Close to the normal number of thunderstorms expected this season

April has arrived and a new weather pattern has moved into the region with increased rainfall. There’s still a chance we could see a few more flakes of snow over the next several weeks, but it looks like we’ve seen the last of the bigger snows for the season.

Cliff and I see thunderstorm activity increasing across North Idaho later this month and into early June. Overall, the number of thunderstorms in the region should be near to a little below normal this year. We will probably have about six thunderstorms with rain and perhaps some hail. There should be another six that are not expected to be quite as strong.

Here in North Idaho, the average number of days with thunder-storms, which include thunder, lightning and rain, across the lower elevations is 14 (one in April, two in May, five in June, two in July, two in August, one in September and October). When you include days with thunder with little or no rain, the average number of days goes up to 25. The normal number of extreme severe weather days in the Inland Northwest for an entire year is slightly less than one.

Many of us plan our vacations in the late spring and summer months. Some of the journeys will involve air travel across the country. During this time, much of the country, especially east of the Rockies, will see the development of thunderstorms during the afternoon and evening hours which can make plane travel a bit tricky.

Strong thunderstorms have strong updrafts of warm air and can exceed 100 miles per hour. When the rising air becomes cooler than the air surrounding it, the rising air will spread out creating an anvil-type cloud. On the other side of the cloud are the downdrafts. This is the area of rain and hail. If there is rotation in the cloud, tornadoes can form, especially in areas east of the Rockies.

Thunderstorms that develop near airports often lead to long delays, creating lots of frustration for passengers. But, safety is a priority with the airlines. In the air, pilots will always try to fly at an altitude where turbulence is minimal. They will do their best to fly around thunderstorms to avoid strong turbulence.

I remember an occasion in the early 1990s when I was on a flight with Cliff and we were heading into a thunderstorm. He was sitting in the window seat and I was in the middle. He looked out and saw the large billowing clouds and said, “I think we’ve had it.” My response was quick and fairly loud as I replied, “We’ve had it?!” I think half the plane heard me. Shortly after, we went through the thunderstorm and the plane was shaking and dipping. It was a wild ride and I was very glad to get on the ground. The pilot got a nice applause when we landed. Cliff and I still have a good laugh over that incident, but it didn’t seem so funny at the time.

There are cases when pilots have to fly through a weather system. Most aircrafts will cruise at an altitude around 35,000 feet. Strong thunderstorms can form as high as 60,000 feet, so the cloud tops can be significantly higher than the altitude of the plane. I will say, however, most pilots do a great job at navigating around severe weather. If you don’t like the potential for turbulence, the best time to fly is early in the morning as the heat from the day can trigger thunderstorm activity during the afternoon and evening hours.

Worldwide, there are estimates between 14 and 16 million thunderstorms that form each year. It’s almost hard to believe, but there are close to 2,000 thunderstorms in progress during every minute of the day. In the U.S., there are approximately 100,000 thunderstorms that form, and, according to NOAA, about 10 percent of them will reach severe levels.

At this time of year, it’s a good idea to keep tabs on the local weather, especially if there are thunderstorms forming in the area. During these conditions, the National Weather Service can issue a “severe thunderstorm watch” or a “severe thunderstorm warning.” A watch means that conditions are favorable for the formation of severe thunderstorm activity. However, a warning means that severe weather is in progress when storm spotters or Doppler radar is producing large hail, high winds and heavy rainfall.

With thunderstorms comes lightning, which is still one of the most mysterious meteorological phenomenon. A single bolt of lightning can be as high as 40,000 to 50,000 degrees Fahrenheit. That’s hotter than the surface of the sun.

It’s not a good idea to venture out during a thunderstorm. The odds of being struck by lightning is any one year is 1 in 700,000. However, the odds of being struck in your lifetime go up to 1 in 3,000. If one happens to be outdoors during severe weather, and the hair starts standing straight up, that means conditions are setting up fast to be hit by lightning. The best thing to do is to hit the ground and even roll to break the bond between the positive and negative charge.

So, when a thunderstorm is looming, it’s a good idea to use a little extra caution.

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Contact Randy Mann at randy@longrangeweather.com