Along with the heat wave that’s expected Monday, Tropical Storm Mario, which briefly died then came back to life, could hit the Bay Area late Wednesday and into Thursday. The storm might produce some dry thunderstorms and a small amount of rain that's unlikely to hit the ground.

As SFist reported, San Francisco and the rest of the Bay Area are expecting 80–90 degree temperatures this week. In San Francisco, such high temperatures happen only a few days a year, when weather patterns briefly shift — calming the ocean breeze, flattening the marine layer, and reversing the wind so it blows offshore from the East Bay, per SFist.  

As SFGate reports, there’s a 15% chance that Tropical Storm Mario, which the Chronicle says is currently “steering a plume of moisture toward California,” will be adding more theatrics to the mix later in the week in the form of dry thunderstorms. Per the Chronicle, the storm died out last week and then started back up over the Pacific — just off the coast of Mexico, as the Instagram account, Rainy Day Weather, reports.

The Chronicle explains that a persistent layer of dry air near the surface will likely prevent rainfall from touching the ground. The lack of moisture could lead to lightning on Thursday and into Friday, posing wildfire risks.

Roger Gass, a Bay Area meteorologist for the National Weather Service, told SFGate his office is keeping an eye on potential fire weather concerns. “There’s a lot of variables in how these things pan out, and generally our confidence is low to moderate. But the impacts of dry lightning would be very bad for fire starts,” he said.

As a bit of consolation, the Chronicle notes that the Bay Area will be hit with mid-level cloud cover and slightly cooler temps leading up to Mario’s potential debut Wednesday night.

Image: Joe Parks/Flickr

Previously: Expect the Heat to Return to the Bay Area Monday and Tuesday

The temperatures have been above 90 degrees pretty much every day of July in Santa Clara County, and the marathon heat wave is believed to be responsible for 19 people dying from the heat there since July 1.

The week of July 4 heat wave simmered down here in San Francisco last weekend, but not so for some other parts of the Bay Area. Consider Santa Clara County, home to cities like San Jose, Sunnyvale, and Mountain View, where temperatures have been above 90 degrees all but three days since July 1, and above 100 degrees for two of those days (while Thursday’s high temperature was 99 degrees).

And there has been a rather tragic outcome to this, as SFGate reports that the July heat wave is being blamed for 19 deaths in Santa Clara County since July 1. The Santa Clara County Office of the Medical Examiner-Coroner has not made a final determination on the cause of some of these deaths, but they are all being investigated as heat-related based on preliminary findings.

The medical examiner’s office noted that the 19 who died this month of suspected heat-related causes ranged in age from 32 to 84 years old, and nine of them were 65 years old or older. Four of them were unsheltered, one was in a transitional housing program.

The coroner’s office pointed out in a statement that “Signs of heatstroke include throbbing headache, confusion, nausea, dizziness, body temperature above 103°F, hot, red, dry or damp skin, rapid and strong pulse, fainting, and loss of consciousness.”

According to the Centers for Disease Control, “1,220 people in the United States are killed by extreme heat every year.”

Related: Orange Smoke Haze Could Be On Its Way to the Bay Area; Also, Inland Areas to Get More Extreme Heat This Week [SFist]

Image: Andrii Ganzevych via Unsplash

After last week's refreshing rainfall, the Bay Area looks like it's headed right back to warmer temperatures.

Meteorologists with the National Weather Service predict that a "summer-like" heat will be returning, with temperatures going as high as 15 to 20 degrees above average for this season, reports NBC Bay Area. According to KRON 4, the average temperatures for this time of year lie somewhere between the 60s and 70s. This quick heat wave should (according to forecasts) mostly only affect temperatures today and tomorrow, with temperatures falling later on in the week.

In San Francisco, temperatures are expected to break 80 degrees by Tuesday. Farther inland, Concord is expected to reach about 90 degrees, and down in Santa Cruz, they're looking at a forecast in the area of the low-90s in the same amount of time.

This is especially worrying for parts of the North Bay, as the temperature in Santa Rosa is expected to climb above 90 degrees, according to the NWS. The rain from last week brought a bit of relief to fire crews still working to contain the wildfires in the form of some increased humidity, which can slow the rate at which the fires can spread.

Related: Ugh: Record-Breaking Heat Could Be Ongoing Trend For SF Bay Area

Many of us likely saw much kvetching on social media Wednesday over the five separate EMERGENCY ALERT messages pushed out to phones in the area advising everyone about the extreme heat — despite the fact that temperatures hovered in the high 70s to mid-80s, and much of the country has to endure far hotter conditions all summer long, albeit usually with more air conditioning. The alerts, while arguably overkill, were issued after the city faced criticism for not issuing such warnings or adhering to a 10-year-old heat plan during the record heatwave on September 1. (Several of my friends posted side-by-side phone screenshots of 78-degree temp readings with the dramatic seeming alerts.)

The text of the alerts was well meaning: "High temps expected Check on neighbors Drink water Cooling & heat safety info at sfdph.org."

SFist reader Steve Kirkham (possibly one and the same Steve Kirkham who is/was a product lead at Airbnb) copied us on a memo he penned to various city officials about his disapproval of the messages. He felt the redundant alerts (at 10:30am, 10:58am, 5:39pm, 5:56pm, and 7:00pm) were unnecessary, and that they at least should have used proper punctuation (good point). And he suggests, "Wireless Emergency Alerts — like anything that requires attention — run the risk of being ignored if misused." I.e., the next time temperature go over 100 degrees and such an alert is more warranted, people may ignore the alert — if they haven't already shut them off under their Notifications menu.

In the end, it's a good thing that people think twice, or even three or four times, about their elderly neighbors and about hydrating, but sure, yesterday was an example of overcompensation for a previous neglectful error.

And it of course only confirmed for newcomers that San Franciscans are seriously weak and sensitive when it comes to heat.

Brace yourselves, everybody. San Francisco is supposed to hit an Indian Summer high of 88 degrees Wednesday — but as we learned during our Labor Day Weekend heatwave, that forecast could be wildly underestimated.

Bay City News has the report via the National Weather Service, and such a forecast is not unusual for this typically hot time of year. The question is whether there are any variables in place like there were on September 1, when meteorologists admit that some subtle wind shifts resulted in SF hitting 106 degrees, about 20 degrees higher than predicted, while inland areas that were predicted to get the brunt of the heatwave were actually not quite that hot.

For now, though, the NWS is saying inland spots around the Bay might hit the lower 90s, so 88 could well turn out to be Wednesday's peak, with another warm day predicted for Thursday as well.

And for what it's worth, Weather Underground is putting Wednesday's high at 80 for central SF, which is lower than the 82 degrees it currently showing for this afternoon in Hunters Point.

Related: Why Forecasters Were Surprised By SF's September 1 Heat Spike

San Francisco's recent heat wave is now San Francisco's deadly heat wave, officials said Wednesday, tracing the demise of three residents to the city's record-breaking temperatures. Add to that a release Thursday from the San Mateo County Coroner saying that three more people died there as a result of the heat — and the death toll may rise as more reports come in from other counties.

The San Francisco Medical Examiner's Office announced that three elderly people died due to “probable” heat-related causes this weekend, the Ex reports.

All three were born in the 1920s or 1930s, lived alone, and died at home, the ME's office says.

None of the deaths were preceded by calls to 911, putting to rest worries that any of the dead were among the 28 life-threatening calls made over a weekend so short on EMTs that fire engine crews had to wait 20 minutes or more for an ambulance to arrive.

San Mateo County Coroner Robert Foucrault told the Chronicle that we can add to that list Patrick Henry of Pacifica, 90; Ernesto Demesa of Daly City, 79; and Loraine Christiansen of Millbrae, 95. Demesa and Henry both lived in homes without air conditioning, Demesa alone and Henry with his wife. Christiansen lived in an assisted living facility.

As noted by NBC Bay Area, "People of advanced ages living independently are the most vulnerable in extreme conditions," saying that the ME's office recommends "well checks and frequent contact to ensure friends, family, and neighbors are healthy and not in need of assistance."

When contacted by the Chron regarding the deaths, Department of Public Health spokeswoman Rachael Kagan said “We will look deeply into these incidents and see what we can learn about improving outreach to elderly and vulnerable populations."

On Tuesday, Supervisors London Breed, Aaron Peskin and Jane Kim called for a hearing on the city's preparation for the heat wave, which the Chron described as "sluggish."

“It is deeply concerning that in a city with San Francisco’s resources, at least three preventable deaths happened as a result of the heat wave — and many more people were affected in non-fatal ways,” Peskin says.

“We will be asking the tough questions to make sure San Francisco is not caught flat-footed again."

And well he should: As previously reported, climate scientists are suggesting that the recent heat wave could be the first of many, as continued climate change makes for conditions leading to extreme temperatures like last weekend's.

"It makes more sense to ask whether global warming made an event more likely," UCLA climate scientist Dr. Daniel Swain says. "And in the case of an unprecedented extreme heat wave, the answer these days is usually yes."

Related: Record-Breaking Heat Could Be Ongoing Trend For SF Bay Area
ABC 7 Weatherman Drew Tuma Collapsed From Heat Exhaustion During Heatwave

*This post has been updated throughout.

Anyone who is dreading a return of 100+-degree temperatures in San Francisco should brace for it to happen again, maybe even this fall. Experts continue to want to be careful to attribute any single weather event to the larger, much more complex process of climate change, but the writing is on the wall: The Bay Area is getting hotter.

Local residents who have long clung to the reliability of Karl the Fog to chill down any summer afternoon or evening, and to the generally temperate, "Mediterranean" weather patterns in and around San Francisco year-round, could be in for some more long-suffering nights like the ones they had — and lamented about on social media — all Labor Day Weekend long.

The New York Times reports on the weird weather that was seen across California this past weekend, noting that this has indeed been the state's hottest summer on record so far. These events included a "microburst" storm in Santa Barbara on Sunday "which involves a shaft of cold air plunging to the earth and fanning out in all directions," and which resulted in the utter chaos of flying umbrellas and screaming on an area beach that you can see in the video below.

And of course SF's unprecedented, record-setting heatwave of Friday and Saturday becomes another weather oddity to chalk up to a likely consequence of climate change. Says UCLA climate scientist Dr. Daniel Swain to the Times, "It makes more sense to ask whether global warming made an event more likely. And in the case of an unprecedented extreme heat wave, the answer these days is usually yes."

Alison Bridger, professor of meteorology at San Jose State University, spoke to NBC Bay Area about her belief that increased carbon dioxide in the atmosphere will continue changing our local weather. "We haven’t finished changing yet," Bridger said. "We have a ridge of high pressure that sat over us, giving us these very warm temperatures. It’s been stronger than average and more importantly it hasn’t moved."

She suggests radical changes in the way we consume energy have to take place, and she also connects severe hurricanes like Harvey and now Irma to this overall global pattern.

San Francisco set an overall all-time high-temperature record on Friday, September 1 which was 106 degrees. The city then broke the record for September 2, previously set in 1991 (94 degrees), when the high hit 102, and it hit 104 at SFO.

Here are all the other Bay Area records broken on Saturday, which included 112-degree temperatures in Calistoga and Gilroy, both of those all-time highs for the month of September.

King City, in Monterey County, also had an all-time record-breaker on Saturday: 115 degrees. The all-time high there had been set in 1955, and that was 113 degrees.

Today's high (Tuesday 9/5) was supposed to be 78 degrees in SF, but Weather Underground already has it hitting 87 in Bernal Heights and 85 in Chinatown.

Sunday, September 10 is also shaping up to be a warm one, but it may be too soon to say how warm. And you can expect sunny, very balmy days all week along, with blessedly cooler nights hovering around 60 degrees (but tonight it's still expected to be 66 degrees at 10 p.m.).

Previously: Scorching Hot Labor Day Weekend Ahead

To help the populace cope with this second day of extraordinary heat, the city has opened four "cooling centers" for the elderly and those most affected by the heat. Also, public pools are all open and free to use today.

“With extreme temperatures in San Francisco expected to continue today, I am urging local residents to take special precautions in an effort to remain safe and healthy," said Mayor Ed Lee in a release.

100-degree temperatures are again expected Saturday after San Francisco recorded its hottest day ever on Friday, with a high of 106.

The ice rink at Yerba Buena is opening its doors to seniors today, and the following four "cooling centers" are open in conjunction with non-profit partners: 1156 Valencia Street, 360 4th Street, 1450 Powell Street, and the Jewish Community Center of San Francisco at 3200 California Street.

The city is also urging people to take advantage of the air condition at the main public library, and at the North Beach, Mission Bay, and Potrero Hill branch libraries.

The following pools are free to use today:

• King Pool - 5701 3rd Street
  
• Sava Pool - 19th Ave & Wawona Street
  
• North Beach Pool - 651 Lombard Ave
  
• Coffman Pool - 1701 Visitation Ave
  
• Hamilton Pool - Geary Avenue & Steiner Street
  
• Garfield Pool - 26th Street & Harrison Street

Related: Scorching Hot Labor Day Weekend Ahead

RIP San Francisco. We had a good run. pic.twitter.com/eURTD2dOju

— Karl the Fog ☁️ (@KarlTheFog) September 1, 2017

I've lived in the Outer Sunset since 2004 and this is the first day that I've never seen a single person in 1) pants 2) a hoodie 3) both. Game over, man. Game over.

Flex Alert: Californians Urged To Conserve Electricity Amid Heat Wave « CBS San Francisco - https://t.co/Gwh5kayTwH (In triple digit temps.)

— Blue Beach Song™ (@BlueBeachSong) June 20, 2017

Thousands of PG&E customers in the East Bay lost power early Tuesday, and while the cause of the outage is not yet clear, it seems likely related to strained power grids amid a heatwave — something that also led to an even larger outage that affected over 40,000 homes and businesses on Sunday. Late Monday evening a Flex Alert was issued statewide asking all residents to shut off all unnecessary lights, set air conditioners to 78 degrees or higher, and generally conserve power between the hours of 2 p.m. and 9 p.m.

The alerts, which call for voluntary power conservation, are issued by the California Independent System Operator or ISO, which oversees the state's electrical grid.

As NBC Bay Area reports, hours after the alert was issued, more than 3,800 PG&E customers in Fremont and 2,500 or more customers in Walnut Creek lost power. Other outages were reported in San Jose, Morgan Hill, and Benicia.

The current heatwave, which is expected to last through Thursday and possibly longer, may not seem that dramatic in San Francisco, where temperatures are just above normal and things are still pleasant. But with triple-digit temperatures persisting for multiple days elsewhere in the Bay Area, a meteorologist with PG&E is now saying this is the single most impactful heat event to hit the region since 2006, as ABC 7 reported.

Meanwhile, dangerous heat is gripping Southern California this week as well, thus the entire statewide grid is feeling the strain. Temperatures in the mountains around LA are expected to exceed 105 in some cases, as the LA Daily News reports. Also, a truck carrying almost 1,000 birds was found in Fresno with the suffering creatures inside, over two dozen of which were either already dead or subsequently died after sitting in 107-degree heat.

And I hope you already own a fan, because as ABC 7 notes, stores all over the Bay are running low on stock, if they have any left at all. Also, good luck finding an air conditioner repairman.

That amber glow is the perfect way to start our Friday! Are you ready for our heat wave?#FridayFeeling #WeekendVibes #BayArea #SanFrancisco pic.twitter.com/bxhV33YQb1

— Natasha Zouves ABC7 (@NatashaABC7) June 16, 2017

We're in for a heatwave through at least Thursday this week, but yesterday, Sunday, is looking like it was the peak in terms of temperatures, with records broken in 10 Bay Area cities. San Francisco hit a high of 88, beating out a record for June 18 set in 1993 by two degrees, as KRON 4 reports — though various weather apps yesterday showed high temperatures in parts of SF as high as 98. It was cooler along the coast but still a great beach day for many, and ABC 7 spoke to some South Bay residents who came to Crissy Field just to cool off (see video below).

Another record was broken at SFO, where the temp hit 97 Sunday afternoon, and in San Rafael and Livermore the highs were 105 and 106 respectively. San Rafael broke a record of 98 that had been set way back in 1962, beating it by seven degrees.

For many East and South Bay residents, the temperature spike left them with no power Sunday, with power grids strained and some 43,000 residences affected as of 8:30 p.m. according to the Chronicle. Part of Oakland's Jack London Square was effected, per a friend of SFist, as were 5,000 homes and businesses in Livermore, according to ABC 7. For the rest of the week, in fact, PG&E is recommending that people try to conserve power between noon and 7:30 p.m.

Also, people in Berkeley, Oakland, Piedmont, and other parts of the East Bay were surprised to see a rogue thunderstorm last night that began with just heat lightning, and culminated in a brief downpour of rain.

The first storm cell hit around 11 p.m., and another took shape about two hours later, according to the Chronicle.

There is no Spare the Air alert in effect for Monday, but look out throughout the week as there may be another one like there was on Sunday.

It's the first real one of spring, so excuse me for being excitable.

And it's already 92 in the Mission you guys!! (As of 1:40 p.m.)

Previously: Record Heat Is Bringing Out Snakes (Watch Out!)

Today's potentially record-breaking heat is causing snakes, both the venomous and non-venomous varieties, to slither and creep into yards and homes, alternately seeking both sun and shade. And as Sonoma County Reptile Rescue Director Al Wolf tells CBS 5, for a variety of other reasons, "Everybody, I’m telling you right now, it’s a good year for rattlesnakes."

Those reasons include abundant grasses from the winter rains that are bringing snakes out for adventures, and a reportedly "huge rodent supply," too. Says Wolf, "The snakes are moving."

Snakes to look out for in the Bay Area include rattlers — which according to this local reptile guide, can be found "in many habitats, including seaside dunes, scrub, grasslands, rocky hillsides, chaparral, open woodlands, and agricultural fields." — and a number of varieties of harmless snakes including the California Kingsnake, the Western Yellow-Bellied Racer, and the Pacific Gopher Snake.

If you find a snake, as some SF friends of mine just did in their garage, you're advised to call Animal Control who will come and remove it for you. Generally speaking, these snakes don't really want to be in developed or urban environments.

But back to the heat: As CBS 5 tells us, records are likely to be broken today as some parts of the Bay Area hit 90 degrees. There was a hot spring like this in 1989 when several local records were set for April 6th, including 87 degrees in San Rafael and 89 degrees in both Richmond and Livermore. And Oakland Airport recorded a temperature of 80 degrees on this day in 1962, but nothing has topped that on April 6th since.

As SFGate tells us, we should top out at 87 in San Francisco today, but Oakland may hit 92.

Previously: Bay Area Temperatures To Hit 'Low 90s' This Week

July, experts are saying, may bring the hottest day of the year to parts of the Bay Area. With the balmy conditions also comes the possibility of a thunderstorm. Hyperlocally, there may be a back sweat situation. It was a warm weekend, so we're mentally prepared.

According to CBS SF, who are doing the 4th of July Weekend forecast early and often this week, coastal fog today will clear and conditions will turn quite muggy with those possible T-storms overnight.

We reach peak temperatures Wednesday, where inland temps will be getting into the upper 90s. For better or worse, Weather Underground says we'll max out at around 75 in the sunnier areas of San Francisco

“What will make this week unique is we began June unseasonably mild, and we will end unseasonably warm,” KPIX 5's Roberta Gonzales tells us “We will have two days in the 100s and then remaining warm inland in the 90s.” Gonzales says that "In particular, I have my eye on Fairfield" for the highest of the highs.

Expect mid-60s temperatures for the big weekend in SF, but if you're traveling to Yosemite, Tahoe or other parts warmer, keep an eye on these rising temps.