National Weather Service United States Department of Commerce

RECORD COLD TEMPERATURES SATURDAY MAY 9TH

May 9th, 2020 was one of the coldest May days in recorded history as numerous sites set records for coldest low and high temperatures. Please click through the photos as we attempt to contextualize one of the coldest days in May ever observed in Pennsylvania! 

 

Here are the observed temperatures and previous cold temperature records for Saturday. 

Source: https://w2.weather.gov/climate/xmacis.php?wfo=ctp

Lows and Highs on Saturday were some of the lowest ever observed in the entire month of May.

Source: https://w2.weather.gov/climate/xmacis.php?wfo=ctp

Minimum and maximum temperatures on Saturday were highly anomalous with low temperatures greater than 15 degrees below normal and high temperatures greater than 25 degrees below normal in Pennsylvania.

Source: https://www.wpc.ncep.noaa.gov/exper/ndfdmxmn/map.html

Records were set across most of the Eastern US Saturday morning. Here's a depiction of the record cold temperatures. Notice the dark blue circles in PA indicating temperatures that break the monthly record low.

Source: http://coolwx.com/record/usamovie.day.php

If we track where Saturday's air mass originated, it becomes clear why it was so cold. Air from northern Canada sunk into the Mid-Atlantic on Saturday, resulting in temperatures in the 30s in northern PA and 40s in southern PA.

Source: https://ready.noaa.gov/HYSPLIT_traj.php

An expansive area of surface high pressure surged into the eastern US, as shown in this NWS Weather Prediction Center map valid at 8AM Saturday. See surface maps from the record-setting May 9ths of 1947 and 1966 below for comparison.

Source: https://www.wpc.ncep.noaa.gov/index.shtml#page=frt

 

Surface map on May 9th, 1947 when Harrisburg's daily record minimum temperatures were set: 

Source: https://library.noaa.gov/Collections/Digital-Collections/US-Daily-Weather-Maps

 

Surface map on May 9th, 1966 when most of the daily record minimum temperatures were set: 

Source: https://library.noaa.gov/Collections/Digital-Collections/US-Daily-Weather-Maps


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Public Information Statement
National Weather Service State College PA
952 AM EDT Mon Jul 6 2020

...PUBLIC INFORMATION STATEMENT...

NOAA Weather Radio station WNG-591 serving Potter and Mckean
counties in northern Pennsylvania will be off the air for
about 1 hour late Tuesday morning or early Tuesday afternoon as
technicians perform preventative maintenance.

$$

Lambert


 

SNOWFALL: Harrisburg (MDT) also received a trace of snowfall, tying the previous daily record set in 1977.