Warm spring about to get even warmer

Published 5:08 pm Friday, March 20, 2020

By Skip Rigney

Temperatures over the past ten days have been much warmer-than-normal for this time of year. By the end of the upcoming week, you may be tempted to think that we have fast-forwarded through spring into summer.
Based on historical data, daily high temperatures for mid-March average in the lower 70s across south Mississippi. However, this year daily highs have been warmer than that every day since March 11th and have exceeded 80 degrees on most days. Last Sunday the temperature at a weather station in Carriere hit 87 degrees.
The airport in Slidell has been keeping records since 1994. With highs in the low 80s, that station set record high temperatures on all but two days out of the last nine, making this their warmest March 12-20 in the last quarter century.
The large bubble of warm air that has enveloped most of the Gulf of Mexico and southeastern United States is associated with a strong dome of high pressure in the upper atmosphere over the same region.
When we have a strong upper high over us, it often happens that at the same time the jet stream is dipping southward on the other side of the country allowing cold air to move out of Canada into the western United States. That was the case this past week as one to three feet of snow fell in the Sierra Nevada mountains of California, and new record cold temperatures were set several days at stations in Washington, Oregon, and California.
Today a weak cool front will push the dome of high pressure down into the Gulf, but don’t expect too much of a cool down. And by Sunday the boundary will be headed back toward us as a warm front. The front will increase our rain chances both days this weekend.
By Monday the weak front will have pushed back to our north leaving us immersed in warm, humid air from the Gulf. The upper level ridge of high pressure in the Gulf is expected to strengthen and expand north as the week continues, and by Wednesday, Thursday, and Friday forecasters expect our temperatures to be far above normal with afternoon highs in the middle to upper 80s.
In over 100 years of weather observing at the Poplarville Experiment Station, it has never reached 90 degrees in the month of March. The mercury has hit 89 degrees three times in March: in 1921 on the 18th, in 2003 on the 25th, and in 1946 on the 30th. There’s a possibility we could flirt with tying or exceeding those all-time record highs for March later this week.
The earliest in the year that Poplarville has reached 90 degrees was on April 11th in 1963. The average date for hitting 90 over the past 100 years has been May 16th. So, if we were to hit 90 later this week, it would truly be extraordinary.
Regardless of whether records are broken this week, expect it to feel very summery. This won’t be a dry heat. With southwest surface winds coming off the Gulf of Mexico, computer weather models are predicting dew point temperatures on Thursday and Friday to be in the upper 60s, which is quite muggy for March.

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