July 2021: Fear of fires turned to fear of floods as a steady monsoonal flow set up over the Rockies. The burn scars from last year’s fires combined with heavy rain brought mudslides and debris onto roads and homes in Boulder, Larimer, and other Colorado counties. On the positive side this weather event brought an end to the threat of fires as forests became wet and strong winds were virtually nonexistent. Rain for the month exceeded 2-3 inches in many locations in the foothills and plains. The monsoon flow was not only wet but was also warm as we had 19 days in the 80s.

Temperature: Average high was 80F, three degrees above normal. The average low was a warm 52 degrees. Over all the month was 2.5 degrees above normal. Highest high was 89F on the 9th and 28th of July. Coldest low was 43F on the 11th. Coldest high was 62F on the 31st after a cold frontal passage and some rain.

Precipitation: Total rain at my weather station was 2.21 inches, a little lower than the 2.68 inches we see normally. We had 14 days of measurable rain. Most of these days were brief thunderstorms of 0.1 or less. The big days were 0.68 on the 6th and 0.55 on the 31st. We had two days with small hail on the 6th and 16th.

Winds: No days exceeded 30 mph. Normally we see one. Great news for firefighters.

Other Features: When rain falls on forest fire burn scars that have little vegetation and soil that is sealed off from moisture percolation, we see serious erosion bringing mud and charred trees downslope into creeks and rivers causing water levels to rise. The result is threats to human and animal life and road and property damage. We saw this repeatedly in Larimer and Boulder Counties and further west.

Outlook for August: It looks like we will stay in a monsoon flow for a couple of weeks, the only change being that the moisture is circulating around the upper level high and will arrive to us from the north. We may see more organized systems in this type of flow. We will see drying around the 8-9th but a return of the moisture is likely by mid month. The remainder of the month will see a return to westerly flow with an increase in wind events. The average high/low on a typical August day are 74F/45F with 2 inches of rain for the month. Winds are normally not active.