April a month of weather extremes in U.S.

Last month was one of the coolest and wettest Aprils in recorded history across the Inland Northwest. At Spokane International Airport, the average temperature was only 41.5 degrees. That is 5 degrees below normal and ranks second in terms of the coolest average reading. The chilliest April was in 1955, with an average temperature of 40.6 degrees.

In downtown Coeur d’Alene, the mean temperature for April was 40 degrees, which is 6.1 degrees below normal. This was the third-coolest April for Coeur d’Alene in recorded history. Only April 1936, which was 7.3 degrees cooler than normal, and April 1951, which was 7.1 degrees below average, were colder.

In terms of precipitation, the Spokane airport measured 1.81 inches of moisture. This is 0.53 inches above normal. Spokane picked up 1.1 inches of snow, which takes the 2010-’11 total to 69 inches. The seasonal average is approximately 46 inches.

Snowfall totals were much higher in Coeur d’Alene. A whopping 7.6 inches fell in April, the third-highest total for that month on record. The most snow recorded for April in Coeur d’Alene was 8.2 inches in 1920. April 1933 is in second place with 8 inches. The city has received 121 inches for the season.

The weather extremes are not confined to our area. Last week’s tornado outbreak in the southern U.S., according to the National Oceanic and Atmospheric Administration, was the largest in history. From 8 a.m. April 25 through 8 a.m. April 28, there were 362 confirmed tornadoes. The bulk of those twisters occurred from the morning of April 27 to the morning of April 28 with 312. There were also 226 twisters in one day, another record-breaker. This event shattered the previous record for a tornado outbreak, which was 148 twisters April 2 through 4, 1974.

April’s preliminary estimate for tornado activity in the U.S. is now higher than 600. The previous record number of April twisters was 267 in 1974. Prior to last month’s outbreak, the old record for the number of tornadoes for any month was 542, in May 2003. The average number of twisters for April is 161.

It’s quite possible that 2011 will go into the record books for the most tornadoes in U.S. history. It’s estimated that 881 twisters have been confirmed so far this season. The record is 1,817 tornadoes set in 2004.