I know I sound like a broken record this point about our severe weather potential late Feburary. Our chances at this point, however, appear to be skyrocketing. This is mainly due to our key failure mode at this point does not appear likely.
Our first day of severe weather appears to be locked in on Tuesday the 27th. The SPC has now highlighted an area of severe weather potential as seen below.
This area is similar to the area we have been talking about in previous blog posts. The threat has been outlined as a 15% risk area from parts of the Plains all the way to the Great Lakes. I would expect the risk for all hazards (hail, strong winds, and tornadoes) with some of which being significant. In fact, a Twitter user mentioned this, named Tornadoclips, stating:
"There is a good chance a significant severe weather even will happen next week."
A significant risk is defined by hail over 2" and Winds over Hurricane Force as well as EF2+ Tornadoes. The main reason I have so much confidence in this is dues to the fact our main failure mode has ceased. This is noted by one Twitter user which I mentioned yesterday, Starinbox. He noted:
"Seems like the trough continues to trend much more favorable for severe compared to yesterday, at least off the GFS (although the Euro hasn't been too far off)."
Our failure mode was expected to be a poor phase of 2 areas of high shear. However, the main storm system now looks to be providing its own area of high to very high shear. This would mean that the shear would be there and along with the enviorment discussed in yesterdays blog, would likely be conducive to volatile severe weather. Shear levels this high would promote a greater risk of tornadoes and strong winds as well, because of the fact that the wind in the Atmosphere is so high. This would promote high ground level winds along with spinning in the clouds.
Diving deeper into the details, the enviorment before this system will likely be primed for severe weather. This is due to high dewpoint from the Gulf surging into that risk area. This would also allow for unstable air, or CAPE, to enter the area and help storm develop. We typically look for values over 1000, and in the image below we can see how high the number are projected to get.
As we can see here, the area that has been outlined by the SPC has that CAPE that we typically look for. I am especially intrigued across and area running from around St. Louis to Chicago roughly, due to their very high shear and abnormally high CAPE.
Moving on to Wednesday the 28th, this area that has been outlined is very broad as seen below. This is a very large area that desructive storm could occur in. In my opinion, this could be the less volatile day of the episode.
This area is basically a shift of that severe weather risk we saw yesterday, just further east. Alarmingly, many large cities are included in this risk. They include:
Indianapolis, IN
Columbus, OH
Memphis, TN
Nashville, TN
St. Louis, MO
And many more are included in this risk. PC Weather Boy on tiwtter nother Wednesdays risk, saying:
"Another round of severe weather looking to be on tap for the majority of the SEAST Tuesday into Wednesday of next week as low pressure dips down deep. "
However, the light at the end of the tunnel is the fact that this day could be less volatile than the previous.
Some folks may wonder why I think this. True, dewpoint will still be sufficent for severe weather, and shear remains very high, but we are missing the main part that makes storms grow, CAPE.
As seen here, this is the max point of energy on that day. Numbers here do not even cross 1000, which is not favorable. There are a few points that do manage to hit 900, but that number is very isolated. Looking at the GFS, the numbers are even lower! This could be very problematic for stroms on Wednesday, but they are still very possible.
The shear at times can make up for what energy is missing. We could see that here. As seen below, the shear values are quite impressive, reaching over 100 knots!
Shear levels this high can be easily conducive for severe weather, even with low CAPE. This leads to a classic "low shear, high CAPE" enviorment. Enviorments like this, at this time of year, are quite common. They can be conducive to tornadic situations at times.
These setups are also awfully tricky to digest, so I will not go into full detail at this time. Expect it in a future blog post however! Also note that the next few blogs will be soley on one day or the other, not collided all together.
Do note, severe weather could be possible on Thursday even further east. This would be another classic "high shear, low CAPE" events. I am very skeptical about this however, due to just so little energy. Due to this low confidence, I will not be getting into it today.
Author: ShearConvection
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