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Bitter cold lurking to our north

By Skip Rigney

A major outbreak of bitterly cold arctic air will be the big weather story across the central United States during the upcoming week. However, the forecast for south Mississippi is more complicated and also much more uncertain than usual.

Forecasters at the National Weather Service’s (NWS) Weather Prediction Center expect a large and intense low pressure system to form over the next few days aloft over Canada. All indications are that the low will spend most of the upcoming week stuck between the Great Lakes of the United States and Hudson Bay in northeastern Canada.

The counterclockwise circulation around the low will create a highway on its western side for several lobes of frigid air to break off and ride down from northwest Canada into the central United States.

However, for much of the week along the central Gulf Coast, we will find ourselves in the vicinity of the front separating polar air from relatively mild air. Some days during the first half of the work week, we will be on the mild side of the front. Tuesday will probably be our warmest day when temperatures during the afternoon could climb above the 70 degree mark.

Sometime late in the week, the arctic air will make another push southward. However, even once the front passes through, it is unclear if the core of the cold air will slide deep into the Gulf or we will receive just a glancing blow.

Some of the computer weather models are hinting that freezing air will eventually flow into the central Gulf Coast region sometime between Thursday and Saturday.

Then low pressure is expected to form along the front as it lies to our south.

If that happens, it would set the stage for an icy mess to occur somewhere in Louisiana, Mississippi, or Alabama sometime between Thursday and Sunday.

Twice each day a forecaster at the NWS Office in Slidell issues a “behind-the-scenes”  discussion explaining their reasoning for the upcoming seven-day forecast. Friday morning’s discussion contained two statements highlighting this unusually difficult prediction: “By midweek, forecast confidence really takes a nosedive given the wide variety of forecast solutions,” and “There is some potential that moisture would overlap with temperatures cold enough to support wintry precipitation. However, anyone who tries to convince you that this is a sure thing is lying.”

One thing is for sure, and that is that late in the upcoming week south Mississippi will be much closer to the front than we will be to the core of the cold. That makes it much harder for forecasters at the NWS in Slidell than their counterparts in, for example, Grand Forks, North Dakota, who are much more confident in their upcoming forecast.

Temperatures in eastern North Dakota fell below zero yesterday, and will probably not make it back into positive territory until next weekend. And, it’s going to be a windy week, with wind chills making it feel like 20 to 50 below zero.

So, even if some of the air from the arctic shows up here next weekend, keep in mind that it will have warmed up enough along the way to feel positively balmy to a North Dakotan.