TheClimateChanger

Here was the weather on September 24, 1950. Perhaps the most notable thing is the temperatures, which are almost unfathomable by today's standards for the month of September. Erie Erie had a high of 48F, and a low of 46F. The comment states: "On the afternoon of the 24th, a dense layer of smoke aloft, together with a lower overcast of cloudiness, caused nighttime darkness so that floodlights were necessary for an afternoon ball game. The phenomenon is without precedent here and caused considerable alarm." Williamsport Williamsport had a high of 52F and a low of 39F. Further down in the monthly summary, the Weather Bureau observer left the following remark: "The most outstanding phenomena of the month was the rather complete obscuration of all sunlight and skylight for a period of two hours late afternoon the 24th due to a thick, high level smoke stratum from western Canadian forest fires. General atmospheric smoke remained till the month's end in a stagnating air mass over the region."

Also, of note, on yesterday's date 73 years ago, Black Sunday occurred in the Commonwealth. When I was looking up the history of wildfire smoke in the Commonwealth earlier in the summer with the seemingly near constant plumes of smoke, I came across this event from 1950. People were very perplexed, and many thought the world was ending or aliens were about to invade. Here are some reports from Bradford and Coudersport area. Bradford Landmark Society - The Day the Sun Went Out In Bradford - Bradford Pa History Historical Society Black Sunday: Darkness falls in the PA Wilds - Pennsylvania Wilds Some good eyewitness accounts on this site, with some even indicating stars were visible. This would suggest a large object eclipsed the sun outside of earth's atmosphere, perhaps giving some credence to the alien spacecraft theory. The official explanation today, however, is a pall of smoke from the Chinchaga firestorm in western Canada. darksunday (the-red-thread.net)

Interesting to see 1921 appear on several lists. That year seems like it was a little taste of the present climate in Pennsylvania, with hot summer months and high annual means as well. Wonder what happened to make it so warm that year.

With 5 days left in the month, the coldest temperatures observed so far are among the absolute warmest on record for the month of September across much of the Commonwealth. Frosty weather has been missing in action, even across the highest of elevations. Williamsport Bradford DuBois Harrisburg/Middleton Mount Pocono Philadelphia Scranton

Also, it's not true that I cherrypicked the summer months. At Flint, the change in annual temperatures is just as great if not more. It is true that Detroit's annual mean has not "shifted" quite as much as the summer mean, but very close. Looking at the past 13 years, the annual mean at Detroit is within a couple tenths of a degree of the 1961-1990 average for Columbus and Dayton, Ohio. The values below compare 2010-2022 (13 years) at Flint to 1961-1990 averages at Toledo and Findlay, Ohio. I expect the Flint average to come up another tenth of a degree when 2023 is finished, but I've excluded 2023 since it's still in progress. First up is annual mean for Flint. The past 13 years have averaged 49.2F for the annual mean. At Toledo, the 1961-1990 average for annual mean was 48.5F. At Findlay, the 1961-1990 average for annual mean was 49.5F. The annual mean temperature at Flint over the past 13 years has been 0.7F warmer than the 1961-1990 normal at Toledo, Ohio and 0.3F cooler than the 1961-1990 normal at Findlay, Ohio. And I can already anticipate the next objection. Oh - but it's mostly being driven by warmer low temperatures. Wrong! The annual mean maximum temperature has shifted even more than the annual mean average temperature. The mean average annual maximum temperature at Flint, Michigan over the past 13 years has been an astounding 59.1F. This is 0.5F warmer than the mean at Toledo for 1961-1990. And 0.7F warmer than the mean at Findlay for 1961-1990.

@hardypalmguy

Similar situation in northern West Virginia. I used a cutoff of 25 missing days to avoid bad data - of course, even a handfull of missing days could potentially affect these numbers. Using the above cutoff, MGW is in 18th place (out of 122 years). Wheeling is in 13th place, out of 67 years - although several years could have received more rainfall than shown due to missing data. Interestingly, Wheeling has received quite a few more recent dry years since the installation of the ASOS at the county airport than other sites. I wouldn't have expected it to be drier there, given its elevation several hundred feet above the river. Allowing for up to 50 missing days, HLG is in 15th place of 80 years. It might be surprising that a lot of the additional years had more rainfall, but often the missing data is simply the observer not indicating 0 precipitation fell. Of course, anytime 28 or more days are missing, there could be an entire month's worth of data missing.

A little bit of D0 noted in parts of western Pennsylvania in the most recent drought monitor update. Somewhat surprised southwest Pennsylvania has escaped the D0 so far. In the threaded record, this year has been the 34th driest to date (out of 153 years). Limiting the comparison to Pittsburgh International Airport records, as the downtown site tended to be a bit drier, it's the 16th driest (out of 72 years). As you can see, only three years this century have been drier to date (2002, 2016, and 2009), and one of those three (2009) is essentially in a tie with this year with just 0.03" less. At Allegheny County Airport, it's been the 4th driest, out of 41 complete years of records (1936-1952, 2000-present).

With two full days of astronomical summer left, Newark is sitting in 10th place for astronomical summer. One caveat, realize the dates can vary by about a day in either direction, but this analysis uses the period June 21 to date for ease of comparison. Prior to 2005, only two warmer astronomical summers are noted (1993 & 1983). While it's in 10th place out of 124 years of data, it is only in third place out of the past three years and seventh place of the past 14 years. So very warm historically - as I noted, it would have been 3rd warmest prior to 2005 - but only about on par for the past decade and a half. And possibly with it being only the 3rd warmest since 2021, it may be a cool astronomical summer in the current climate.

The only reason the 1931-1960 average is that much higher than the 1961-1990 average in the threaded records is because the first half of that data were from the city offices. Unlike Detroit, the airports are 300 to 500 feet higher in elevation than the cities - not to mention the decreased urban heat island effect from moving away from a rooftop in the central business district to a suburban location. It might have been a bit warmer, but not by 1.5F. My original analysis used 1961-1990 average for a few reasons - none of which involved picking cherries: (1) Most importantly, this was the date period referenced in the original claim; (2) It represents what was considered to be the "normal climate" a lot of us experienced when we began following the weather in the 1990s and start of the 2000s; and (3) It avoids the problem of mixing in data from various locations, altitudes and exposures (see note above) - all of the records compared were from the same locations and with more modern and reliable equipment characteristic of the late 20th century.

Yeah, this is a notable combination for Hagerstown: 3rd warmest and driest YTD. Surprisingly, very little drought with most of Washington County labelled only as abnormally dry (see below). Regarding temperatures on a year-to-date basis, 8 out of the top 10 warmest have occurred since within the past 14 years, and expanding out a bit (not shown) 9 of the top 12 and 10 of the top 14. Curiously, 3 of the top 6 driest YTD periods have also occurred in the past 14 years, with 5 of the top 6 from the 21st century. 3rd warmest year to date Driest year to date Maryland Drought Monitor

Heck of a way to run a cool summer!

HOT DIGGITY DOG! With the fall equinox looming in a few days, I figured I'd take a look at the numbers for astronomical summer. Although, admittedly, the date of the summer solstice can vary slightly from the 6-21 start I used. This has been the 3rd warmest astronomical summer to date in Bradford, Pennsylvania (out of 65 years): This is the 14th warmest at Harrisburg (out of 136 years): This is the 19th warmest at Williamsport (out of 129 years): Just across the Mason-Dixon line, this has been the 11th warmest astronomical summer at Hagerstown, Maryland:

Just a little friendly banter in the banter thread. But since you've written a lot here, I will respond. There have been 9 years with fewer 90 degree days at Detroit than this summer, plus 3 additional years with 2 each. That's 13 years [out of 150] with 2 or fewer days of 90+, or a historical incidence of about once every 11 years (and as you can see, it used to be a lot more common until recent decades). It's not as noteworthy as you are making it out to be. Furthermore, just a short jog down I-75 and Toledo has had 11 90+ degree days, with a maximum temperature of 93F. So I bet many parts of southeast Michigan had more than 2 90-degree days. I could accuse you of cherrypicking, but I won't because we are analyzing Detroit. I don't see how anything I previously posted was cherrypicked? I took the summertime temperature data from the two first-order sites in southeast Michigan, and compared it to the 1961-1990 mean for several first order sites hundreds of miles south. No cherrypicking involved - I limited the analysis to summertime, because we just finished summer and those were forecast summertime temperature changes. It's also not outside the climate envelope of southwest Ohio, which is the region I was comparing. Dayton has had 5 years with 2 or fewer 90+ days since 1950, including 3 with no 90+ days (see below):

GFS suggests the dry pattern persists through at least the end of the month. Will need to keep an eye out for any rogue tropical development, however. Here is the total QPF on the 12z run through 6z on 10-1:

While not the official observational site anymore, Allegheny County Airport (AGC) has received only 0.22 of an inch of rainfall so far this month. Looking through the observational records, which encompass 502 months of data [July 1, 1935 to September 15, 1952, as the official observational site; and February 1, 1999 to present with the installation of the ASOS], the driest month recorded at AGC is 0.53" in November 1939. Here are the 10 driest and wettest months observed at AGC (obviously September 2023 is not yet done). September is a month that can be very wet or very dry. It is generally a drier period of the calendar year, but occasional visits from remnant tropical cyclones can produce copious amounts of rainfall. Officially, at Pittsburgh International Airport (PIT), there has been 1.30" of rain this month, with 1.14" of that occurring on the 7th (the bulk of which fell in a single hour).

Incredible Starlink pass this evening. They were very bright in the night sky.

Nice.

Interesting. Although by 10 am, it's running right in line with all of the other local airports. I did look at some local PWS in the western Allegheny area, and they were mostly in the upper 30s to mid 40s this morning. But by 10:15 am, upper 50s and low 60s areawide. I do think it might be running a bit warm, but PIT has never done well in radiational cooling compared to much of the area. A lot of asphalt and its site on a flattened hilltop are not exactly conducive for radiational cooling. Many of the traditionally cooler sites are in valleys or at least on valley slopes with higher terrain in the vicinity.

Chilly morning, especially outside of Allegheny County with some upper 30s noted in the north. Some of the coldest lows in the region include 39 at Zelienople (PJC), Youngstown (YNG), and Franklin (FKL), 40 at New Castle (UCP), 41 at Washington (AFJ), 42 at Butler (BTP), and 43 at New Philadelphia, Ohio (PHD). The Virginia Tech mesonet site in the Canaan Valley National Wildlife Refuge (an elevated frost hollow) dropped to 30.6F.

Lol, no doubt. September 1881 is probably the legit warmest September in history, but that value is probably 3-5 degrees too high. I doubt that record will ever be broken. And I did want to point out, there's a weird trend/pattern where PIT runs 2-4 degrees warmer than AGC in the late morning, but by early to mid-afternoon the two sites are equal or AGC is actually a tad warmer. In any event, it looks like the sensor may be running a bit high at the moment - but probably no more than about a half degree. But it probably seems worse because I suspect the previous sensor was running 0.5-1F too cool for awhile. I did notice it was running warmer until the 1"+ rainfall earlier this month, so I suspect some of the difference was legitimate. PIT was one of the drier locations in SW PA in August (nearly an inch below normal, when many spots were well above normal), and plus there's a lot of construction/turned over soil around the airport grounds, so the locally drier soils were probably helping to push the temperatures up there. Since the rains earlier this month, it's actually been running a bit cooler than AGC. Incidentally, AGC largely escaped the storms earlier this month, and has only picked up 0.15" for the entire month to date - with little if anything on the immediate horizon.

Just looking over those maximum temperatures, and you can see there was a much more significant warming at PIT relative to AGC in the 2017-18 timeframe, and, on the flipside, it was highly unusual for AGC to have a September average maximum of 1.0F warmer than PIT last year.

How about daily average maximum temperatures? PIT is running 0.3F warmer than AGC this month. That's not surprising at all: PIT has averaged 0.1F warmer than AGC for daily average maximum temperature in the month of September for 1999-2022, so that's only a 0.2F difference from the long-term mean difference. PIT: 75.6F mean daily maximum temperature AGC: 75.5F mean daily maximum temperature