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Moisture will fuel thunderstorms as far west as central and western Pima County

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Posted at 10:55 PM, Jun 25, 2021
and last updated 2021-07-01 08:14:35-04

TUCSON, Ariz. (KGUN) — A shift in our weather pattern will open the door for a big surge of moisture to bring June to a close.

High pressure over Colorado will slide south and help push some moisture into eastern Arizona. Most thunderstorms will occur over Graham, Greenlee and Cochise counties and will produce some gusty outflow wind. The outflow wind will spread westward and could produce a few thunderstorms over the mountains to the east of Tucson.

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We’ll notice the first wave of moisture as early as Sunday evening. High pressure over Colorado will slide south and help push some moisture into eastern Arizona.

This will set the stage for more widespread thunderstorm activity on Monday and Tuesday. More moisture will be available to fuel thunderstorms as far west as central and western Pima County. Some thunderstorms will produce gusty wind, heavy rain and frequent lightning.

Rainfall early in the week will help keep moisture in place to fuel more thunderstorms for the remainder of the week. On top of that, we’ll see another surge of moisture arrive from the south as we go into the second half of the week. This is when we could see more widespread rain activity with some embedded thunderstorms.

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Rainfall early in the week will help keep moisture in place to fuel more thunderstorms for the remainder of the week.

The late week moisture surge could be enhanced by some tropical moisture. Tropical Storm Enrique has formed to the southwest of Manzanillo, Mexico and is expected to drift northwest into the middle of next week. With high pressure setting up over northern Mexico, this will help draw some of Enrique's moisture over southern Arizona.

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The late week moisture surge could be enhanced by some tropical moisture.

One thing that may limit thunderstorm activity towards the middle and end of the week is cloud cover. If we get too much cloud cover, the sun won’t be able to heat the ground to get any good convection going. Without some form of lifting mechanism, we won’t see any thunderstorms.

It’s still a little too early to tell how much rain will fall across the region but early indications have some models predicting over two inches of rain for several locations across southeastern Arizona over the course of next week. Some localized flooding may occur in areas that receive repeated rainfall during the week.

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Some localized flooding may occur in areas that receive repeated rainfall during the week.

The benefits of a prolonged period of time with passing rain showers and thunderstorms can’t be overemphasized. The Southwest is in dire need of some significant rainfall to help fill our reservoirs, extinguish wildfires, reduce wildfire danger and bring much needed rain to our thirsty desert. Let’s hope this all comes together to get monsoon off to a great start!