By Skip Rigney
The tornado that hit Picayune on Wednesday night was embedded in a line of severe thunderstorms that had started earlier in the day in eastern Texas and then passed through southern Louisiana. The storms were caused by a powerful cyclone, an alternate term for a low pressure system, centered near Memphis. Cyclone circulation covered an immense area of over half a million square miles from Wisconsin to the northern Gulf and from Oklahoma to North Carolina.
Due to the intensity of the cyclone, the abundance of warm and humid Gulf air and changing wind directions with height, the National Weather Service (NWS) issued several tornado watches in the southern Gulf on Wednesday. , sounding the alarm that conditions were favorable for tornadoes and severe thunderstorms.
They issued a tornado watch for southern Mississippi and southeast Louisiana, including Pearl River County, at 1:55 p.m. Wednesday afternoon, effective until 10:00 p.m. that evening.
As the squall line passed through Pearl River County, the NWS radar at Slidell detected a particularly strong storm embedded in the line near Picayune moving northeast at 45 mph. At 6:49 p.m., meteorologists at Slidell’s office issued a severe thunderstorm warning for southeast Pearl River County.
Moments later, radar evidence suggested the storm could generate a tornado. Integrated into the large area of raindrops moving away from the radar, the raindrops over a small area near Picayune were blowing towards Slidell, indicating that the storm was turning.
In addition to the pulse of energy from the radar reflected from the raindrops, some of the energy was reflected back to Slidell by a mixture of larger objects. This is often because debris is being lifted into the air.
So at 6:52 p.m., three minutes after issuing the severe thunderstorm warning, Slidell’s NWS issued a tornado warning that “a severe thunderstorm capable of producing a tornado was located near Picayune, moving heading northeast at 40 mph “.
The next day, meteorologists from the NWS of Slidell came to Picayune to investigate the damage. They concluded that it took less than five minutes for the tornado to land south of East Canal Street, cross I-59 just north of Boley Creek, and then dissipate just south of Sycamore Road, a road to ‘just over three kilometers long. At its widest, the twister was a little wider than a football field. They estimated the peak winds to be 110 mph.
Thunderstorms on Wednesday also produced heavy rains. Totals of two to five inches were common throughout the county. Parts of the Wolf River drainage area in eastern Pearl River County received nearly six inches.
After the thunderstorms passed, a cool front circling around the cyclone swept through the region on Wednesday evening. The cyclone moved slowly northeasterly and now covers much of the eastern seaboard of the United States.
This puts us in a northwesterly flow for the weekend, and the mass of cool, dry air that has blown through our area is expected to persist until Tuesday or Wednesday. By Thursday, another fresh front is expected to approach our region.
However, weather models predict that the cyclone associated with this front will be much smaller and weaker than this week’s.
Thus, any showers that form with the front should be light and the risk of severe weather low.