Turn toward a wetter pattern expected

Published 10:44 am Sunday, May 22, 2022

By Skip Rigney

Showers and thunderstorms will be increasing over south Mississippi over the next several days, and a generally wet pattern is forecast to take hold during the first half of June.

Most areas in the county are still running four to twelve inches below the 25-inch historical average for January through May 20th, even after 0.5 to 1.5 inches of rain fell in parts of Pearl River county last weekend. Thunderstorms, which rolled into the county on high altitude flow from the north last Saturday and Sunday nights, produced pea-sized to marble-sized hail in McNeill and several other locations. The hail was the result of warm temperatures near the ground combined with subfreezing temperatures at lower altitudes than what is typical for this time of year.

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By last Monday, pressures and temperatures were increasing in the middle atmosphere above us, putting a lid on the development of showers and thunderstorms. So, despite plenty of surface warmth and humidity, most locations in Pearl River County haven’t had any rain since last Sunday night.

However, that high pressure system is being nudged away from us this weekend as a cool front slowly drifts our way from Arkansas and Oklahoma. The closer it gets, the more unstable the atmosphere will become ahead of the front.

With plenty of moisture streaming in from the Gulf of Mexico on southerly winds, that’s a recipe for about a 50/50 chance that wherever you are in Pearl River County today (Saturday) you will see one or more showers or thunderstorms.

Sunday, Sunday night, and Monday, no matter where you are in Pearl River County, you will probably see several rounds of showers and thunderstorms, because the weak front is expected to stall very near us. Rainfall totals of one to two inches are likely for the period, and locally heavier amounts are certainly possible.

By Tuesday the front puts it into reverse, retreating slowly northward. That may allow shower coverage to decrease to the more typical summer-like scattered category for Tuesday through Thursday, but forecast confidence is lower than normal for the middle and latter part of the upcoming week, as different models are presenting differing solutions. So, additional significant rainfall is not out of the question for Tuesday through Thursday.

There is the possibility that late in the work week the front makes a final, valiant surge southward. That would put us into drier air as early as Friday and possibly extending through next weekend, which in turn would allow for overnight temperatures to drop into the lower 60s, or even a little cooler.

However, if any drier, milder air does sneak into south Mississippi, it won’t stay long. A wetter-than-normal pattern appears likely for early and mid-June according to the monthly outlook issued on Thursday by NOAA’s Climate Prediction Center (CPC). Long-range modeling indicates that the upper wind flow will favor rising motion in the lower and middle levels of the atmosphere over the Gulf of Mexico and adjacent areas of the northern Gulf Coast and Florida during the first half of June. That upward air motion is expected to combine with a vigorous daily sea breeze to enhance the development of showers and thunderstorms up to 50 miles or more inland.