By Skip Rigney

This week will likely go down as the warmest final week of December on record, not only in Pearl River County but across much of the United States from the southern and central Great Plains eastward to the Mid-Atlantic seaboard.

Daily high temperatures in our area have ranged from the middle 70s to near 80 degrees every day since Christmas Eve, and they are forecast to continue to do so through New Year’s Day. The average of daily high and low temperatures for the nine day period from December 24, 2020 through January 1, 2022 is on track to exceed anything for that date range in 107 years of weather observations at the Poplarville Experiment Station. The only similarly warm period at the end of December occurred in 1971 when the mercury in Poplarville climbed above 75 degrees for six consecutive days.

In what meteorologists refer to as a “highly amplified” pattern of temperatures and atmospheric pressures, cold air and a trough of low pressure aloft have plunged southward over North America’s Pacific coast, while warm air and a ridge of high pressure aloft have dominated the southeastern United States.

However, changes are underway. The trough and ridge are now moving from west to east, which is the usual progression for waves in the atmospheric flow this time of year. That movement will allow a cold front to finally sweep eastward and southward from the Great Plains toward the Atlantic Coast and arrive in south Mississippi sometime Saturday night.

The strong front, in conjunction with the eastward moving trough of low pressure aloft, could produce a severe weather threat somewhere in the Deep South on New Year’s Day. Although the greatest risk is likely to be north of Pearl River County, make sure you are able to receive alerts on your mobile phone or NOAA weather radio Saturday and Saturday night in case watches or warnings are issued.

Showers are likely ahead of the front, but precipitation totals in Pearl River County probably won’t exceed one-half of an inch according to National Weather Service forecasters. There’s a chance some of us won’t see much more than a few sprinkles on Saturday afternoon or evening.

When the front passes us, the rain and the severe threat will end as winds shift to the northwest bringing colder, drier, and more stable air into the area. Sunday is forecast to be a windy, raw day. Even if sunshine makes an appearance, temperatures will hold steady or even slowly fall into the 40s.

A freeze is likely Sunday night and early Monday morning as temperatures are predicted to drop into the 20s for the first time this winter. Temperatures on Monday will climb upward through the 30s and 40s, perhaps into the lower 50s, before falling into the 30s overnight Monday into early Tuesday.

For lovers of warm winters who will be sent into shivers by the cold start to the week, relax. Computer weather models indicate that by Monday, another ridge of high pressure and warm temperatures in the middle atmosphere will build from Mexico northward all the way into southern Canada and then begin to slide eastward, changing our weather back to mild by mid-week.