As we go farther along into spring, the number of thunderstorms across the Inland Northwest will likely increase. This is the time of year when the warmer air from the south pushes northward and mixes with the cooler air from Canada. These air mass collisions will often lead to widespread thunderstorm activity.
We’ve already had one day – March 6 – at the airport with a thunderstorm. Areas east of Spokane have reported at least two thunderstorms for the 2013 season. Speaking of March, the airport ended the month with an average temperature of 41.2 degrees, one degree above normal. The total precipitation was 0.82 inch, well below the normal of 1.61 inches.
The average number of days with thunderstorms in the Inland Northwest is 11 – one in April, two in May, three in June, two in July, two in August and one in September. Don’t be surprised to see 13 to 15 days in Spokane with thunder, heavy rains, hail and, in some cases, damaging winds. Later in the spring and early summer, we could see several days with severe weather conditions. It’s also possible that one of those severe storms may produce a tornado, but the chances of that happening are very low.
The spring and summer period is the peak of the thunderstorm season in the Inland Northwest. Although we do see a number of days with severe weather conditions, they don’t compare to the ones in the Great Plains’ infamous Tornado Alley.
In areas east of the Rocky Mountains, the warm and humid waters from the Gulf of Mexico, combining with the cooler air from the north produce tornadic activity over much of the central and eastern U.S. Our region is protected from those elements from the Cascade Mountains to the west and the Rockies to the east.
In terms of our local weather, another chilly air mass from Canada will move across our region by this weekend. More rain showers are expected in the lower elevations with snow in the mountains. However, it may be cold enough to give us a rain and snow mix in the lower elevations.
The rest of the spring season will produce more wet weather. By mid- to late June, conditions should turn drier than normal, which would point to a great summer season across much of the Inland Northwest.