The La Niña climate pattern is one of the main drivers of weather in the U.S. and the world, especially in late fall, winter and early spring.

* Heavy rains from Tropical Storm Priscilla's remnants caused significant flooding in Arizona.

* Phoenix experienced its fourth-wettest October day on record with 1.97 inches of rain.

* A flood watch remains in effect as saturated ground increases the risk of flash flooding.

Heavy rains from the remnants of Tropical Storm Priscilla caused significant flooding across parts of south-central Arizona on Sunday, Oct. 12, marking the fourth-wettest October day on record for Phoenix with 1.97 inches of rain.

A flood watch remains in effect through late Monday as scattered showers and thunderstorms continue across the region.

The heaviest rainfall and greatest flood risk is expected in higher terrain areas north and east of Phoenix, the National Weather Service said.

How much rain will Phoenix get?

Phoenix could see 1 to 2 inches of rain Monday, with the highest flash flooding threat during the early afternoon and evening.

Even as thunderstorms become less widespread than in previous days, saturated soils mean moderate rainfall could quickly trigger flooding. Localized heavy downpours, isolated strong wind gusts and small hail were also possible.

"Due to all the recent rainfall, soils are saturated, so it won't take much additional rainfall to cause flash flooding," the National Weather Service wrote.

Temperatures were expected to remain below normal throughout the week. Drier air arriving Tuesday, Oct. 14, should reduce rain chances, but officials caution residents to avoid flooded streets and remain alert, as runoff is more efficient on already saturated ground.

What is a flash flood?

Flash floods can develop within six hours of heavy rain, dam or levee failure. They can uproot trees, destroy buildings and bridges and trigger mudslides. Flash floods are usually characterized by raging torrents after heavy rains.

Flash floods can even occur in areas that aren't receiving rain, the weather service warns.

Warning vs. watch: What is a flash flood warning?

A flood watch is issued when conditions are favorable for flooding, according to the the weather service. It doesn't guarantee flooding will occur, but it means flooding is possible.

A flash flood warning is issued when a flash flood is imminent or already happening, USA TODAY reported. If you're in a flood-prone area during a flash flood warning, move to higher ground immediately.

Remember: Turn around, don't drown.

What to do during a flood warning

* If advised to evacuate, do so immediately.

* Use a battery-powered radio or TV to get the latest emergency information.

* Do not walk through floodwater -- just 6 inches of moving water can knock you off your feet.

* Turn around, don't drown. Never drive into a flooded street. Two feet of moving water can sweep away a car, and roads may be washed out.

* Watch for fire hazards.

* Move to higher ground.

* Stay alert and keep weather notifications on.

* Keep children away from floodwaters - they can hide rocks, trees, and debris.

Arizona weather watches and warnings

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Brandi D. Addison covers weather across the United States as the Weather Connect Reporter for the USA TODAY Network. She can be reached

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