ChescoWx

Over the last 25 years, Since 2001 PHL Airport warming is statistically clear in both its raw and NOAA-adjusted records. By comparison here in the nearby philly burbs of Chester County PA our warming is less or about 40% smaller than the PHL heat island. The warming across Chester County has not been statistically significant using either the raw or NCEI adjusted data over the last 25 years! The gap between the two (+0.34°F/decade) is consistent with an urban/airport effect. One more point of interest: NOAA’s data adjustment only trims PHL’s trend slightly (0.86 → 0.78). So, importantly whatever UHI warming that is in the airport record over this window, the homogenization is removing very little of it!

Over the last 25 years, Since 2001 PHL Airports warming is statistically clear in both its raw and NOAA-adjusted records. By comparison Chester County’s warming is about 40% smaller and not statistically significant using either the raw or NCEI adjusted data. The gap between the two (+0.34°F/decade) is consistent with an urban/airport effect. One more point of interest: NOAA’s data adjustment only trims PHL’s trend slightly (0.86 → 0.78). So, importantly whatever UHI warming that is in the airport record over this window, the homogenization is removing very little of it!

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 upper 30's to low 40's. It should be one of the better weather weeks of the year with almost no chance of rain. By Sunday morning we should see lows in the low to mid 30's with a freeze possible in the colder valleys! Temperatures will be near normal through Friday but this weekend we drop to about 5 degrees below normal, before we return to near normal by Monday. Of note 82 years ago today back in 1944 the Chester County Area was at the start of a 2 day storm that left as much as 1.63" of rain at Phoenixville 1E. This was the remnants of an unnamed hurricane which tracked within about 120 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 upper 30's to low 40's. It should be one of the better weather weeks of the year with almost no chance of rain. By Sunday morning we should see lows in the low to mid 30's with a freeze possible in the colder valleys! Temperatures will be near normal through Friday but this weekend we drop to about 5 degrees below normal, before we return to near normal by Monday. Of note 82 years ago today back in 1944 the Chester County Area was at the start of a 2 day storm that left as much as 1.63" of rain at Phoenixville 1E. This was the remnants of an unnamed hurricane which tracked within about 120 miles of the county.

I have added some additionals stations within 3 miles of the Chester County border to enhance our climate data. The support and rationale is included in our latest study on the website. Thanks! https://chescowx.com/chester-county-area-3-mile-rule/

I have added some additionals stations within 3 miles of the Chester County border to enhance our climate data. The support and rationale is included in our latest study on the website. Thanks! https://chescowx.com/chester-county-area-3-mile-rule/

Over the last 25 years Chester County has shown minor but not significant warming....however PHL Airport is as always off to the races with warming.

No data is of course perfect but it is the best historical validated data we have from the time of record

Almost a 20 degree spread in morning low temperatures today within just a few miles across the area this morning. Elevation and terrain impacts.

Almost a 20 degree spread in morning low temperatures today within just a few miles across the area this morning. Elevation and terrain impacts.

The minute we put the words scientific and consensus together we know it is fake news!

Today we should see highs from mid 60's in ridge locations to the low 70's in valley spots with lows tonight in the upper 30's to low 40's. It should be one of the better weather weeks of the year with almost no chance of rain. By Saturday morning we should see lows in the low to mid 30's with a freeze possible in the colder valleys! Temperatures will be near normal through Thursday but by Friday we drop to about 5 degrees below normal, before we return to near normal by Sunday. Of note 7 years ago today back in 2019 Chester County was at the start of a 3 day storm that left as much as 1.56" of rain at Coatesville 1E. This was the remnants of Tropical Storm Nestor which tracked within about 190 miles of the county.

Today we should see highs from mid 60's in ridge locations to the low 70's in valley spots with lows tonight in the upper 30's to low 40's. It should be one of the better weather weeks of the year with almost no chance of rain. By Saturday morning we should see lows in the low to mid 30's with a freeze possible in the colder valleys! Temperatures will be near normal through Thursday but by Friday we drop to about 5 degrees below normal, before we return to near normal by Sunday. Of note 7 years ago today back in 2019 Chester County was at the start of a 3 day storm that left as much as 1.56" of rain at Coatesville 1E. This was the remnants of Tropical Storm Nestor which tracked within about 190 miles of the county.

We saw 2 stations across the Chesco area record their first freeze. Below is some season lows to date history through today.

We saw 2 stations across the Chesco area record their first freeze. Below is some season lows to date history through today.

With some lower spots with a chance to have their first freezing temperature attached is the average, earliest and latest dates on record.

With some lower spots with a chance to have their first freezing temperature attached is the average, earliest and latest dates on record.

Of note 54 years ago today back in 1972 Chester County was experiencing a rare early season snow event that left as much as 3.0" of snow at Morgantown. After a little rain yesterday with between 0.1" to 0.3" falling, today our high temperatures were reached at midnight. Daytime temperatures today will remain in the upper 40's to Low 50's which is about 10 to 15 degrees below normal daytime highs for mid-October. The NWS has issued a freeze warning for tonight with temperatures near freezing or below in valley locations to just above freezing on the ridge tops. Temperatures will run 4 to 8 degrees below normal through Monday before we return to near normal by Tuesday, but by Saturday we drop to about 4 degrees below normal. We look to stay dry through Saturday according to the ChescoWx model.

Of note 54 years ago today back in 1972 Chester County was experiencing a rare early season snow event that left as much as 3.0" of snow at Morgantown. After a little rain yesterday with between 0.1" to 0.3" falling, today our high temperatures were reached at midnight. Daytime temperatures today will remain in the upper 40's to Low 50's which is about 10 to 15 degrees below normal daytime highs for mid-October. The NWS has issued a freeze warning for tonight with temperatures near freezing or below in valley locations to just above freezing on the ridge tops. Temperatures will run 4 to 8 degrees below normal through Monday before we return to near normal by Tuesday, but by Saturday we drop to about 4 degrees below normal. We look to stay dry through Saturday according to the ChescoWx model.

Not that much rain so far today here in Chesco

Enjoy today! Highs should reach the mid to upper 70's which is about 10 degrees above normal. A strong cold front will cross the region tonight with a line of storms during the evening hours. Temperatures will fall from the upper 50's at midnight to lows in the upper 40's by morning. Behind the front is some very chilly air for mid-October. Temperatures during the day tomorrow will struggle to escape the 40's across the ridges with low 50's in the valleys. By Sunday morning we should see lows in the mid 30's with a freeze possible in the colder valleys! Temperatures will run well below normal through Monday before we return to near normal by Tuesday. We look to stay dry through the new work week according to the ChescoWx model. In weather history on this date in 2009 the county high only averaged 41 degrees...the coldest October 16th since records began in 1890!

Enjoy today! Highs should reach the mid to upper 70's which is about 10 degrees above normal. A strong cold front will cross the region tonight with a line of storms during the evening hours. Temperatures will fall from the upper 50's at midnight to lows in the upper 40's by morning. Behind the front is some very chilly air for mid-October. Temperatures during the day tomorrow will struggle to escape the 40's across the ridges with low 50's in the valleys. By Sunday morning we should see lows in the mid 30's with a freeze possible in the colder valleys! Temperatures will run well below normal through Monday before we return to near normal by Tuesday. We look to stay dry through the new work week according to the ChescoWx model. In weather history on this date in 2009 the county high only averaged 41 degrees...the coldest October 16th since records began in 1890!

Of note 72 years ago today back in 1954 Chester County was on the last day of a 2 day storm that left as much as 1.60" of rain at Coatesville 1SW. This was the remnants of Hurricane Hazel which tracked within about 80 miles of the county. Today we should see highs in the upper 60's to near 70 which is about 5 degrees above normal with lows tonight in the 50's. Temperatures will run about 11 degrees above normal Friday but by Saturday we drop to 4 to 9 degrees below normal, before we return to near normal by Tuesday. By Sunday morning lows will be in the low to mid 30's with a freeze possible in the colder valleys! Our best chance of rain is Friday with around 0.30" according to the ChescoWx model.