Monsoon intensifies, higher chances of storms through Monday evening

Posted: Updated:
PHOENIX (3TV/CBS 5) -

The monsoon is expected to intensify Sunday evening, and that means a better chance of storms moving into the Valley through Monday morning.

An inverted trough situated across southeastern Arizona, deep moisture, decent dynamic forcing and higher instability will fuel thunderstorms, that could be severe at times, from the high country through the Valley.

Storms will develop first along the Mogollon Rim, White Mountains and SE Arizona late this morning and this afternoon. Steering flow will come from the east and southeast, so there's a good chance for storms and outflows to move into Metro Phoenix this evening and into early Monday morning. Some of these storms will be capable of damaging winds and large hail.

These storms are also expected to be slow-movers, so with abundant moisture to work with, flash flooding will also be a threat from the mountains to the Valley. Blowing dust is also a possibility.

Storm chances remain elevated through Monday before the inverted trough tracks northward. This will open the door for a drier air mass to start moving into Arizona for Wednesday and Thursday, decreasing the amount of storms we see in Arizona, and dropping storm chances for the Valley.

High pressure will reposition itself across the Four Corners region by the end of the week and into next weekend, reigniting monsoon conditions and increasing storm chances once again.

In Metro Phoenix, look for a high of 99 today with a 20 percent chance of storms after 11 a.m. Storm chances increase to 40 percent this evening and into the overnight hours.

For Monday, a high of 97 degrees with a 30 percent chance of storms is in the forecast. Storm chances drop to 20 percent Tuesday and 10 percent Wednesday, as highs rise back up to the low 100s.

[SPECIAL SECTION: Weather]

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