TheClimateChanger

I think most people would be thrilled with this outcome. July 1936 was generally summer of yesteryear standards compared to recent years outside of a 7-8 day extreme heat wave. Even including the heat wave, it was generally at or below modern normals in much of the eastern US. Just by way of example, at New York City, the average high was 86.0F and the average low was 66.4F, with a mean temperature of 76.2F, which is 1.3F below the 1991-2020 normal. Excluding just 8 days [7/8-7/15], the average high plummets to 83.1F and the average low drops to 64.5F, producing a very comfortable mean of 73.8F over that 23-day stretch. With modern amenities like A/C, it wouldn't be too difficult to weather a similar stretch. Especially if it meant the rest of the month produced low temperatures not seen in decades.

Looks like there may be a pretty solid plume of smoke, including concentrated surface smoke, on Thursday extending from northern Michigan into the Chicagoland area and southern Wisconsin. Potential exists for degraded air quality.

Not super impressively ranked, and kind of cherrypicked on the date range, but it has been the 10th coldest mean minimum temperature on record for the period from May 1 through yesterday (6/18) at PIT. Obvious data quality concerns, the 1907 reading was from downtown, and the 1945 at AGC, and would likely rank higher if measured at the current observation site. On the flip side, the 1960s are probably overrepresented as the surroundings around the airport were still very rural then and the airport itself less developed.

Here is what the smoke pall looked like from 35,000 feet this morning over Illinois.

Webcams revealing some of the filthy air over the Twin Cities today:

Well, I generated the table in Excel, but the data was sourced from here: CLIMOD 2 (cornell.edu) Select "Seasonal Ranking", and then set variable to "Minimum Temperature" and summary to "Minimum", select the month or other time frame you want to see, and use station ID "MKETHR" [THR for threaded records, if you just use MKE it will only return records from the airport].

This can't be normal, can it? How can it be in the mid and upper 90s on the coast of James Bay and the south end of Hudson Bay, and in the 70s here?

You should be in a pretty good spot, especially in the coming decades. People probably said the same about southern Michigan in the 1860s, as you can see from this table displaying the average monthly coldest minimum temperature by decade at Lansing: how can you plant anything in a spot where the first freeze occurs in August and sometimes in July (like 1863)? Now 160 years later, and it seldom drops much below 50F in those months, and the first freeze doesn't occur until October. The September mean monthly minimum so far this decade is 9F higher than the August mean monthly minimum from the 1860s.

Average coldest monthly minimum low temperature in the warm season by decade, at Lansing, MI:

There can be impacts in the Minneapolis-St. Paul metro area, and possibly Chicago.

Not seeing much talk about this, but I am becoming increasingly concerned about the potential for an impactful wildfire smoke event. That is a dense pall of smoke with a substantial near surface density. If correct, visibility can be reduced to under three miles and air quality can reach unhealthy levels.

Despite its location in the tropics and right next to the ocean, San Juan is warming at about 3.5F per century. The current normal annual temperature of 80.9F was never reached in any year prior to 1972. Last year, the mean temperature was 80.9F, which is considered to be "normal" today, but was 23rd warmest (out of 124 years) and warmer than any year prior to 1972.

Been hearing of a heat wave in Puerto Rico, so figured I'd take a quick dive into the data. Easily the hottest start to June on record in San Juan:

I've seen a little chatter on Twitter that the recent warming may be related in part to a reduction in sulfur emissions from shipping and/or water vapor from the 2022 Hunga Tonga eruption. I don't buy either of these theories - First, aerosol optical depth across the northern Atlantic has been much higher than typical due to the intense plumes of smoke from the Canadian wildfires. Moreover, wildfire smoke has a greater cooler potential by mass than sulfate aerosols emitted by shipping, and can be lofted into the upper troposphere and lower stratosphere by pyrocumulonimbus and even downstream convection. The North Atlantic heat wave is happening IN SPITE OF very high levels of climate-cooling aerosols, not DUE TO low levels of aerosols. As for the volcano theory, this theory is basically akin to a "volcanic summer" - i.e., a brief, but rapid, warming due to stratospheric water vapor. Doing some research, I could find zero evidence that this phenomenon has ever been observed prior to 2022. There can be warming from volcanoes, but it's usually due to a series of volcanoes or a few intense eruptions emitting large amounts of greenhouse gases and follows an intense volcanic winter. Obviously, Hunga Tonga is not the first explosive undersea volcano - nearly 70% of earth's surface is covered by water, so there's likely been a lot more of those type of eruptions than explosive terrestrial eruptions. Despite this, there is zero evidence of a volcanic summer ever occurring, which would be easy to detect. They've detected numerous volcanic winters. Any impact from Hunga Tonga is likely minimal, and if anything more likely to have resulted in some cooling of the climate system. In my opinion, the warming is more likely the result of continued, record-breaking, emissions of greenhouse gases, rapidly developing El Nino conditions, and perhaps positive feedback loops being triggered, with the two mechanisms proposed above a very small part of any observed warming.

For reference, here is what the 21z RAP is showing for hour 51. As you can see, this is a massive plume, enveloping all of Saskatchewan, most of Alberta and Manitoba, western Ontario, and even parts of Nunavut.

Both the RAP and HRRR agree that another massive pall of smoke will form and cover all or most of Alberta, Saskatchewan, Manitoba, and western Ontario early next week. Many of these areas look likely to experience degraded air quality and limited sun. A bit concerned we could see this intrude into the upper Midwest and perhaps elsewhere as we head into the middle of the week, with a northwest flow aloft west of the Great Lakes upper low. Regardless of whether this enters the US airspace, many places in Canada look likely to see unhealthy to hazardous air quality. This is the 00z HRRR depiction of vertically integrated smoke and near surface smoke. We see the south end of a dense pall of smoke, including a substantial near surface component. The RAP gives the true size of the smoke pall, as much of it lies outside of the HRRR grid.

This is why I always use to say I’m a climate skeptic. Skeptical that it wasn’t much worse than the mainstream view, not that it wasn’t happening. They say it’s warmed 1C since preindustrial, but in fact it’s warmed nearly 1C just since the 1981-2010 average. This should be a smoking gun that they’ve been downplaying this, but I doubt that’s how many will report it.

Driest and warmest year to date at IAD. For the record, DCA with a much longer POR, is 4th driest & 2nd warmest on record YTD.

Looking back at the last 31 days, can certainly see the flash drought. Temperature rankings are based on mean maximum temperatures, which mitigates the urban heat island effects. I didn't realize it had been so warm, since a lot of the heat has been disguised in the means by somewhat cooler minima due to the dryness. Just by way of example, Moline is 2nd warmest by mean maximum temperature in the last 30 days, but would only be 13th if measured by mean. Chicago is 8th by mean maximum, but only 15th if measured by mean. For more extreme examples, Lansing is 7th warmest by mean maximum, but only 19th if measured by mean. Detroit is 9th warmest by mean maximum, but only 33th if measured by mean. Toledo is 6th warmest by mean maximum, but only 32nd if measured by mean. Moline, IL: Driest on record, 2nd warmest on record Minneapolis, MN: 6th driest on record, 4th warmest on record Chicago, IL (16th driest on record, 8th warmest on record) Green Bay, WI (Driest on record, 3rd warmest on record) Duluth, MN (2nd Driest on record, 5th warmest on record) Lansing, MI (Driest on record, 7th warmest on record) Detroit, MI (2nd driest on record, 9th warmest on record) Toledo, OH (Driest on record, 6th warmest on record)

Looks like MSP is off to an absolutely scorching start to summer. Second warmest on record for first eight days of June, and would have been first if it occurred during or before 2020. Third warmest when measured by mean maximum to minimize impacts of growing UHI. Wouldn't have expected this with the northerly flow and wildfire smoke limiting insolation.

DuBois received 0.11" of rain this morning. This is the first rainfall since May 20, and only the second since May 9 when a trace was recorded. The last measurable rainfall prior to May 20 was on May 7.

I think I can smell the fires now, unless it’s a local fire.

Not sure if it runs a bit cool, but the AWOS at Zelienople Municipal Airport is down to a chilly 36 this morning: https://w1.weather.gov/data/obhistory/KPJC.html

Pretty close to the record hourly minimum dewpoint at KPIT right now.