Fall brings weather pattern change, storm source shifts

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Winter is a time when the Valley can get some rain, too. (Source: 3TV/CBS 5) Winter is a time when the Valley can get some rain, too. (Source: 3TV/CBS 5)
(3TV/CBS 5) -

We know the monsoon brings thunderstorms and rain to the Valley during the summer, but it isn't our only rainy season.

 

[MOBILE/APP USERS: Click/tap here to see photo of monsoon storm with lightning]

Phoenix and Arizona have two distinct rainy seasons. The monsoon and the winter, or at least the Phoenix version of winter. 

To get rain in the Valley during the fall and winter months, we mainly look to the northwest. 

[MORE: Weather blog]

All summer long a large area of high pressure over the Pacific Ocean blocks storms and sends them north. That ridge, the Pacific High, breaks down as we get into the fall and winter months.

[RELATED: Monsoon 2017: A mixed bag (so far)]

After a very dry few months in California, storms during the winter are once again allowed to meander down the West Coast and across the Great Basin.

During winter months in Arizona, we keep a close eye on the Gulf of Alaska, the birthplace for many storms that bring Valley rain and mountain snow.

[APP/MOBILE USERS: Click/tap here for picture of storm that formed in the Gulf of Alaska]

If you look at monthly data, the winter holds a good portion of the average rainfall in Phoenix. In January, February and March, Phoenix can pick up around .91 to .99 inch of rain each month. 

[RELATED: Phoenix Rainfall Index looks at the big rain picture]

The only other time we see as much rain is during the monsoon, with July and August each bringing around an inch of rain.

[SPECIAL SECTION: Arizona Monsoon 2017]

So while many of the elements that helped fire monsoon storms came from the south, this winter, listen for meteorologists to talk about storms dropping in from the north! 

[RELATED: Rain totals on azfamily.com]

Click/tap here to download the free azfamily mobile app.

Copyright 2017 KPHO/KTVK (KPHO Broadcasting Corporation). All rights reserved.


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