WEATHER
Frigid air is expected to trail the storm.
Snowpack protects northern winter wheat from frigid temps.
Frigid temps to persist for several more days.
A moderate or strong La Niña like the one currently underway typically produces a drier than normal weather pattern across the southern U.S.
Showers also are benefiting winter wheat on the Plains.
A surge of cold air is expected to trail the front.
Freezes occurred as far south as west-central Texas overnight.
Meteorologist Gail Martell provides a South American weather update.
Meanwhile, rain is falling in the Pacific Northwest and will arrive in the northern Plains during the second half of the week, USDA says.
Hot temps and dryness are stressing crops.