Sources of summer weather vary
Published 7:00 am Tuesday, June 26, 2018
Have you noticed? The weather is in a rut. If variety is the spice of life, our weather is in the middle of a diet of unsalted, white rice.
Most weeks from June through sometime in September in Pearl River County, and for that matter in most of the southeastern United States, you can randomly pick a summer weather forecast from the previous fifty years and have a pretty good chance of being right.
The basic elements are the same. Warm nights. Hot days. Muggy. A mixture of sun and clouds. Some afternoons a shower and maybe even a big thunderstorm right on top of you. Other afternoons no rain, but thunderclouds in the distance.
The tedium of the day-to-day summer weather doesn’t mean that there isn’t some occasional meteorological drama. Thunderstorms are the most frequent source of this season’s weather excitement, and even danger. Their lightning is always worthy of respect, and from time-to-time their downdraft winds are strong enough to cause some havoc. More often those winds give us a brief, cool respite from the summer heat.
There’s no doubt that much of the time our summer weather is much more uniform from day-to-day than any other season of the year. The jet stream several miles high in the atmosphere with its energetic meanderings and associated surface cold and warm fronts, low pressure systems, and shields of rain, is usually far to our north.
So, when we are in a monotonous stretch of summer weather, we can easily forget that every summer is punctuated by some significant weather systems, and occasionally a summer comes along that is noticeably different from the normal.
Here along the Gulf Coast, the most frequent summer weather mischief is caused by atmospheric disturbances coming from the tropics. Most of these are much too weak to even be designated a tropical depression, but they are frequently strong enough to give us an extended period of numerous showers and thunderstorms.
The other end of the spectrum occurs when the high pressure systems over the western Atlantic Ocean, or the southern Great Plains, or both, are very strong. The subsiding air associated with these systems squashes showers before they can form.
When those high pressure systems dominate our weather pattern, our temperatures can climb into the upper 90s, and we get very little rain. It doesn’t happen often, but sometimes that pattern can persist for much of the summer, leading to drought conditions.
What about this week? The computer weather models don’t show any tropical systems entering the Gulf of Mexico. And although a strong upper high will be over the Great Plains, the models predict that we will remain on the eastern edge of that hot air mass, keeping the triple digit heat confined to places like Abilene, Texas, and Manhattan, Kansas.
In other words, from south Mississippi eastward to south Alabama and westward to south Louisiana, the monotony of typical summer is forecast to continue for at least another week. In fact, that’s a pretty good bet for most weeks for the next two months.
By Skip Rigney