2.98 mi NNE of Balch Camp
- Reported by
- Mesonet
- Coordinates
- 36.940, -119.100
Twenty four hour storm rainfall was 1.53 inches at Wishon Dam.
Winter Storm, Kern Cty Mtns
- When
- February 5, 5:00 AM PST to 8:00 AM PST
- Where
- Kern Cty Mtns forecast zone
- Reported by
- Mesonet
Strong Wind, Se Kern Cty Desert
- When
- February 7, 4:15 AM PST to 12:30 PM PST
- Where
- Se Kern Cty Desert forecast zone
- Measured
- 41 kt (47 mph) measured gust
- Property damage
- $500
- Reported by
- Mesonet
What these are
- Dense Fog
- Fog reducing visibility to a quarter mile or less, filed where it caused accidents or disruption.
- Winter Storm
- A storm that brought snow, sleet or freezing rain at warning levels, usually over several hours or days.
- Heavy Rain
- Rainfall totals unusual for the place and season that did not produce a flood.
- Strong Wind
- Non-thunderstorm winds below high wind criteria that nonetheless caused damage or casualties.
After NWS Directive 10-1605, the rules offices file Storm Data by.
The same day elsewhere
- Heavy Snow and Winter Weather in New Mexico, February 3 to 4, 2010
- Heavy Snow and Winter Weather in Texas, February 3 to 4, 2010
- High Surf in Hawaii, February 3 to 4, 2010
- Winter Weather in Oklahoma, February 3 to 4, 2010
- Heavy Snow in Oklahoma, February 3 to 4, 2010
- Flooding in Texas, February 3, 2010
- Dense Fog in Utah, February 3 to 4, 2010
- Dense Fog in Colorado, February 3 to 4, 2010
- Dense Fog in Colorado, February 3, 2010
- Freezing Fog in Arkansas, February 3, 2010
- Heavy Snow in Kansas, February 3 to 4, 2010
- Extreme Cold in Alaska, February 3 to 4, 2010
More
Every storm in California in 2010Every state in 2010This day in weather historyWarnings in California, February 2010
Sources
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: 218394, 218395, 218396, 218397, 218391, 218392, 218398, 218390, 218393.