ChescoWx

"needs" to be "corrected" with estimated homogenization adjustments

The state of Delaware study findings are now up and available at https://chescowx.com/raw-vs-ncei-delaware/

Agree 100% the actual data is clear and consistent across the entire USA not just Yellow Medicine or Chester County.

Since this concerns the impact of Climate Change across the entire USA and not just one individual county - I am happy to share the below study of Actual raw temperature data vs. the NCEI adjusted data for the entire Continental USA. Please find the below combined US 48 state findings (PA and NY are already posted an online). For the full reports and individual state and county findings as they are released over the next 46 days please check out https://chescowx.com/raw-vs-ncei-state-by-state/ THE MAIN STUDY FINDINGS FOR THE CONTINENTAL USA The NWS raw trained observer temperature record shows no significant warming at all in the contiguous 48 states since 1895!! (+0.01 °F per decade). In fact the temperature trend lines across the entire USA are basically flat from 1895 through 2026! However by contrast NCEI's adjusted temperatures show significant warming in the contiguous 48 states since 1895 (+0.18 °F per decade). That difference between the two trend lines is statistically significant. Combining the 48 statewide records of actual readings, each weighted by the state's land area, gives +0.01 °F per decade from 1895 to 2025 (95% range -0.04 to +0.05), about +0.1 °F in total. NCEI's published contiguous-U.S. series gives +0.18 °F per decade (range +0.12 to +0.23), about +2.3 °F in total. Of note NCEI's adjusted temperatures are lower than the actual readings in every single decade from the 1890s through the 1990s. To dig deeper into these continental US wide findings including please check out https://chescowx.com/raw-vs-ncei-co ntiguous-us/

Our 2nd state in the Nationwide Actual Raw vs. NCEI Adjusted Study for New Jersey is now available for review and download. For much more detail including study design, by decade breakdowns, county by county maps and breakdowns for all State Counties that compare actual vs NCEI trends for each NJ county please go to https://chescowx.com/raw-vs-ncei-state-by-state/ The main finding The NWS raw trained observer temperatures show significant warming in New Jersey since 1895 (+0.15 °F per decade). NCEI's adjusted temperatures show about twice as much warming (+0.31 °F per decade). That difference between the two trend lines is statistically significant. Averaging what New Jersey's observers actually recorded, county by county and weighted by county area, gives +0.15 °F per decade from 1895 to 2025 (significant), about +2.0 °F in total. NCEI's published statewide series gives +0.31 °F per decade (significant), about +4.1 °F in total. NCEI's series runs 1.4–1.7 °F below the actual readings in every decade from 1895 through the 1940s; 0.7–1.1 °F below them in the 1950s to 1970s; 0.4–0.6 °F below them in the 1980s and 1990s; within 0.2 °F of them from 2000 on. NCEI's adjusted temperatures are lower than the actual readings in every decade from the 1890s through the 1990s.

I really can't remember such a great stretch of weather in a long time! The GFS for East Nantmeal keeps us mild through the first week of November

Today we should see highs from low 60's in ridge locations to the mid 60's in valley spots with lows tonight in the low to mid 40's. Highs will reach well into the 60's to near 70 degrees through Friday which is 5 to 9 degrees above normal before we chill down a bit to near normal by Saturday for the trick or treaters, but by Sunday we warm to the mid 60's which is 4 to 8 degrees above normal. It has been a while since our last rain but a chance of a shower or two next Wednesday according to the ChescoWx model. Of note 14 years ago today back in 2012 the Chester County Area was at the start of a 3 day storm that left as much as 6.97" of rain at the Nottingham DEOS. This was the remnants of Hurricane Sandy which tracked within about 20 miles of the county.

Today we should see highs from low 60's in ridge locations to the mid 60's in valley spots with lows tonight in the low to mid 40's. Highs will reach well into the 60's to near 70 degrees through Friday which is 5 to 9 degrees above normal before we chill down a bit to near normal by Saturday for the trick or treaters, but by Sunday we warm to the mid 60's which is 4 to 8 degrees above normal. It has been a while since our last rain but a chance of a shower or two next Wednesday according to the ChescoWx model. Of note 14 years ago today back in 2012 the Chester County Area was at the start of a 3 day storm that left as much as 6.97" of rain at the Nottingham DEOS. This was the remnants of Hurricane Sandy which tracked within about 20 miles of the county.

A certain local PA MET just messaged me on X and said the number that stunned him most in the study was the flip from only 19% of counties showing any statistical warming in PA with raw data to once we include the NCEI adjustments....to seeing the impressive jump to an overwhelming 95% of all counties. To quote him "things that make you go hmmm!"

Our first state of the Nationwide Study is now complete. First up is the state of Pennsylvania. We will release one state per day over the next 47 days. For much more detail including study design, by decade breakdowns, county by county maps and breakdowns for all State Counties that compare actual vs NCEI trends for each state please go to https://chescowx.com/raw-vs-ncei-state-by-state/ If interested in seeing your state next up on the list please let me know and we will do our best to release that state within 2 days. Thanks again! The main finding for Pennsylvania is the actual readings show no warming at all since 1895! NCEI's published series shows significant warming. Averaging what Pennsylvania's observers actually recorded, county by county and weighted by county area, gives a flat statewide trend from 1895 to 2025 (-0.02 °F per decade, not significant). NCEI's published statewide series warms +0.17 °F per decade, about 2.2 °F in total. The two diverge at +0.19 °F per decade (p < 0.001). NCEI's series runs 1.5–1.8 °F below the actual readings in every decade from 1895 through the 1940s, about 1.0 °F below in the 1950s and 0.7 °F in the 1960s. It is within about 0.35 °F from the 1970s on. The short version NCEI's 67 counties add up to its statewide series. Weighting NCEI's county values by area reproduces its Pennsylvania statewide series within 0.03 °F in every year. Building the state from counties is therefore a like-for-like comparison. The actual readings show no significant statewide trend. They give -0.02 °F/decade (95% range -0.10 to +0.06). NCEI's series gives +0.17 (range +0.10 to +0.24). The ranges do not overlap. The two trend lines are significantly different. The gap between NCEI's statewide series and the actual readings grows at +0.19 °F per decade (95% range +0.15 to +0.22, p < 0.001), so NCEI's adjustments add a statistically significant amount of warming. County by county, NCEI's adjustments add significant warming to the trend in 25 of 43 counties (58%) and significant cooling in 0. NCEI cools the early record in nearly every county. From 1895 through the 1940s, NCEI's county series is cooler than the actual readings in 90–100% of counties in each decade, by a median of about −0.9 to −1.7 °F. The share is 77–81% in the 1950s–70s, about 53% in the 1980s and 1990s, and about 31–33% after 2000. Recent decades match. From 2000 on, the median county difference is about 0.0 °F. NCEI is cooler than the actual readings in 32% of county-decades and warmer in 41%. County verdicts flip toward warming. 43 counties have long enough raw records for a trend. In the actual readings, 8 (19%) show significant warming, 31 (72%) no significant trend, and 4 (9%) significant cooling. In NCEI's county series, 41 (95%) show significant warming and none show cooling. NCEI's trend is steeper in 42 of 43 counties; Philadelphia is the only exception. The 1930s lose their warmth. In the actual readings the 1930s average +0.9 °F against the 1991–2020 normal, the warmest decade before the 2020s. NCEI puts the 1930s at -0.7 °F. Chester County fits the pattern. The actual readings from Chester County's GHCN-Daily stations give -0.01 °F/decade (not significant), against +0.24 °F/decade (significant) for NCEI's Chester County series over the same years.

10 of the 22 Chesco area stations most at relatively higher elevations have yet to record a below freezing temp. Here in EN I usually don't see a freeze till November and this year looks like no exception. Of note I receive the least amount of freezing days across these observation sites.

10 of the 22 Chesco area stations most at relatively higher elevations have yet to record a below freezing temp. Here in EN I usually don't see a freeze till November and this year looks like no exception. Of note I receive the least amount of freezing days across these observation sites.

Looking ahead at the ensemble models it looks like above normal temperatures continue over the next month. That said keep in mind that our average normal temperatures continue to drop quickly over this timeframe. It also looks to be wetter than normal. Some models are even hinting at some accumulating snow by the week before Thanksgiving.

Looking ahead at the ensemble models it looks like above normal temperatures continue over the next month. That said keep in mind that our average normal temperatures continue to drop quickly over this timeframe. It also looks to be wetter than normal. Some models are even hinting at some accumulating snow by the week before Thanksgiving.

Today we should see highs from low 60's in ridge locations to the mid 60's in valley spots. This is about 3 degrees above normal with lows tonight in the mid 30's to low 40's. Temperatures will be near normal Wednesday but by Thursday and Friday we warm to near 70 degrees which is 6 to 10 degrees above normal, before we return to near normal by Saturday. It has been a while since our last rain but our next soaking rain looks to arrive Monday with around 1.0" possible according to the ChescoWx model. Of note 14 years ago today back in 2012 the Chester County Area was at the start of a 4 day storm that left as much as 6.16" of rain at West Chester 2NW. This was the remnants of Hurricane Sandy which tracked within about 20 miles of the county.