ChescoWx

Charlie again the above does not answer the questions as I have the above data. The question is why were each and every Chester County station cooled to even lower than Coatesville ever reported? You mention above that Coatesville had a "cool bias" - then why give all of the Chester County stations the what you call "a well deserved bias adjustment" to make them all cooler". This bias adjustment resulted in actually cooling the all Chester County station average to cooler than the station (Coatesville) with the cool bias you mentioned above do you see my point?? This is in fact what happened in 73 of 77 years between 1895 and 1970 - as the average NCEI temperature for the county was lowered to below any averages reported by any station including Coatesville.

Charlie not crickets you have simply only showed the cumulative adjusted data...without any data that supports such post hoc adjustments across every single available station in Chester County PA. Did they use another counties data as the control? Berks? Montgomery? Lancaster? Where is proof that 95% of the county obs required after the fact adjustments?

And let me guess you think they respect you? I have been recommended by Tony Gigi with the NWS in Mount Holly to be interviewed by the Philadelphia Inquirer and my data has been used consistently by the NWS as a trained NWS spotter and the Inquirer for my detailed and stringent compliance with 20 plus years of daily weather observations. Now you go.....

Timmy you sure have insults but as always come up a wee bit short on facts and data! Psst by the way my weather station data and equipment has as always been continually verified by MADIS with the latest note being "These values are within the acceptable range. This probably means that your sensor is sited correctly and is calibrated correctly"

Hey bdgwx how about showing me the analysis specific to Chester County PA that details what station or area they used as the control to make the after the fact adjustments to the NWS cooperative data for 95% of the years from 1895 thru 1970??

Right!! So again what is the scientific explanation in Chester County PA for why they adjusted average temperatures down to a mark not just down to the lowest recorded station value....but took them all down below any available station obs for 73 of 77 years? Does that feel right to you?

Of course not an answer from you Tim...call me stunned!! LOL

GFS ensemble catching on to snow chances next week...

Some really interesting statistics for Chester County PA that really makes you question some of the historical temperature trending data we see. Incredibly the NCEI data set for Chester County PA. Of note from 1895 through 1970 (77 years) the reported average Chester County PA temperatures for 73 of those 77 (95%) years is now reported as lower than any available reporting site in the county in those years. So are we to assume all stations in Chester County were faulty and or needed post hoc adjustment for 95% of the reporting observations through 1970??

Some really interesting statistics for Chester County that really makes you question some of the historical temperature trending data we see. Incredibly the NCEI data set for Chester County PA. Of note from 1895 through 1970 (77 years) the reported average Chester County temperatures for 73 of those 77 (95%) years is now reported as lower than any available reporting site in the county in those years. So are we to assume all stations in Chester County were faulty for 95% of the reporting observations through 1970??

Some really interesting statistics for Chester County that really makes you question some of the historical temperature trending data we see. Incredibly the NCEI data set for Chester County PA. Of note from 1895 through 1970 (77 years) the reported average Chester County temperatures for 73 of those 77 (95%) years is now reported as lower than any available reporting site in the county in those years. So are we to assume all stations in Chester County were faulty for 95% of the reporting observations through 1970??

Sunny skies should be the rule through Thursday. Chillier today with temps remaining in the 30's but warming trend starts tomorrow topping out well into the 50's by Saturday. Shower chances increase on Sunday night and much colder air appears likely with even some wintry weather chances next week. Records for today: High 66 (2008) / Low 6 below (1895) / Precipitation 3.00" (1896) / Snow 12.3" (2010)

Sunny skies should be the rule through Thursday. Chillier today with temps remaining in the 30's but warming trend starts tomorrow topping out well into the 50's by Saturday. Shower chances increase on Sunday night and much colder air appears likely with even some wintry weather chances next week. Records for today: High 66 (2008) / Low 6 below (1895) / Precipitation 3.00" (1896) / Snow 12.3" (2010)

In comparing the NCEI average post observation temperature adjustments applied to the actual recorded averages recorded by the NWS Chester County Coop data show the average temperature data was adjusted downward every single year from 1895 through 2004 or for 110 consecutive years. The greatest adjustments were reductions in average temperatures of 2.76 degrees in 1945 / 2.69 degrees in 1943 /2.62 degrees in 1942 / 2.58 degrees in 1951. Conversely. In the 18 years since 2005 every year has been adjusted upwards with the exception of 2019 with the greatest adjustments upward to temperatures being applied to 2018 +1.87 degrees and 2005 with a +0.66 degree adjustment. https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/time-series/PA-029/tavg/ytd/12/1895-2023

In comparing the NCEI average post observation temperature adjustments applied to the actual recorded averages recorded by the NWS Chester County Coop data show the average temperature data was adjusted downward every single year from 1895 through 2004 or for 110 consecutive years. The greatest adjustments were reductions in average temperatures of 2.76 degrees in 1945 / 2.69 degrees in 1943 /2.62 degrees in 1942 / 2.58 degrees in 1951. Conversely. In the 18 years since 2005 every year has been adjusted upwards with the exception of 2019 with the greatest adjustments upward to temperatures being applied to 2018 +1.87 degrees and 2005 with a +0.66 degree adjustment. https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/time-series/PA-029/tavg/ytd/12/1895-2023

Since 2000 using the 1991-2020 average temperature for December through February which is 32.8 degrees here in Chester County - we have seen 10 winters that have averaged below normal temps.... but none have been below normal since the DFJ of 2015 - winters with below normal DJF have been 2000/2001/2003/2004/2005/2009/2010/2011/2014/2015

Since 2000 using the 1991-2020 average temperature for December through February which is 32.8 degrees here in Chester County - we have seen 10 winters that have averaged below normal temps.... but none have been below normal since the DFJ of 2015 - winters with below normal DJF have been 2000/2001/2003/2004/2005/2009/2010/2011/2014/2015

Most spots were in the 20's to start the day with the lowest I could find in both Warwick Township and down in Kennett Square at 22 degrees. Tomorrow and Wednesday look to be close to normal temps while the rest of the week should see above normal temps rising into the 50's toward the weekend. Next week should see a return to a stretch of below normal temps. Records for today: High 66 (1991) / Low 11 below (1918) / Precipitation 1.90" (1907) / Snow 12.0" (1907)

Our beautiful stretch of February weather looks to continue for most of the next week with average to above temps and sunshine much of the upcoming week. The rumored pattern change to colder....if it occurs is still at least 10 or more days away. Records for today: High 63 (1991) / Low 1 below (1898) / Precipitation 1.35" (1920) / Snow 9.1" (1995)

Go Phillies!!!!!

Our beautiful stretch of February weather looks to continue for most of the next week with average to above temps and sunshine much of the upcoming week. The rumored pattern change to colder....if it occurs is still at least 10 or more days away. Records for today: High 63 (1991) / Low 1 below (1898) / Precipitation 1.35" (1920) / Snow 9.1" (1995)

Things have been slower on the work front so finally had a chance to download and consolidate all 23 available Chester County climate data sites (see below table for detail). All stations have been weighted equally for all years they were reporting data . I then compared the all average temperature by decade data to the NCEI NOAA Chester County PA average temperatures reported by decade. As expected the greatest downward post observation adjustments to the data were during the warmest raw data reported decades of the 1930's and 1940's with a gradual reduction in cooling that started in the 1950's finally resulting in what are now warming adjustments during the most recent 2 decades.

Things have been slower on the work front so finally had a chance to download and consolidate all 23 available Chester County climate data sites (see below table for detail). All stations have been weighted equally for all years they were reporting data . I then compared the all average temperature by decade data to the NCEI NOAA Chester County PA average temperatures reported by decade. As expected the greatest downward post observation adjustments to the data were during the warmest raw data reported decades of the 1930's and 1940's with a gradual reduction in cooling that started in the 1950's finally resulting in what are now warming adjustments during the most recent 2 decades.

Back to back snowstorms "only" 2 weeks away.... as that well respected MET says....delayed but not denied!!

Happy Groundhog Day to those that celebrate! No shadow this year so spring is around the corner....or maybe not! Some light rain overnight with County totals including East Nantmeal 0.13" / Atglen 0.11" / Chester Springs 0.14" / Glenmoore 0.14" / Devault 0.11" / West Chester 0.12" / London Grove 0.11" and Kennett Square 0.09", Looks like some great winter weather on tap for much of the upcoming week with sunny skies and seasonably chilly but not cold temps. A nice break after all the drearies! Records for today: High 60 (1967) / Low 6 below (1918) / Precipitation 1.69" (1897) / Snow 8.5" (1897)