Pittsburgh/Western PA Summer 2023

[CoraopolisWx]

Good old fashioned gusty northerly. 
Line held together longer than I thought earlier. 

[Rd9108]

34 minutes ago, RitualOfTheTrout said:

Yeah, The line is weakening pretty quickly now, that probably saved us from the worst winds, but rain and lightening show did not disappoint. 

Honestly I'm at work and don't feel like sitting on power lines so I'll take the lightning and avoid the winds. 

[north pgh]

Yes lots of lightning. I haven’t had a good lightning storm in a while. Just over an inch of rain. Winds were gusty but probably didn’t make it past 45 mph or so. Looking forward to a less humid day tomorrow.

[TheClimateChanger]

 

So far, we have been fairly lucky, although snowfall has trended downwards over the past several decades. Since 1950, I calculate the trend as a loss of 7" per century, so a fairly slow decline. But looking at the map posted by Brian Brettschneider, it looks like the oranges and reds aren't looming too far to our south. Do you guys think we will eventually reach a level of warming where snowfall in Pittsburgh plummets on the order of 25 or 50 percent?

[TheClimateChanger]

3 minutes ago, TheClimateChanger said:

 

So far, we have been fairly lucky, although snowfall has trended downwards over the past several decades. Since 1950, I calculate the trend as a loss of 7" per century, so a fairly slow decline. But looking at the map posted by Brian Brettschneider, it looks like the oranges and reds aren't looming too far to our south. Do you guys think we will eventually reach a level of warming where snowfall in Pittsburgh plummets on the order of 25 or 50 percent?

 

For context, here is the graph for Pittsburgh since 1950. The first few years are from AGC, the rest at PIT. I used 1950, as I feel that's the start of reasonably reliable snowfall records. Not to mention, the early years were all downtown.

[jwilson]

35 minutes ago, TheClimateChanger said:

 

So far, we have been fairly lucky, although snowfall has trended downwards over the past several decades. Since 1950, I calculate the trend as a loss of 7" per century, so a fairly slow decline. But looking at the map posted by Brian Brettschneider, it looks like the oranges and reds aren't looming too far to our south. Do you guys think we will eventually reach a level of warming where snowfall in Pittsburgh plummets on the order of 25 or 50 percent?

I think that's probably likely as our climate moves towards a facsimile of Atlanta.  Pittsburgh is a bit too far from the lakes to get the "real" influence and too far from the coast to benefit from all the coastal bombs that are forming nowadays with warming waters.  Hence why the coastal sections all run in the positive deviations.  It's also not at a high enough elevation to generate the kinds of mountain snows we'd see in the ranges.  We tend to nickel-and-dime our way to 40" as it is, and I would imagine tiny shifts in climate can make some of those little events become less common or more likely to be rain showers.

[KPITSnow]

4 hours ago, TheClimateChanger said:

 

So far, we have been fairly lucky, although snowfall has trended downwards over the past several decades. Since 1950, I calculate the trend as a loss of 7" per century, so a fairly slow decline. But looking at the map posted by Brian Brettschneider, it looks like the oranges and reds aren't looming too far to our south. Do you guys think we will eventually reach a level of warming where snowfall in Pittsburgh plummets on the order of 25 or 50 percent?

 

I think anecdotally we’ve all kind of felt this, but what really sticks to me is the amount of times we are right on a line between snow and rain, and this is where small deviations from historical norms would have large impacts.

 

I also feel the frequency of mid range events has drastically dropped. Clippers were fairly common when I was growing up but seem nearly non existent now. Advisory level 2-4 inch type of events also seem way rarer. 
 

We were lucky the last few years to have some larger events but if we don’t get those like last winter without the 2-4 events, clippers , and even lake effect events that would drop a couple inches I’d image we will start noticing it more 

[Ahoff]

Looks like maybe some heat this week.  We'll see how it shakes out.

[Ahoff]

If there's one day that looks like a 90 degree day, right now it's Friday.  NWS forecasts 93.

[Ahoff]

Pretty much as I expected, Friday looks to be the only day to hit 90 out of this period.  Crazy it goes from potentially 4 to probably 1.

 

Just not our summer for heat again.

[TimB]

Just now, Ahoff said:

Pretty much as I expected, Friday looks to be the only day to hit 90 out of this period.  Crazy it goes from potentially 4 to probably 1.

 

Just not our summer for heat again.

On the plus side, it looks like a slam dunk and the chances of being shut out are pretty much nonexistent.

[TimB]

That said, it’ll be interesting to see if PIT can get to 95. The only 95 in the past 11 years is suspect, as it was recorded in that period in September 2018 when the sensor was running high (AGC topped out at 92 on the same date). Throw that out and it’s the longest streak without hitting 95 in the entire period of record.

[Ahoff]

3 hours ago, TimB said:

That said, it’ll be interesting to see if PIT can get to 95. The only 95 in the past 11 years is suspect, as it was recorded in that period in September 2018 when the sensor was running high (AGC topped out at 92 on the same date). Throw that out and it’s the longest streak without hitting 95 in the entire period of record.

But our extremes are getting higher somehow, lol.

[Ahoff]

4 hours ago, TimB said:

On the plus side, it looks like a slam dunk and the chances of being shut out are pretty much nonexistent.

I wouldn't even go that far.  Plenty of time between now and Friday, and I'm sure there have been 93s that turned into 89s, lol.

[TheClimateChanger]

1 hour ago, Ahoff said:

But our extremes are getting higher somehow, lol.

That's because extreme heat is exceptionally rare. There have only been 21 years since records began at Pittsburgh International Airport in September 1952, in which the mercury reached 95 or better. There have only been 2 years since records began there, in which the mercury reached or exceeded 100 degrees.

Honestly, the 95+ readings in the late 1980s through mid 1990s were very likely inflated by the use of the HO-83 hygrothermometer in that era, which has a known, significant warm bias - particularly on sunny days with light winds in the warm season. So it's not suprising to find 30 of the 69 days of 95+ occurred between 1988 and 1995, in a period of about a decade or so in which that hygrothermometer model was in use. All 3 100+ readings at PIT also occurred in that era.

From 1956 through 1987, a period of 32 years, there were 16 days in which the temperature reached or exceeded 95 degrees, spread across 8 years.

[TheClimateChanger]

Looking more closely at the data, there are 69 days of 95+ in 71 years, which is an average of just under 1 per year. However, those 69 days were spread across only 21 years, meaning the actual incidence of a 95 or better reading is only roughly 2 out of each 7 years. It is much more common not to reach 95 than it is to reach that value. Using historical averages, approximately 5 out of every 7 years would be expected to reach no more than 94 degrees. In years in which it reaches at least 95 degrees, it is much more likely than not to reach that value multiple times. Of the 21 years in which 95 or better was reached, 13 of them reached that figure on multiple occasions.

Further, 8 years failed to even reach 90 - meaning it is 4x more likely that the temperature will not exceed 89 than it is to reach 100. Historically, about 1 in every 9 years at PIT fails to reach 90. There were no years between 1953 and 1975, inclusive, in which it failed to reach at least 90. The longest stretch since 1975 with no years topping out at 89 or below is 9 years, set three times - 1983 to 1991; 2005 to 2013; and 2015 to 2023. If it reaches 90 or better next year, we will be in the longest consecutive stretch with no years topping out below 90 since 1976.

[Ahoff]

1 hour ago, TheClimateChanger said:

Looking more closely at the data, there are 69 days of 95+ in 71 years, which is an average of just under 1 per year. However, those 69 days were spread across only 21 years, meaning the actual incidence of a 95 or better reading is only roughly 2 out of each 7 years. It is much more common not to reach 95 than it is to reach that value. Using historical averages, approximately 5 out of every 7 years would be expected to reach no more than 94 degrees. In years in which it reaches at least 95 degrees, it is much more likely than not to reach that value multiple times. Of the 21 years in which 95 or better was reached, 13 of them reached that figure on multiple occasions.

Further, 8 years failed to even reach 90 - meaning it is 4x more likely that the temperature will not exceed 89 than it is to reach 100. Historically, about 1 in every 9 years at PIT fails to reach 90. There were no years between 1953 and 1975, inclusive, in which it failed to reach at least 90. The longest stretch since 1975 with no years topping out at 89 or below is 9 years, set three times - 1983 to 1991; 2005 to 2013; and 2015 to 2023. If it reaches 90 or better next year, we will be in the longest consecutive stretch with no years topping out below 90 since 1976.

Right extreme heat is rare here, which is why it doesn't seem our summer extremes are really getting much warmer.

[TheClimateChanger]

Fairbanks, Alaska has had as many 90-degree days as us this summer: 

National Weather Service : Observed Weather for past 3 Days : Fairbanks, Fairbanks International Airport

[Ahoff]

Way under performed highs today.  At least by 5 degrees from this morning's forecast.

[TimB]

Tomorrow’s record warm min is within reach. Record is 74.

[Ahoff]

9 minutes ago, TimB said:

Tomorrow’s record warm min is within reach. Record is 74.

Forecast is for 74 tonight.  If we get rain and storms like is forecasted, I'd bet we fall below 74 though.

[TimB]

1 minute ago, Ahoff said:

Forecast is for 74 tonight.  If we get rain and storms like is forecasted, I'd bet we fall below 74 though.

Yeah, pretty dependent on what happens with the dying MCS coming out of the Midwest tonight.

[Ahoff]

3 minutes ago, TimB said:

Yeah, pretty dependent on what happens with the dying MCS coming out of the Midwest tonight.

I'm actually surprised to see such a high forecasted low.  Mid 70 lows, like mid 90 highs are tough to get here.

[Ahoff]

Heat advisory tomorrow.

[Ahoff]

Lingering morning clouds are never good for 90s here, lol.  The high starting temps can help though.  Will we make it today?

[TimB]

It was still 82 with a heat index of 85 at PIT at 3:15 this morning, but alas, a thunderstorm dashed our chances at a record warm min.

[Ahoff]

8 minutes ago, TimB said:

It was still 82 with a heat index of 85 at PIT at 3:15 this morning, but alas, a thunderstorm dashed our chances at a record warm min.

I thought we would do it too, when I saw it bottomed out at 75 then rose to 76, only to drop to 72.  72, if that's the low is still pretty warm.

But 82 at 3 am is still really wild.  Wonder how many times it was that warm at that time of night?  Can't be many.

[TimB]

13 minutes ago, Ahoff said:

I thought we would do it too, when I saw it bottomed out at 75 then rose to 76, only to drop to 72.  72, if that's the low is still pretty warm.

But 82 at 3 am is still really wild.  Wonder how many times it was that warm at that time of night?  Can't be many.

The record for that hour is 85 on 6/29/12. Of course, that was following a day that got to 95. Yesterday only got to 88.

The official low in the climate record for that date is 66, but that occurred at 11:59pm. That morning bottomed out at 80.

 

[Ahoff]

10 minutes ago, TimB said:

The record for that hour is 85 on 6/29/12. Of course, that was following a day that got to 95. Yesterday only got to 88.

The official low in the climate record for that date is 66, but that occurred at 11:59pm. That morning bottomed out at 80.

 

That was a hot day.  I thought it was 97 that day, but either way.  Yeah, impressive though to top out at 88 and still cling to 82 at 3 am.  Not a bad showing, lol.

[TimB]

9 minutes ago, Ahoff said:

That was a hot day.  I thought it was 97 that day, but either way.  Yeah, impressive though to top out at 88 and still cling to 82 at 3 am.  Not a bad showing, lol.

Yes, was 97 the afternoon of the day it was 85 at 3am. It was 95 the afternoon before.