Weathercatch: September rains don’t make big splash in our region

Even though September marks the last month of our region’s dry season, we typically experience some replenishing rainfall, either as a big thunderstorm or a few showers here and there.

And usually we welcome it.

Coming on the heels of the hottest and driest period of the year, September rains often bring at least some measure of relief to our heat-weary psyches, parched yards and overworked sprinklers.

We certainly would have welcomed a refreshing rain Sunday through Tuesday of this week. Local weather apps said it was sunny but when we stepped outside, we saw a thick blanket of gray. Widespread smoke from regional wildfires diffused the sun and led to unhealthy air quality across much of the Inland Northwest. A small storm system that moved in on Monday delivered too little rain to scour the atmosphere of smoky air.

Last year in early September, we faced similar smoky conditions, but the outcome was different than what we’re facing now. After a record-breaking stretch of dry weather, rain finally arrived on Saturday. It wasn’t much – just 0.23 of an inch in Spokane, 0.16 of an inch in Pullman and 0.17 of an inch in the Coeur d’Alene area. Nonetheless, it was the first of four rainfalls in the Spokane area that brought the month’s rainfall total to 1.35 inches. In just four days, we received as much precipitation as in the previous six months combined.

Sometimes the rain arrives in the form of a big thunderstorm. On Sept. 15, 2013, the state experienced a rare deluge when a large storm system unleashed heavy rains, thunder and lightning from Seattle to Spokane. A weather station near Moses Lake recorded 1.2 inches of rain in just 15 minutes. For perspective, consider that the average rainfall for all of September is about 0.04 inches in that vicinity.

This month, we’ve had no big storms or series of showers to put a major dent in our dry conditions. On Wednesday morning, a few clouds dropped a little moisture across Eastern Washington and North Idaho. Prior to this week, only 0.01 inches fell on Sept. 3 and 0.03 inches on July 15. Although air quality gradually began to improve on Tuesday afternoon, it was mostly due to a new air mass that nudged the smoke east, not because of a hard rain.

In some parts of the country, heavy rains come like clockwork in September, fueled by the monsoons in the desert Southwest and tropical storms in the Southeast. And though our region typically gets more rain during this period than the summer months, heavy rainfall isn’t common.

Rain has been scarce and warmth abundant this month, but it appears we’re entering a transition. The new 10-day outlook from the National Oceanic and Atmospheric Administration’s Climate Prediction Center is calling for cooler temperatures and rain, but not the ground-drenching kind.

For that, we’ll probably have to wait for October.

Nic Loyd is a meteorologist in Washington state. Linda Weiford is a writer in Moscow, Idaho, who’s also a weather geek. Contact: ldweiford@gmail.com.