On the edge of heavy rain this week

Published 7:00 am Tuesday, August 9, 2016

We get a break from typical summer weather this week with more clouds and rain and less heat. The forecast is much more challenging than usual for this time of year because we will be near the edge of a major rain-producing system. A shift of that system by only 100 miles could make a big difference in how much rain falls in Pearl River County.

Expect numerous showers and thunderstorms this week, well above the number and coverage that we see during typical summer days. Although the most likely times for showers will still be late morning through the afternoon and into early evening, which is typical for summer, this week there’s a chance that showers and thunderstorms can pop up anytime, day or night.

National Weather Service forecasters predict that Pearl River County will likely receive a total of two to four inches of rain spread out over the next seven days. But, they anticipate even heavier rains along the three Mississippi Gulf Coast counties, eastward along the coasts of Alabama and the Florida Panhandle, and in the northern Gulf of Mexico. Don’t be surprised if you hear of some weekly rainfall totals in those areas of ten inches or higher.

Sign up for our daily email newsletter

Get the latest news sent to your inbox

Why all the rain? Most of the computer weather models are predicting that a surface trough and low-pressure system, unusually well-defined for this time of year, will meander around the Gulf South most of the work week. There is also a low-pressure circulation in the middle and upper altitudes of the atmosphere.

The unstable, rising air associated with the low-pressure systems in combination with a virtually unlimited supply of moist, tropical air will provide the ingredients for more widespread rain than is usual during the summer. The total moisture throughout the atmospheric column over us this week will be near record high levels.

The distribution of rain is forecast to be quite lopsided. The heaviest rain will be to the east and south of the low-pressure center, The center of the low will likely be very near us most of the week. The rain coverage is forecast to fall off dramatically to our north and west. The Global Forecast System, which is the National Weather Service’s premier computer model, is predicting a total of near 10 inches of rain at Dauphin Island, Alabama between now and Monday, while predicting less than two inches over the same time period in Alexandria, Louisiana.

A shift of 100 miles or less in the location of the heavy rains could mean that our weekly total may only be a couple of inches, or we could find ourselves much closer to the 10 inch totals. There could also be quite a bit of variation in rainfall totals across the county.

 Because of the increased clouds and rain, our high temperatures are forecast to stay down in the middle to upper 80s most of the week instead of the 90s that are typical of this time of year.

By Skip Rigney