Pittsburgh/Western PA Spring 2024

[meatwad]

Tornado Warning
for Allegheny County

Issued by National Weather Service
Pittsburgh, PA
4:40 PM EDT Fri, May 17, 2024

The National Weather Service in Pittsburgh has issued a

* Tornado Warning for... East central Allegheny County in southwestern Pennsylvania... Northwestern Westmoreland County in southwestern Pennsylvania...

* Until 515 PM EDT.

* At 440 PM EDT, a severe thunderstorm capable of producing a tornado was located over Aspinwall, or near Penn Hills, moving east at 15 mph.

HAZARD...Tornado.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without shelter. Mobile homes will be damaged or destroyed. Damage to roofs, windows, and vehicles will occur.  Tree damage is likely.

* This dangerous storm will be near... Penn Hills, Plum, O'hara Township, Oakmont, Fox Chapel, Aspinwall, Verona, and Blawnox around 445 PM EDT. Springdale around 450 PM EDT. New Kensington and Lower Burrell around 500 PM EDT. Arnold around 505 PM EDT.

Other locations impacted by this tornadic thunderstorm include Cheswick.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest floor of a sturdy building. Avoid windows. If you are outdoors, in a mobile home, or in a vehicle, move to the closest substantial shelter and protect yourself from flying debris.

Please report severe weather by calling 412-262-1988, posting to the NWS Pittsburgh Facebook page, or using Twitter @NWSPITTSBURGH.

&&

 TORNADO...RADAR INDICATED; MAX HAIL SIZE...0.00 IN
 

[meatwad]

Flash Flood Warning
for Allegheny County

Issued by National Weather Service
Pittsburgh, PA
5:17 PM EDT Fri, May 17, 2024

The National Weather Service in Pittsburgh has issued a

* Flash Flood Warning for... Central Allegheny County in southwestern Pennsylvania...

* Until 815 PM EDT.

* At 517 PM EDT, Doppler radar indicated thunderstorms producing heavy rain across the warned area. Between 1 and 2 inches of rain have fallen. Additional rainfall amounts of 0.1 to 0.5 inches are possible in the warned area. Flash flooding is ongoing or expected to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar indicated.

IMPACT...Flash flooding of small creeks and streams, urban areas, highways, streets and underpasses as well as other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include... Pittsburgh, Penn Hills, Mount Lebanon, Bethel Park, Monroeville, McKeesport, Plum, West Mifflin, North Side Pittsburgh, Baldwin, Upper St. Clair, Scott Township, Wilkinsburg, Whitehall, South Park Township, Robinson Township, Munhall, Jefferson Hills, North Versailles and Brentwood.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood deaths occur in vehicles.

&&

 FLASH FLOOD...RADAR INDICATED
 

[TheClimateChanger]

https://twitter.com/nwspittsburgh/status/1791577628924912053?s=46

[KPITSnow]

I saw the wall cloud. Driving down from North hills down 279 around 415/420. Looked suspicious but not completely abnormal, and checked to see if warnings but saw none. 
 

if I would have known I’d have tried to chase a bit down towards millvale 

[Ahoff]

I don’t remember having so many tornadoes in a season in the area, but it also seems the events are so very isolated instead of large area wide severe events.  Very strange weather patterns this season.

[TheClimateChanger]

On 5/5/2024 at 10:31 AM, Ahoff said:

Our average high this time of year is around 70, This week doesn't really look 10 above average.  And if a majority of them month is below average, in my eyes it's below average, lol.

I doubt it will be three weeks of below average though.  Honestly, they shouldn't even put out those long range predictions, they almost always change.

Well we managed three below normal days (officially). I don’t really see many opportunities for below normal temps over the next 7-10 days. Looks well above normal through Wednesday, and then cooler but likely still above normal late next week into the start of the holiday weekend.

[TimB]

Currently the 17th warmest May on record with a very warm stretch coming up the next 3 days. Could reach top 10 by the end of the month (3rd or 4th at PIT) the way it’s looking now. It’s starting to feel like this stretch of obscene warmth that’s been pretty much continuous since winter 2022-23 with a small break last May/June is never going to end.

[TheClimateChanger]

2 hours ago, TimB said:

Currently the 17th warmest May on record with a very warm stretch coming up the next 3 days. Could reach top 10 by the end of the month (3rd or 4th at PIT) the way it’s looking now. It’s starting to feel like this stretch of obscene warmth that’s been pretty much continuous since winter 2022-23 with a small break last May/June is never going to end.

I think all the Canadian wildfire smoke screwed us in May and June last year. Even when it wasn't noticeable on the surface, there was almost always some concentration in the atmosphere. The next strong El Nino should be interesting.

[TheClimateChanger]

4 hours ago, TimB said:

Currently the 17th warmest May on record with a very warm stretch coming up the next 3 days. Could reach top 10 by the end of the month (3rd or 4th at PIT) the way it’s looking now. It’s starting to feel like this stretch of obscene warmth that’s been pretty much continuous since winter 2022-23 with a small break last May/June is never going to end.

It will be interesting to see if we can sustain this. At Morgantown, the mean temperature so far this year has been 48.5F.

If you look at a place like Raleigh-Durham, NC, you can see 13 years were as cool or cooler, and 21 years within 0.5F of that figure, clustered generally within a 100-year period. Temperatures that low no longer occur in Raleigh-Durham, so including the full nearly 140 years of data would produce a incidence far below what the historical incidence. You can see that when the airport opened in that time frame from the late 1950s through 1980s, temperatures as low or lower than 2024 in Morgantown would have occurred about 1 in 4 years.

Even Greenville-Spartanburg, South Carolina has had 10 years as cool or cooler. While there's nearly 130 years of record, they were all clustered in the first 80 or so years of the POR, implying a historical incidence of about 1 in 8 years.

While still below the median, you can see temperatures like those at Morgantown so far this year were still fairly common in the 20th century in the Carolinas. Definitely within the envelope of a normal 20th century climate of the Carolinas, and about normal for 20th century Oklahoma City [albeit with cooler highs & warmer lows - less continentality].

[TheClimateChanger]

If you look at a place like Oklahoma City, the comparison is even starker.

Fully 32 years, almost all from prior to the 21st century, were as cool or cooler than Morgantown in 2024 for the period from January 1 through May 19.

And 45 years, no more than 0.5F warmer.

So at those levels, 2024 in Morgantown has seen temperatures that would have been expected about once every three years historically in OKC, and nearly every other year if you include years within 1/2 degree Fahrenheit.

[Ahoff]

On 5/18/2024 at 11:10 PM, TheClimateChanger said:

Well we managed three below normal days (officially). I don’t really see many opportunities for below normal temps over the next 7-10 days. Looks well above normal through Wednesday, and then cooler but likely still above normal late next week into the start of the holiday weekend.

Yeah, they were way off.  That’s why those long range outlooks really aren’t worth even putting out.

[TheClimateChanger]

On 5/20/2024 at 8:17 AM, TimB said:

Currently the 17th warmest May on record with a very warm stretch coming up the next 3 days. Could reach top 10 by the end of the month (3rd or 4th at PIT) the way it’s looking now. It’s starting to feel like this stretch of obscene warmth that’s been pretty much continuous since winter 2022-23 with a small break last May/June is never going to end.

Jumped up to 8th place already on the month to date, with another ridiculously warm (relative to average) day coming in today. Low was just 67F this morning.

[north pgh]

[Rd9108]

So what this is telling me is that my golf league may get a little dicey here later 

[Ahoff]

Luckily, a big miss with the severe storms last night.

[meatwad]

Tornado Warning
for Allegheny County

Issued by National Weather Service
Pittsburgh, PA
4:59 PM EDT Sat, May 25, 2024

The National Weather Service in Pittsburgh has issued a

* Tornado Warning for... Southwestern Beaver County in western Pennsylvania... Northern Washington County in southwestern Pennsylvania... Western Allegheny County in southwestern Pennsylvania...

* Until 530 PM EDT.

* At 459 PM EDT, a severe thunderstorm capable of producing a tornado was located near Shippingport, or 8 miles southeast of East Liverpool, moving southeast at 20 mph.

HAZARD...Tornado.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without shelter. Mobile homes will be damaged or destroyed. Damage to roofs, windows, and vehicles will occur.  Tree damage is likely.

* This tornadic thunderstorm will remain over mainly rural areas of southwestern Beaver, northern Washington and western Allegheny Counties, including the following locations... Raccoon Creek State Park, Hanover Township, Frankfort Springs, and Pittsburgh International Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest floor of a sturdy building. Avoid windows. If you are outdoors, in a mobile home, or in a vehicle, move to the closest substantial shelter and protect yourself from flying debris.

Please report severe weather by calling 412-262-1988, posting to the NWS Pittsburgh Facebook page, or using Twitter @NWSPITTSBURGH.

&&

 TORNADO...RADAR INDICATED; MAX HAIL SIZE...<.75 IN
 

[TimB]

Looks like maybe that airport cell was a hailer. Might we get our official trace of snow for May?

[Rd9108]

It hailed like pea sized hail down in the north shore yesterday. Wasn't much but it did come down for a minute or two.

[TheClimateChanger]

 

[TheClimateChanger]

 

[Mailman]

Mesoscale Precipitation Discussion 0330
NWS Weather Prediction Center College Park MD
514 PM EDT Sun May 26 2024

Areas affected...PortIons of the Upper OH Valley and the Central
Appalachians

Concerning...Heavy rainfall...Flash flooding possible

Valid 262113Z - 270113Z

SUMMARY...A long-lived QLCS with heavy showers and thunderstorms
will be crossing through portions of the upper OH Valley and the
central Appalachians over the next few hours. Given locally wet
antecedent conditions, the rainfall may be enough to cause some
instances of flash flooding.

DISCUSSION...The latest satellite and radar imagery shows a
long-lived and severe QLCS advancing quickly east through portions
of the upper OH Valley, and this will be reaching into portions of
the central Appalachians over the next couple of hours. The
downstream thermodynamic environment across the central
Appalachians is moderately unstable with MLCAPE values as high as
1000 to 1500 K/kg across areas of eastern OH/southwest PA and much
of WV. However, a stronger pool of instability is noted farther
south over eastern TN involving the broader Cumberland Plateau
region where some MLCAPE values are as high as 2000 to 3000 J/kg.

Rainfall rates with the storms are likely to be highest over areas
of eastern TN and far western NC where the greatest instability
and concerns for more discrete cell-development ahead of the
remaining QLCS will occur over the next few hours. Rainfall rates
here will likely approach or exceed 2"/hour, with some spotty 3 to
4 inch totals possible.

Farther north across much of WV and into eastern OH and especially
southwest PA, the progressive nature of the QLCS will limit
overall storm totals to 1 to 2 inches, but there may be some
rainfall rates of up to 1 inch in as little as 30 minutes as the
initial convective line arrives. The activity should tend to
maintain some convective vigor given the downstream instability
environment, and areas even east of the Appalachians may see
convection survive heading later into the evening hours.

Large areas of the central Appalachians in general are rather
moist, and portions of northern WV, southeast OH and southwest PA
saw heavy rains last evening and overnight which have resulted in
elevated streamflows. Given this and the locally rugged terrain
helping to enhance runoff further, some localized areas of flash
flooding will be possible over the next few hours.

[Mailman]

Not much of anything here.

[Rd9108]

Ehh it rolled through, rained pretty hard was windy, my lights flickered and then it was gone. Not much lighting. I'm guessing it weakened as it pushed east. 

[TimB]

3rd place right now for wettest spring on record. Need another 0.1” to pass 1933 for 2nd place, which is still possible. Over an inch behind 1901 so not likely we top the list.

[TheClimateChanger]

12 hours ago, TimB said:

3rd place right now for wettest spring on record. Need another 0.1” to pass 1933 for 2nd place, which is still possible. Over an inch behind 1901 so not likely we top the list.

Good shot at warmest spring on record as well, but it's going to come down to the wire due to the current cool down. 1921 finished at 56.6F. I think we'll probably finish around there.

Also, it is the sixth warmest May on record to date, but I think we drop out of the top 10 there due to the current cool snap to end the month. Still probably top 4 or 5 at the airport site.

[TimB]

If the month ended yesterday, we’d be the 3rd warmest May at Pittsburgh International. But since we have 4 cooler days left in the month, we’ll likely end up 4th.

And if we don’t drop below 56 before midnight, it’ll be the 22nd day this month with a low temperature higher than the May 31 normal low of 55. The only year with more was 1896, when records were taken somewhere in the UHI.

[TimB]

7 minutes ago, TheClimateChanger said:

Good shot at warmest spring on record as well. 

Plugging in the forecast for the next 4 days, I come up with an average for the full spring of 56.5. It looks like 1921 had a warm end of May to finish at 56.6, so we might end up 2nd unless we overperform on temps, which we usually do so not out of the question.

[TheClimateChanger]

1 minute ago, TimB said:

Plugging in the forecast for the next 4 days, I come up with an average for the full spring of 56.5. It looks like 1921 had a warm end of May to finish at 56.6, so we might end up 2nd unless we overperform on temps, which we usually do so not out of the question.

Yeah, I updated to hedge my bets. Might wind up coming in a tenth of a degree below 1921, officially.

[TheClimateChanger]

12 minutes ago, TimB said:

Plugging in the forecast for the next 4 days, I come up with an average for the full spring of 56.5. It looks like 1921 had a warm end of May to finish at 56.6, so we might end up 2nd unless we overperform on temps, which we usually do so not out of the question.

Would easily be the first seasonal warm record from the airport site. Closest previously is summer 1995, which finished 0.7F below the record hot summer (officially, 1900).

Edit: Actually spring 2012, which finished at 56.3F, 0.3F below 1921. Either way, second place is guaranteed this year, because, even with the cooldown, the mean of the next 4 days will be somewhat above the existing average of 56.4F. So we can only go up from here - whether its one tenth or two tenths will decide whether we match 1921.

[TheClimateChanger]

A couple other thoughts. On the year to date:

Morgantown

Pittsburgh

For the period January 1 to May 27:

At Oklahoma City, there have been 34 years that were the same or cooler than Morgantown's 2024. All but one occurred in the 103 years from 1891-1993. So basically, Morgantown's 2024 temperatures thus far have been as warm or warmer than about 1 in 3 years at OKC during the 20th century. Even PIT's average of 48.2F is as warm or warmer than 9 years at OKC - all which occurred in an 80 year stretch between 1899 & 1979. So, on average, about 1 in 9 years to date would have been expected to be the same or cooler at OKC during the early to mid 20th century.

Knoxville, Tennessee has seen 13 years at or below 48.2F and an incredible 47 years at or below 49.8F - again the vast majority of which occurred in the late 19th or 20th century [and, in the case, of the former, exclusively in that timeframe].

Bristol/Johnson City, Tennessee has seen 44 years at or below 48.2F [out of 87 years total]. 69 out of 87 years have been cooler than 49.8F. There's a bit of elevation at the airport there, but only 306' from PIT and 282' from MGW. That's less than the elevation gain from downtown Pittsburgh to PIT. I only put this caveat due to expected pushback, but actually the elevation loss at Knoxville Airport is nearly as substantial than the elevation gain to Tri-Cities Airport.