Monsoonal rains may hit Summit this week
July 3, 2012
Afternoon clouds, dark and heavy with the promise of rain, continue to roll into Summit County this week, bringing the first splash of monsoon moisture to the region, but forecasters say it’s not enough.
Forecasts show 30-50 percent chances of precipitation and thunderstorms every day through the end of the week, the first signs of the monsoons that were uncertain to reach Colorado.
Long-range predictions, however, are less clear when it comes to moisture, projecting only the possibility of normal conditions, according to the National Weather Service.
“It’s getting going already,” meteorologist Kyle Fredin said. “We see some moisture over the area for the next five to seven days. Past that, it starts turning toward seasonal normals. They don’t expect too much in the way of extreme dry or extreme wetness.”
Seasonal normals in Summit County call for 1.36 inches of precipitation in June and 2.21 inches in July, but last month saw less than .2 inches of moisture.
While the storms predicted for the coming week will help, boosting stream flows – currently in the 25th percentile – by 200 or 300 cubic feet per second, those increases are short-lived.
Experts say the region needs weeks of soaking rains to begin to recover from extreme drought conditions.
“The best scenario to hope for is that you’d have a prolonged period, maybe a month or more, of getting some rain at least every couple days,” Colorado River Basin Forecast Center hydrologist Greg Smith said, noting that the evening sprinkles Summit has seen recently aren’t nearly enough. “It’s hard to say if something like that is going to happen.”
It would be monsoonal flow winds that would bring the moisture if it did eventually arrive. The winds help move moisture in from the eastern Pacific Ocean and, to some degree, from the Gulf of Mexico into the Southwestern states.
Current predictions show just a chance for the Western Slope to see that above-average rainfall this month. The above-average temperatures that have shattered records across the state over the last month remain in the forecast as well, according to the National Weather Service’s Climate Prediction Center.
Ultimately, forecasters say, relief may not be possible this summer.
Summer weather patterns, with their isolated and short-lived thunderstorms, do not tend to provide the kind of sustained moisture Colorado needs to recover from current drought conditions, experts said.
“It’s really something that you’re unlikely to see during summer thunderstorm activity,” Smith said. “It’s not basin-wide like big (snow) storms. … It doesn’t really soak in, and it runs off pretty quickly.”
The real moisture tends to arrive in the winter and spring with longer snowstorms spanning larger areas.
Current El Nino patterns indicate the coming winter may fall to the dry side of normal west of the Continental Divide.
The Vail Daily’s Scott Miller contributed to the reporting of this story.