Severe weather is forecast to erupt across the Central and Southern Plains on Sunday. All modes of severe weather will be possible in the highlighted zone.
The culprit is an upper level low that is forecast to track eastward across the United States this weekend and early next week. The weather ahead of the trough of low pressure will be ripe for the development of severe storms. If you have friends or family members in the highlighted area, be sure to advise them to continue to monitor updated forecasts and have multiple ways of receiving weather warnings.
Storms will be ongoing late Saturday night and Sunday morning across central Nebraska and points southward. Storms will strengthen during the day and progress eastward with time. The magic hour across the Heartland could be as early as noon and folks across the Ozarks will see some of the strongest storms during the afternoon hours before the activity shifts across the eastern part of Missouri and central Arkansas by the evening.
Energy Helicity Index or EHI 0-1km is forecast to be as high as 4 or 5 across southern Arkansas and northern Louisiana by 7pm Sunday. Values will be slightly lower to the north but still high enough for supercells to potentially produce strong tornadoes.
The long range models are in agreement regarding the evolution of the upper low as it progresses across the Plains on Sunday and then into the Mississippi Valley on Monday. It's still too far out to forecast with much detail and especially on a mesoscale or small scale level.
On Monday, the system shifts eastward and so does the threat for severe storms. Once again, computer models indicate another round or rounds of severe storms forming across the lower Mississippi Valley and into western Tennessee. It looks like a potential volatile set-up with the synoptic pattern on Monday across Mississippi and strong tornadoes will be possible.
While severe storms will be possible during the late afternoon hours across west Alabama on Monday the greatest threat for severe storms is on Monday night into Tuesday morning. The models differ on the speed of the storms as you can see below. We should get a better idea regarding timing and strength once the storm system is sampled better in the coming days.
The GFS model is much slower regarding the progression of the low and could produce another round of severe weather on Tuesday PM if this model solution pans out. This is something we'll have to track closely. Upper lows that become cut off from the main flow can be tricky to time and speed and timing can mean the difference between low instability and high instability.
As Dr. Tim Coleman said in a previous blog post, "We'll see thunderstorms Sunday night all the way through Tuesday. We still need a couple more days to get more details on the wind shear for rotating storms and possible tornadoes."
Now is the time to prepare for potential severe weather and be sure to have a plan in place. Have multiple ways of receiving weather info Sunday night and Monday. NOAA weather radio may be back online in Birmingham by Monday, but we don't know yet, so have a backup plan (phone apps, text messages, etc.)
This is the first real active set up this year and hopefully every one is prepared for potential severe storms. There are things you might want to do ahead of time to prepare for strong winds, etc.
1. Make a list of items to bring inside in the event of a severe thunderstorms.
2. Make trees and shrubbery more wind resistant by keeping them trimmed and removing damaged branches.
3. Protect your animals by ensuring that any outside buildings that house them are protected the same way as your home.
4. Have an emergency preparedness kit put together.
For item details click here: http://www.redcross.org/prepare/location/home-family/get-kit
If you have any questions feel free to contact us,
Jill Gilardi Fox 6 Meteorologist