Today: Feb 20 , 2020

Three Back-to-Back Storms This Week

17 January 2017   Dr. Curtis James

Get your winter gear ready.

The figure above indicates the forecasted high in orange (with error bar denoting the range of ensemble forecast members), average high for this time of year in orange (dashed line), forecasted low in blue (with error bar), average low this time of year in blue (dashed line), and forecasted wind speed in purple. Note that the wind speed forecast is sustained wind (not gusts), and it is based on only one model (not an ensemble).

Weather Discussion:

I know what you’re thinking. This hardly seems like Arizona weather, especially for a La Niña episode. But would you believe that three more back-to-back storms are expected from Thursday – Tuesday?

A brief period of high pressure should prevail now through Wednesday for mostly sunny skies, light wind, and warming temperatures…but after that the weather will rapidly deteriorate. By Thursday, a strong core will develop in the upper-level jet stream and take aim at the southwestern U.S., with Arizona on the north side of the jet’s exit region. This quadrant of the jet is a location favorable for rising motion, and the jet will remain to our south for at least 6 days, bringing us unsettled weather from Thursday through next Tuesday.

A series of three troughs will move with the jet stream across Arizona on Thursday, Friday – Saturday, then again Monday – Tuesday of next week. Expect cooler, windier weather with a chance of rain/snow with each of these systems. Thursday will likely see more rain than snow, with possibly only up to an inch of wet snow accumulation at the elevation of Prescott by the end of the event (with higher amounts possible in the mountains around town). The second storm on Friday night – Saturday will likely be cooler and bring greater potential for accumulating snow (perhaps 2-4 inches during the latter half of the event from Friday night - Saturday). There may be some sun mixed with clouds Sunday – Monday before the third system. Forecasts are still largely uncertain, but the third storm on Monday - Tuesday could be the strongest and coldest of the three storms. The current forecasts are indicating about 6 inches of snow accumulation in Prescott next Monday – Tuesday with higher amounts to be anticipated in the mountains around northern Arizona. I will send updates as needed.

Just like Seattleites who leave the office to bask in a rare sun break, Prescottonians may be begging for relief from the stormy weather by next Wednesday. Bottom line is, the long-range forecasts for Prescott are indicating about 1.75” of rain/melted snow (and about 8 inches of snow accumulation) within the next 8 days. Enjoy!

C. James

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 ( 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

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