Monsoonal moisture and the odds of seeing flash flooding

Not every monsoon is the same, and some can bring more rain than others. Rain totals this time around will vary quite a bit, with areas south of Highway 50 getting more rain than areas to the north. There’s more of a fire risk north of I-80 where there is less moisture to work with. Most spots will get between .10-.50” of rain by Tuesday night. Localized spots could get over an inch.

A monsoon is defined as a change in wind direction. High pressure is located east of Nevada, and with clockwise flow, southerly winds are wrapping around the ridge, bringing in ample moisture. Moisture or water content can be measured in a variety of ways and at different levels of the atmosphere. It’s even muggy outside, which is rare for our area. Dewpoints are in the 50’s, which is high for Reno. Precipitable water values are also above average, with plenty of water to work with. No need for a winter coat, but you’ll want an umbrella, rain boots, and a rain jacket.

The rain will come and go with a significant round of showers and storms developing Monday evening and again Tuesday afternoon. Cities along and east of 95 will see more steady rain through 1 am, with pockets of heavy rain and embedded thunderstorms. Reno will see some showers as well. The rain will look like leap frog on radar, with one storm or shower developing to the north of the current one. This will lead to narrow bands of higher rain totals compared to its surroundings.

Thanks to more instability, or food for thunderstorms, Tuesday will be the most active day this week. The storms will be numerous and stronger than today. Gusty winds and localized flash flooding can’t be ruled out. Especially over burn scars. A Flood Watch is issued for northeast Nevada on Tuesday, where the rain will be heavy at times. Eastern Nevada is also located closer to the ridge itself.