Update on Severe Weather Threats for Tuesday-Wednesday

So Tuesday and Wednesday are still looking like potentially very active days for severe thunderstorms on the Central and Southern Plains. Tuesday’s event will be focused in my neck of the woods…the most intense activity expected over Southeast Nebraska, Southwest Iowa, into far Northwest Missouri and much of Northern Kansas. Wednesday event will be much more extensive. Most intense activity currently likely over far Southeast Nebraska into western Missouri, the eastern half of Kansas and much of western and central Oklahoma.
While Wednesday has garnered a lot of attention, looking at computer model trends, it appears Tuesday has the potential to be an intense day for significant severe weather. The combination of favorable vertical wind profiles (wind shear), instability (for rising motions) and increasing low level moisture (needed for enhancing the instability) is increasing the risk for scattered rotating supercell thunderstorms to develop during the afternoon ahead of a southwestward moving cold front and northeast of a surface low over northern Kansas.
The shear profiles being shown in the lowest levels of the atmosphere and the moisture content for lower thunderstorm bases means these supercell storms may be longer lived than expected in earlier forecasts and therefore capable for producing multiple tornadoes and perhaps an isolated strong tornado (EF-2 or stronger).
The Storm Prediction Center has indicated that there is a 10%+ risk of a strong tornado over the hatched region. There is also an elevated risk for very large hail in the supercells as strong updrafts will be allowed to build very thick hailstones (2 inches+). Damaging winds are of course likely over the region under some storms (60 mph gusts+). 
Meanwhile, Wednesday remains likely to be a significant event day for a large area, although it will be complicated. Areas from Central Oklahoma through Central Kansas to extreme Southeast NE could see an enhanced threat for very large hail and multiple tornadoes, including a higher strong tornado potential possible if the set up lives up to its full potential, but that is still up in the air. There are still questions about coverage and when storms will begin (too many starting earlier in the afternoon will mean a “messy” event with lots of storms and not as many isolated storms to produce stronger tornadoes). There is also some variability about how far north the warm sector will be into Southeast Neb/Southwest IA in the wake of the Tuesday storms, which could mean a greater risk for my area yet again.
Much to be determined! Stay tuned for updates if you live in these areas.
–Meteorologist Nick Humphrey

Author: Meteorologist Nick Humphrey

Meteorologist and geoscientist in Lincoln, NE. Seattle, WA native. Love weather, storm chasing/photography and planetary science.

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