The U.S. Thunderstorm Season

Do you eagerly await the first crackles of thunder every year or could you do without the consequences these storms can bring? Just like the primed spots for tropical development shift in the Atlantic Basin from June to November, did you know that thunderstorm season shifts around the U.S. as well?   

February-March   

The U.S. thunderstorm season really gets underway during late winter and with the arrival of spring. The Deep South spanning from eastern Texas and Oklahoma to western Georgia, or better known as part of “Dixie Alley,” becomes prime breeding ground for thunderstorms. 

In February and March, warm, moist air from the Gulf of Mexico once again streams northward as winter begins its retreat. However, winter’s cold blasts can still dive deep into the southern tier and an active storm track allows the clash of these two distinct air masses to produce thunderstorms, with the prime spot for stormy skies being Dixie Alley.   

April-May   

During the heart of spring, the thunderstorm season shifts north. April and May are huge months for tornadoes and severe weather across the U.S. Spring gains a better footing, allowing surges of warm air to flow northward, but strong cold fronts provide fuel for storms to develop.

The classic Tornado Alley becomes the hotbed for thunderstorms, stretching from the southern and central Plains to the central and lower Mississippi valley. Thunderstorms also begin to expand northward into the Ohio Valley and Mid-Atlantic. Even the Upper Mississippi Valley and Lower Great Lakes get in on the thunderstorm action as the warmth expands in May.   

Across the Deep South, the first heat waves of the year begin to expand, allowing the Gulf Coast to get a break from severe thunderstorms.  

However, cold blasts such as the one that just delivered a chilly Mother’s Day across the middle of the U.S. and northern Tier, are still possible. Spring and winter’s final battles occur in May before summer takes hold in the year’s next month, June.   

June  and July   

Thunderstorms are common anywhere from the Plains to the Carolinas and Mid-Atlantic as summer gets underway. The best chance for storms resides across the central Plains, Ohio Valley, the Carolinas, and the lightning capital of the world, Florida.    

Thunderstorms continue to nudge towards the northern U.S. during mid-summer. Places like Bismarck, N.D., Minneapolis, Chicago and Albany, N.Y., see periodic thunderstorms. Storms are still likely across the southern Plains and South, but the best severe potential resides closer to the Interstate 70 corridor in the central and eastern U.S.    

Not to be outdone, the Mountain West thunderstorm season ramps up in July. The thunderstorms in this part of the country can often spark fires due to abundance of lightning and lack of rain. The Southwest monsoon also begins to take shape later in July. Places like Tucson, Ariz., and Phoenix often see thunderstorms during the afternoon and evening. These thunderstorms can provide much-needed relief from the triple-digit heat. It’s ordinary for days in July to be cooler than days in May and June across the Desert Southwest due to the return of clouds and rainfall.   

August 

Thunderstorm coverage occurs practically anywhere in the U.S. in August as heat and humidity envelops much of the nation. Essentially, any location from the northern Plains, Great Lakes and Northeast to the Deep South are at risk for thunderstorms.  However, severe wind gusts, tornadoes and large hail are less common in thunderstorms as summer concludes.   

September-October   

Thunderstorms become less frequent as fall arrives. The hot spot for thunder and lightning includes the southern Plains, but storms can occur as far north as the upper Mississippi Valley and southern New England as powerful cold fronts return. 

The full transition into fall leads to quieter skies across much of the U.S.  The southern Plains to Mid-South offer the best chance for thunder rumbles and severe weather is far less likely across the U.S.   

One curveball that can enhance thunderstorm development during the fall is landfalling tropical systems. Areas in the Southeast, Florida and the Gulf Coast are most susceptible to being impacted by a tropical system that can cause numerous thunderstorms, some of which can be severe.   

November through  January   

As colder arrives in the northern latitudes, the thunderstorm development is usually confined to the South late fall into winter. Places like Tyler, Texas, New Orleans, Little Rock, Ark., Jackson, Miss., Birmingham, Ala., and Atlanta are more likely to see a thunderstorm than St. Louis, Cincinnati and Washington, D.C., for instance. Severe weather usually only occurs in major storm systems that sweep out of the West or comes north from the Gulf Coast during this period.     

The unique clash of air masses in the United States leads to thunderstorm development in every month of the year. While parts of the South see more thunderstorms annually, even the northern Tier gets their fair share. Understanding the climatology of thunderstorms can help predict when your area may have the highest chance to experience quite the light show and be at risk for this dangerous weather. 

Sources: spc.noaa.gov

Story Image: Lightning in the fields of Valparaiso, Ind. (NOAA Weather in Focus Photo Contest 2015)