During a heat wave dense fog from a very shallowed lowered marine layer occurred August 6 to 7, 2024.
Every event with a place to put it; 5 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
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 SGX wrote it up.
During a heat wave dense fog from a very shallowed lowered marine layer occurred August 6 to 7, 2024.
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 San Diego, CA wrote its last area forecast discussion before the first event at Aug 5, 8:35 PM PST, 3 hours 25 minutes earlier.
Area Forecast Discussion
National Weather Service San Diego CA
935 PM PDT Mon Aug 5 2024
.SYNOPSIS...
A shallow marine layer will keep low clouds and fog closer to the
coast this week each night and morning. Hot weather continues for
inland areas as high pressure remains anchored over the desert
southwest and southern Rockies. Clouds and isolated thunderstorms
are expected this afternoon through Wednesday, with Wednesday
seeing the highest chance of storms in the deserts and mountains.
Our weather will cool off slightly by the middle of the week, then
warm up again by the weekend with mountain storm chances
increasing once again.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
No significant changes to the forecast this evening as a shallow
marine layer will limit the inland extent of the marine layer this
evening and overnight. Temperatures are expected to decrease
through the first half of the week as moisture increases each
subsequent day through the first half of the week.
Previous Discussion 153 PM Monday August 5, 2024
.SHORT TERM (Through Wednesday)...
Moist southerly flow aloft is helping to increase cloud coverage
across the mountains this afternoon. Radar imagery depicts showers
and weak storms beginning to form up near Twentynine Palms and
along the spine of the peninsular ranges in Baja California. We
will continue to monitor the area this afternoon, though towering
cumulus is still not particularly visible across northern SD or
RIV mts at this hour. Increasing instability is predicted as the
area of high pressure over the southern Rockies centers near the
Four Corners region. Chances for showers and storms will increase
by Tuesday and peak on Wednesday. An easterly wave will skirt
south of the area as well, which would help promote the growth of
thunderstorm activity during this time period.
Hot temperatures are noted inland this afternoon with some near triple
digit readings across the foothill and mountain areas, such as
Ramona, Pine Valley, Anza, and Silverwood Lake. Today will be the
peak of the heat for many with high to locally extreme heat risk.
Tuesday will be slightly cooler but still hot for inland areas. If
you must be outside, please remember to seek shade when available
and take breaks if doing any labor or outdoor recreation.
Wednesday will be the cooler days of the week as well. Areas near
the coast are expected to remain under the marine layer's
influence with patchy clouds and fog in early mornings and high
temperatures in the 70s.
&&
.LONG TERM (Thursday into the weekend)...
A slow warm up will once again occur across the region for the
long term period. Saturday looks to be when the heat will peak,
though it will not be as hot inland as today. The area of high
pressure mentioned above will retrograde back over the southern
Rockies by the end of the week, which will lead to a better set up
for monsoonal moisture to make it back into the area. Agree with
NBM POPs where slight chances are depicted by the weekend across
the mountains and deserts. Otherwise, other areas should remain
dry with continued warm weather by the weekend and into early next
week.
&&
.AVIATION...
060400Z...Coast/Valleys...Low clouds building along the coast with
bases 600-800ft MSL and tops to 1200ft MSL. CIGs expected for most
coastal sites by 12z, with clearing around 15z-16z. Confidence in
CIGs/timing at KSAN is moderate (50%). Some localized VIS reductions
down to 1-3SM possible for higher coastal terrain and valleys
through 16z. Better chances for low clouds/VIS reductions for
coastal sites tomorrow evening, with CIGs possible as early as 06z
Wednesday.
Mountains/Deserts...Unrestricted VIS and high clouds through Tuesday
morning. TSRA over the mountains possible Tuesday late morning
through evening with SCT-BKN Cu with bases to 12000ft MSL. Gusty and
erratic winds and localized VIS reductions near any storms. Mod
up/downdrafts near mountains. Any storms diminish by 02z Wednesday,
with high clouds continuing overnight.
&&
.MARINE...
No hazardous marine conditions are expected through Saturday.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Excessive Heat Warning until 11 PM PDT Tuesday for Apple and
Lucerne Valleys-Coachella Valley-San Bernardino and
Riverside County Valleys-The Inland Empire-San Diego County
Deserts-San Gorgonio Pass Near Banning.
Heat Advisory until 11 PM PDT Tuesday for Orange County Inland
Areas-Riverside County Mountains-San Bernardino County
Mountains-San Diego County Mountains-San Diego County
Valleys-Santa Ana Mountains and Foothills.
PZ...None.
&&
PUBLIC...Suk
AVIATION/MARINE...ZuberThe national radar mosaic for the moment the first event began.
5 dense fog. Local standard time, as filed.
San Diego city Mission Beach lifeguards reported dense fog 1/4 SM visibility.
Huntington Beach lifeguards reported 1/8 SM visibility from dense fog, shallow marine layer.
San Clemente lifeguards reported dense fog with 1/8 SM visibility.
Newport Beach lifeguards reported dense fog 1/4 SM visibility or less on the beach.
San Diego airport reported 1/4SM fog at 0600 August 7, 2024. North Island Coronado reported 1/4SM fog at the same time.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2024Every state in 2024This day in weather historyWarnings in California, August 2024
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: 1214429, 1214432, 1214433, 1214431, 1214428.