Feels like summer, but spring still not over
Published 7:00 am Tuesday, April 18, 2017
By Skip Rigney
We are getting to the time of year when the disturbances and cold fronts coming toward us from the northern and western parts of North America are getting weaker.
The jet stream is not dipping as far south, and so, cold fronts slow down as they approach the southern states. Many cold fronts stall, then get thrown into reverse and retreat northward as warm fronts. Other cold fronts become stationary over north Mississippi before gradually disappearing from the weather map.
Instead of looking to our northwest for our next weather systems, forecasters begin to look to the western Atlantic. As spring transitions toward summer, a ridge of high pressure in the western Atlantic becomes stronger. The ridge becomes a semi-permanent feature. It affects our weather as its western tip noses into the Gulf of Mexico.
This high-pressure system is known as the Bermuda High, because its center can often be found within a few hundred miles of the island of Bermuda in the Atlantic Ocean.
This is the situation setting up for most of this week. The Bermuda High is in place over the western Atlantic and surface high pressure will extend westward into the Gulf of Mexico. Upper air disturbances and a cool front will stay well to our north throughout the rest of the workweek.
Meanwhile, the clockwise circulation of air around the Bermuda High will cause those of us on its western side to experience surface winds from the south. Those winds will bring warm and relatively humid air from the Gulf of Mexico across the coastline into Pearl River County.
At the same time, upper levels of the atmosphere above us will also be dominated by high pressure.
The result is a forecast for a lot of sunshine. There is a slight chance widely scattered, summertime-type afternoon showers today and Wednesday. However, on Thursday and Friday drier air in the upper levels of the atmosphere will drop our rain chances into the slim-to-none category.
Overnight temperatures will only fall into the 60s, and afternoon highs will be in the middle and possibly even the upper 80s.
With weather like that on tap, you might be tempted to think that spring left us and summer has come to stay.
But lovers of spring, and, for that matter, haters of the heat and humidity of summer, should not lose heart yet. After all, it is still April.
The various computer weather models are predicting that by this weekend a cool front will be headed our way out of Texas, and this cool front will have enough kick to make it past us.
Before the front passes it will increase our shower and thunderstorm chances for Saturday afternoon and night. It’s too early to tell whether the showers will linger into Sunday.
Based on these models, forecasters are predicting that Sunday we will be back into the 70s for the daytime high. Nighttime lows may even slip down to near 50 degrees Sunday night and Monday night.
If those predictions hold true, Sunday and Monday might actually be a little cooler than the long-term climate averages, which for the beginning of the fourth week of April in Pearl River County are in the middle 50s for lows and near 80 degrees for highs.