Southwest Colorado appears to be headed into a dry spell, and even the monsoon may be drier than average, according to the National Weather Service.
There is a slight chance of thunderstorms with “spotty” showers in the high country on Saturday and Sunday, but after that, the extended forecast calls for dry and hot weather.
The onset of the monsoon, which usually arrives in mid-July, appears to be arriving later than usual, said Chris Sanders, a meteorologist with NWS.
“Typically, we look for a big ridge of high pressure to set up over the center part of the U.S.,” Sanders said. “That’s the most favorable pattern to get moisture to come up into the area. Right now, we’re seeing the exact opposite, where we’re having troughing coming into that area.”
Sanders said troughing can lead to drier air and shuts off the feed of moisture needed to produce afternoon storms in Southwest Colorado.
The pattern has the potential to remain stagnant going into August, but there may be some surges of moisture. It depends on what happens with the high-pressure ridge over the West Coast. Where exactly the ridge sets up will play a role in the possibility of moisture being pulled from the coast into the Rocky Mountain West.
Sanders said it is difficult to determine when the monsoon will arrive, but typically, the monsoon starts during early to mid-July.
It is “finicky” to predict how much rain will actually fall, he said.
“These are scattered thunderstorms that one place could get some rain while the other one’s didn’t,” Sanders said. “So it’s hard to kind of determine that, but the signs are pointing toward potentially maybe drier than average as far as the amount of moisture that we see of rainfall during the time of the monsoon.”
It is possible the weather pattern could shift going into August, creating a wetter pattern that could make up the difference.
“It’s really hard to say after three months where we’ll end up,” Sanders said.
With drier periods, Southwest Colorado could experience slightly above-average temperatures, at least going into late July. Thunderstorms could bring cloud cover and rain, which cool things down.
The average high temperature for Cortez is 89 in July and 87 in August. In Durango, the average highs are 86 degrees for July and 84 degrees in August.
bmandile@durangoherald.com