Pennsylvania Monthly Records: An Update (& More)

Today I will take a look at how I was able to uncover some corrections for the Pennsylvania weather records, including one that I recently discovered. I will also share some other cool weather observations that I found in the process and debut a new feature on the Stormsell website!

Diving into the Data

Last year I started digging through the NCEI website and discovered the Cooperative Weather Observations where you can download the historical handwritten weather observations. I began looking at records from major weather events. Many times the observer would include interesting comments about the weather.

I also began looking at some of the observations from weather records like warmest temperature ever recorded in the state. I started going through the entire list of monthly records from the PA State Climatologist website. The more that I looked I started to find that there were some errors in the way the observations were taken or the way they were written down and/or calculated. In some cases the records were entered wrong when digitalized.

Weather observations from Phoenixville from July 1936.

Among the records that were corrected included the record for maximum temperature for April where the high temperature for Port Clinton and Blosserville were both entered wrong digitally. These records were tied with two other observations of 98° so the record did not change.

For the maximum snow record for the month of June many locations were listed to have recorded snow in June of 1950. Looking at the handwritten records it is clear that this was not snow but hail. The other observations of flurries in the month of June are legitimate!

Since I first made the maps in 2019, the only record that has been broken which was the snowfall record for the month of May. Laurel Summit recorded 11.3" of snow in May 2023 beating the old record of 8.5" set in Bradford in May 1989.

December Maximum Snow Record

There is one record that I have been wanting to find the handwritten observations for that I wasn't sure even existed. The search has gone on without any luck for many years, long before I started the record reanalysis. The record snowfall for the month of December of 96.0" was set in 1890 at Blue Knob, just up the mountain from where I live.

The only information that I was able to find was that the observations were taken at by the post master at the post office (this was in the village of Blue Knob not at the top of the mountain where the ski resort is today). Many of the handwritten records from pre-1900 were unavailable from the COOP record site. I was able to find state data in the Monthly Weather Review with the Blue Knob snow total listed.

In December of 2017 a lake effect snow event brought incredible snowfall to Erie. 50.8" of snow was recorded between 7am on December 25th and 7am December 26th! This brought the total for the month of December to 120.9", breaking the record for most snow for the month of December that was set in December 1890 at Blue Knob.

All new records set are reviewed by the State Climate Extremes Committees. After the review was finished, it was found that the snowfall measurements for Erie were not taken properly. New corrected snow totals were determined with 32.6" falling in the 24 hour period ending at 7am on the 26th. With this adjustment, the monthly total is now 93.8" placing the 1890 record from Blue Knob back on top.

This brings us to a couple of months ago while doing research for the 1936 Saint Patrick Day flood. I stumbled across a dataset on the NCEI site titled 'Pre-Weather Bureau Observation Networks.' After some digging I had found what I had long been looking for: the handwritten observations from Blue Knob.

Weather observations from Blue Knob December 1890.

The observations show that the snowfall record is not legitimate. First off, the totals were not added correctly. Adding the totals gives 86.0", not 96.0". This was corrected by a reviewer with the incorrect total crossed out. A closer look reveals that it also appears that the snow was never actually measured with a ruler. All of the snow totals are exactly calculated at a 10:1 ratio. Also, the records list the snow totals to the nearest hundredth while snow is measured to the nearest tenth.

Weather observations from Blue Knob December 1890.

While the exact amount will never be known, a lot of snow did fall. Pittsburgh recorded 41.3" during that same month- the snowiest month on record for the Steel City until February 2010! Additionally, measuring snowfall is very complex and difficult even today as exhibited by the December 2017 record from Erie. Regardless, the adjusted total of 93.8" puts Erie back on top with the December monthly total snowfall record. The record has been corrected on the PA State Climatologist website.

Pennsylvania weather extremes for the month of December.

Other Notable Observations

The handwritten weather observations have given additional information about past events that you don't get when just looking at the statistics. I have used the COOP observations in past blog posts such as the 1950 smoke pall where the observers described the eerie sky to great detail. 

May 1889 weather observations from Johnstown.

As we approach the anniversary of the Johnstown Flood there are a number of neat observations from that event that I Have uncovered including the river gauge & rain gauge observations from Johnstown. The observer simply noted 'Rain Gauge carried away.' The Pittsburgh observations also noted debris from Johnstown was seen floating down the Allegheny River on June 1st and 2nd. Observations from Johnstown would not resume until December of 1889.

Weather observations from Pittsburgh during June 1889.

When I found the Blue Knob records, the snow observation from December 1890 was not the record of most interest for me. The observations began in April 1889, one month before the Johnstown Flood and Blue Knob recorded one of the largest 1 day totals from May 30-31, 1889, with 7.90".

Blue Knob sits in the Bob's Creek Watershed which borders the watershed that flows into the South Fork of the Conemaugh River and what was the South Fork Dam. I was blown away by the very descriptive summary that the observer wrote on the back of the May 1889 observations which reads:

"On the 30th at 3 P.M. it commenced raining

with a light wind from the S.East. and at dark the

rain came down in torrents and the wind came at 

very strong in squalls at intervals during the whole

night and about daylight on the following morning it was 

accompanied by hail which broke the twigs and branches off

of the trees - and it continued to rain in torrents until

the night of the 31st. This storm of rain fall is the 

heaviest that has fell on these mountains since 1838-

We are completely isolated all wagon roads are impassible bridges

destroyed E - W. South + West, Reservoir destroyed south of South Fork-

which has flooded South Fork - Johnstown and Rail Road also at Bens Creek to

Lillies dealing death and destruction- total rain fall in 24 hours 7.90"

Weather observations from Blue Knob for May 1889.

As we approach the anniversary of May 31, the Johnstown Flood is not the only major weather event to occur on this date. Two tornado outbreaks have also occurred on May 31st, including the most deadly and devastating tornado outbreak in Pennsylvania history. These two observations from Corry and Clermont mention the nearby tornadoes from that day in 1985.

Weather observations from Corry May 1985.

Weather observations from Clermont May 1985.

One more weather observation of interest comes from Gettysburg during July 1863 while the Battle of Gettysburg was taking place. While the weather was not all that interesting it is still neat to see the actual written weather data from the historical event. The observer made a simple note of the battles on the back.

Gettysburg weather observations from July 1863.

There are many, many more historic weather observations to uncover and it goes well beyond Pennsylvania.

New Records on the Stormsell Website

My Pennsylvania Temperature and Precipitation page on the Stormsell website hosts a bunch of tables and maps of recent and extreme weather observed in the commonwealth. Every month I post temperature and precipitation statistics for 9 cities across the state. I also have temperature and precipitation extreme maps including the monthly extremes from the PA State Climatologist that I reviewed above.

New temperature and precipitation records are
 now available on Stormsell weather website.

I have now added new tables with extreme daily and monthly records from cities across the state. Check it out here!

Wrapping Up & Looking Ahead

May is quickly coming to an end which means it is time to get started on the May monthly review. That will be available in the first week of June. Have a great Memorial Day!

Remember to always look up!

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