Riders in this weekend’s Iron Horse Bicycle Classic may have a little extra incentive to pedal faster – the unusually wet afternoon storms that have loitered over the Durango area in recent weeks.

No, monsoon showers aren’t here yet.

“It’s too early for the M-word to be used,” said Erin Walter, the service hydrologist at the National Weather Service Grand Junction office.

Monsoon season typically ramps up in July, bringing bursts of heavy rainfall similar to what has occurred in recent afternoons.

Although it is not an early monsoon season, the amount of precipitation this month has been abnormal, Walter confirmed.

At the Durango-La Plata County Airport, 0.82 inches of rain have fallen this month, exceeding the typical amount of precipitation by one-fourth of an inch. Walter said a low flow pulling moisture from both the Pacific Ocean and the Gulf of Mexico is to blame.

“It just started rotating over the Four Corners for several days,” Walter said. “... Every afternoon we'll start to see those storms because it (moist air) is lifted over the higher terrain. You have good moisture and it is a little bit cooler air overhead, so storms are able to continuously build. Some of them are pretty slow-moving, which is why we saw some good heavy soakers in isolated areas.”

As moisture-laden air is forced upward by the topography of the San Juan Mountains, it cools and condenses, forming rain droplets. Although the outlook for this weekend is somewhat drier, Walter said that precipitation is still possible in higher elevation zones. Storm systems are expected to build over the San Juans, bringing lightning and wind gusts.

“We still have the moisture sitting around, so it’s (thunderstorms) possible almost every afternoon in that high terrain,” Walter said.

Iron Horse riders must clear Molas Pass by 1:20 p.m., hopefully landing them in Silverton before afternoon storms arrive.

rschafir@durangoherald.com