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The threat of thunderstorms that could lead to lightning-sparked wildfires prompted the National Weather Service to issue a Red Flag Warning for much of Western Washington and the Cascades beginning Saturday morning.

KING 5 Chief Meteorologist Jeff Renner said, As the ridge of high pressure that's kept us hot and dry moves east, winds aloft will shift to southerlies. That will direct moist and unstable air northward into Washington during the day Saturday and especially Saturday evening.

Renner: When we say 'unstable' we mean once the air begins rising, it will tend to continue rising. The result is the towering Cumulo-Nimbus clouds that can produce thunder, lightning and hail.

Lightning strikes were largely over the Pacific Ocean just off Washington's coast, but the National Weather Service has expanded the Red Flag warning into Sunday. The amount of rain is likely to be small, providing little moisture to a region that has seen no rain since mid-July.

Track the changing weather conditions with the KING5 First Alert Forecast.

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