Veterans Day Severe Weather Potential Next Week


The weather currently is fairly quiet across the US. However, as we move towards the middle of next week, severe weather looks to be a definite possibility across areas from the Southern Plains eastward to the mid-south. Let us get into the details of this particular threat. The forecast model run we will look at for this blog post is this morning’s 12z GFS.

12z GFS 2m Dewpoint 7 PM Wednesday12z GFS SBCAPE 7 PM Wednesday

One factor that we look at is the amount of moisture available. With this particular storm setup, the amount of moisture should not be a factor at all. The amount of surface based Convective Available Potential Energy shown here is a bit deceiving, given the other parameters shown below…

12z GFS Surface Wind 7 PM Wednesday 12z GFS 850mb Wind 7 PM Wednesday 12z GFS 500mb Wind 7 PM Wednesday

With this particular setup, the wind fields are very impressive. In one aspect, note the changing of the wind directions from the surface, to 850 mb (5,000 feet), and 500 mb  (18,000 feet) above ground level. The other aspect is the magnitude of the winds. This aspect looks to be supportive for potential supercell thunderstorm development.

12z GFS 6km Shear 7 PM Wednesday 12z GFS 1km Shear 7 PM Wednesday

The amount of shear being forecast in the lower 1 kilometer and 6 kilometers are more than sufficient for potential supercell thunderstorm development. When you see the reds and purples on the 6 km shear map shown here, this particular aspect would indicate the atmosphere is very unstable.

12z GFS 1km Helicity 7 PM Wednesday 12z GFS 3km Helicity 7 PM Wednesday

Another aspect to look at is the amount of storm relative helicity in the lowest one kilometer and three kilometers. The areas showing in the orange and grey colors are areas which have the highest amounts of helicity. These amounts are far more than sufficient for supercell thunderstorm development, and possible tornado activity.

12z GFS Lifted Condesation Level 7 PM Wednesday 12z GFS 3km Energy Helicity Index 7 PM Wednesday

The Lifted Condesation Level (shown above) indicates areas which would see the best potential for tornado activity. As one can plainly see, the areas in light grey from the lower Great Lakes down to the mid south look to have the best potential for tornado activity. Also, the Energy Helicity Index highlights the same general area for Wednesday Evening’s severe weather potential.

12z GFS 1km Vorticity Generation Parameter 7 PM Wednesday 12z GFS SBCIN 7 PM Wednesday

Two more parameters we look at here are the Vorticity Generation Parameter (VGP), along with the Surface Based Convective Inhibition (SBCIN). With the VGP, it indicates which areas see the best chances for tornado activity. Areas from the mid-south to the lower Great Lakes see such potential. With the SBCIN values shown above, that indicates storm developement should not be hindered that much.

We will be watching the very latest on this developing weather situation for next week here at Weather or Knot. Stay tuned.

Posted on November 7, 2015, in Uncategorized. Bookmark the permalink. Leave a comment.

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