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Historic April rains were triple the average

By Skip Rigney

This April was one of the wettest in the lifetimes of even the oldest residents of southern Pearl River County. Rainfall as of Friday morning totaled 14 to 16 inches for the month in many locations from Picayune to Carriere and eastward into Hancock County. Other locations in the county were not far behind with totals that ranged from 9 to 14 inches. There was even the possibility that a little bit more rain might fall on Friday as scattered showers were forecast. Rainfall totals are based on a combination of reports from volunteer observers and estimates from the National Weather Service (NWS) radar in Slidell.

South Mississippi, southeastern Louisiana, and south Alabama had the distinction of being the wettest area in the entire nation in April. Gulfport, Slidell, New Orleans, Baton Rouge, McComb, and Pascagoula all reported April 2021 as being in their top five wettest Aprils on record with monthly totals through the first 29 days ranging from 12.01 to 15.23 inches according to the NWS in Slidell.

That’s a far cry from the four to five inches that was the average April rainfall across the region for the 30-year period from 1981-2010. As an aside, later this month NOAA will be releasing updated 30-year climate normals using data from 1991-2020. Preliminary peeks at the new averages indicate that our area trended about one-half inch wetter during April in this most recent 30-year period.

May is typically a month of transition for the Gulf South. We begin the month in a late spring weather pattern. Cool fronts are still relatively common visitors, although they are more likely to stall near the coast than they were earlier in the spring.

That will be the case to start May 2021. A cool front moved through late Friday, allowing less humid air to flow into Pearl River County to start our Saturday. However, the frontal boundary has already stalled along the Louisiana coast, and will be headed back north as a warm front with showers and thunderstorms on Sunday. Some of Sunday’s storms have the potential for being severe and rainfall could be heavy.

Rain chances will decrease Sunday night as the warm front moves to the north, but they won’t be zero as we will be immersed in the warm, juicy air mass south of the front. Daytime heating on Monday will likely bubble up scattered, short-lived showers across south Mississippi.

By Tuesday and Wednesday, another cool front will be slowly heading our way from Texas and Arkansas, once again raising our rain chances and the slight possibility that some thunderstorms could reach severe levels.

The weather models predict that the midweek cool front will have enough momentum to keep pushing well to our south and east. Behind it a continental high pressure system, drier conditions, and late spring temperatures should take over sometime Thursday and continue into next weekend.

We should savor that post-frontal air mass, because cool fronts will become less frequent by the middle and end of May. Fronts will tend to stall to our west and north as they are held back by the Atlantic high pressure system, sometimes referred to as the Bermuda high, as it moves into its summertime mode, growing stronger and extending further westward into the southeastern United States.