NWS says severe weather season was 'unusually quiet'
GRAND FORKS - The National Weather Service says this year's severe weather season was "unusually quiet," with the number of severe weather reports well below normal.
The Grand Forks station's warning area tallied 145 reports, compared with an average of 397 reports per year since 1996.
The warning area covers eastern North Dakota and western and west-central Minnesota.
Severe weather reports may include high winds of 58 mph or greater, tornadoes and hail 1 inch in diameter or greater, the weather service said in a statement. For comparison purposes, the weather service used three-quarters of an inch for hail, which was the standard for the Grand Forks warning area before this year, meteorologist Bill Barrett said.
The weather service said this year will go down as the quietest severe weather season since its Grand Forks office opened in 1995.
The quiet season was attributed to a persistent flow of colder air from Canada that resulted in summer temperatures well below normal.
"This colder air inhibited thunderstorm formation, especially severe thunderstorms that require heat, moisture and instability to cause large thunderstorms to grow and produce severe weather," according to a weather service statement.
The most active severe weather season in the past 13 years was in 2001, with 705 severe weather reports.
There are no specific dates designating the start and end of severe weather season, but the weather service typically issues its first severe weather report in April and its last report in September, Barrett said.