Confidence has grown that today is a day of high impact severe weather with all possible hazards.
Moderate risk expanded this morning and now includes a large portion of the Mid-Mississippi River Valley from the Wisconsin border down to northern Mississippi.
What does that mean? All in all, that means that people inside this defined risk area have the highest probability of experiencing today’s strongest storms.
However, it’s important to point out that anyone in any of the areas identified on the map above has a good chance of getting severe weather today. Don’t let your guard down just because you’re in the yellow (light) or green (marginal) group. Storms do not follow the boundaries drawn on the map. Severe weather is still possible in these areas, only sporadic or isolated, but not widespread.
Armando wrote an in-depth blog about this threat yesterday, so this morning I’ll just update the timing and expected threats.
The storm will start shooting in the early afternoon. For now, it looks like two possible storms for many people in today’s risk areas.
The first ring can be especially strong when separate (single) supercells form in the warm open region. Strong, prolonged tornadoes can occur from these cells as well as large hail.
The second round will come in front of the cold. This can also start out sporadically, but quickly evolves into a line. This current will eventually overtake separate cells in the open warm region and become the main mode of convection. Damaged winds, some exceeding 75 miles per hour, will become the primary hazard. However, tornadoes will still be possible with any superclass embedded within the stream itself.
The threat to severe storms will linger into the hours of the night, weakening some storms with an eastward-moving range in the early morning.
With a strong low-level jet aircraft and a roar mid-range jet spot, this will be a high cut environment. Plus a lot available instability and elevators, and we have a capable environment very dangerous weather.
The map above is the modeled auto-updating ranges. This should not be done verbatim at the location nor the confirmed tornado tracks. Updraft autopilot shows us the potential spin of a modeled storm (a supercell). Whether or not it creates a tornado depends on other variables.
However, as we can see, today’s storms will be more likely to turn. This is geared towards supercells, as mentioned. Supercell will be capable of generating heavy hail, strong winds and yes, a few tornadoes. Cyclones formed from the aforementioned superclasses can be strong (EF-2+) and prolonged.
You will notice the UH bands decrease in intensity with the eastward range. At this point, convection will develop into a line and damaging winds will become the main hazard. However, as mentioned above, one or two tornadoes can still occur in the line.
- A large portion of the Mississippi River Valley and surrounding areas are threatened by extreme weather today.
- Two hurricanes are possible for many people in the identified risk area. Don’t let your guard down after the first round.
- People need more than one way to get alerts. A NOAA weather station with battery backup should be your primary source and at least one other source (weather app, wireless EMA, radio, etc.).
- DO NOT rely on outdoor sirens as a primary source of warning. They are not designed for indoor listening and may not be audible in some cases either.
- Charge your devices and keep them charged. There is a risk of widespread wind damage and possible power outages for hours.
- The storm will move very quickly. It is important to act immediately if there is a warning.
- Make sure your safe space is ready to go. This should be on the lowest floor of your house in the most interior location you can find. Put as many walls between you and the outside as possible. Everyone needs hard-soled shoes and a helmet.
- Due to the potential magnitude of the damaging wind threat, take shelter during severe thunderstorm warnings as if there were tornado warnings.
- Alert your friends, alert your family. Increase awareness and prepare as much as possible before the event so that no one is caught off guard.
Since this severe threat covers such a large area, it is nearly impossible for me to specifically cover everyone’s area. Check your local NWS forecast and also the coverage of your local broadcast meteorologists for specific times and threats. They had your return today.
About the author
Meteorologist – ’22 Mississippi State Writer for Weather.us and Weathermodels.com. Focus on weather communication. BoyMom x1, CatMom x5. Twitter: @MegGulledgeWX