TheClimateChanger

Looking at NowData, there are only two instances of a high greater than 90 after August 9 - August 28, 1973 & September 3, 2011. Bradford registered it’s earliest 90+ reading on record just last year, when it reached 90 on June 16, 2022. The prior record was July 2, 1966.

May see some monthly all-time record highs in some of the higher elevations with the upcoming heat wave. Bradford could possibly see it’s latest 90 degree day on record, and DuBois could approach the monthly record high of 91.

Will be interesting to see whether IAD can eclipse the monthly record of 99F, and set a new latest date for a maximum of 100F or better. The current record is August 27, 1987, when it reached exactly 100F.

Although outside this subforum, worth noting Denver reached 99 today. I checked on NowData, and that was a daily record and equals the third warmest reading on record in the month of September. The only warmer readings were 100 on September 2, 2019, and 101 on September 5, 2020. It also reached 99 on September 7 & 8, 2022, and September 10, 2021. Prior to 2019, it had never reached 98 in Denver in the month of September. With today’s high of 99, it has now reached 98 or better on nine occasions in the past 5 years. In the context of the past five years, a pretty typical early September heat wave in Denver. But it would have been a new monthly record high prior to 2019. Records for Denver date to 1872.

How closely do the PRISM numbers agree with the officially tallies from NOAA? A mean of 72.98F would be 15th warmest overall, between 2007 & 1933. I would have thought this would be a Top 10 hottest summer with the record-breaking heat in the south and parts of the west. Note that the PRISM anomaly is based off 1991-2020 climatology, whereas the NOAA anomalies are based off the cooler 20th century mean [1901-2000]. Also worth noting that while this may be the 15th warmest summer overall, it is warmer nationally than all but three summers prior to 2000 (those three being the notorious drought years of 1934, 1936 & 1988).

The NWS point-click forecast centered on KMSP, shows a high of 96 on Saturday, 100 on Sunday, and 99 on Labor Day (see below). Saturday's forecast value is one shy of the daily record, and the other two would be new daily records. More significantly, this would be the second latest 100+ reading on record for the Minneapolis-St. Paul area. The latest 100+ reading is September 10, 1931, when the mercury is said to have climbed to an incredible 104F. That is the only 100+ reading on record in the month of September in the Minneapolis-St. Paul area dating back to 1872. The current second latest 100+ reading is August 17, 1947, when it reached exactly 100F, so that September 10, 1931 is really an aberration. Obviously, can't break the September 10, 1931 record, but there is a decent chance of the second latest 100+ reading on record, and potentially the first time two days of 100+ were recorded in the month of September if Labor Day is just slightly warmer than presently forecast. For the record, there is only one occasion when the month of August has had more than one 100+ reading in the Minneapolis-St. Paul threaded record - 1947, when it reached that figure 4 times. And there are only two dates in the entire threaded history where it's reached 100 or better after August 15 - 8/17/1947 & 9/10/1931.

Old Farmer's Almanac says an old-fashioned winter wonderland is on tap for this winter. I'm not so sure I believe this, especially with a potential Super El Nino. They even claim it will snow for the Steelers home game on December 23rd. I think when you start making specific predictions like that, you're no longer practicing any semblance of meteorology, or science, but something more akin to astrology or pseudoscience.

Sorry, it's difficult to be optimistic. Even in a relatively cooler summer, it's still exceedingly difficult to come anywhere near cold records. I think the low at PIT in the current cool snap was 58 this morning, which is only a couple degrees below normal. As an aside, excluding today, PIT has averaged 55.3F over the first eight months of the year. The last 8 years have averaged 54.7 for Jan-Aug, and the last 14 years have averaged 54.3 for Jan-Aug. By comparison, the mean at Clarksburg, West Virginia for Jan-Aug from 1948 to 1980 was 53.9F. We are now warmer than the typical climate in Clarksburg, West Virginia for the mid to latter part of the 20th century. This year has also been warmer than about 1 in every 4 years over that same stretch at Charleston, West Virgina, and the mean at PIT for the past 8 years is warmer than roughly 1 in 6 years at Charleston, West Virginia for the period 1948-1980. In other words, the last 10-15 years at PIT are now warmer than a typical mid/late 20th century climate in northern West Virginia, and approaching the 20-25th percentile of similar elevations in southern West Virginia. Hard to be an optimist. And like I said, I'm not even looking at 1800s or early 1900s, I'm just looking at temperature records only a little more than 40-70 years ago. Probably in the lifetime of some posters here. And it might be easy to blame the heat island, but I would point out Clarksburg has averaged 57.8F so far this year (2.5F warmer than PIT) and Charleston has averaged 58.8F (3.5F warmer than PIT). So if it's that, then there must be some urban warming to blame in West Virginia as well.

Ok, well, it looks like eastern Pennsylvania did a bit better in terms of cold. The 44F at Mount Pocono was only the 33rd warmest minimum for the month of August (since 1902). In western Pennsylvania, whenever there is a cold snap these days, it's accompanied by thick stratocumulus from the Great Lakes preventing radiational cooling from occurring. But, on the same token, Mount Pocono has not been below 40F in the month of August since 1992. From 1902-1992 - a total of 92 years, but for which only data exists for only 86 years - there were 46 years in which the temperature dropped below 40F in the month of August. In other words, a temperature that used to be observed more frequently than every other year has not occurred in over three decades.

As I noted here, it was at or below freezing throughout western Pennsylvania outside of the heat island areas in August 1982. It was even 38F in suburban Washington, D.C. at Dulles International Airport. What was the low temperature in Cashtown in August 1982? Are you saying the ASOS temperatures are incorrect or unreliable? And, if so, why would they just start being wrong in recent years?

I don't know what this matters. The only first-order stations to reach below 50F were Bradford (47F) and Mount Pocono (44F). The minimum was exactly 50 at Johnstown-Cambria County and Altoona. These stations have been in the same location for decades. Sheltered valley locations can get quite a bit colder than mountain locations.

At Bradford, the temperature used to drop to at or below freezing about once every five or six years in the month of August. It has not dropped below 40F since 2014.

At Bradford Regional Airport, the monthly minimum of 47F was just one shy of the warmest of record for the month of August behind 1980's low of 48F. Records date to 1957. It was also the fourth warmest minimum for any month. Also of note, July 2023's minimum of 49F tied 2020 for the warmest of record.

The monthly minimum temperature for August at DuBois - Jefferson County Regional Airport was 51F, which ties 1980 for warmest minimum temperature. Records date to 1962. Additionally, it was the 7th warmest monthly low temperature for any month. All six warmer minima occurred in July. Of note, this past July's minimum temperature of 53F was the second highest of record, behind 54F from 2020.

Also, of note, Miami's low of 83F was just one shy of the all-time record warmest minimum temperature there. This was an unusual 12:24 a.m. reading, so just at the very beginning of the calendar day. The rest of the day was 84F+. What is interesting is Wikipedia indicates that the all-time record warm low of 84F occurred twice - on August 4, 1993 & September 7, 1897. You can tell this was authored several years ago. In the new normal, an 84F low occurs pretty much every single year, often multiple times in a year. Since this article was written, a low of 84F has been observed nine times at Miami (August 5, 2017, September 8, 2017, July 14, 2019, June 25, 2020, June 27, 2020, June 29, 2020, July 31, 2020, September 3, 2020, and July 20, 2023).

The temperature at Naples dropped to 86F yesterday, which still was the warmest minimum on record at the airport. Using the expanded records for Naples area, which extend back to 1942, we can find one more alleged instance of an 86F low temperature, which is said to have occurred on August 17, 1943 (see below).

Upper 80s in western Pennsylvania looks about right, too. That's what the forecast is calling for Sunday. You never see the GFS spit out 110F for Pittsburgh.

Not sure if it will hold, but in the wake of Idalia, Naples Municipal Airport (APF) appears to have had a low of only 87F this morning. Short period of record, but looking back on the records, which date to 2003, this appears to be the warmest low over those 21 years. The daily mean of 90F, should it hold, is also the highest in the 21 year period. Naples, Naples Municipal Airport (weather.gov)

I think the high of 85 would have been on the 28th, but observed at 7 am on the 29th and ascribed to the date on which it was read. But even so, yes, the max thermometer at that station was clearly reading too high. Probably being exposed to some sunlight at some point. Looking at other observations around the region, there was indeed a large diurnal range. But it was more on the order of high 60s / low 70s for afternoon highs, not 80.

Even Reddit is complaining about the heat already.

The airport is at 2100 feet. The town is more like 1400-1500 feet, so it was probably a few degrees warmer in town. At the airport elevation, no, I don't believe it would be practical to grow tomatoes outside of a greenhouse in a natural climate. In the native climate, the frost-free period seems to be too short. You might get a few tomatoes, but I doubt much yield. Today, it would probably be much more feasible since summertime frosts no longer occur.

Ok, so I did some further research. Here was the article in the WaPo from 8/30/1982, discussing the cold snap: A Cold Snap Replaces Usual August Steambath - The Washington Post Note the record low of 38F in suburban Washington, D.C. at Dulles International Airport. A location more noted for its hot, subtropical climate and lack of snow, saw temperatures dipping into the 30s. As you can see, most people absolutely loved that weather: Of course, they did. Who doesn't like a crisp morning, followed by a warm, sunny afternoon in the 70s? The article does speculate that there could be crop damage from the midwest where temperatures dropped into the 20s. But if we look at the actual data, we see 1982 corn yield came in way above trend. The poor yield years (1983, 1988, 1991, 1993, 1995, 2002, 2011, and 2012) were from heat and drought (except 1993 may have been heat and flooding). The best yield years occur in cold, wet summers (1992, 2004, & 2009). The point being a little frost in August is probably not a big deal. The still high sun angle and short nights probably limited any frost to a couple hours near sunrise, with rapid melting by 7-7:30 am, preventing any significant damage. I mean perhaps yields would have been slightly higher without the cold snap. But it's clear from the data that heat and drought are a much bigger threat to agriculture than a quick, early frost.

I didn't know Bradford, Pennsylvania was an important agricultural region.

Anyways, I'm allowed to be upset about the loss of a natural climate. Regardless of whether the elimination of occasional late summer frosts and freezes were advantageous to agriculture. Just look at Bradford, Pennsylvania. Used to be one of the coldest spots in the country. August freezes in 1965, 1968, 1972, 1976, 1982, and 1986. None since 1986. It hasn't even been below 40F in the month of August since 2014, and the last time below 38F was in 2004. I mean look, it's barely dropped below 50F this month. This type of a change has to have a drastic impact on the local ecosystem. Just because it hasn't impacted the U.P. to the same degree yet, don't think you won't escape these changes. Bradford, Pennsylvania is in one of the most remote parts of the eastern U.S., surrounded by the Allegheny National Forest.

The point is not silly or stupid. Sure, the 1982 cold snap was a record-breaker. Now, we're lucky to see a day or two below 50F, but it used to dip into the 30s in August regularly. It's that dramatic of a change. We likely won't see 1982 conditions for two months.