A very active jet stream pattern is setting up across the Central Plains and will bring the potential for multiple rounds of severe weather late Sunday night through Wednesday.
Sunday, April 10 night/Monday, April 11 morning
A cold front will approach from the northwest and begin to slow down and stall over our area. Showers and thunderstorms are expected to form along this boundary overnight tonight AFTER MIDNIGHT in NW Arkansas. A few storms may push south far enough to impact the River Valley, although storm chances are certainly greater the farther north you go.
As storms develop, the environment will be favorable for rotating supercells. The majority of these storms are expected to be elevated. This means damaging straight-line winds and large hail will be the primary concerns. However, low-level moisture and wind shear (changing of wind direction and/or speed with height) will be sufficient enough that we cannot rule out a possible tornado completely. You will need a way to get severe weather alerts while you sleep as this will occur overnight Sunday into Monday morning.
For the morning commute, a couple of strong storms may still be present in NW Arkansas. Scattered rain showers will also linger a little bit into the later morning.
Monday, April 11 afternoon/evening
After the late Sunday night/Monday morning severe weather threat, another round of severe storms is possible in the evening hours.
Monday morning’s round of storms could create an outflow boundary that stalls across NW Arkansas and the River Valley. An outflow boundary is created by the relatively cold descending air from a thunderstorm and can trigger new thunderstorms. As another upper-level wave moves in, storms will fire along this boundary and quickly tap into an environment favorable for supercells.
Damaging straight-line winds, large hail, and isolated tornadoes will be possible. Locations in the hatched area on the hail risk have the greatest potential to see hail over 2″ in diameter (hen egg/lime size).
An important note about the Monday afternoon/evening round of storms! We are not expecting a widespread area of supercells. However, areas that get supercell development could see potentially high impacts. The exact location of where the outflow boundary stalls will be the biggest factor in determining who gets the storms. Keep monitoring the forecast throughout the day on Monday for changes.
Tuesday, April 12
The third round of storms is expected on Tuesday, but won’t move in until the evening and continue possibly into the overnight hours. The Storm Prediction Center currently has a majority of the area until level 2/5 (slight) risk. At this time, the level 3/5 (enhanced) risk is in eastern Oklahoma with significant severe weather impacts (hail over 2-inch in diameter, EF2+ tornadoes, and/or wind gusts 75 MPH or greater) possible.
Changes to the forecast and risks are likely between now and Tuesday evening. At this point, it is something to monitor and watch (especially with the more imminent severe weather threats on Monday).
Wednesday, April 13
The fourth and final round of severe weather is expected on Wednesday, April 13. Currently, models expect rotating thunderstorms to develop in the NW Arkansas and River Valley region during the work & school day. We expect the cold front (and severe weather threat) to finally move eastward into central Arkansas by the late afternoon/evening hours.
At this time, the Storm Prediction Center highlighted the region for two different risks. The 15% chance (yellow-shaded) area is equivalent to a “slight risk” while the 30% (orange-shaded) area is similar to an “enhanced risk”. Having an SPC severe weather risk over an area this far out is not uncommon, but it certainly needs watching. The SPC only issues risks this far out when forecast consistency and confidence are high. Just like the Tuesday severe weather risk, the best thing to do at this point for Wednesday is to continue to monitor the forecasts.
Stay updated on the forecast!
As with any severe weather event, staying up to date on the forecast and monitoring conditions is the best way to stay safe. You can get the latest updates from your NWA Weather Authority team from the FREE NWA Weather Authority app, on social media, and online!