Rare ‘high risk’ severe storm outbreak could fuel intense twisters
A multi-day severe storm outbreak in the U.S. could spill some thunderstorms into Canada this weekend
A rare ‘high risk’ for severe weather is in effect Saturday for parts of the U.S. Deep South as a dangerous multi-day severe storm outbreak gets underway.
Several distinct rounds of severe weather are likely through the weekend. Each round of storms could produce widespread damaging wind gusts, intense tornadoes, and large hail.
We could even see some rumbles of thunder creep into Ontario this weekend as the region falls under this powerful storm’s influence.
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Powerful storm system responsible for severe weather
A robust Colorado low developing on Friday is responsible for the severe weather outbreak unfolding across the central and southern U.S. into this weekend.
This will be a powerful low-pressure system that could rival the intense storm we saw just last week. The system’s minimum central air pressure could drop to around 976 mb, which may threaten some monthly air pressure records for the month of March in places like Nebraska, Iowa, and Minnesota.
Significant damaging wind threat on Friday
The year’s first moderate risk for severe thunderstorms—a four out of five on the categorical scale used by the U.S. Storm Prediction Center (SPC)—is in effect for a wide swath of the Mississippi River valley, including the cities of St. Louis, Missouri; Des Moines, Iowa; and Memphis, Tennessee.
An intense squall line could develop across the region, packing significant wind gusts of 120-160+ km/h. These wind gusts could lead to widespread tree damage and power outages. Embedded tornadoes are also possible.
These storms will begin in the late afternoon hours and continue pushing east overnight into early Saturday morning.
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Near-historic wildfire weather anticipated Friday
Intense winds and dry air wrapping around the western side of the Colorado low will give rise to extremely favourable conditions for wildfire development across the southern Plains states on Friday.
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The SPC issued a high-end extremely critical fire weather risk for a large swath of Texas and Oklahoma as gusty winds and low humidity spread over the region. Given the conditions present on Friday, a “wildfire outbreak appears likely” according to the SPC. Multiple fires were already burning as of early Friday afternoon.
High risk tornado outbreak possible on Saturday
The main event arrives Saturday. The SPC issued a high risk—a full level five out of five—for portions of Mississippi and Alabama ahead of Saturday’s risk for severe weather.
A high risk indicates forecaster confidence in a significant tornado outbreak across the affected areas. Saturday is only the 66th day since Jan. 1, 2000, that the SPC has issued a high risk, and it's exceptionally rare for the agency to issue a high risk a day in advance.
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Storms will start in the southern U.S. and Midwest during the late morning hours, again pushing east as the day wears on.
Intense, long-track tornadoes are possible throughout portions of Louisiana, Mississippi, Alabama, Georgia, and Tennessee. This includes the cities of New Orleans, Mobile, Birmingham, and Atlanta. The greatest risk for intense tornadoes will fall in and around the high risk area.
Thunderstorms in the region could also produce widespread wind gusts of 120+ km/h, as well as hail the size of golf balls or larger.
Historically, this is right around where you would expect tornado activity to ramp up as spring takes hold across North America.
Storm tracks into Ontario with thunder risk
Our low-pressure system will track into northwestern Ontario late Friday, potentially bringing the risk for some non-severe thunderstorms as the system moves into the region.
Focus will turn toward southern Ontario looking ahead to this weekend. The first round of rain moving into southwestern Ontario on Saturday morning could bring some embedded thunderstorms into the region.
A secondary low will develop off a cold front and kickstart an additional round of widespread rain over the region for our Sunday. Embedded thunderstorms are possible throughout all of southern Ontario—and could even push into northeastern sections of the province.
Localized ponding, pooling, and flooding is also possible with the incoming rain and mild temperatures causing snowmelt.
Stay with The Weather Network for all the latest updates.