When is the monsoon going to end? Meteorologists say it’s still up in the air. | SummitDaily.com

When is the monsoon going to end? Meteorologists say it’s still up in the air.

Rain clouds above Chihuahua Lake are pictured on Sunday June 19, 2022, as afternoon rains moved into the area.
Eiliana Wright/Summit Daily News archive

For the past several weeks, scattered thunderstorms have kept strict fire restrictions at bay and river conditions looking better than they did in 2021, but for those who are looking for a dry summer, the question remains: When will the monsoon end?

The North American Monsoon is a shift in the wind pattern with continuous moisture flowing from the Gulf of California into the southwest region of the country. This usually happens when clockwise high pressure and counter-clockwise low pressure settle in over the region. Depending on its strength and where it lands, parts of Colorado also receive effects from the weather pattern.

Frank Cooper, a meteorologist with the National Weather Service in Boulder, said that though moisture arrived in Summit County earlier than expected, it could still last throughout the summer. 

“Usually, it goes through about mid-August. Once we get this pattern, it’s generally around that time,” Cooper said. “It could end a little sooner or could even last a little later, but right now, generally, it goes from mid-July to mid-August. But it started a little early for (the mountains) this year.”

According to Colorado State University’s Colorado Climate Center, the North American monsoon affects parts of the state in different ways at different times of the year. For the southwest portion of the state, the highest precipitation months are July, August and September, based on data from 1981 to 2010. For central Colorado, there are two peaks: one in late spring and another during monsoon season at the end of the summer. For the northeast portion, patterns look different. For that region of Colorado, monsoon conditions are not apparent in the almost 30 years of data. Peak precipitation occurs in the early summer and wanes after that.

This year, however, the monsoon was earlier than normal. Meteorologists began predicting an increase in moisture in mid to late June rather than toward the end of summer in July or August. While increased precipitation may have given local water a boost, some public safety officials are closely watching how recent grass and brush growth could turn into fire fuel later this year. Since the monsoon came early, they said, that leaves a greater time in the late summer and early fall for drier, hotter weather. 

For the next 14 days in Summit County, temperatures are expected to be warmer, but precipitation is also expected to be above normal, as well, according to the National Weather Service’s Climate Prediction Center.

According to historic precipitation data, Breckenridge had an above-average June with 1.54 inches of rain compared to the average 1.06 inches. In 2021, July was the wettest month of the year with 3.22 inches in those 30 days. 

As monsoonal moisture continues in the region, Summit County is expected to receive more rain. This graph shows monthly measures of precipitation in Breckenridge this year.

Traditionally, March and April bring the most precipitation because of snow, but when looking at summer rainfall, July and August account for the wettest months. Since 2000, July has had the most rainfall in the summer for 12 years. August took the top spot for seven years, June had two and September was the wettest in one year. 

Cooper said for the rest of this week, there will be chances of rainfall and thunderstorms across the mountains. 

“It looks like the best chance is going to be Tuesday through Thursday of this week,” Cooper said. “Looking at highs in that time, it’s somewhere in the upper 70s to near 80 degrees with lows in the mid to upper 40s. Then it looks like maybe Thursday and then Friday, there’ll still be a chance of thunderstorms each afternoon and evening — maybe a little less. But again, persistent high temperatures right around 80 degrees with lows in the mid 40s.”

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