ChescoWx

Actually it's 25 sad little stations to best analyze the climate of Chester County PA. The true defining question to ask is.....can a man get pregnant?

So what is the "required adjustment" for these reverse heat island impacts when they moved to the more suburban sites?? Should the adjustment... at let's say Coatesville be to adjust the temperature up or down?? What years should be decreased and which ones increased??

Charlie so where was the Philadelphia obs taken in the above data you are using? It looks to me like the Philadelphia data from the 1890's thru 1930's was taken near Roxborough correct??

Coatesville and West Chester "more urban" than Philly in 1936? It was just warmer west of Philly in 1936 before the UHI contamination of Philly was underway.

By popular request....More updated charts based on the data refinements last week identified by Charlie. As you can see below with the actual raw data (blue) over the last 130 years (at least here in Chester County PA) there is almost a flat trend to our annual average temperatures by decade. Of course if we apply the NCEI adjustments we now see the warming trend. I will also attach the NCEI adjustments by decade. Which after 11 decades of consistent cooling adjustments...we now have post observation warming adjustments being applied.

Hey Frank sounds like another of the Ghost Stations found right here in PA

A refresher for those considering joining the dust bowl heatwave deniers. Showing how Chester County like most of the USA experienced summers hotter than we have experienced since...even in our current warming cycle of climate change. https://arcfieldweather.com/blog/2024/7/3/the-deadly-heat-wave-of-july-1936in-the-middle-of-one-of-the-hottest-summers-on-recordin-the-middle-of-one-of-the-hottest-decades-ever

There continues to be an alarming rise in dust bowl heatwave deniers....they continue to attempt to use altered adjusted data to chill that historical heat. While reviewing all of the post hoc data adjustments details for the long term Chester County PA stations I found plenty of missing data points for both West Chester and Phoenixville.. I have included their raw unaltered data for the below summertime average temperature historical review of the years these deniers focus on most 1930's thru 1950's. Below is a comparison of the actual raw data along with the significant cooling adjustment following NCEI adjustments. Coatesville individual post hoc site NCEI altered average summertime temperatures are in red. Chester County PA NCEI county wide altered average temperature following NCEI adjustments are in purple. Of note, as I dove into the handwritten observations for Coatesville there appears to be no need for time of observation adjustments for Coatesville, During the time frame of all of these significant cooling adjustments the time of observation for Coatesville was taken by the observer at the following times. 1930 thru 1942 at both 8am and 8pm; from 1942-1945 it was 8pm. After 1945 it was taken at 8am.

Most spots across Chester County over the last 7 days have received between 1" to over 3" of rain. Here in East Nantmeal we have received 3.07" of rain since last Thursday. Spots across Southern Chester County have been generally on the lower side of these amounts with more to the North across the county. A nice stretch of weather through the weekend is on the way. Relatively low humidity and temps not far from normal to slightly below. Chester County daily records for today: High 100 degrees at West Chester (1988) / Low 50.6 at Nottingham (2014) / Rainfall 2.75" at Phoenixville (2019)

Most spots across Chester County over the last 7 days have received between 1" to over 3" of rain. Here in East Nantmeal we have received 3.07" of rain since last Thursday. Spots across Southern Chester County have been generally on the lower side of these amounts with more to the North across the county. A nice stretch of weather through the weekend is on the way. Relatively low humidity and temps not far from normal to slightly below. Chester County daily records for today: High 100 degrees at West Chester (1988) / Low 50.6 at Nottingham (2014) / Rainfall 2.75" at Phoenixville (2019)

Widespread 90's again yesterday. In fact yesterday was the first time I have recorded back to back 90 degree days in East Nantmeal since July19-21st in 2020. Another shot at 90 today...but with a strong front sweeping in from the west by late PM or early evening it may keep some folks just below 90 degrees. Strong storms are again possible this evening and then a great stretch of weather with temperatures even a little below normal for Thursday and Friday. Of note on average tomorrow the 18th is the warmest day of the year...for those who love winter average temps begin a slow fall that will continue until the coldest day of the year on January 21st. Daily Chester County records for today: High 101 degrees at West Chester (1988) / Low 42 degrees at Devault (1954)/ Rain 2.61" at Phoenixville (2018)

Widespread 90's again yesterday. In fact yesterday was the first time I have recorded back to back 90 degree days in East Nantmeal since July19-21st in 2020. Another shot at 90 today...but with a strong front sweeping in from the west by late PM or early evening it may keep some folks just below 90 degrees. Strong storms are again possible this evening and then a great stretch of weather with temperatures even a little below normal for Thursday and Friday. Of note on average tomorrow the 18th is the warmest day of the year...for those who love winter average temps begin a slow fall that will continue until the coldest day of the year on January 21st. Daily Chester County records for today: High 101 degrees at West Chester (1988) / Low 42 degrees at Devault (1954)/ Rain 2.61" at Phoenixville (2018)

Below is the average summertime (June thru August) average temperatures by decade for Chester County since the 1890's. The hottest complete decades were back in the 1930's and 1940's. We are only 3 years in to the 2020's but so far we are tied for 2nd warmest decade but plenty of years left to work on this decade.

Here in East Nantmeal we exceeded 90 degrees for just the 2nd time this year (90.5) with the 2nd hottest day of the year behind only the 91.9 on June 22nd. Other area high temps yesterday included Brandwine Airport (95.0) Chester Springs (94.9 ) and Warwick Twp. (94.0). Today will be even hotter with widespread mid to upper 90's. Shower chances increase later today and again tomorrow as a cold front moves through later Wednesday. It will turn much more comfortable by Thursday with temperatures closer to average for what is normally our warmest week of the year. Chester County Records for today: High 100 degrees at Coatesville (1900) / Low 46 degrees also at Coatesville (1929) / Rain 2.66" at Kennett Square (1911)

Here in East Nantmeal we exceeded 90 degrees for just the 2nd time this year (90.5) with the 2nd hottest day of the year behind only the 91.9 on June 22nd. Other area high temps yesterday included Brandwine Airport (95.0) Chester Springs (94.9 ) and Warwick Twp. (94.0). Today will be even hotter with widespread mid to upper 90's. Shower chances increase later today and again tomorrow as a cold front moves through later Wednesday. It will turn much more comfortable by Thursday with temperatures closer to average for what is normally our warmest week of the year. Chester County Records for today: High 100 degrees at Coatesville (1900) / Low 46 degrees also at Coatesville (1929) / Rain 2.66" at Kennett Square (1911)

Most spots except the higher elevations hit 90 degrees yesterday more of the same today and then even hotter Monday and Tuesday with mid to upper 90's especially in lower spots. Cold front slices thru by Wednesday night with temps close to normal but most importantly lower humidity by late week. Chester County records for today: High 102 degrees in Phoenixville (1954) / Low 50 degrees at Devault (1960)/ Rain 4.00" at West Grove (1975)

Most spots except the higher elevations hit 90 degrees yesterday more of the same today and then even hotter Monday and Tuesday with mid to upper 90's especially in lower spots. Cold front slices thru by Wednesday night with temps close to normal but most importantly lower humidity by late week. Chester County records for today: High 102 degrees in Phoenixville (1954) / Low 50 degrees at Devault (1960)/ Rain 4.00" at West Grove (1975)

The West Chester Data set has a ton of gaps or corrupted data (see raw data below) on the NCEI Bias calculations. It appears that about 32% of the years from 1893 to 2017 are impacted.

Hey Charlie...of note when reviewing the Coatesville 2W data from 1983 to 2007. There seems to be no adjustments between raw and adjusted etc. for any years....but the raw numbers unlike the Coatesville 1 SW data seems to be off almost every month and generally warmer than the actual observations. One example is January 1985. The below is the observations and this matches the data set I have been using. This averages out to a 24.2 average temperature for the month but the NCEI data lists the raw average for the month as 25.0. Any thoughts??

Hey guys thanks to Charlie (Chubbs) I was just able to figure out how to find detailed NCEI adjustments for individual stations in Chester County. I am starting with the original Coatesville 1SW station . Below is an analysis of the actual/raw average annual temperature data vs. the NCEI altered data for Coatesville 1SW from 1894 thru 1982. As discussed before NCEI has multiple reasons stated to support these adjustments. (Time of observation/ station moves/ equipment or siting issues etc.) But of interest the chilling adjustments were consistently applied to the first 71 years (1894 thru 1971) The greatest chilling adjustments were applied to the oldest data with at least 2 degrees F adjustments made from 1897 thru 1922 along with 1931-35 and 1941-45. The end result with the altered data (red) flips what the raw data (blue) clearly shows as cooling trend during those years....to now a clear warming trend. The greatest overall chilling adjustments were made to the October thru December months. But 100% of all months for all years were chilled for April through October. February had the least number of months chilled with 75 of the 89 months while January and March both saw chilling adjustments to 78 of the 89 months on record.

Below is the impact of the altered data for Coatesville 1SW from 1894 thru 1982. The chilling adjustments were consistently applied to the first 71 years (1894 thru 1971) The greatest chilling adjustments were applied to the oldest data with at least 2 degrees F adjustments made from 1897 thru 1922 along with 1931-35 and 1941-45. The end result with the altered data flips what the raw data clearly shows as cooling trend during those years....to now a clear warming trend. The greatest overall chilling adjustments were made to the October thru December months. But 100% of all months for all years were chilled for April through October. February had the least number of months chilled with 75 of the 89 months while January and March both saw chilling adjustments to 78 of the 89 months on record.

Very disappointing rain totals across the county yesterday and today. Most spots were under 0.10" of rain. There are still some rain chances today but dry does beget dry so not real optimistic. We "dry out" tomorrow and start to heat up with widespread 90's again likely by Monday through Wednesday before sharply cooler to near to below normal by Thursday. Chester County records for today: High 97 degrees at West Chester and Coatesville (1954)/ Low 50 degrees at Phoenixville (1974) / Rain 6.20" at Devault (1975)

Very disappointing rain totals across the county yesterday and today. Most spots were under 0.10" of rain. There are still some rain chances today but dry does beget dry so not real optimistic. We "dry out" tomorrow and start to heat up with widespread 90's again likely by Monday through Wednesday before sharply cooler to near to below normal by Thursday. Chester County records for today: High 97 degrees at West Chester and Coatesville (1954)/ Low 50 degrees at Phoenixville (1974) / Rain 6.20" at Devault (1975)

Thanks Charlie this is great! I have just started downloading this data and will add it to my data set and use it for more analytics and review. Thanks again!

We had some light rain earlier with more just entering the county from the south. We should see a few rounds of rain some heavy through tonight into tomorrow morning. Many spots could pick up at least 1" to 2" of rain - higher amounts are possible. With the rain temps will be a bit below average (83 degrees) today. We dry out and heat up again by Sunday. Chester County records for today: High 104 degrees at Phoenixville (1936) / Low 45 degrees also at Phoenixville (1945) / Rain 4.02" at KMQS Coatesville Airport (2013)