Happy first day of spring! After breaking into the 60s three times this year, spring might have already started for some. For us forecasters however, spring begins March 1. Spring marks a time of more intense storm systems, increasing temperatures, and drastic shifts in weather for Wisconsin. To stay prepared in this season, I have compiled the data to bring you the Spring Climate Outlook.
What is a Spring Climate Outlook?
This is a seasonal forecast, aimed at predicting weather within the bounds of meteorological spring: March 1 through May 31. Just like our other forecasts, this is broken into sections, but instead of days, the sections are months. As we look back at historical averages and trends, outlook models and climate guidance shape these into a trustworthy forecast for the season.
March: Starts starkly lower than the average daily temperature of 32, models show high-pressure dominance in the Eastern Pacific and Western Atlantic. This rules the first half of March, sending higher temperatures and notably above-average rainfall through the Great Lakes. Historically, March posts the least amount of liquid precipitation out of the spring months. This is partially due to the monthly snow average being over 6.5 inches. Snow might return briefly late March, but temperatures bounce right back, mostly staying in the higher 30s and low 40s.
April: As the old adage goes: “April showers bring May flowers”. To be sure, this April should bring enough of those. Commonly beginning the severe weather season in Wisconsin, April holds about 4 inches of rain. Due to a shifting El Niño/Southern Oscillation (ENSO) trend to a more neutral pattern, models show this to be higher. ENSO monitors Pacific wind and temperature anomalies, and from this scientist correlate specific global weather patterns. An ENSO neutral trend in the winter places the Polar Jet Stream below Wisconsin, but with the La Niña transition going into spring and the Polar Jet Stream retreating, storm systems likely send increased precipitation through the upper United States, including Wisconsin. Consequently, temperatures show a trend slightly above the average highs of mid-50s and lows of upper-30s. This means the final frost of the season should fall within April.
May: May flowers have to weather the storms, as the ENSO trend keeps the storm track near Wisconsin. Milwaukee likely sees rainfall above the average 3.5 inches. Snow should finish by late April, but Wisconsin can always turn frigid, especially in the spring. Temperatures should hold near to the historical trends in May, but with the ENSO transition, we could see some temperatures over the month significantly below and above the average mid-60s. Just as we saw in February, this year might hold some more weather records.
