Spring Swings

Spring Swings…

Meteorological spring begins on March 1st., kicking off a series of months that has a reputation for producing a variety of extreme weather, including major snowstorms, large tornado outbreaks and serious flooding.

The official start to spring might not be until March 20, but meteorologists break down the seasons into groups of three months, based on the annual temperature cycle around the globe. Meteorological spring runs from March 1 to May 31 every year.

Wide-ranging weather impacts occur in these three months because of a battle between warmer air trying to budge farther northward and the last of winter’s cold plunging southward out of Canada. That temperature contrast fuels a strong jet stream and, therefore, highly variable weather conditions.

Here are five reasons spring is the most dynamic season.

1. Spring Is Still a Snowy Time of Year

March 2018 proved major snowstorms can still occur in spring. The Eastern Seaboard was hit by four nor’easters in three weeks, including winter storms Quinn, Riley, Skylar and Toby.

March, or even April, are actually the snowiest months of the year in the Rockies and High Plains. Additionally, many cities across the nation’s northern tier don’t see their average last measurable snow until April.

2. Peak of Tornado Season Arrives

Tornado outbreaks are probably the weather event most often associated with spring.

Tornado activity in the Lower 48 begins to increase in March before peaking in April, May and June. Those are the core months for tornadoes, but they can occur at other times during the year.

March averages the fewest tornadoes in spring, with 77 per year. That average increases to 187 in April and 275 in May.

The area where there is a higher risk for tornadoes in spring shifts from the Deep South in March toward the Plains and Midwest from April into May. That follows the northward migration of the jet stream further into spring.

3. Spring Floods

River flooding often occurs in spring, particularly in the Ohio Valley, Mississippi Valley, Red River Valley (North Dakota and Minnesota) and parts of New England.

A sharp warmup in an area with significant snowpack during spring can quickly cause melting, allowing rivers to rise over their banks.

The worst flooding happens when bouts of heavy rain move across an area where the ground is already saturated from winter snowmelt or rain. Since the ground cannot absorb any of the rain, serious flooding may occur, potentially inundating city streets and even homes.

Flash flooding is also an increasing threat in spring as thunderstorms become more numerous. Thunderstorms can produce rainfall rates of more than an inch per hour. If that heavy rain persists for several hours at a time in a particular area, major flooding can occur.

4. Temperature Swings

Spring is also known for its changing temperatures since teases of warmth are often taken away in an instant.

This is particularly the case in March and April, when strong low-pressure systems moving through the central and eastern states draw warm air ahead of them into the northern tier of the country. That could result in a brief couple of days with some enjoyable warmth.

But an inevitable cold plunge typically arrives after the storm departs, taking away the brief glimpse of spring temperatures.

Later in spring, the atmosphere becomes less prone to wild temperature swings, allowing for longer-lasting periods of warmer weather.

5. A Windy Time of Year

Gusty winds often accompany potent spring storms before, during and after their passage through the Lower 48.

The windiest time is early spring. March is the windiest month for many cities from the Plains to the East Coast.

Sometimes, those winds can contribute to blowing dust in the Southwest and Plains states.