Tornado Outbreak Likely with Damaging Winds – High Impacted Day!
An outbreak of severe thunderstorms appears likely Sunday into Sunday night, with the greatest threat expected from Louisiana east-northeastward through much of the Southeast and Tennessee Valley. Tornadoes (including some that are strong and long-tracked) will be possible along with widespread damaging winds.
“A very volatile environment will be in place across Mississippi and Alabama during the afternoon and evening hours, as rich Gulf moisture lifting northward results in CAPE values around 1500-2500 J/kg. Dew points/instability have trended upward in our northern counties from previous forecasts. 80-90 kts of 0-6km bulk shear will be present, with 400-600 m2/s2 of 0-1km SRH and 200-400 m2/s2 of 0-500m SRH and large curved low- level hodographs. Southwesterly shear vectors in the warm sector becoming more southerly close to the front and will be supportive of both an intense QLCS and supercells developing ahead of the line. The strong 0-6km and 0-8km shear will help these supercells stay ahead of the line, supporting the threat of strong (possibly violent) long-track fast-moving tornadoes. The QLCS will also be capable of producing widespread damaging winds and embedded tornadoes with embedded supercells, which could be strong as well, not just brief spin-ups.”
IMPORTANT – Keep in mind that many community storm shelters have closed due to the COVID-19 virus. Now is the time to find out if yours has closed and make other plans for sheltering for in the case you must take action. The determination on whether to open a shelter is made at the local or county level.
Image Info: Seymour, Missouri – Safe Room Remains “Open”!
Widespread Severe Weather Outbreak Expected!
Here is a look at the Supercell Composite, Watching the area in darker orange for stronger storm development.
However, it’s important to note we are still 3 days away and things will change on the exact placement, however, we can get a good idea where the overall risk is positioned!
Are you prepared?
Now will be a good time to check your weather radios and have several ways to receive watches & warnings
Day 3 Outlook is already a Moderate Risk!
An extremely dangerous, life and property threatening outbreak of severe thunderstorms with long-tracked, strong, destructive tornadoes is likely on Sunday into early Monday.
At this point, it’s not a matter of if but now how bad it will ultimately be. All of the parameters we look at to forecast major, historic outbreaks are there.
The posted images below show a “significant tornado parameter” for late Sunday afternoon. As you can see, the STP is extremely high, and this falls within the moderate risk area and that is the most likely area for long-tracked, strong, destructive tornadoes.
The ejecting shortwave trough initially over the southern High Plains Sunday morning is forecast to move quickly eastward and then northeastward through the period, as it moves around the periphery of a deepening longwave trough over the central CONUS.
As this occurs, a surface low will move eastward to the Mississippi Valley by Sunday afternoon, and then rapidly deepen and move northeastward into the lower Great Lakes by Monday morning. Very strong mass response will draw rich low-level moisture northward into portions of the Southeast.
Probability of severe weather Outlook on Day3
..East Texas into the Southeast…
Ingredients for a potential severe thunderstorm outbreak still appear likely to come together Sunday. Moderate to locally strong destabilization in conjunction with an 80-100 kt midlevel jet and 50-60 kt low-level jet will result in a very favorable environment for organized convection.
Ongoing storms across east TX Sunday morning will likely spread northeastward with time and become increasingly surface based as they encounter rapidly increasing low-level moisture, with additional development possible further south near the lower MS River valley by late morning.
As the downstream airmass heats and destabilizes, long-track supercells may evolve out of the morning convection and track northeastward into portions of MS/AL, with a corresponding risk of strong tornadoes, large hail, and damaging wind gusts. Some upscale growth is possible with time, which would result in a corresponding widespread damaging wind risk, given extremely strong wind fields. Some threat of damaging wind and a few tornadoes will likely reach portions of the Carolinas by 12Z Monday.
…Mid MS Valley into the OH Valley…
Destabilization in the vicinity of the primary surface low into the mid MS Valley/OH Valley is more uncertain, given the potential for disruptive convection further south.
However, favorable wind profiles and closer proximity to the ejecting shortwave will support some severe thunderstorm threat in this region as well, with a conditional risk of all hazards given sufficient destabilization.
SPC/Storm Prediction Center: Dean/Dial.. 04/10/2020