Colorado’s mountains are famous for their afternoon and evening thunderstorms in the summer. We have all heard the hiker’s mantra, “be below treeline by noon”. This is to avoid becoming the next Colorado lightning statistic. In fact, the leading weather related cause of death in Colorado is lightning. That is why it is so important to take a close look at the forecast before embarking on a hike or backpack. It also helps to be able to read the clouds, as they often portent what the weather will be like in the few hours.
On Sunday we did an afternoon hike along the Continental Divide Trail (CDT) from Henderson Mine to Berthoud pass. Much of this hike is well above treeline. As I discussed in my Saturday evening post, Sunday turned out to be a superb day, one in which the atmosphere became even more stable as the day progressed. In this picture taken around 3 PM from the CDT, notice the structure of the clouds:
The clouds are fairly flat with very little vertical growth. This is a great indicator of a stable atmosphere, one that does not promote the vertical development of clouds that could eventually lead to rain. Also notice how high the bases of these clouds appear. That is a good indicator of how dry the air is. The lower the humidity, the higher air must rise before it can cool enough to result in condensation and cloud formation. Overall, a relatively dry atmosphere which inhibits cloud growth is a much better day for hiking that a humid one with a good deal of instability.
June tends to be one of our driest months here in the Colorado Front Range, and we often see many days like Sunday which are rain free and great for outdoor activities.
Our stretch of nice, but warm, weather will last through Wednesday with daytime temps in the 75 t 0 80 F range. Cooler air and moisture associated with a deep low in the Pacific Northwest will arrive in the Front Range Foothills on Thursday and Friday bringing at least a chance of some beneficial rain.
Here is the Weather Underground forecast: