The severe weather has steadily increasing over the last week to ten days across the Southern Plains. However, the first major severe weather issue of the season is a distinct possibility. As a result, The Storm Prediction Center has highlighted much of Oklahoma, SE Kansas, N Central Texas, and Far NW Arkansas for the risk of severe weather the middle of next week (Tuesday). This is a day seven outlook. While not uncommon, it is relatively rare to get a risk area defined this far out.
For this particular blog posting, we will focus on the threat in Oklahoma for Wednesday of next week. Model data for this post will come from the 0z GFS run late this Wednesday Night.
This particular setup looks to be a classic southern plains severe weather setup. On the surface dewpoint map above, notice the brown area (dry air) in far west Oklahoma and the Texas Panhandle. Also, notice the green/aqua area (Central and East Oklahoma). That is a dryline setup. When you add the plentiful amounts of surface based instability across much of Oklahoma Tuesday evening, the potential is there for supercell thunderstorm development.
Here is another thing that is of much concern. Notice how the surface winds are south to southeast, the 850 mb winds are more south to southwest, and the 500 mb winds are mainly southwest. This is a classic recipe for any supercell thunderstorm to gain rotation within it.
Another aspect of this that is impressive is the amount of helicity in the lowest one and three kilometers Tuesday evening. The areas in yellow and orange look to have the highest potential for sustained updrafts with any thunderstorm that develops.
One aspect that will not be lacking is the amount of shear in the lowest one and six kilometers Tuesday Night. Both amounts of shear (shown above) are more than sufficient to help sustain supercell thunderstorms for a longer period of time.
With the Lifted Condensation Levels projected to be below 1000 meters across much of central and eastern Oklahoma Wednesday Night, that area will see higher potential of tornadic supercell thunderstorms. There is some surface based inhibition in Central and Eastern Oklahoma for Tuesday Night. However, given this potential setup, that inhibition could be broken easily.
This is what concerns us. The 0-1 km Vorticity Generation Parameter is off the scale across much of Oklahoma, and especially true in north central Oklahoma. That red (and purple area) indicate where tornado potential is highest for Wednesday Night.
SUMMARY : A severe weather episode looks to be a distinct possibility Tuesday Evening and Night across much of Oklahoma. All modes of severe weather are in play (Damaging Straight-Line Wind, Large Hail, and Tornadoes). We will keep you up to date with the latest.