Name: Heat in California, June 22 to 24, 2018
Start: 2018-06-22T11:00
End: 2018-06-24T19:00
Location: California

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 4

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.

A large high pressure ridge strengthened off the California coast on June 22 and slowly built inland through June 24 providing the San Joaquin Valley with it's first prolonged period of triple digit heat in 2018. As a result of the widespread triple digit heat in the San Joaquin Valley during this period, several municipalities opened cooling centers during the afternoon hours. The ridge weakened and moved east of the area on June 25 allowing for cooler air to push into the San Joaquin Valley and end the hot spell.

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 Jun 22, 2:33 AM PST, 8 hours 27 minutes earlier.

Area forecast discussion, Jun 22, 2:33 AM PST, 8 hours 27 minutes before

Area Forecast Discussion
National Weather Service San Joaquin Valley - Hanford CA
333 AM PDT Fri Jun 22 2018

.SYNOPSIS...High pressure will remain over the region into this
upcoming weekend. Dry conditions with well above normal
temperatures will continue.

&&

.DISCUSSION...High pressure now amplifying off the CA coast with
a dry northwest flow prevailing over central CA. Increased onshore
p-grads resulted in some breezy to windy conditions over the Kern
County Mountains and Deserts where some gusts above 40 mph have
been observed.

The ridge is progged to build inland today which will help squish
the marine layer more (it is currently around 1000 feet deep). As
a result, any residual marine air in the San Joaquin Valley will
mix out by later this morning allowing for temperatures to
rebound in a big way in the San Joaquin Valley today where
widespread triple digit heat is anticipated. WRF indicating the
ridge will build further inland on Saturday with continued rises
in heights and thicknesses taking place across our area which will
allow for temperatures to reach their highest levels since last
September. Once again widespread triple digit heat is anticipated
for the San Joaquin Valley, lower Southern Sierra Foothills and
the Kern County Deserts. A Heat Advisory was issued for the San
Joaquin Valley for this afternoon into Saturday as this will be
the first extended period of very hot temperatures for our area
this year.

The ridge axis is progged to push east of our area on Sunday and
Monday which will allow for a slow cooling trend to take place,
but temperatures will remain above normal. The medium range
models indicate a pair of troughs moving through the PAC NW next
week which will maintain an onshore flow pattern over Central CA
and as a result temperatures will lower to near seasonal normals
by the end of next week. Otherwise, dry conditions will continue
with little or no cloud cover anticipated as RH progs are
indicating a dry atmosphere over our area.

&&

.AVIATION...VFR conditions will prevail across the Central CA
interior during the next 24 hours.

&&

.AIR QUALITY ISSUES...On Friday June 22 2018... Unhealthy for
sensitive groups in Fresno... Kern... Kings and Tulare Counties
and Sequoia National Park and Forest. 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.php for additional information
an/or to provide feedback.

&&

.HNX Watches/Warnings/Advisories...
Heat Advisory from noon today to 8 PM PDT Saturday CAZ089>092.

&&

public...DS
avn/fw...Durfee
synopsis...DS

weather.gov/hanford

Event by event

4 heat. Local standard time, as filed.

Heat, W Central S.J. Valley

When: June 22, 11:00 AM PST to June 24, 7:00 PM PST
Where: W Central S.J. Valley forecast zone
Reported by: Mesonet

Daytime highs ranged between 100 and 105 degrees at most locations between June 22 and June 24.

Heat, E Central S.J. Valley

When: June 22, 11:00 AM PST to June 24, 7:00 PM PST
Where: E Central S.J. Valley forecast zone
Reported by: Mesonet

Daytime highs ranged between 100 and 105 degrees at most locations between June 22 and June 24.

Heat, Sw S.J. Valley

When: June 22, 11:00 AM PST to June 24, 7:00 PM PST
Where: Sw S.J. Valley forecast zone
Reported by: Mesonet

Daytime highs ranged between 100 and 105 degrees at most locations between June 22 and June 24.

Heat, Se S.J. Valley

When: June 22, 11:00 AM PST to June 24, 7:00 PM PST
Where: Se S.J. Valley forecast zone
Reported by: Mesonet

Daytime highs ranged between 100 and 105 degrees at most locations between June 22 and June 24.

What these are

Heat: Heat below excessive heat criteria that still caused deaths, injuries or significant impacts.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in California in 2018 Every state in 2018 This day in weather history Warnings in California, June 2018

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: 754942, 754943, 754944, 754945.