Phoenix weather: Weekend monsoon forecast

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By Christina O'Haver By Christina O'Haver

PHOENIX -- We’re still anticipating an upswing in monsoon thunderstorm activity this weekend. Right now, it looks like the thunderstorm chances will peak Saturday night into Sunday morning then gradually taper off through Monday.

With the increase in moisture, we’re also looking at temperatures below normal for this time of year. Saturday and Sunday around metro Phoenix many locations may see high temperatures only in the 90s. The average high this time of year is 105 degrees.

Models continue to show a region of low pressure currently centered over southern Baja moving northwestward with western portions of it moving across Arizona late Saturday through Sunday. Models are in good agreement that Saturday afternoon into Sunday afternoon will be active as this feature interacts with deep moisture.

A caveat is that there will not be enough instability available for the wave to take advantage of because of excess cloud cover and cooling effects of outflow air from mountain storms.

The first half of the next workweek continues to look like a downtrend in storm activity as the inverted trough departs and drier air moves into the region. As a result, the amount of moisture will go down and temps will head back up.