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).
Weak low pressure aloft will spin counterclockwise along the California Coast the next few days in advance of a stronger trough that will dig south from Canada into the Great Basin. The first low will help to usher moist air back into Arizona today through Monday, leading to a chance of showers or thunderstorms. Thunderstorms that form Saturday to Sunday will move to the northeast or east-northeast at about 10 mph and be capable of locally heavy rain and possibly small hail. On Monday, the vertical wind shear will strengthen in advance of the second trough, causing storms to become possibly better organized or even severe (with possibly larger hail) and propagate toward the east-northeast or east at about 25 mph.
By Tuesday, the chance of thunderstorms will diminish as the wind becomes westerly aloft and ushers drier air across the area. Also expect breezy and cooler conditions for early next week in association with the second trough moving through the Great Basin. The latter half of next week should be mostly sunny and mild.
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!
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Official National Weather Service forecast