Monsoon Sweeps Back In

02 September 2019   Dr. Mark Sinclair
We should see some monsoon activity this week.

Weather discussion:

I’m getting this out a day early because there is a significant change in the weather starting tonight, along with a threat of strong thunderstorm winds later today (see attached). 

As expected, the mid-level anticyclone that steers our monsoon moisture has moved to a more favorable position near the Four Corners region, moving moisture into northern Arizona. Dew points in the Prescott area, currently around 39F, are expected to rise rapidly in the next few hours as a moisture surge pushes moisture into northern Arizona. Expect storms to form to our east then to push west-southwest into Yavapai County later this evening, with a 60% chance of showers and thunderstorms. Some of these storms may be severe, with gusty and damaging winds in excess of 50 kt near thunderstorms. Storms may continue well into the evening.

Thunderstorm chances will become more widespread Labor Day as moisture continues to stream into Northern Arizona. Temperatures will be several degrees cooler as cloud cover increases.

For the rest of the week, expect scattered thunderstorms each day, but decreasing later in the week.  Models are hinting at an active pattern next Sunday-Monday timeframe as a trough from the Pacific interacts with monsoon moisture.

Additional notes for the weather nuts out there:

Hurricane Dorian is still approaching Florida. I’ve attached a meteogram from the Bahamas that shows impressive forecast winds and precipitation there.

Official Hurricane forecasts can be found at https://www.nhc.noaa.gov/ Click on Dorian for more details.

Stay safe. Remember that standing under a tree is NOT a safe place during a thunderstorm because trees can be hit by lightning and large branches can break off trees during strong thunderstorm winds. I’ve just spent three days with a chainsaw clearing up broken branches from last Wednesday’s storm in Humboldt.


Met Mail is an unofficial weather discussion and forecast transmitted once or twice a week via e-mail by the Embry-Riddle Department of Meteorology (http://meteo.pr.erau.edu/). Embry-Riddle offers an undergraduate bachelor-of-science degree program in Applied Meteorology. Please spread the word to all potential qualified candidates!

Further Information:

ERAU Applied Meteorology degree program

Official National Weather Service forecast

Embry-Riddle Aeronautical University: Website | Facebook | Twitter | YouTube