Excessive Heat and Heat in California, June 27 to 29, 2021

Name: Excessive Heat and Heat in California, June 27 to 29, 2021
Start: 2021-06-27T10:00
End: 2021-06-29T19:00
Location: California

June 27 to 29, 2021 · NWS HNX · 11 events in 11 counties and zones

A strengthening ridge along with an offshore flow pattern brought a short lived return of dangerous heat the area as much of the San Joaquin Valley exceeded 105 F on June 27 while portions of the Kern County Deserts exceeded 110 F. Increased clouds helped lower temperatures below dangerous level in the San Joaquin Valley on June 28, but high temperatures across the Kern County Deserts were 1-3…

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 11

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.

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 27, 3:00 AM PST, 7 hours earlier.

Area forecast discussion, Jun 27, 3:00 AM PST, 7 hours before

Area Forecast Discussion
National Weather Service Hanford CA
400 AM PDT Sun Jun 27 2021

.SYNOPSIS...
A warming trend will continue over the weekend resulting in hot
temperatures through next week. Isolated to scattered showers and
thunderstorms are possible over much of the mountains beginning
Monday and spreading into much of the region for Tuesday through
late next week.

&&

.DISCUSSION...
Amplified ridging remains over the west coast with the center of a
~598 decameter high over southern British Columbia bringing record
breaking heat to the Pacific Northwest. Temperatures will climb up
several more degrees today across the central California interior.
An Excessive Heat Warning goes into effect this afternoon for the
Kern County Desert, the San Joaquin Valley from Fresno County south,
and the adjacent West Side Hills. This does not look to be quite as
hot as the last heat wave but will result in high temperatures as
much as 15 degrees above normal. The Heat Warning goes into Monday
as well with little change in temperatures. Only slight cooling is
anticipated for Tuesday and Wednesday and may warrant an Advisory
for the heat. Triple digit highs are expected to prevail across the
lower elevations through the end of the week, but gradually lower.

Mid level moisture will be on the increase today and may result in
some afternoon cumulus development over the Sierra Nevada. There
is a slight chance of showers and thunderstorms over the Sierra on
Monday. But storms would be high based with dry boundary layer air,
resulting in little if any rainfall. Moisture continues to increase
on Tuesday but storms may still be dry. Considering this along with
the very dry fuel conditions, a Fire Weather Watch is in effect for
the potential of dry lightning over the Sierra Nevada on Monday and
Tuesday. An easterly wave may bring an additional surge of moisture
by midweek which could turn storms wet. Ensembles are indicating the
moisture may linger through the week before diminishing next weekend.

&&

.AVIATION...
VFR conditions will prevail throughout the central CA interior
for at least the next 24 hours.

&&

.AIR QUALITY ISSUES...
On Sunday June 27 2021...Unhealthy for sensitive groups in
Fresno...Kern 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.html for additional information
an/or to provide feedback.

&&

.HNX WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning from 11 AM this morning to 8 PM PDT
Monday for CAZ179-182>189-198-199.

Fire Weather Watch from Monday afternoon through Tuesday evening
for CAZ592>594.

&&

Public/Aviation/Fire Wx........DCH
PIO/DSS........................MV

weather.gov/hanford