Watching potential severe weather set-up for Wednesday

A classic Carolina cold air damming regime will be setting up later tonight into Tuesday.  This is when cold air gets trapped up against the mountains, and we see temperatures 10-20° colder than the surrounding area. This set-up can save us from severe weather often but it can also lead to severe weather as the cold air moves out. Wednesday looks like one of those set-ups where the wedge front interacts with a strong storm system and brings the potential for severe weather and even a few tornadoes.

Wednesday Convective Outlook:


Wednesday surface map:

The typical wedge setup with a strong low-pressure system to our west. The warm front or wedge front will be moving back north. The triple point where the cold front, occluded front and warm front meets could cross right over the I-85 corridor through the day on Wednesday.



Typical High Shear Low CAPE event:

This is a set-up where wind shear or energy is off the charts, but CAPE or storm fuel is low. These are notorious around the Southeast in the winter and early Spring. The wind energy is so strong that you only need small amounts of CAPE or thunderstorm fuel to get tornadoes and severe weather. Often there is no thunder, and the storms are just around 20-30,000 feet tall. Which is a very low topped for thunderstorms.

SHEAR or wind energy:


CAPE or Thunderstorm FUEL:


850 mb winds or what we call the low-level Jet at 5,000′:


STP (Significant Tornado Parameter):

The combination of strong wind shear, low-level jet, and just enough CAPE means the potential for rotating storms. Especially along the retreating wedge front as it moves north. Storms along a squall line or even smaller discrete cells that interact with this front will have to be watched very carefully. I’ve see this set-up so many times that I always get a bit worried when I see it. We may go all day and be fine then get that one storm that tracks just right to form a tornado. The Reedy Creek tornado in March of 2012 is a perfect example of this type of set-up. The sounding below shows the intense shear and potential for tornadoes right along I-85 near Charlotte. Be weather aware Wednesday.

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