Occasional Thoughts on Climate Change

[GaWx]

13 hours ago, chubbs said:

Could be mixing of dryer air from aloft. As the ground warms the depth of mixing increases.

Thanks, Charlie. Check these hourlies out from last evening:

7PM 
AUGUSTA-BUSH   MOSUNNY   99  49  18 SW13      29.72  HX  96  TC  37     
AUGUSTA-DANIEL MOSUNNY   99  52  20 SW8       29.75F HX  96  TC  37  

 

8PM 

AUGUSTA-BUSH   FAIR      89  72  56 SE12      29.74R HX  96  TC  32     
6HR MIN TEMP:  89; 6HR MAX TEMP: 103;                                  
  
AUGUSTA-DANIEL FAIR      97  53  22 SW9       29.77R HX  94  TC  36     
6HR MIN TEMP:  97; 6HR MAX TEMP: 103;

 

9PM 

AUGUSTA-BUSH   CLEAR     88  68  51 S15G29    29.76R HX  91  TC  31     
AUGUSTA-DANIEL CLEAR     90  73  57 S10G20    29.78R HX  98  TC  32

 Note that from 7PM to 8PM Bush’s winds shifted from that very dry/hot SW direction to a much cooler/higher dewpoint (10 cooler/23 higher!) SE direction. But Daniel didn’t shift to SE and thus hardly changed. But then Daniel had the big change from 8PM to 9PM after their winds finally shifted away from the hot/dry SW winds.

[chubbs]

Remember the big spike in 95F days in Phoenixville in the mid-20'th century that didn't occur at other regional sites (posted upthread). Per chart below, the July diurnal temperature range also increased in that period. The increase in diurnal range isn't matched at West Chester or Coatesville. Probably shelter-related as a non-aspirated thermometer will be more prone to shelter problems. Resetting the max/min thermometer in the late afternoon and evening as was the usual practice back in the day would compound the problem.  In any case its clear that the raw data need a bias correction.

[chubbs]

Here are the annual average temperatures for the 3 main historic coop sites in Chester County.  Further evidence that Phoenixville ran warm in the mid-20'th century. Not that the other sites don't have potential data inconsistencies. Need to include other stations to fully resolve. When I look at the Chesco coop data I don't see any reason to worry about the NOAA bias adjustments. Every one that I have checked in detail is justified.

[ChescoWx]

26 minutes ago, chubbs said:

Here are the annual average temperatures for the 3 main historic coop sites in Chester County.  Further evidence that Phoenixville ran warm in the mid-20'th century. Not that the other sites don't have potential data inconsistencies. Need to include other stations to fully resolve. When I look at the Chesco coop data I don't see any reason to worry about the NOAA bias adjustments. Every one that I have checked in detail is justified.

So you're saying you think Phoenixville had problems but maybe not any of the other sites? So heck lets adjust the average temperature at all 4 sites to a level below what any of them actually reported because of finding one site that just might have had a warm bias.....that of course makes zero sense! With your analysis you are never able to actually explain what the adjustment should have been and the rationale for each individual site. For example tell us at each site.... In 1903 Phoenixville should be adjusted by 1.2 degrees / Coatesville adjustment should be 0.4 degrees  / West Chester 0.7 degrees and Kennett Square 0.3 degrees.

[ChescoWx]

So let's take all of the stations down to an average temperature lower than any station ever recorded for all of these years. How exactly did NCEI NOAA arrive at the need to make up a number for the county and make it lower than any thermometer almost each and every year? . Example for 1945 they somehow decided lets take the Chesco temp down to 2.8 average degrees BELOW what any station in the entire county actually reported that year. Where is the supporting calculation?? Charlie can you supply the detail for this large adjustment??

[TheClimateChanger]

As we approach the half-way point of 2024, I figured it would be a good time to review the weather and past climate. Anyone who has followed me since the 1990s knows that I have consistently been the most accurate voice on climate change - even back to when I was but a wee lad of ten years. So far, everything is playing out largely as I had projected.

For western Pennsylvania, this has undoubtedly been the hottest year on record to date. At Pittsburgh International Airport, the mean temperature has been 52.0F. In the threaded record, only 1880 is warmer. However, this was at the downtown city office - sited about 400' lower in elevation than the airport, and is not a reliable reading [as with most of the 19th century data in the threaded record]. From 1953-1979, the city office averaged 2.6F warmer than the suburban airport, with an annual range of +1.1F to +3.8F. Therefore, we can surmise that the mean temperature in downtown Pittsburgh is near 54.6F, with a high confidence interval of 53.1F to 55.8F.

At Morgantown, West Virginia, the mean temperature has been 53.4F. Second to 1880, but Morgantown's records from that era also appear to suffer from a substantial warm bias. What is fascinating to me is 1998 is missing the entire month of March, and 2024 is still nearly a half degree Fahrenheit warmer! If you were alive in 1998, you can recall how it was a HUGE deal how warm it was in so many places. So to see this El Nino just completely blowing that away - even excluding a winter month - is incredible.

At Wheeling, West Virginia, the mean temperature has been 52.1F, which is 1F above 1921. No data in this station thread 1954-1998, although only 1998 & 1991 would be warm year candidates. Worth noting the pre-1954 records were taken from a location adjacent to the Ohio River (at an elevation of less than 700 feet ASL, while the modern records are at the airport with an elevation of 1200 feet ASL).

[TheClimateChanger]

Very similar conditions can be noted in south central Pennsylvania, at locations like Hagerstown, Maryland [just across the state line] and Harrisburg/Middleton Area, Pennsylvania.

Hagerstown, Md.

Harrisburg/Middleton, Pa.

 

[TheClimateChanger]

So what is the significance of this data? While NOAA continues to downplay the warming, we can see in fact that temperatures 100 years ago were routinely 8-10F cooler than the temperatures observed in 2024.

The temperatures observed in this region in 2024 are more typical of 20th century East Tennessee (lower elevations).

In fact, if we key in on Knoxville, Tennessee, for the period 1872-1996 (125 years), what we discover is this: 

9 years [all on or before 1985] had a mean temperature at or below 52.1F.

34 years had a mean temperature of 53.4F or lower.

59 years had a mean temperature of 54.6F or lower.

Turning instead to Tri-Cities, Tennessee [Bristol/Johnson City Area]... and I know the elevation here is a bit higher, but only by like 200-300 feet compared to the airports I showed in the Upper Ohio Valley. In fact, the elevation gain here is comparable to the elevation loss in comparing those locations to Knoxville and less than the elevation gain in the threaded records for those very locations.

Anyways from 1938-2016, a period of 79 years, we find the following:

44 years had a mean temperature at or below 52.1F.

67 years had a mean temperature at or below 53.4F.

All but 4 years had a mean temperature at or below 54.6F.

[TheClimateChanger]

Some other oddities that don't jive with the official narrative. The mean winter temperature at Elkins, West Virginia [elev: 2000 feet, population almost nothing] over the past 9 winters is more than one half of a degree warmer than the mean temperature of all winters in Washington, D.C. [elev: near sea level, population: a very big city] from 1871 to 1921. This is a place that averages near 70 to 80 inches of snow per year historically, that is now warmer in the wintertime than the subtropical climate of the District of Columbia.

[TheClimateChanger]

8 minutes ago, TheClimateChanger said:

Some other oddities that don't jive with the official narrative. The mean winter temperature at Elkins, West Virginia [elev: 2000 feet, population almost nothing] over the past 9 winters is more than one half of a degree warmer than the mean temperature of all winters in Washington, D.C. [elev: near sea level, population: a very big city] from 1871 to 1921. This is a place that averages near 70 to 80 inches of snow per year historically, that is now warmer in the wintertime than the subtropical climate of the District of Columbia.

Another thing I've noticed in reviewing old phenological records is that the same species of trees leafed out in northern Ohio later than they did this year in the Upper Peninsula of Michigan. And temperatures from that era in Cleveland were in fact comparable to those observed in Marquette this year. Very interesting finding to me.

You won't see any of this reported anywhere. Like you would think it would be important news, but I guess not. Oh, but do carry on about how NOAA's 2 degree warming estimate for U.S. is wildly overblown. 

[FPizz]

48 minutes ago, TheClimateChanger said:

As we approach the half-way point of 2024, I figured it would be a good time to review the weather and past climate. Anyone who has followed me since the 1990s knows that I have consistently been the most accurate voice on climate change - even back to when I was but a wee lad of ten years. So far, everything is playing out largely as I had projected.

For western Pennsylvania, this has undoubtedly been the hottest year on record to date. At Pittsburgh International Airport, the mean temperature has been 52.0F. In the threaded record, only 1880 is warmer. However, this was at the downtown city office - sited about 400' lower in elevation than the airport, and is not a reliable reading [as with most of the 19th century data in the threaded record]. From 1953-1979, the city office averaged 2.6F warmer than the suburban airport, with an annual range of +1.1F to +3.8F. Therefore, we can surmise that the mean temperature in downtown Pittsburgh is near 54.6F, with a high confidence interval of 53.1F to 55.8F.

At Morgantown, West Virginia, the mean temperature has been 53.4F. Second to 1880, but Morgantown's records from that era also appear to suffer from a substantial warm bias. What is fascinating to me is 1998 is missing the entire month of March, and 2024 is still nearly a half degree Fahrenheit warmer! If you were alive in 1998, you can recall how it was a HUGE deal how warm it was in so many places. So to see this El Nino just completely blowing that away - even excluding a winter month - is incredible.

At Wheeling, West Virginia, the mean temperature has been 52.1F, which is 1F above 1921. No data in this station thread 1954-1998, although only 1998 & 1991 would be warm year candidates. Worth noting the pre-1954 records were taken from a location adjacent to the Ohio River (at an elevation of less than 700 feet ASL, while the modern records are at the airport with an elevation of 1200 feet ASL).

Who are you that I could have followed you since the 90s but you've been on this site since 2021?

[chubbs]

22 hours ago, ChescoWx said:

So you're saying you think Phoenixville had problems but maybe not any of the other sites? So heck lets adjust the average temperature at all 4 sites to a level below what any of them actually reported because of finding one site that just might have had a warm bias.....that of course makes zero sense! With your analysis you are never able to actually explain what the adjustment should have been and the rationale for each individual site. For example tell us at each site.... In 1903 Phoenixville should be adjusted by 1.2 degrees / Coatesville adjustment should be 0.4 degrees  / West Chester 0.7 degrees and Kennett Square 0.3 degrees.

No, that's not what I am saying at all. We have plenty of weather stations outside of Chester County to help. The first thing scientists did when stating to develop climate information was investigate how well weather stations were correlated. Turns out they are very well correlated and the correlation extends to roughly 1000 km depending on the region and season. NOAA is looking at much more data when estimating Chester County temperatures and bias adjustments than you are.

You are also looking at the adjustments in the wrong way. The adjustments are station-specific and are completely independent of the county average.  The adjustments are based in the monthly change in temperature from one year to the next, not on the absolute value. As an example if Phoenixville warms by 1F, while the stations relevant to Phoenixville  don't warm, Phoenixville's adjustment will change by 1F reflecting a probable change at the Phoenixville site. The shelter could have been moved for instance. Has nothing to do with the absolute temperature level at Phoenixville, or any other site, or the County average. The county average is only calculated as the last step after all the stations have been bias adjusted, and the individual station values has been mapped to a 5 by 5 km grid covering the entire country.

Furthermore Phoenixville, West Chester and Kennett Square are all warmer locations than the county on average due to their location and elevation.  Not surprising that they are warmer than the NOAA county average before or after adjustment.  The "adjustments" that you are coming up with are much larger than NOAA's, not even close in many cases.    You don't understand what NOAA is doing and are way off-base in your criticism.

[chubbs]

10 hours ago, ChescoWx said:

So let's take all of the stations down to an average temperature lower than any station ever recorded for all of these years. How exactly did NCEI NOAA arrive at the need to make up a number for the county and make it lower than any thermometer almost each and every year? . Example for 1945 they somehow decided lets take the Chesco temp down to 2.8 average degrees BELOW what any station in the entire county actually reported that year. Where is the supporting calculation?? Charlie can you supply the detail for this large adjustment??

Easy explanation. The older Chesco stations aren't representative of the County as a whole: low elevation, in the warmer part of the county, and they tend to be biased warm; and, in addition, NOAA is using weather stations that are outside of Chester County. NOAA takes advantage of the fact that weather station data is correlated for hundreds of miles. Instead of four stations, tens to hundreds of stations can provide relevant data on Chester County temperatures.

Per chart below NOAA has Chester County right where it should be: closer to Allentown than Philadelphia. Note however that Coatesville is very close to NOAA in 1940 and after 1947, further confirming the NOAA the result. In contrast, by just averaging the Chesco stations, you think Chester County is as warm as the Philadelphia Airport or the Newark Delaware Ag farm during the war years. A silly result.

 

[ChescoWx]

19 hours ago, chubbs said:

Easy explanation. The older Chesco stations aren't representative of the County as a whole: low elevation, in the warmer part of the county, and they tend to be biased warm; and, in addition, NOAA is using weather stations that are outside of Chester County. NOAA takes advantage of the fact that weather station data is correlated for hundreds of miles. Instead of four stations, tens to hundreds of stations can provide relevant data on Chester County temperatures.

Per chart below NOAA has Chester County right where it should be: closer to Allentown than Philadelphia. Note however that Coatesville is very close to NOAA in 1940 and after 1947, further confirming the NOAA the result. In contrast, by just averaging the Chesco stations, you think Chester County is as warm as the Philadelphia Airport or the Newark Delaware Ag farm during the war years. A silly result.

 

The true silly part is believing that using data from outside the county being observed makes any sense at all!!  I will continue to rely on the actual factual stations in the actual factual county we are observing and not rely on a machine adjusted fake number that totally discounts all of the confirming similar data validated by the NWS at the time of observation in the county of interest.

[donsutherland1]

Whenever Phoenix and Tucson experience exceptional heat, climate change denial accounts attribute the heat due to the cities' Urban Heat Island (UHI) Effect. They take cover behind the fact that UHI is a real phenomenon. However, on closer inspection, their argument disintegrates when comparisons are made with trends at U.S. Climate Reference Network (USCRN) sites. Phoenix does not have a nearby USCRN site. However, Tucson does.

The Tucson 11W USCRN site has seen summers warm by about 0.83F per decade since it started reporting in 2003. Tucson has seen summers warm by about 1.26F per decade during that same period. USCRN sites are those that have been selected for their stability (no changes such as urban development). Thus, they offer a good proxy for assessing changes purely due to climate change.

If one assumes that the Tucson 11W provides a good proxy for the impact of climate change in the area, including Tucson, then one can attribute the additional warming of Tucson to non-AGW factors, principally UHI. That assessment finds that nearly two-thirds of the summer warming that has occurred in Tucson is due to AGW. The remainder is due to UHI. One can get greater confidence in this assessment by taking a look at the Tucson population data from 2003-2023. during that time, Tucson's population grew 33.8% which is virtually identical to the share of warmth the USCRN comparison attributes to UHI. Therefore one can confidently assert that nearly two-thirds of Tucson's increasing warmth during summers is being driven by climate change, not UHI.

 

 

[chubbs]

On 6/28/2024 at 12:59 PM, ChescoWx said:

The true silly part is believing that using data from outside the county being observed makes any sense at all!!  I will continue to rely on the actual factual stations in the actual factual county we are observing and not rely on a machine adjusted fake number that totally discounts all of the confirming similar data validated by the NWS at the time of observation in the county of interest.

As usual you are carefully cherry-picking your "facts" to preserve your worldview. Using weather data outside the county makes perfect sense. Weather data is correlated for hundreds of miles and the historic data within the county is very limited. Bottom-line: You don't like NOAA's result; and you'll dismiss/deny any evidence that supports NOAA. As I said above, you live in a different Chester County than I do. The Newark Ag farm is less than 10 miles away from me. I want that data reflected in my climate history. Its just as relevant as any station in Chester County.

Not that you couldn't do a better job analyzing the Chester County data by itself. For instance, per chart above,  you don't need data from outside the county to bias adjust the Coatesville wartime warm spike.  You also don't need any data outside the county to identify the excessive heat at Phoenixville in the 30s, 40s, and 50s, just increases the confidence in doing so. Not surprising that you are way off for Chesco in that period.

[ChescoWx]

2 hours ago, chubbs said:

As usual you are carefully cherry-picking your "facts" to preserve your worldview. Using weather data outside the county makes perfect sense. Weather data is correlated for hundreds of miles and the historic data within the county is very limited. Bottom-line: You don't like NOAA's result; and you'll dismiss/deny any evidence that supports NOAA. As I said above, you live in a different Chester County than I do. The Newark Ag farm is less than 10 miles away from me. I want that data reflected in my climate history. Its just as relevant as any station in Chester County.

Not that you couldn't do a better job analyzing the Chester County data by itself. For instance, per chart above,  you don't need data from outside the county to bias adjust the Coatesville wartime warm spike.  You also don't need any data outside the county to identify the excessive heat at Phoenixville in the 30s, 40s, and 50s, just increases the confidence in doing so. Not surprising that you are way off for Chesco in that period.

And you of course cherry pick one month out of 1,572 months of data.....

[ChescoWx]

The machine based revisionist history of our climate in Chester County continues to more modern times. Just last August 2023 - NOAA/NCEI increased the average temperature by an entire 1.0 degrees to 73.1 degrees for Chester County PA from the actual average of 72.1 degrees. Why was this done? Well of the 16 current stations in the county only 2 of them.....KOQN Airport (74.2) and Phoenixville (73.7) (always our warmest stations) were above 73.1. Was there a time of observation adjustment? Poor equipment? Siting issues?? Keep in mind they cooled every single year from 1893 thru 2005 and have now warmed each and every year since 2006.....

[bdgwx]

Relevant to this discussion is [Hausfather et al. 2016] who found that the required adjustments to USHCN (now nClimDiv) are effective when compared to USCRN. If anything, however, the adjustments still leave USHCN biased too low. During their overlap period through 2024/05 the trend is +0.56 F/decade (+0.31 C/decade) for nClimDiv compared to +0.69 F/decade (+0.38 C/decade) for USCRN.

[chubbs]

1 hour ago, ChescoWx said:

And you of course cherry pick one month out of 1,572 months of data.....

You aren't paying attention. The charts I posted upthread show that Phoenixville ran warm for decades.

[chubbs]

3 hours ago, ChescoWx said:

The machine based revisionist history of our climate in Chester County continues to more modern times. Just last August 2023 - NOAA/NCEI increased the average temperature by an entire 1.0 degrees to 73.1 degrees for Chester County PA from the actual average of 72.1 degrees. Why was this done? Well of the 16 current stations in the county only 2 of them.....KOQN Airport (74.2) and Phoenixville (73.7) (always our warmest stations) were above 73.1. Was there a time of observation adjustment? Poor equipment? Siting issues?? Keep in mind they cooled every single year from 1893 thru 2005 and have now warmed each and every year since 2006.....

And you just complained about me cherry-picking one month. For all your complaints, NOAA matches the recent trend at your house closely. How is that? Simple, your house doesn't change from year-to-year. Making your house a much better platform to judge if temperatures are changing with time than a network of stations that  is constantly changing.

[donsutherland1]

58 minutes ago, chubbs said:

You aren't paying attention. The charts I posted upthread show that Phoenixville ran warm for decades.

The regression analysis I ran also showed a clear bias at Phoenixville relative to nearby sites. The 1915-48 period there is unreliable. I am strongly confident that Phoenixville never got close to 44 95° days.

[bluewave]

41 minutes ago, donsutherland1 said:

The regression analysis I ran also showed a clear bias at Phoenixville relative to nearby sites. The 1915-48 period there is unreliable. I am strongly confident that Phoenixville never got close to 44 95° days.

Very obvious error since there is no way Phoenixville would ever have that many more 95° days than Baltimore. The most 95° days Baltimore had during that period was 19 in 1931.

Time Series Summary for Baltimore Area, MD (ThreadEx) - Jan through Dec
Click column heading to sort ascending, click again to sort descending.

1	1931	19	0
2	1941	18	0
3	1944	17	0
4	1930	16	0
5	1943	14	0
-	1934	14	0

 

 

 

 

[donsutherland1]

39 minutes ago, bluewave said:

Very obvious error since there is no way Phoenixville would ever have that many more 95° days than Baltimore. The most 95° days Baltimore had during that period was 19 in 1931.

Time Series Summary for Baltimore Area, MD (ThreadEx) - Jan through Dec
Click column heading to sort ascending, click again to sort descending.

1	1931	19	0
2	1941	18	0
3	1944	17	0
4	1930	16	0
5	1943	14	0
-	1934	14	0

 

 

 

 

Absolutely. The numbers there are obviously wrong. They should not be relied upon.

[TheClimateChanger]

The historic heat wave continues across eastern North America, with a number of monthly high minimum readings in danger of falling today, including a couple of all-time records.

 

[Typhoon Tip]

Now in addition to counties in PA ... the conspiracy has apparently reached the ECMWF CO's modeling operations branch ...

.. because look what they've done. They've gone and diabolically seeded the model to hide any and all negative anomalies that would make this outlook even menial to climatology

[ChescoWx]

5 hours ago, chubbs said:

And you just complained about me cherry-picking one month. For all your complaints, NOAA matches the recent trend at your house closely. How is that? Simple, your house doesn't change from year-to-year. Making your house a much better platform to judge if temperatures are changing with time than a network of stations that  is constantly changing.

Who cares about my house?? It is an insignificant non issue in the data analytics - Charlie you do get this correct??

[ChescoWx]

4 hours ago, donsutherland1 said:

The regression analysis I ran also showed a clear bias at Phoenixville relative to nearby sites. The 1915-48 period there is unreliable. I am strongly confident that Phoenixville never got close to 44 95° days.

Than we drop Phoenixville and it still makes no difference in the analysis!!

[chubbs]

3 hours ago, ChescoWx said:

Who cares about my house?? It is an insignificant non issue in the data analytics - Charlie you do get this correct??

You didn't understand my point. The best way to evaluate whether NOAA the Chesco long-term temperature trend correct is to use reliable stations with long-term records, your house included. The stations I trust, including your house, both inside and outside the county, have similar trends as NOAA. I don't care about a one month temperature in your network. I care about the long-term trend.

The problem with comparing your average and NOAA. Is that your average is not the County average temperature. Its the average of the group of weather stations. You are making no attempt to match your station network to the characteristics of the county.

There are two problems. The older stations are not representative of the county as a whole and the network is changing in time. As illustrated upthread, If the network changes in time a simple average will skew the trend. Your current network appears to be more representative of the county, but that means its a poor match to the older stations. The current network is also largely made up of stations that aren't used for climate analysis. When you can't match the NOAAcounty average or trend, its due in large part to: 1) changes in your station network, 2) other method differences between you and NOAA, and 3) differences in the stations you are using and not due to NOAA's bias adjustments. In any case the bias adjustments for each station are all published. Not sure why you feel a need to overestimate the bias adjustmets and misrepresent their true nature..

The best way to evaluate the bias adjustments that are given to individual stations is to compare the station to other stations in the region. When I do that I don't see a problem with NOAA's adjustments. Phoenxiville, West Chester and Coatesville 1SW all deserve the bias adjustments that I have checked.

 

[Typhoon Tip]

https://phys.org/news/2024-06-extreme-summer-climate-weather.html

You know... just an extending comment on this article above.   I was particularly intrigued by this statement/excerpt,

"... Very large and strong heat domes, like the Northeast event—which reached higher into the atmosphere than any previous June event— "

I was suspecting that this was true - relative to climate.  We've seen excessive ridge heights tower to nearly 600 dam in the past, but not prior to July.  Certainly ... not to 40 N.  I hadn't bothered to find any sources that keep track of that metric, historically.  This article indirectly makes the comparison/assertion. 

But what makes this interesting is that in the case of June 2024, this heat dome did not appear to receive an inject of elevated kinetic air layer from the west.   I've referred to these type of phenomenon as "Sonoran heat release" - a geographical region that is perhaps more usefulness as an identifier. Probably just southwest heat release would be more precise. ... anyway,  there is an all but codified hallmarked synoptic evolution that transpires, leading to a release event.

+PNA traps air in the SW that is subjected to very high daily insolation. We can get a feel for this by looping WV imagery on satellite, during the +PNA mode, and noting the anticyclonic motion to the atmosphere over that region of the continent.  

Changes upstream in the Pacific than send a d(index) significant enough to alter the signature over the downstream continental mid latitudes, effectively bringing a heights falls toward the west coast --> dislodging the erstwhile trapped ultra hot air layers and sending them down stream. 

If/when that happens and the NAO is entering or is in a stasis +NAO ( rising escape latitudes of the westerlies, as well as tending to make the flow zonal through the Canadian Maritime ),  the combination of these hemispheric scaled changes teleconnects to geopotential ridge eruption over the eastern mid latitude continent.  

We saw this series leading the June 2024 heat wave, but interestingly ... there wasn't a very highly charged air mass available from the SW in this case.  Idiosyncratically, there was an early quasi monsoonal response taking place during the 'ejection phase', and this interfered with daily clouds and convection over the source region in keeping the 850 mb ~ lower.  

It's really the difference between the more common 97 type high temperature results in June 2024, versus "hot Saturday" in 1975, or the July 2011. 

This historically hot ridge ( or "dome" ), really left about 5 to 7 pesos on the field... Notwithstanding, the attribution aspects with CC were never really tested (imho) with the June 2024 event. A perhaps limited "syntergistic heat wave" is what really took place from the TV to NE regions.  Simplest conclusion, it could have been hotter!  Not only that, there is an identifiable series in the pathway to making that happen that appeared to be missing.