Pittsburgh, Pa Summer 2024 Thread.

[Digger]

NWS point and click has my location at a high of 100 for Tuesday and Wednesday, and that's not the heat index either. A mile or so away from me they've got it as 101.

[meatwad]

URGENT - WEATHER MESSAGE
National Weather Service Pittsburgh PA
953 AM EDT Sat Jun 15 2024

OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>022-029-
031-073>078-WVZ001>004-012-021-509>514-152200-
/O.NEW.KPBZ.EH.A.0001.240617T1500Z-240622T0000Z/
Tuscarawas-Carroll-Columbiana-Coshocton-Harrison-Jefferson OH-
Muskingum-Guernsey-Belmont-Noble-Monroe-Mercer-Venango-Forest-
Lawrence-Butler-Clarion-Jefferson PA-Beaver-Allegheny-Armstrong-
Washington-Greene-Westmoreland-Higher Elevations of Westmoreland-
Fayette-Higher Elevations of Fayette-Indiana-Higher Elevations of
Indiana-Hancock-Brooke-Ohio-Marshall-Wetzel-Marion-Monongalia-
Ridges of Eastern Monongalia and Northwestern Preston-Preston-
Eastern Preston-Western Tucker-Eastern Tucker-
Including the cities of Grove City, Brookville, Clarion, Ford
City, Butler, Kittanning, Steubenville, Washington, Murrysville,
Carrollton, Moundsville, Kingwood, New Castle, Davis, Canaan
Valley, Parsons, Thomas, Cambridge, Salem, Coopers Rock,
Franklin, Hermitage, Lower Burrell, Wellsburg, Terra Alta,
Bruceton Mills, Fairmont, Woodsfield, Wheeling, Oil City,
Pittsburgh Metro Area, Armagh, Columbiana, Zanesville,
Greensburg, Hendricks, Beaver Falls, Tionesta, Aliquippa,
Follansbee, Donegal, Saint George, Weirton, Ligonier, New
Martinsville, Ellwood City, Ambridge, St. Clairsville, Champion,
Indiana, Caldwell, Monessen, New Philadelphia, Ohiopyle, Monaca,
Latrobe, Coshocton, Waynesburg, Hazelton, Sharon, Dover,
Canonsburg, East Liverpool, Malvern, Punxsutawney, Uniontown,
Morgantown, Rowlesburg, Cadiz, Martins Ferry, and New Kensington
953 AM EDT Sat Jun 15 2024

...EXCESSIVE HEAT WATCH IN EFFECT FROM MONDAY MORNING THROUGH FRIDAY
EVENING...

* WHAT...A prolonged, potentially historic heat wave is forecast to
  begin on Monday and persist through at least Friday. Dangerously
  hot conditions are possible each day, with widespread heat index
  values of 100 or above forecast. The potential length of this
  event will add to its impact as well.

* WHERE...Portions of east central Ohio, northwest, southwest, and
  western Pennsylvania, and northern and the northern panhandle of
  West Virginia.

* WHEN...From Monday morning through Friday evening.

* IMPACTS...Heat related illnesses increase significantly during
  extreme heat and high humidity events.

* ADDITIONAL DETAILS...Visit weather.gov/safety/heat for more
  information on heat safety.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.

Do not leave young children and pets in unattended vehicles. Car
interiors will reach lethal temperatures in a matter of minutes.

Monitor the latest forecasts and statements for updates.

&&

$$

 

[Mailman]

Looking a bit cloudy midweek?

[Ahoff]

Wonder when the last time we had and excessive heat watch or warning was?  2012?

[Mailman]

9 minutes ago, Ahoff said:

Wonder when the last time we had and excessive heat watch or warning was?  2012?

2019, it seems.

 

[Ahoff]

1 hour ago, Mailman said:

2019, it seems.

 

Oh, certainly don’t remember that one.  Probably downgraded to Heat Advisory.

Edit: Oh, I do remember this.  This was the last day of my parish's festival, the dew point touched 80 that day.  Never felt humidity like that here.  High was only 90, but with a dew point that high, it was brutal.

[Ahoff]

1 hour ago, Mailman said:

Looking a bit cloudy midweek?

I’d be surprised if we’re totally clouded with the high being pretty nearly over us.  Maybe a few clouds, but couldn’t imagine total cover.

Or maybe they’d be those high thin clouds that still let the sun through, but a little more filtered.

NWS not too interested in widespread cloudiness, though they do mentione how it could happen, but say that possibility remains pretty low for now.

[TimB]

2 hours ago, Ahoff said:

I’d be surprised if we’re totally clouded with the high being pretty nearly over us.  Maybe a few clouds, but couldn’t imagine total cover.

Or maybe they’d be those high thin clouds that still let the sun through, but a little more filtered.

NWS not too interested in widespread cloudiness, though they do mentione how it could happen, but say that possibility remains pretty low for now.

That whole forecast discussion is surreal. Never seen anything like that.

[Ahoff]

10 minutes ago, TimB said:

That whole forecast discussion is surreal. Never seen anything like that.

Just seems the high may be setting up perfectly (or imperfectly depending on how you look at it) for us to maximize on the potential.  We’ll see if this was overhyped or not by this time next week.

[blackngoldrules]

Latest forecast for Pittsburgh.

Sent from my SM-G991U using Tapatalk

[Ahoff]

Here's the forecast for KPIT.

 

[TheClimateChanger]

 

[Ahoff]

24 minutes ago, TheClimateChanger said:

 

Interesting they’d use downtown as the temperature not the official at the airport.

[Ahoff]

NWS is starting to come back down to more reasonable temps.  Look a couple degrees off each day.

[Ahoff]

Forecast is slipping down.  Not looking historic now.  They’re introducing rain into the forecasts.  That’s the killer, lol.  Maybe we’ll get a few low 90s and one or two days at 95 at most.

[Rd9108]

1 hour ago, Ahoff said:

Forecast is slipping down.  Not looking historic now.  They’re introducing rain into the forecasts.  That’s the killer, lol.  Maybe we’ll get a few low 90s and one or two days at 95 at most.

Oh no I'm so sad......

[Ahoff]

13 minutes ago, Rd9108 said:

Oh no I'm so sad......

Lol.  Well, if it was hyped as historic I'd like to see historic.  They always get out ahead of their skis, and look foolish afterward.  There is still a possibility toward the end of the week for very high temps, but once the adjustments down start, they rarely stop.  Kind of like snowstorms, lol.

[TheClimateChanger]

 

[TheClimateChanger]

On 6/14/2024 at 9:54 AM, TimB said:

I seem to recall a heat wave in 2016(?) that was hyped with upper 90s in the forecast and then we officially topped out in the low 90s a couple days. But that wasn’t a weeklong gates of hell kind of thing.

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

 

 

 

[TheClimateChanger]

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.

[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.

[TimB]

26 minutes ago, TheClimateChanger said:

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

 

 

 

So what you’re saying is, we may not have hit 100 in 1995 and maybe not even in 1988 with current ASOS technology? That if we had the current ASOS in place at its current location, it’s entirely possible that the location where Pittsburgh International is has never reached 100 degrees in the history of the city’s existence?

[TimB]

Anyway, plenty of opportunities for extreme heat this week and beyond. Seeing plenty of evidence that the heat simply reloads later in week 2 after a short break.

[TheClimateChanger]

43 minutes ago, TimB said:

So what you’re saying is, we may not have hit 100 in 1995 and maybe not even in 1988 with current ASOS technology? That if we had the current ASOS in place at its current location, it’s entirely possible that the location where Pittsburgh International is has never reached 100 degrees in the history of the city’s existence?

Well, the 103F on July 16th is probably legitimate. But honestly, yeah, I suspect the others would have topped out in the upper 90s. I get flamed frequently for bringing this up on here, but I'm not making it up. There's literally a plethora of studies showing the readings from the era to be high. Obviously, 1988 was super hot either way. Of the 38 days of 90+, 26 of them were 93 or better. But it's not 100% comparable to the current siting and equipment.

And not all readings, just at the "first order" climate sites - typically larger airports.

[TheClimateChanger]

49 minutes ago, TimB said:

So what you’re saying is, we may not have hit 100 in 1995 and maybe not even in 1988 with current ASOS technology? That if we had the current ASOS in place at its current location, it’s entirely possible that the location where Pittsburgh International is has never reached 100 degrees in the history of the city’s existence?

Also part of the reason why 1992 doesn't look that cool at most of the airports. At PIT Airport, it's only 8th coolest summer [tied with 1960], but on NCEI (which obviously has a lot more data), it's second coldest for Allegheny County [since 1895].  1992 being the one year that stands out in the era due to the Pinatubo eruption.

[TimB]

A little after 11am in mid-June and it’s already warmer at PIT than it was at any point during 2004.

[TheClimateChanger]

1 hour ago, TimB said:

So what you’re saying is, we may not have hit 100 in 1995 and maybe not even in 1988 with current ASOS technology? That if we had the current ASOS in place at its current location, it’s entirely possible that the location where Pittsburgh International is has never reached 100 degrees in the history of the city’s existence?

Regardless, I think some of these commenters on X forget its only June. 1988 had 4 90+ days at this point, and the 5th didn't occur until the 20th. We will be just one day below that. There were 8 by the end of June. Decent odds we match or exceed that, given the likelihood of more heat before the month is through. The mean temperature for June 1988 was 68.5F, nearly 1F below the current average. We are already at 68.4F and will be far above 70F before the end of this week. Incidentally, we've also had less than half the amount of rain this June compared to what we had at this point in June 1988, at the airport. I've barely managed a third of an inch IMBY so far. Of course, this also began a stretch in 1988 where there was basically no rain until the middle of July.

Heat built back in on the 4th that year with a high of 93 after a low of 54! I think these same people would be saying "it's JUST SUMMER!" on July 4, 1988. And if someone pointed out that there's been more 90s recorded than in X number of years [decades], they'd say "it hasn't felt that hot. I've had my windows open most nights!" given all the nights in the 40s and 50s. Of course, after the 4th through August, it was a blazing inferno.

Could be a case of "be careful what you wish for."

[jwilson]

Thanks for all your work, ClimateChanger.  Nice to see all that information accounted for.  I kind of figured improvements in data collection and analysis would help account for apparent oddities in climate measurables.

I know the NWS has their protocol and reasons for messaging a certain way, but I also think they should stay away from certain verbiage in long-term forecasting.  Especially given the local microclimatolgy that seems to moderate with time.  Geographically speaking, we don't really do extremes here.

[TimB]

First 90 is official. 

[TheClimateChanger]

Up to 94F, which matches the highest temperature since 2018. And as @TimBpointed out, I suspect some shenanigans were afoot with the sensor during that event. Prior to today, only 4 days had reached 94F since 2012.