Heat wave arriving as 2 weather systems clash over Southern California (Orange: theater, beach)

[Chimérique]

Fiddlehead, here is another example of how looking at only averages for the day and dumbing it down to an entire month lack in giving a complete picture of weather. (data from usclimatedate.com)

City A: Average low is 60F, all 30 days the low temp is 60F

City B: Average low is 60F, 15 days its 65F+, 15 days its 55F or less.

City A: Although the low may actually reach 60F; it stays at 60F for only 5 hours in a month.

City B: It stays at 60F for 30 hours a month.

Which city is more comfortable overall? Which city cooler?....City B, right, but you wouldn't know that if you relied only on the average low temp for the month.

[Chimérique]

Average daily LOW temp for June, July, Aug, Sept
(usclimatedata.com)

June
Fresno - 61F
Los Angeles - 58F
Sacramento - 56F
San Jose (Bay Area) - 50F

July
Fresno - 66F
Los Angeles - 62F
Sacramento - 58F
San Jose (Bay Area) - 58F

Aug
Fresno - 65F
Los Angeles - 62F
Sacramento - 58F
San Jose (Bay Area) - 58F

Sept
Los Angeles - 62F
Fresno - 61
San Jose (Bay Area) - 58F
Sacramento - 56F

Regarding cooling in the morning and night these averages gives us a picture of the weather, but it does not tell us:

That San Jose has a lot more wind and that the marine layer does not burn off as early as it does in LA.

That San Jose has a marine layer with full cloud cover while Sacramento has bit and pieces of the marine layer, often no clouds at all despite being as cool as San Jose.

Fresno may cool into the 60's but it warms up quicker than the other cities and in the evening its 10 degrees sometimes 20 degrees hotter than Sacramento at night.

Although Sacramento is as cool as San Jose in the morning, San Jose will stay in the 70's most of the afternoon; whereas, Sacramento will stay comfortable until noon but by late afternoon it likely will be in the high 80's or 90's.

[Fiddlehead]

To veer our discussion back to the topic, I would agree that the degree of marine influence will affect the amount of time it is hot. That should affect this heat wave as most others. Since the prevailing wind is onshore, it stands to reason that those areas which are most favorably position to receive it will tend to run cooler.

I have not studied hourly data, but I do think that the cool morning, warm to hot afternoon pattern fits a number of areas outside the immediate coastal belt, or even the delta. For example, I worked landscaping in Chico, and the mornings were typically fine until about 11 am, then the blowtorch would kick in. The same in most of the San Joaquin Valley. Halfway decent mornings, and hot afternoons. I would imagine that Sacramento would be even more amplified, with nice morning and even cooling enough to take an evening jog before dinner (if you eat late). Other areas that have pretty interesting patterns are Paso Robles in the Central Coast Range, and places like Ukiah and Happy Camp in in the northwest coastal mountains. Such places get MUCH hotter than the coast in the afternoons, but cool down into the low 50s at night. Some such areas have an amazing diurnal range

Happy Camp, CA.
HAPPY CAMP RS, CALIFORNIA - Climate Summary

Paso Robles, CA.
PASO ROBLES, CALIFORNIA - Climate Summary

Both areas tend to have hot days and cool nights. Whether you classified them as hot or cold climates would depend upon the type of work you do and when you do it.

A thing that is interesting about N. California in general is the spectacular heat waves the area gets most summers. Growing up in the blazing S. San Joaquin Valley, I recall 105-108F most summers. In N. California, many areas (even Sacramento) hit 110F just about every summer. Happy Camp and Willow Creek routinely break 110F, and Chico to Redding often break 115F. Now granted they tend to be short-lived, but N. California heat waves are hotter than hell at times. Same with the Rogue Valley. If a strong high pressure is over NW Nevada and offshore flow kicks in, Medford can hit 110F, even though the averages are 20F lower.

As for the current heat wave, it seems like it is centered in S. California /AZ. The Central Valley seems just a little above normal.

[BayAreaHillbilly]

Sat and Sun San Mateo County coastal microclimates were into the low 80s at the beach and toying with 90 back into the hills a bit. Today we have the onshore back. Only weak onshore this AM but we know that will ramp up (like it always does).

[Fiddlehead]

I was checking out the weather in Los Gatos, and the overnight lows were very high (above 70). I suspect that is an indicator of offshore flow. I recall camping in the Big Sur Mtns. many moons ago, and it was hot and stuffy. Must have been a similar weather pattern.

I was wrong about saying this is a S. California pattern. Looks like the whole state is cooking.

[Californiaguy2007]

It reached 110 in Bakersfield today,but i'm sure other parts of the state reached hotter temps.

[MtnSurfer]

Originally Posted by Fiddlehead

I was checking out the weather in Los Gatos, and the overnight lows were very high (above 70). I suspect that is an indicator of offshore flow. I recall camping in the Big Sur Mtns. many moons ago, and it was hot and stuffy. Must have been a similar weather pattern.

I was wrong about saying this is a S. California pattern. Looks like the whole state is cooking.

Yep, lots of records were shattered across the state.

"From Monterey to Napa, forecasters recorded record temperatures, according to the National Weather Service.

It was 104 degrees in Napa and 83 in Monterey, breaking records of 100 degrees in 1950 and 81 degrees in 1966.

Forecasters said it was 90 degrees in San Francisco, 97 in San Jose and 92 in downtown Oakland. Those temperatures were all records, NWS officials said."
Bay Area sizzles during weekend heat wave | abc7news.com

Redding is forecasted to be 109 tomorrow.

[Fiddlehead]

I just saw that it hit 104 F and 106 F in Merced yesterday and today, breaking former records of 101 F for both days. I guess it was indeed hot all over.

122 F in Death Valley. Probably not even close to a record, but HOT!

[Chimérique]

It was 87F in Hollywood at 7pm, a bit too warm, very very slight onshore flow, but no clouds, no morning dew on the windshields like you usually get.

[Chimérique]

I guess I'm missing all these record breaking temps, as it's been PERFECT on the LA Coast.