ChescoWx

Made it up to 88.7 on the VP2 - last 90+ was way back on June 30th/ But did touch 89.2 on Ambient and up on the roof the Tempest did hit 90.7 for the 7th time this summer (roof mounting can get me my 90's!)

Has August been off to a chilly start? yes! the 1st 4 days are the coolest start to August in NWS history since 1894 in the Western Chester County philly burbs..of course that means some hot days ahead of us to help even us out before months end - below are the top 10 coldest starts to August

Kind of interesting with today's Hi/Lo splits of 73.4/58.6 the average temperature for the 1st 2 days of August have been the chilliest first 2 August days on record in Western Chester County PA since NWS COOP records began back in 1894 - average temp of 65.2 which is 9.8 degrees below normal....which of course means some nice heat on the way next week even if you are not a model watcher.....

Today will set a new record low max temp (68.7) for Western Chester County PA breaking the old mark of 73 set in 2013...and the earliest August high temp below 70 degrees since August 3, 1921- 100 years ago! Also 0.32" of rain today

July temp departures across the entire US

Here in Western Chester County PA - we finished the month just a tick below normal - making this the 3rd below normal month (February/May/July) over the 1st 7 months of 2021. Allentown (ABE) also recorded a below normal month but for ABE that is their 4th below normal month so far in 2021.

This morning's low of 55.4 was our coolest since the 52.0 on June 25th

Looks like both down the shore in Sea Isle City and up in NW Chesco - both socked in pretty good with clouds....despite that still suspect we see some firing across the area this PM - Hoping the Phillies get in their twin bill today!

I am not sure who the moderators are here....but I was running a similar thread on another area weather site and I have been banned for posting what they deemed as controversial and divisive content - which is the same as appears in this thread about Western Chester County PA data. I want to be sure I am not offending anyone here - I put this under it's own thread to make sure if you find it tiring or think what I post is looney tunes you can go to another thread. I as always try to keep this fact based with data analytics when appropriate. Feel free to PM me if you do not feel comfortable replying in this thread if you would like me to stop posting this data. This site has always been very easy going and open to opinions but maybe I have misread the environment where in some cases data or opinions are not always welcome. Thanks to all! Paul

90+ readings at all reporting stations across Eastern PA with the exceptions of Mount Pocono / Lehighton / KMQS - Coatesville / Pennridge and of course East Nantmeal at 86.9 - 22nd 90+ day at PHL while KMQS /KPTW and East Nantmeal combined with 21 such days

Another great comment on my data analysis....I love when professional METS weigh in - another brilliant comment!! This is Gold!!!! "I don't see how you can do that unless there is a proven calibration issue. Accuracy of instrumentation comes down to whether it is calibrated correctly or not. Adjust the sensor, not the dataset"

This latest analysis has certainly sparked some discussion as an example one professional MET just weighed in on my twitter feed with - Brilliant!!! "I'd have to look into that. Very fine line there with adjusting past recorded data that was once official record unless there was a known sensor problem. Because then it can be viewed as a political or narrative-based adjustment"

I clearly have some time on my hands this week....so I dove deeply into the data and as a 1st set of analysis. I have now completed an annual temperature trend analysis of all available NWS Coop sites across Chester County PA. Seven NWS COOP sites were included in the review with the 1st analysis examining the reported average annual temperatures at all locations across the County with a comparison to the annual temperatures and subsequent warming observed with the Philadelphia data set. The NWS COOP sites included in this analysis were Coatesville/Chesco / West Chester / Phoenixville / Devault / Chadds Ford / Honey Brook and Glenmoore observation sites. I have attached all of the analysis and charts below - the clear conclusion 6 of the 7 sites are consistent and well aligned. All sites have at least 60 years of 100% complete consecutive daily obs/data. While the pooled SE PA Observations clearly show warming....we cannot find anywhere close to that degree of warming across the vast majority (85%) of the entire Chester County COOP stations. Some key findings: 4 of the 7 sites (ChescoWx / West Chester/ Phoenixville and Devault show no warming at all over the analyzed period... but actually some slight cooling....these sites are not aligned at all with the warming seen outside of Chester County with the Philadelphia observations 2 of the 7 sites (HoneyBrook and Chaddsford) with the shortest data years (60) show some slight warming but again the degree of warming is nothing like that seen with the Philadelphia data Only 1 site of the 7 observation sites shows warming that is comparable to the Philadelphia obs - that would be the Glenmoore site

I just started to analyze the West Chester NWS COOP data today - I bumped up the 2 longest running long term weather COOP sites in Chester County - Coatesville and West Chester PA against the Philadelphia long term data for annual average temperatures at all 3 locations (I have scrubbed out any non-comparative years so the comparison below is all years from 1894 to 2016) The Chester County long term sites are nicely aligned and are clearly NOT warming (Blue West Chester and Red Coatesville) (this is not cherry picking of data - I am simply using the longest continuous data sets in Chester County PA with 123 years of data without any missing days for analysis) ....now the overlaid Philadelphia data as you can clearly see is much more supportive of the warming posit and shows clear sharp warming (green trend line) . For full transparency I should mention that on another forum an excellent poster had previously informed me it has been determined that Coatesville had a warm bias earlier in the 20th century and expect I will soon hear that it now appears based on this data that the West Chester PA COOP observer suffered the same fate as the Coatesville observers with similar poor instrument/technical issues that now requires that both the Coatesville and West Chester observations be cooled in the combined pooled data set to better show the true warming trend.

Of course KLGA suffers from the same problematic heat island issues of most major airports in the US.....which always is a cause for pause - although the post obs adjustments to historical obs to "correct" the old warm bias is prevalent.....but are these adjustments correct? Are they adjusting to help support the story? All issues for those way beyond my pay grade.....

With this AM's 59.7 low this marks the 1st time we have had 3 straight low's in July in the 50's since July 7-9, 2018. For the month of July of course still no 90 degree days here in Western Chesco and we are now just a tick above average temps for the month.

Through 1st 18 days of July this is the 11th warmest (75.1 avg. temp) start to July in Western Chesco with the top 5 being 78.3 (1988) / 76.7 (2012) / 76.6 (2013) / 76.5 (1994) / 76.1 (2006)

The good news for those that hate the heat is that tomorrow on average is the warmest day of the year - at least in Western Chesco.....we then begin the slide to the coldest average day - which is January 21st - stay cool my friends!!

Wow! you are deeper into the heat island than even KPHL.....stay cool my friend!! Still only 3 days over 90 in the Western burbs