ChescoWx

The Bastardi Storm incoming - lock it up!!

So you think the 1st 15 days of the year have been warm? You are correct this is the 5th warmest first half of January since 1894. The top 10 warmest are below.

Per that well respected meteorologist "Jan 20. End of California Deluge pattern. Meanwhile winter coming back big time for the US Buckle up. Major winter storm plains this week, likely first accumulating snow I-95 corridor next. Bottom line"

Most spots across the county dropped into the lower 20's this morning. Tonight should be the last below freezing temps until Saturday morning. A couple chances of some rain first tomorrow night and then rain is likely by Thursday. Overall looks like between 0.50" and 1.00" of rain are possible by Friday. There are signs of a change in the weather patterns which may get folks talking about some snow potential as we close out the month of January. The record high for today is 61 degrees set in 1932. The record low is 10 below zero set today in 1982. Our daily precipitation record is 1.71" from 1924. The daily snow record is the 10.0" of snow that fell today in 1945.

Today should see a return to near normal January temps with highs in the upper 30's. Sunny tomorrow before a chance of rain Tuesday with a much better chance by Thursday. The warmest day looks like Wednesday when we could touch 50 degrees. Cooler again by the end of the week. The record high for today is 70 degrees in 1932. The record low is 3 below zero from 1988. Daily precipitation record is 1.07" Daily snow record is the 6.0" that fell today in 1927.

Today was our first below freezing day (high was 31.6) and below normal temperature day since December 27th.

Agreed RedSky is the snow capital of SE PA - I have seen only a little over 50% of that!!

Below is an analysis of all Chester County PA data from all available sources with at least 6 complete decades of history. The most complete data sets have 13 complete decades of data. In the data below all decades that had temperatures fall from the previous decade are in blue and those that rose are in red. Data in black showed no change decade to decade. When averaging all reporting sites across the county we see that 6 decades trended colder from the prior decade and 6 decades trended warmer. Overall the 1930's and 1940's were the warmest decades and we have still not returned to those warm levels Five of the Top 10 warmest decades occurred prior to 1960. We have seen no more than 3 consecutive warming decades and no more than 3 consecutive cooling decades since the 1890's.

those would make it more difficult for him to back into the conclusion he's already made and to which he's trying to force the data to conform, so I doubt he is handling those very real and significant issues at all. Hi guys, Thanks for the questions. For consistency I did not adjust any of the reported data for all of the long term Chester County PA sites. The assumption being all COOP sites were instructed to record obs at the same time during the periods based on the US Department of Commerce - Weather Bureau directions as included in the bureau's monthly and annual footnotes . The same assumption was made for any potential instrument changes that the individual observer would have been instructed to make. There were no noted station moves for Phoenixville, West Chester or Glenmoore. The combined Coatesville (Coatesville 1 SW) data indicates 3 station moves during the period 1888 through 1982. These moves were within 1.5 NM with the ASL elevation variance being within 80 feet. A 4th move was made in 1983 (Coatesville 2W) with a move 1.5 NM north to an elevation of 640 feet. These readings continued through December 31, 2007 and were combined and reported by the PA State Climatologist. The Coatesville 2W station ceased operations on 12/31/07. We then performed a detailed statistical analysis of the NWS Trained Spotter Data (mine) at East Nantmeal (9.2 NM to the NE and 45 feet higher in elevation). Both sites which both reported daily data in parallel from December 1, 2003 through December 31, 2007. This analysis of 1,492 daily average temperature observation points across 49 months of weather data supported a rejection of the null hypothesis. That hypothesis being the 2 data points are not the same and cannot be combined. The resulting p-value rejected that null hypothesis and in fact was highly significant and the similarity of the data was not attributable to chance. Importantly, this means the 2 data points (Coatesville 2W and East Nantmeal) have been determined to be scientifically one and the same and may be appropriately combined for analysis and reporting. I hope this helps!

A few light flurries have been seen here in East Nantmeal this AM. Today will be mainly cloudy with limited sun. Our temps will struggle to get above freezing especially along the higher ridges in western spots of chesco. Today will be our first below normal day of the year. However, by tomorrow will return to normal to just above temps which will continue for the rest of the upcoming week. Our next chance of rain arrives on Tuesday AM....if it arrives early enough we may see a touch of freezing rain. Wednesday will be the warmest day of the week with highs approaching 50 degrees. Cooler weather is on tap to close out the week. The record high for today is 73 degrees set in 1932. The record low for today is also the coldest temperature ever recorded in Chester County of 19 degrees below zero - today back in 1912. Of note Phoenixville's all-time record low is also 19 below zero which was recorded on January 22, 1961. West Chester's all-time low reading was the 16 below zero that was twice observed both on January 22, 1984 and February 10, 1934. Record precipitation for today is the 1.78" that fell in 1921. Our daily snow record is the 14.3" that fell today way back in 1910.

Some very light flurries now falling here in East Nantmeal temp at low for the day at 28.0

It is snowing and 33 degrees in Sea Isle City this morning.....

Of note the average snow for the Western Burbs of Philly in Chester County is 19.4" from January 12 - February 28th - the EURO average on the weeklies still shows continuing below normal snowfall but does at least show some snow...

Below is the updated analysis comparing PHL Airport vs. All long running Chester County Observation Sites from 1940 through 2022. For the year 2022 all Chester County locations reported lower average temperatures vs. 2021. ranging from 0.4 to 1.0 degrees cooler than the prior year. Philadelphia was 1.0 degree warmer than 2021. The analysis for the last 82 years since 1940 shows overall trends of modest cooling at the Chester County stations at Glenmoore and slight warming at Phoenixville and West Chester with Coatesville/East Nantmeal showing the most warming but only very modest warming at best. Philadelphia's trends of course shows pronounced steady warming that is continuing to accelerate.

From Larry Cosgrove "When you consider that a cross-polar flow is a possibility in this configuration (likely to repeat in mid/late February), you can see the possibilities here. It might take the East Coast cities a while to get involved with the cAk domain, but I am confident that the Interstate 95 corridor will get in on the winter action at some point. The analog forecasts still call for a much milder March. But before we get there, may you live in exciting times."

4th lowest in satellite era for December....of course satellite era is not very long...current warm cycle doing it's thing!!

A few showers will pass through this morning as a cold front has just crossed the county. We have picked up 0.23" of rain since yesterday. Temperatures today will fall from our 2am high temp of 52.3 degrees we have now fallen to 46.7. We should see temps falling below freezing by 8pm this evening. Tomorrow will be our first below normal day of the year an first since December 27th. Tomorrow will also be windy. Temps should once again moderate back to above normal by Monday with our next chance of rain arriving Tuesday. The record high for today is 68 degrees set back in 1932. Our record low is the 11 degrees below zero reading from 1912. Daily precipitation record is 1.34" and our daily snow record is the 6.0" that fell today in 1964.

We have some modest elevation at the KMQS and East Nantmeal stations (~660 ft ASL) that seem to make some diffference...although honestly 88 or 91 with humidity is still hot any way you slice it!!

Always funny you fall back on faulty sensors or observation reports when the figures don't work out....

As clearly shown below the trend away from the PHL heat island airport for 90 degrees is clearly falling over the last 10 years - the disparity when compared to PHL continues to grow. The suburban locales averaging high single digit amount of 90+ days while PHL now heating up into an average of low 30's per summer. This is all over no more than a 30 nautical mile distance from the airport.

We did have some wet snow overnight that turned to some light rain with 0.05" of liquid falling. Today looks cloudy with some drizzle and more rain later in the day and this evening. We could pick up up to another 0.20" of rain. Today will be the warmest day of the next week with temps possibly reaching 50 degrees. Drying out by tomorrow PM. Much chillier Saturday with our first below normal temp day of the year. Another warming trend begins next week. The record high for today is 64 set in 2020. The record low is 7 degrees from 1981. Daily rain record is the 1.98" that fell in 1983. Our record snow for the day was the 5" that fell today in 1982.

I have made no adjustments to any analysis ever. I am a believer in climate change (it is real and constant throughout history and will continue forever) but believe this change is cyclical and not unusual. The 3 stations have been analyzed and deemed valid for analysis based on the following detailed reviews. The data set comprises only the National Weather Service COOP observations from 1888 to 1982 for Coatesville 1SW when that station moved per NWS direction to a nearby location in Coatesville beginning in 1983. That location was only 2 miles to the NW at an additional 300 ft elevation change - that station remained in use till 12/31/07. The data of both of those stations was deemed acceptable and combined by the Pennsylvania State Climate Office and is posted on their website with climatology stats using the combined 2 stations. So now we have data from 1888 through 2007 that is included in this data set. However, the Coatesville NWS observer stopped reporting in December 2007. Without that data I was required to do a statistical analysis to determine if the daily data that had been recorded at both the Coatesville NWS observer station and my NWS spotter data in East Nantmeal for Chester County (at the same elevation ~660 ft ASL) which were taken concurrently daily from 12/1/2003 through 12/31/2007 would be found statistically the same - this is critical because if this statistical significance test had failed we would not have been able to use this data for the ongoing analysis I perform. However, based on the detailed statistical analysis performed we were able to show that both data sets are statistically one and the same based on the highly significant ( p-value results were well under 0.05 required). This detailed statistical analysis provided the support that allows us to have high confidence that the total data set being used is valid and appropriate for analysis. Sorry for the long winded explanation (more than most folks would want) but want to ensure why we are so confident in these raw Chester County data sets. Thanks! Paul

The endless roll of lake cutters is really amazing.....I remain however a big believer in all things equaling out in most years. I suspect the winter is over crew will be proven wrong with at least a couple wintry events and if one threads the needle....spots like PHL that average in the low 20's for annual snow could be 75% of normal for the year. For us N and W folks that average in the mid-30's for annual snowfall....I suspect a well below normal year is increasingly likely. By the way thanks to all of you for not killing me over my winter forecast!!

Charlie you miss the point there is no slant or cherry picking data with my analysis....I have no incentive to skew anything I simply analyze the factual reporting of all available NWS COOP and spotter reports for a long period of time for Chester County PA. The fact is does not support the global warming hypothesis is not my problem. You never say my data is wrong....simply that it needs to be massaged. You can continue to post your adjusted pooled multi-station data for Southeast PA....and I will continue to report on what the trained observers and spotters report and report the facts both warm and cold for the available long term stations in my county.