We finish out a warm March, ironically with one of our coldest days of the month (2nd coldest, 22 on 3/1 the coldest). We had two days where we hit 66 degrees. A handful more that were close.
Here is the outlook for April (The Weather Company/IBM). We (Wisconsin, upper Midwest) look to be warmer than normal for April.
April for Wausau average 44 degrees. Our average high for the month of April is 61. The April record high was 91 in 1952. 2020 was the 10th coolest April on record as far as the average highs at 52 degrees. As far as the overall average temperature, it was 40.4. Cool as well.
The outlook for April 2021 is based on several things. One is a Negative NAO. North Atlantic Oscillation. This is expected to create a blocking pattern, which is a ridge of high pressure over the North Atlantic near Greenland which would produce an amplified jet stream pattern, which could bring cooler temperatures southward from Canada into portions of the Northeast into the second week of April if it hangs around that long.
This blocking pattern coupled with the negative phase of the North Atlantic Oscillation will bring the quick blast of near record cold to the East as April begins.
What is the NAO? Overall complex, hard for me to fully understand. The NAO has multiple possible definitions. The easiest to understand are those based on measuring the seasonal average air pressure, sea surface and air temperature difference between stations, such as: Reykjavik, Iceland, Azores islands, Gibraltor and Lisbon, Portugal.