Cooler Air Returns As Spring Begins
Spring Helps Transition From Winter To Summer
After spending 12 days under an unseasonably warm air mass, cooler air is set to move in as we inch closer to the official start of spring. After spending days in the 60s, 70s even 80s, the thought of snow returning may sound absurd but spring/fall are transition seasons so seeing flakes falling isn’t out of the ordinary.
As winter ends and spring begins, the jet stream starts to make its way back north and warmer air replaces the cold, dry air mass that has been sitting over an area for the last couple of months. The same thing happens during fall, except it’s backwards; cold, dry air moves south and replaces the warm air mass that is typical for the spring and summer months.
850mb Temperatures, Monday morning
850mb Temperatures, Tuesday morning
As you know, the jet stream is just that, a stream, that systems at the surface ride in as they make their way from one end of the US to the other. During the heart of summer/winter, the air masses typically don’t change that often so the systems at the surface are only influenced by one air mass. However, during transition seasons like spring and fall, the low/high pressure systems are influenced by two different air masses that are often characterized by sharp temperature differences and moisture content. Because these systems are influenced by the two air masses, there are periods of time, like the one we just experienced, where temperatures are unseasonably warm then, like what we will experience, temperatures cool back down to normal.
850mb Temperatures, Sunday morning
The contrasting air masses also help provide the ingredients for late/early season snow and ice events. As stated before, the warm air out of the south typically contains more moisture than the cold, dry air from the north. When the ingredients are right, a low pressure system taking not only the right path but experiencing the correct air mass at the right time, places could receive snow or ice later/earlier in the season.
Moist Skew T, Wednesday morning
New Snow, Friday night
There isn’t any snow in the seven day forecast however, that doesn’t mean it isn’t out of the question. A series of low pressure systems will ride along the jet stream bringing us cooler air; that air is actually more normal for this time of year. Though we aren’t forecasting snow, both March and April are the snowiest months for the Northern Plains because of the increasing moisture in the atmosphere and the contrasting temperatures. Hopefully you’ve enjoyed the unseasonably warm air we’ve experienced because we could still see snow during this transition season into summer.