Storms tonight ahead of cool front
By Skip Rigney
Strong to severe thunderstorms are a possibility tonight as a strengthening low pressure system passes to our north moving from northeast Texas through Arkansas.
Warm, humid air from the Gulf of Mexico streaming northward across Mississippi today and tonight in the southeastern quadrant of the low pressure circulation will provide the fuel needed for thunderstorms to develop.
The intense low pressure system extends from its surface location upward five miles high in the atmosphere tilting westward to Oklahoma with increasing height. Upward motion and instability to the southeast and south of the center of the low will provide the extra lift needed to pump up some of tonight’s thunderstorms to the severe level.
The tilt of the low pressure system from surface to higher altitudes means that, for hundreds of miles around the center, winds will be changing direction depending on height above ground. That wind shear can get thunderstorms spinning and raises the risk of tornadoes.
As of Friday morning, the National Weather Service Storm Prediction Center in Norman, Oklahoma, forecast a moderate risk of severe weather on Saturday and Saturday night over northern Louisiana and west-central Mississippi. The SPC forecasters placed a slight risk of severe thunderstorms, including the possibility of tornadoes, over the entire state of Mississippi and southern Louisiana. You can get the latest severe weather outlook from SPC by going to www.spc.noaa.gov and clicking on the Convective Outlook tab.
It looks likely that the main line of thunderstorms will get to Pearl River County tonight, probably after you’ve gone to sleep. Consider putting your cell phone with its weather alert app on the bedside table tonight.
A cool front extends southward from the center of the surface low. As the low pressure system moves northeastward, it will drag the front eastward through south Mississippi Sunday morning.
The air behind the cool front will bring an end to the 80s that we have experienced over the past several afternoons. This past Wednesday was the warmest day since last October in Pearl River County. The Mississippi State University Experiment Station in Poplarville recorded a high temperature of 85 degrees. Several unofficial personal weather stations across the southern part of the county posted even warmer readings for Wednesday.
The cool air flowing into our area on northerly winds may make Sunday night one of our coolest nights during the entire month of April as the temperature dips into the 40s. Highs on Sunday and Monday afternoons will reach only the low to middle 70s with low humidity.
However, by Tuesday, winds will be shifting back to a southerly direction, and temperatures and humidities will be increasing ahead of another area of low pressure developing in the southern Great Plains. Some widely scattered showers may begin to pop up by Wednesday.
By Thursday or Friday the Great Plains storm system and its associated cool front could, once again, bring together the ingredients necessary for some severe thunderstorms in the Gulf South. At the very least there’s a high chance that we will see some showers Thursday or Friday before that system moves to our east.