ST. LOUIS – The National Weather Service has issued a frost advisory from Saturday evening to Sunday morning for several counties just west and north of St. Louis.

After reaching the 80s last weekend, temperatures have dipped considerably to the point where frost could form overnight.

NWS says temperatures could dip to the mid or low 30s during the early morning hours of Sunday.

Emergency landing: Flight bound for Sacramento returns to St. Louis

A frost advisory is in effect mainly for counties north of Interstate 44 in Missouri and north of Interstate 64 in Illinois. For now, St. Louis County and St. Charles County are not part of the advisory, though some counties nearby could see frost.

The cooler conditions could kill crops, sensitive vegetation and damage unprotected sources of plumbing. Make sure to take plants inside or cover as necessary, and also to protect plumbing from the cold.

Temperatures are expected to warm up into the 60s on Sunday and 70s on Monday in much of the St. Louis region.