A new stable storm system moving into the Pacific Northwest Sunday is expected to produce severe storms in the South this week.
The Storm Prediction Center issued an early warning forecast, calling for “a significant severe weather event” in parts of the lower Mississippi River Valley on Tuesday.
“This storm system will have the potential to produce severe thunderstorms capable of tornadoes, damaging straight-line winds, and large hail,” said Bill Bunting, head of forecasting operations at Storm Prediction. Center, on CNN Weather. “Details about areas most at risk from tornadoes will become clearer as Tuesday approaches and smaller trends become more apparent.”
A Level 3 of 5 enhanced risk for severe storms has been issued across the region including Memphis. However, Tuesday’s greater storm threat could affect more than 25 million people from east Texas to southern Indiana.
The prediction center also noted in its forecast discussion Sunday morning that “a category upgrade will be possible in future outlooks,” meaning the storm’s severe threat has the potential to rise to Level 4 or 5 out of 5 as Tuesday approaches and the forecast gets higher. clear
Regardless, this week’s storms are expected to be strong and potentially damaging. Be sure to keep up to date with the latest forecast as it develops over the next couple of days.
You can follow along with CNN’s Weather updates here.
The system is likely to bring tornadoes and damaging winds to the lower Mississippi River Valley after dark Tuesday, which could be particularly dangerous.
“Unfortunately, it appears that the severe storm threat will continue into the evening and overnight hours on Tuesday,” Bunting said.
The time of day when a tornado occurs also makes a big difference in the fatality rate. Tornadoes at night are more dangerous because many people are asleep and unaware that they need to find a safe location.
While the greater tornado threat for this particular event exists during the day, there is still a possibility for some rotating storms during the evening hours.
Areas most at risk for storms Tuesday night include southern Illinois down into Louisiana.
“Another challenge with nighttime tornadoes, especially in the fall and winter, is that storms often move very quickly, sometimes 50 or 60 mph,” Bunting said. “This means you should make decisions quickly and take shelter based on the information contained in a severe thunderstorm or tornado warning, and not wait until the storm arrives.”
Bunting pointed out another concern is the potential for flooding, thanks to heavy rains resulting from repeated cycles of thunderstorms.
Widespread rainfall in the range of 1 to 2 inches is expected, but some isolated locations could see up to 4 inches.
Although tornadoes in the US can occur any month of the year, they are most common during the spring due to the collision of cold and warm air as the seasons change. The same combination of temperatures also occurs in the fall, so you often see a second “severe season” later in the year.
“While severe storms occur less regularly in the fall and winter than during the spring/summer months, major severe weather outbreaks occur during this time of year,” Bunting said. “Just think back to last December and the record number of tornadoes for the month and the massive death toll.”
Earlier this month, a Level 3 severe storm risk was issued three days ahead of time, before it was upgraded to a Level 4 risk. Dozens of tornadoes were reported across Texas, Oklahoma, Louisiana, and Arkansas causing damage to many homes and businesses.
If Tuesday’s threat is raised to a Level 4 threat, it will be the first time there have been two Level 4 threats issued anywhere in the US in the month of November.
“You can see that while the spring months are our busiest time climatically, there is a secondary increase in tornado activity in November,” said the National Weather Service in New Orleans.
Texas sees the most tornadoes (7) in the month of November on average, followed by Alabama (6), Louisiana (5), and Mississippi (5).
“Severe thunderstorms in autumn and winter can be very damaging, and can sometimes catch people off guard as thunderstorms tend to occur less frequently in the colder months,” Bunting added. “Now is the time to revisit, or develop, a severe weather emergency plan for you and your family.”
Know where you’re going if bad weather hits, and make sure flashlights are working and cell phones are fully charged in case you experience a power outage.