Freeze warnings go into effect Monday night in the highest elevations of the Upstate, but more South Carolinians could see frost or freeze conditions by midweek.
The first significant cold snap of the season is set to plunge much of the eastern half of the United States below freezing this week. Surface observations Monday afternoon depict a strong cold front crossing the Upstate, with stout northwesterly winds behind the front dragging in an anomalously cold and dry air mass for mid-October. A surge of warm and breezy weather ahead of the cold front has allowed for highs Monday to reach into the lower and middle 80s across the Midlands and Lowcountry. The above-average temperatures to kick off the work week will not last much longer.
On the heels of an early week cold frontal passage, low temperatures in portions of the Upstate are forecast to drop into the upper 20s and lower 30s for several consecutive hours. If the forecast for lows below freezing comes to fruition, it would likely mark the end of the growing season in places like Greenville-Spartanburg, Rock Hill, and Anderson. The heart of the cold air mass arrives Tuesday night, with lows in the Upstate possibly below freezing while areas like the Midlands and Lowcountry experience temperatures in the mid-30s.
Despite sunny skies Tuesday and Wednesday, much of the state will struggle to get to 60 degrees during the afternoon. Several locations from the Upstate to the Lowcountry could see record-cool high temperatures Wednesday with highs topping out only near 60. In the Augusta area, one has to go back to the 1870s to find high temperatures as low as what's forecast Wednesday.
It does not look like this early-season chill will linger long, as temperatures are forecast to inch closer to average by early next week.