While the temperature was expected to go up Sunday night into Monday morning—possible reaching a high of about 47 degrees by 2 a.m.— it's expected to drop throughout the day to about 34 degrees by 5 p.m.
Widespread fog is expected before 9 a.m., and rain showers, possibly mixed with snow, are expected after 11 a.m.
Monday night will see a low of about 5 degrees, with wind chill values making it feel like 10 degrees below zero. Winds from the west will run from 22 to 26 mph, with gusts as high as 40 mph.
The extreme cold snap will continue Tuesday, with a daytime high of about 14 degrees. Wind chill values will make it feel like 13 degrees below zero, according to the NWS.
Daytime highs the rest of the week will range from 29 degrees Wednesday to about 50 on Saturday.
There's a chance of rain and snow on Thursday and rain on Friday.
See the entire week's weather forecasts for the Dundalk area on the NWS website.