Heat in California, June 3 to 4, 2020

Name: Heat in California, June 3 to 4, 2020
Start: 2020-06-03T10:00
End: 2020-06-04T19:00
Location: California

June 3 to 4, 2020 · NWS HNX · 13 events in 13 counties and zones

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 13

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 area of upper high pressure centered over the four corners region strengthened on June 3 and pushed an upper low off the southern California coast southwest and further away from the region. This resulted in a warming trend over the area as the mid and high level cloud cover which had been prevalent over the area during the previous few days eroded. High temperatures across the San Joaquin Valley and Sierra foothills were mainly between 99 and 103 degrees on June 3. The high remained the dominant feature over the area on June 4, and temperatures continued to rise with afternoon highs over the San Joaquin Valley and Sierra foothills mainly between 102 and 106 degrees. The high broke down and shifted east on June 5 while temperatures lowered to near normal levels as an upper level trough pushed into California.

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 3, 1:52 AM PST, 8 hours 8 minutes earlier.

Area forecast discussion, Jun 3, 1:52 AM PST, 8 hours 8 minutes before

Area Forecast Discussion
National Weather Service Hanford CA
252 AM PDT Wed Jun 3 2020

.SYNOPSIS...
Well above normal afternoon temperatures can be expected over the
region during the next few days with a return of triple digit
heat in the San Joaquin Valley, lower foothills and desert
today and Thursday. Isolated afternoon thunderstorms are possible
over the high Sierra Wednesday and Thursday. A cooling trend will
begin Friday accompanied by showers and isolated thunderstorms
over mainly the higher terrain. The weekend will be much cooler
with gusty winds.

&&

.DISCUSSION...
Closed upper level low pressure centered off of Baja California
has been streaming mid and high level clouds over the region for
the past several days. The clouds have been wreaking havoc on the
Max temperature forecast for the past couple of days and
yesterday was no different. Many areas in the SJV where the clouds
were, barely broke 90 degrees. However, areas to the north where
it cleared out were in the mid to upper 90s. It was 94 at Los
banos and 91 at Bakersfield...very unusual temperature pattern.
Unless you have cloud cover.

The upper low is drifting west and is expected to take its clouds
with it today. So I have a bit more confidence with the Max
temperatures today and tomorrow. Tomorrow looks to be the hottest
day as the four corners ridge will build west and heat us up.
Guidance has been running warm but it has been consistent with the
forecast over the past several runs. We are seeing a surge of
moisture that will impact the Sierra today with showers and
thunderstorms this afternoon. We are seeing the showers and
thunderstorms waning on Thursday and increasing again on Friday.

Once we get through the next couple of days and the hot spell over
the region, we can look forward to a significant cooldown by
Sunday. At least a 25 to 30 degree swing from high temperatures
on Thursday to high temperatures on Sunday will remind us that it
is still spring in the Central California Interior. Friday we will
see the front pushing through later in the evening and we will
see an increase in showers and thunderstorms...mainly in the
Sierra and even in the Kern mountains. We will also see an
increase in winds across the coastal range and through the Kern
county mountains that will continue into Saturday and possibly
Sunday. A rapid warming trend is expected early next week as we
see Max temps rise from the mid 70s in the SJV on Sunday to back
into the mid 90s by Wednesday. It is expected to be dry early
next week as an upper level ridge builds back in to the region.
The rollercoaster ride of hot to cool back to hot again is pretty
normal for this time of year. But at least the hot spells are
short this time of year. Next couple of months will be a different
story.

&&

.AVIATION...
VFR conditions can be expected throughout the central California
interior during the next 24 hours.

&&

.AIR QUALITY ISSUES...
On Wednesday June 3 2020... Unhealthy for sensitive groups in
Fresno and Kern 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
and/or to provide feedback.

&&

.HNX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 2 PM this afternoon to 7 PM PDT Thursday for
CAZ180>189.

Heat Advisory from 2 PM this afternoon to 7 PM PDT this evening
for CAZ179.

&&

public/aviation/fw....JDB
pio/idss...............MV

weather.gov/hanford