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Freeze warning extended in the West; flash flood warning issued in Ohio Valley

In the West, farmers worry about their citrus crops as temperatures dip below freezing. The National Weather Service extended its freeze warning to Tuesday. NBC's Kristen Dahlgren reports.

The weather appears to have flip-flopped this week, with a freeze descending on California and parts of the East Coast boasting uncharacteristically balmy t-shirt temperatures into the 60s.

West Coast produce farmers worried about their citrus crops as a freeze warning extended to Tuesday. Six Western states experienced record lows.

The National Weather Service said this will likely be the coldest weather of the season, with early Monday morning dipping into the mid-20s in some of the coastal valleys and on the central coast away from the beaches.

Meanwhile, nearly 100 cities on the East Coast topped record highs.

Where warm met cold, weather erupted. Heavy rains caused flooding in Indiana and a tornado destroyed a church in Kentucky. The National Weather Service issued flash flood warnings for Louisiana to the Ohio Valley through Monday morning.

--Reporting by NBC's Kristen Dahlgren and Isolde Raftery.