TheClimateChanger

The history of temperature measurement in America is to constantly produce cooler readings as technology has improved and standards revised, and then have people complain about adjustments and claim it was hotter in the past. Considering the ASOS is installed at 1,203 feet ASL and the buildings in which the downtown temperatures were taken many decades ago were from about 720 to 750 feet, taken on a rooftop with only passive solar shielding (LiG thermometer housed in a shelter, and no fan aspiration), one can only wonder what the temperature would be today. Absolutely ridiculous that mean temperatures over the past 24 months have been on par with the hottest years in the threaded record. Anyways, y'inz stay cool out there this week. Already up to 82F as of 9:51 a.m., with a heat index of 84F. 90+ looks like a foregone conclusion today, unless a storm forms by noon and sits over us the rest of the day.

When you consider instrument bias, what looks like a similar (if not hotter) stretch of summers in the late 1980s and early to mid 1990s, in fact, is cooler than most recent summers. You can choose not to believe this, but my bet would be warming will soon be sufficient to surpass 1995. And in the next couple of decades, warming will be substantial enough that numerous summers will be surpassing 1995. Because that's what the trend shows since installation of the ASOS in 1996. We finally have nearly 30 years without the NWS making some significant change to siting or instrumentation, and look, it's warming and FAST. Regression shows 2.2F of warming over that period in the summertime.

IMO, the problem boils down to this: The NWS sees "oh, this is the strongest ridge on record" and looks at past similar setups and then correctly assumes temperatures will be even higher this go around. Makes sense, since H85 temperatures are higher and ridge heights much higher, but there's no bias correction from the past observations. I've repeatedly - and correctly - pointed out that ASOS runs about 1-1.5F cooler than the HO-83 hygrothermometer it replaced in 1995/96. There's a reason why so many of those summers in the roughly 10-year span when the defective HO-83 was in place are among the hottest on record. The bias was not equal between night and day, but higher during the day - particularly on sunny days with light wind and a high sun angle. The same conditions that are typical of heat waves. So some of those days were likely overcounted by 2, 3 even 4F. This also coincided with some hot summers, no doubt, but not as hot as the records would suggest. Sources: climo_rpt_96_2.pdf (colostate.edu) - Study of 79 first-order climate sites between 1994 & 1995 found an average annual max temperature bias of +1.16F, and an average annual low temperature bias of +0.95F from the HO-83 relative to the ASOS installation. Comparison of ASOS and HO-83 temperatures at Lincoln, Nebraska from November 1991 through October 1992 (noaa.gov) - 12-month study from Lincoln, Nebraska study 1991-92. ASOS was from 1.4 to 2.6F cooler for maximum temperatures every month, and from 0.7 to 2.5F cooler for minimum temperatures. An Investigation of Temperature Discontinuities Introduced by the Installation of the HO-83 Thermometer in: Journal of Climate Volume 8 Issue 5 (1995) (ametsoc.org) - Another study, somewhat smaller estimate of 0.6C bias - actually suggests less bias in summer, but not sure that is correct. Ironically, I learned about this decades ago from climate change deniers. At that time, they were blaming climate change (in part) on this faulty sensor. Obviously, a ridiculous argument since U.S. first order airport sites make up a very small fraction of the USHCN sites, and almost zero percent of the global climate stations [the majority of which is water, after all]. But I correctly guessed it would turn to pointing to these same years as being evidence it wasn't warming as much as they said. The HO-83 Hygro- thermometer « Climate Audit - cites some more sources, particularly about Tuscon and how the NWS could not confirm a global warming signal in the deadly Chicago heat wave of 1995 because the readings were likely inflated by instrument bias

I think it factors in climo. Point-click centered on Bradford Regional Airport in north central Pennsylvania has 92, 95, 95, 93 and 91 next week. Since records began in 1957, there have only been 2 June days there in the 90s: 90 on 6/16/2022, and 93 on 6/22/2022. The all-time record is 97F on 7/16/1988 and 7/21/2011. And only one year saw more than 4 90+ readings: 1988, with 8.

Centered on the airport has 92, 95, 95, 93, and 91 Monday through Friday. There have only been two days in the 90s in June since records began at the airport in 1957: 90 on 6/16/2022 and 93 on 6/22/2022. The all-time record is 97F on 7/16/1988 and 7/21/2011. Only one year has had more than 4 90+ days: 1988, with 8. So if that comes to fruition, you would have more 90s than any entire year on record except for 1988, and 5 days in a row with temperatures that are either warmest or second warmest of any prior June day. Other than the fluke 93F in 2022, no other June exceeded 89F.

Wtae does have a 97 for next Saturday, but that’s really far out. Anyways, getting a decent thundershower here. No wind, but moderate rain and some thunder & lightning.

Interesting little random patch of fog on southern Lake Michigan.

The weather algorithm must have broke.

Stick a fork in it, people.

Worried about flash drought too, depending on how much rain falls today. I’ve only received about a quarter of an inch this month, and the airport is just over a third of an inch. CPC didn’t include western Pennsylvania in the flash drought outlook, presumably because it’s been one of the wettest starts to the year. But given the lack of rainfall recently and the prospective heat wave and continued lack of rainfall, they probably could have.

Looks like flash drought potential for the Ohio Valley, including parts of the eastern Corn Belt, and Mid Atlantic.

The first 90F of the year at Detroit. Current forecast has 90s Monday through at least Thursday (see below). If it can get to 7 90+ days by the 22nd, that would be pretty elite territory. Only 3 years have had more than 7 90+ days by June 22 at Detroit, and it's some impressive company [1934, 1988, and 1994]. Sunday Partly cloudy in the morning then clearing. Highs in the mid 80s. Sunday Night Partly cloudy. Lows in the upper 60s. Monday Warmer. Partly cloudy. Highs in the mid 90s. Heat index readings in the upper 90s. Monday Night Partly cloudy. Lows in the lower 70s. Tuesday Mostly sunny in the morning, then becoming partly cloudy. Highs in the mid 90s. Heat index readings in the upper 90s. Tuesday Night Partly cloudy. Lows in the mid 70s. Juneteenth Partly cloudy. Highs in the mid 90s. Heat index readings in the upper 90s. Wednesday Night Partly cloudy. Lows in the mid 70s. Thursday Partly cloudy. Highs in the mid 90s.

Also true, although the latter half of June kind of bucks that overall trend with the majority being observed at the airport - mostly 1994 and 1988 (including 2 of the dates when 98F was reached).

True to an extent, but at least in June, the daily records there are only 2 or 3F warmer on most days. The all-time record is 100F (last set in 1966), and the highest hourly heat index is 112F. That's also at the airport, which is only about 300 feet above sea level. So anyone living in a more elevated location of south central Pennsylvania can probably shave 2-4F off those readings.

I guess it depends on your definition of insanity. Considering the all-time record June temperature in Pittsburgh (since 1874) is 98F, and the highest hourly heat index in the month of June (since 1942) is 106F, the latter would definitely qualify as insanely hot in Pittsburgh. I'd have to say mid 90s is probably the threshold for June. That would get you near the daily record on all but a handful of days in the month.

It's happening, Tip. Buckle in.

The map on the left is not a believable presentation. It's almost never 3F hotter in Wheeling and Pittsburgh than Columbus and Dayton in this weather pattern - let alone 2F hotter than Charleston. And several degrees hotter than Baltimore, Washington and Philly in the coastal plain.

The European temperature forecasts in hot summer patterns always seem to be off for this part of the country. Always has a very " warm wintertime" pattern with hot air funneling up the Ohio Valley bringing in temperatures across western Pennsylvania and northern West Virginia which are hotter than places to the west. This is a common temperature pattern in the winter, but almost never happens in the summer. Realistically, to get upper 90s in southwest Pennsylvania, you would want to see low 100s across western/central Ohio and Indiana. Not cooler temperatures in the lower to mid 90s.

Yeah, I'm going to take the under there. I have to doubt we have daily record highs on 4 of 5 days next week, break the monthly record high, tie the old monthly record high on another day, and have a third day within 1F of the monthly record - all within a 5-day stretch.

Yes, it would be fairly unusual if the heat pans out. For sh*ts and giggles, I ran out the Accuweather forecast temperatures for Pittsburgh International and came up with a mean of 72.9F. It looked like it was returning more downtown Pittsburgh than the airport, so I re-ran using the forecast for Carnot-Moon and came up with a mean of 72.3F. The NWS point-click forecast centered on PIT would get us to 69.8F by the 18th, which matches what Accuweather shows for Carnot-Moon. Neither of these values are close to the record in the threaded history, but the warmest June at PIT is 1967 with a mean of 73.0F, followed by 72.9F in 1994, 72.6F in 1991, and 72.3F in 1996. June is one month that hasn't had a lot of top tier warmth in recent years. If the Accuweather forecast were to verify, it would be the warmest in about 30 years. Wouldn't normally put too much stock in it, but it tracks the NWS forecast for the next week. And CPC has us in a ridiculous 80-90% chance of above normal in the 8-14 day period (June 19th through 25th). That's about as high as they ever go.

For Detroit, the highest hourly heat index on record back to 1942 for the month of June is 109F on June 28, 2012. So I'm going to have to take the under there.