Dangerous Heat Sets Sights on Southern United States

High wet bulb temperatures and related heatwave mass casualty events have spanned the globe during the record hot summer of 2015. Now, it appears the Southern United States is also falling under the gun of life-threatening heat and humidity.

Gulfs of Mexico, California Host Screaming Sea Surface Temperatures

As with so many recent heatwaves with the potential to produce mass casualty events, the story starts with sea surface temperatures in excess of 30 degrees Celsius (86 Fahrenheit). And across a broad region of the Gulf of Mexico and all throughout the Gulf of California ocean surface waters now feature temperatures in the range of 30 to 33 degrees C (86 to 91 F).


(A tell-tale pool of 30 C+ water is gathering in the Gulfs of Mexico and California. Such hot water is a support for deadly wet-bulb readings in the range of 30-33 C. Image source: Earth Nullschool.)

These are waters warmed by increasingly vicious human hothouse conditions. A world ocean facing a global fever that is 1 degree C (1.8 F) hotter than the more placid, less dangerous temperatures of 135 years ago.

In the Gulfs of Mexico and California, this heat has concentrated — pushing the waters there into 1-4 C above average ranges. Generating a dangerous reservoir of latent heat. One featuring ocean temperatures similar to those that kicked off heatwave mass casualty events in India, Pakistan, Japan and Egypt this summer. But this feature of the human hothouse is now focusing in on the Southern US — creating conditions that are increasing the risk of heat stress, heat injury and possibly loss of life.

The steaming waters of our southern gulfs will feed dangerously high wet bulb temperatures throughout a large region from the Carolinas to Florida through the Gulf States and on into the Southwest over the coming days and weeks. Ocean temperatures hot enough to support wet bulb readings in the range of 30 to 33 degrees Celsius. Dangerous levels very close to the maximum human threshold of 35 C.

NOAA Predicts Heat Indexes to Skyrocket

Concordantly, a similar measure used to determine how hot it feels outside is set to skyrocket throughout the southern US over coming days. In many regions heat indexes are predicted to exceed 100, 105, 115 or even 120 degree readings.

High Heat Index US South

(Forecast heat index map for Monday, August 24. Over the next seven days, heat index values are predicted to remain in dangerous ranges across large sections of the Southern United States. Image source: NOAA.)

Regions at greatest risk include Southern California, Arizona, and the Gulf Coast states of Texas, Lousiana, Mississippi, Alabama, Georgia and Florida.

Heat index values in excess of 105 F (40 C) are considered dangerous. Those crossing a 127 F (53 C) threshold are considered exceedingly dangerous. The NOAA forecast now includes dangerous heat indexes predicted for the above regions lasting for at least the next seven days. And with sea surface temperatures likely to remain much hotter than average near the area of highest impact through the end of August, these high-risk heat conditions have the potential to continue for some time.



Earth Nullschool

Heatwave Mass Casualty Events of 2015

Wet Bulb

Heat Index

Hat tip to DT Lange

Leave a comment


  1. Looks like Orleans and Jefferson Parishes won’t get clobbered by 110 F heat indices. Some comfort.

    With all that hot water (hurricane fuel) in the GoM, I’m more concerned with what might come after. Even with our El Niño on steroids. 😮

    • Just to clarify. The image above is the forecast for next Monday — the 24th. Today was a bit of a foretaste for the coming week.

      You’re right about those sea surface temperatures as fuel for hurricanes in the Gulf. If we have a system pop there and if sheer isn’t too bad — lots of potential.

    • Robert In New Orleans

       /  August 18, 2015

      My gut feeling is that most if not all of the Gulf Coast will be intolerably hot in the Summer within the decade or two as almost everything associated with CC seams to be happening sooner rather than later. :-/

      • Steven Blaisdell

         /  August 18, 2015

        Yep. I can feel it already. I don’t use AC, and the difference here in Central TX is palpable. Nights don’t cool until just before dawn, and even then it’s hardly ‘cool.’ Days are consistently and noticeably hotter, day in and day out. I think that’s the big difference – the distribution has been shifted to the right, i.e., not only is it consistently as hot or hotter; there are almost no ‘cool’ days or nights anymore.

        Most folks here, of course, can only barely sense this change as almost everyone exists 24/7 in AC. I can feel it, though. Been here 22 years; it’s been plenty hot before, but not like it is now (and has been the last few years).

  2. climatehawk1

     /  August 17, 2015

    Tweet scheduled.

  3. Robert, you’re amazing. You keep cranking out the posts, full of up to date and essential information.

    Joe Romm writes about the current El Niño, a record smashing 2015, and a possible third record year in 2016.

    • El Niño just hit +2.0 C… We are deeper and deeper into Monster territory, my friend.

      And Joe’s right. The heat bleed off this beast will extend into 2016, possibly netting us 3 back to back record hot years.

      Thanks for the kind words. Looks like my El Niño update shows up tomorrow. Worth noting — we have basically been in El Niño ocean conditions since October of 2014. If we hadn’t had that minor dip to +0.4 last winter, we’d be closing in on one year of official El Niño conditions with no near term end in sight.

  4. labmonkey2

     /  August 18, 2015

    Climate State has a link to an article on – Rather interesting and supports/enhances your current article – although there appeared to be some confusion on the disappearance/reappearance of the current El Nino by the reporting scientists.,-scientists-warn/

    The new research, which McPhaden was not involved in, reviews all the available scientific evidence on ENSO and climate change, concluding that extreme El Niño events will happen more often as the climate warms.

    If emissions stay very high, the authors expect extreme El Niño events with impacts similar to the one in 1997/8 will almost double in frequency by the end of the century, from about once every 28 years today to once every 16 years.

    As the climate warms, the scientists also expect to see an increase in extreme La Niña events. As the authors say in the paper:
    “ENSO-related catastrophic weather events are thus likely to occur more frequently with unabated greenhouse-gas emissions.”

    In the comments section there is a link to an audio discussion with Kevin Hester. Just note that his interview starts at about 06:10 of the program. Nicely done.

    “I talk about the coming climate wars in this episode of Michael C. Ruppert’s former show The Life Boat Hour.”

  5. labmonkey2

     /  August 18, 2015

    RS – I pushed the post comment button then realized there were two links. D’OH!
    won’t happen again

  6. Robert In New Orleans

     /  August 18, 2015

    Since you are talking about Louisiana, here is a fascinating article about land loss and local peoples attitudes about it; not unlike CC and how people perceive it.

    View story at

    • Robert In New Orleans

       /  August 18, 2015

      To access the article click on the actual headline: “Louisiana Loses Its Boot”

      • Thanks, Robert.

        I tried googling the article in Matter when I read the Times-Picayune piece on this. I got nowhere, ARRRRGH!!!.

    • Cat and I visited New Orleans recently. It really is a mad place — something strait out of Cthulu slowly sinking into the Gulf.

      • Yes, it’s gotten fashionable. We just got a windfall in the form of the $19 bn BP settlement. I’m hoping it goes toward coastal restoration, but with Jefferson Parish already directing its cut or a part thereof toward parish employees’ wage and salary hikes, I’m not optimistic.

      • Robert in New Orleans

         /  August 19, 2015


        The state of Louisiana (aka state of incompetence) needs to spend the BP settlement on relocating vulnerable residents, but in true to life form, the money will find its way into the pockets of politically connected contractors. They will then proceed to build a Maginot line of defenses that have no chance of longterm success.

        • Well they just finished on one Maginot Line of defenses (levees)… so they’re going to build another? (Sigh) You’re probably right on this one. Right now they’re talking of “diversions.” What they need to do is de-grade the river levees in strategic positions.

          BTW take a look at google-earth or google-maps on Lower St Bernard Parish near Delacroix… a LOT of the land shown on the 2000 map ain’t there no more.

  7. – Thanks, Robert.

    – It seems like all the heat (a monstrous amount at that) we (homo saps) have created when we burned so much FF has now become this ‘Frankenstein’ (Thx, M. Shelley) of a carbon to heat monster now running loose in the global village — its water, its air, and its land.
    So much heat — and so many humans who can exist only within a very narrow temperature range.

    – “Frankenstein” Quotes from Goodreads:

    For the times, “Nothing is so painful to the human mind as a great and sudden change.”

    For the RS team, “Beware; for I am fearless, and therefore powerful.”

    ― Mary Shelley, Frankenstein

    • I wonder if there’s a tolerance we’re not yet paying attention to. I sometimes wonder if the increased rates of evaporation result in a net overall risk of dehydration. It’s kind of a common sense link to heat. But it’s a global issue now.

      • Q; Isn’t evaporation a process in itself? The transfer is energy, yes?

        – I think of an elderly neighbor who insists on have a large fan on high speed blowing across him and drawing out his body moisture.
        Me, I use a very small 6″ fan on LOW speed that either pulls in cool air, or evacuates hot.
        I do the same with a 8″ fan on LOW for the entire 2nd floor of my building.
        I’m like the ‘First Mate’ (Site Monitor) in a century old wooden rooming house, and keep the heating and cooling systems functioning with minimal energy.

        • You run a tight ship, DT. Don’t forget to drink water.

          I’m in Maryland. My wife and I went to the pool this past weekend. It was hot — low 90s. Back when I was a kid, this would have been crazy heat. But I’m used to it now. Cat, on the other hand, has low tolerance and I have to watch her for the effects of dehydration and heat exhaustion. Well, this weekend, at the pool, she had some dehydration issues and I had to take her home and get her to drink water.

  8. – The latest fire & smoke map from US Airnow:

  9. Syd Bridges

     /  August 18, 2015

    That heat and humidity may cause a huge spike in electricity demand. I hope that the heavy rains of May and June will supply sufficient cooling water to the power stations so that the people in those regions can remain cool/. Large scale power outages could leave them in a perilous position as has happened in parts of Asia this year.

  10. labmonkey2

     /  August 18, 2015

    Just contemplating this current run of ‘luck’ we are in, climate wise, since the industrial age and thought about a bad what-if while we’re all withering in the heat.
    Wouldn’t it be a hoot (not really) if there were a large CME all of a sudden? Take out the power grid, knock out all electronics and satellites, and push us over the brink since we wouldn’t be adding all that aerosol pollution to somewhat cool the planet.

    That would certainly be the end of most of us.

    • dnem

       /  August 18, 2015

      Been thinking exactly that as I try and get the damn kids off their stoopit devices and into the friggin ocean here on vacay. Just bring on a big CME or EMP and fry ’em all. Ok, that’s my grumpy old guy comment for today.

  11. Andy in SD

     /  August 18, 2015

    you can file this under “thank you captain obvious”….

    Asia’s Rapidly Shrinking Glaciers Could Fuel Future Conflicts

  12. Andy in SD

     /  August 18, 2015

    Glacial Outburst on Mount Ranier in Washington

    “The sound of boulders rolling and smashing — it just got louder and louder and you could hear trees snapping,” said Beason, who was on the park’s Westside Road when one of the flows raced through the Tahoma Creek drainage.

  13. A bit of healthy competition for the Tesla PowerWall down under…

    Take THAT, Tesla: Another Oz energy utility will ship home batteries

    The Tesla PowerWall announcement is having an effect in Australia, but perhaps not the one Elon Musk predicted: utilities are moving to head it off with their own solar/storage offerings.

    Shortly after the Tesla battery launch, NSW’s AGL announced its solar customers could add electrical storage, and now Queensland’s Ergon energy is toying with the same idea.

    Ergon’s managed to secure government funding for a trial: the Australian Renewable Energy Agency (ARENA) has agreed to hand over AU$400,000 to support the $2.6 million project.

    Ergon will offer solar PV panels from SunPower and batteries from Sunverge (the two companies inked a partnership late in 2014, nominating Australia as one of their target markets).

    Initially, the Ergon offering will be tested in 33 homes, which will get a 4.9kW array feeding either 12kWh or 5kWh storage.

    The systems, to be installed in the Queensland locales Cannonvale, Toowoomba and Townsville, will be centrally monitored to manage what’s fed into the grid and reduce peak load on the network.

    The company says it will feed data back to ARENA to help manage the impact of renewables on Australia’s national energy market.

    As noted at Reneweconomy, Ergon has found that leaving customers in charge of their solar usage is a pain in the neck. Customers receiving a 44c per kWh feed-in tariff tend to push electrons towards the grid during the day (when their own demand is low), and save their own usage for the evening peak.

    That’s pushing the envelope for its wires and substations, leading the company to consider buying out customers’ feed-in tariff contracts. That would encourage users to run appliances when there’s the most electricity coming off the roof.

    In light of that, a centrally-managed offering makes sense.

    • Abel Adamski

       /  August 18, 2015

      “Customers receiving a 44c per kWh feed-in tariff tend to push electrons towards the grid during the day (when their own demand is low), and save their own usage for the evening peak.”

      Has nothing to do with being at work during the day and home during the evening, doing washing, laundry and cooking and vacuuming and watching TV.

      We are in trouble if that is the level of comprehension of our private sector

  14. Abel Adamski

     /  August 18, 2015

    An interesting article

    “For centuries, the oceans steadily cooled mostly due to large and frequent volcanic eruptions with some of the most frigid conditions occurring in what is known as the Little Ice Age.

    But that began to change in the 19th century, when humans started burning more fossil fuels and increasing greenhouse gases in the atmosphere. According to a study published Monday in the journal Nature Geoscience, manmade global warming ended a cooling trend that had lasted from 801 to 1800 A.D.

    “Today, the Earth is warming about 20 times faster than it cooled during the past 1,800 years,” said Michael Evans, second author of the study and an associate professor at the University of Maryland’s Department of Geology and Earth System Science Interdisciplinary Center. “This study truly highlights the profound effects we are having on our climate today.”

    The study also highlights the importance of the oceans in understanding climate change.

  15. Caroline

     /  August 18, 2015

    Robert, I’m wondering about your thoughts on Obama’s final approval to drill in the Arctic. I know you had hope that if we “put his feet to the fire” he would do the right thing regarding climate change. In fact, you felt he was making progress.
    This is not a digression—– your posts are excellent—- yet the fact that Obama approved drilling in the arctic should tell us something about the ROOT of the problems that you so brilliantly describe.
    We can talk about renewables, reducing C02 emissions, until we’re blue in the face (literally at this point, it seems) but until we accept that the underlying political system is broken, pathological and omnicidal —- the situation will continue to deteriorate while we stand on the sidelines watching and/or blogging about planetary collapse. What to do about it . . I don’t know—– but I do feel that if one denies the root of the problem, we will not solve it.

    • It’s a bad move that sends all the wrong signals. It demonstrates an attachment to the old, limited resource dominance based, policies that cause so many problems and that keep us dependent on fossil fuels for far too long.

      To this point, each new productive well, each new coal plant, each new gas fired plant, each new internal combustion engine extends the lifespan of fossil fuel burning. And that’s something we shouldn’t be doing at the moment. So I think it’s shameful that Obama has gone ahead and approved the Shell project, especially after so many worked so hard to put his feet to the fire. So many people who put their necks on the line to protect their children and loved ones from more carbon spewing oil wells sunk into the Arctic seabed just got the message loud and clear from Obama — ‘we’re not really too concerned about our future.’

      Obama has done many good things with regards to climate change. He’s using the EPA to regulate carbon, he’s committed to cutting overall carbon emissions by more than 30 percent through 2030, he’s pushed CAFE standards through the roof, and he’s helped to drive solar energy prices lower even faster than they would have been lowered otherwise. He’s at least helped to delay the Keystone Pipeline. But, sometimes, as with fracking, as with other pipeline construction, and as with the Shell Arctic drilling expedition, his policies cut against the grain of a necessarily rapid reduction in carbon emissions. Such backsliding is shameful and there is, at this time when human caused climate change is displacing people, on average at the rate of 8,000 each day, when heatwaves are now killers that stretch hospitals to the breaking point, when we have crossed or are crossing the Eemian boundary which implies a lock on 20-25 feet of sea level rise for our cities and islands, when James Hansen’s storms are brewing in the North Atlantic, and when a monster El Nino is cracking wide the Pacific to ooze out yet more heat, there is absolutely no excuse for it.

      My statement for Obama stands. We need to keep holding his feet to the fire. He, unlike the mad beyond nightmares republicans, is at least influenceable. And for this backward action the appropriate response is shaming. We need a leader who’s a climate hawk — not a climate chicken.

      • Loni

         /  August 18, 2015

        Well put, Robert. The United States will shortly, if it hasn’t already, taken over the reins of the Arctic bordering countries ‘Chairmanship. From that ‘bully pulpit’ the U.S. should be setting standards to protect from extraction, that which this world cannot and must not use.

      • Caroline

         /  August 18, 2015

        Thank you for your response and—-as always, thank you for what you do. We need your voice now more than ever. Please keep it up. You’ve got quite a team here and while I’ve felt your moderation has been a bit severe at times, it has helped keep this VITAL conversation on point.
        This move, this approval to drill in the arctic is heartbreaking, gut wrenching—–your latest post is a powerful antidote to despair (not an option)
        with gratitude,
        ps worried about CB

        • Thanks for the kind words, Caroline. And thanks for asking your questions.I’m worried about CB too. Will be trying to contact him through Facebook later today.


          The comments section is for the folks who want to stay on mission. To help solve the problems and get the word out. It’s not a platform for nihilism, malinformation, fossil fuel messaging shenanigans, or for sewing discord. From jump, I’ve been clear what’s acceptable here. There’s a difference between simply talking about a problem and actually working to solve it. From wallowing and focusing on distractions or keeping the message a sharp as elf-forged swords.

          Does this make me a nice, teddy-bear, moderator? Probably not. But I’m not here to be nice to folks who are wandering about in apathy, wedded to bad information, attempting to sock puppet or manipulate the forum, attempting to build themselves up by attacking an accessible moderator, or polarized to the point where they can’t support functional solutions. And any whiff of fossil fuel industry influence is enough to bring a comment down.

          The quality of the conversations we have is important. Especially those that are on public display. Simply having a conversation is not enough. We don’t have very much time.

      • Abel Adamski

         /  August 19, 2015

        Thank you R.S for the information, analysis and excellent site.
        It fulfills a need due to not only your hard work and diligence, but especially the input and links and information from the scribbler team and others who join in at times.

        I too am very concerned for C.B. It was his last and best friend he lost. I know well that place, I lost my everything for 36 years and the hole seems endless and the future empty, the black dog calls in too often. I have made a point of avoiding the solace of the bottle or other substances whilst I embrace the grief and loss knowing that is the only way through the cloud.
        My everything was a special one not just to me, but as a being and that story would have my sanity questioned, the knowledge and information that came with that does colour my viewpoints and comments, but the future can and must be changed in the present. There is a life after this one, and we do meet again. In the meantime we must do the best we can to help create a better world for all life, as you have said, Love in its purest sense is everything
        CB shows he cares and is a good man, we must keep on trucking.

  16. Leland Palmer

     /  August 18, 2015

    Giving the phrase “a home by the sea” different, more sinister connotations.

    We have solar, which has turned air conditioning in the summer from a huge drain of money to a break even proposition that doesn’t even drive our electric bill up.

    But, it just occurred to me – if the whole grid goes down due to air conditioning demands, our grid tied solar won’t keep the AC going. And, in ten or twenty years, in Santa Rosa, California, that could kill us during one of these high heat index events.

    Having a high heat index event in Santa Rosa, California, might require that the California current, bringing cold water down from the northern Pacific, be lower or non-existent in the future. But can we count on this current to continue flowing?

  17. Tropical Depression Four is born! Headed for the Carribean; best to watch this one. I think it’s going to go places.

  18. Reblogged this on GarryRogers Nature Conservation and Science Fiction (#EcoSciFi) and commented:
    Let’s hope the “greatest nation on Earth” can handle this emergency.

  19. Spike

     /  August 19, 2015

    Robert can you advise on how to get SST numbers on Earth nullschool? I can get the colours that show hot spots but when I click on the area of interest I get the location only and not the temperature value? Currently attempting to find temps in the Med, which is also looking very warm.

  20. International Trade Facilitators

     /  October 30, 2015

    Hi Robert,

    This email address ceases to exist at 24:00 GMT today (30th October) when my ISP closes business.

    I’ve been trying to change my email address on wordpress with no effect. I’ve tried to find the subscribe for new posts option on your blog, again to no effect. Can you either give me a link to where I can subscribe or subscribe for me. My new email address is

    Thanks Brian

  1. Dangerous Heat Sets Sights on Southern United States | Artic Vortex

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