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Severe WX Severe threat 3/30-3/31

AJS said:
Also am quite bummed that I won’t get to chase this weekend. I’ve got an open water tournament to attend so I won’t be able to chase this weekend.

However, the models continue to show a perhaps impressive outbreak around the 4th of April and if time allows, I may make the drive up to some of those states.
Click to expand...
Well, you have open invitation to Monroe County, MS. I'm sure, like with this upcoming threat, we'll be in the bullseye for that one.
 
I'll say this. The Euro has been the most aggressive and consistent than the GFS regarding this weekend it seems.
 
So with the recent curiosity about the N AL area (and I know quite a few of you live in the area), I ran the 12z WRF-ARW model centered on Birmingham, AL and a grid of about 300 miles square. I also did high resolution, with a 2 km resolution. Here's some of the highlights:





The Composite Radar shows a couple of rounds of cells coming through. It actually wants to make the early morning Monday round semi-linear, which is interesting.

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The SBCAPE isn't all that impressive during the times it aligns with the convection. This may be a big limiting factor, but the model could just be misaligning the arrival of the CAPE also, so we'll see.

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So for most of the event, there's modest (but sufficient) levels of SRH in the 0-500m level (the level most important for tornadoes), but as the front comes through, there is a significant boost in low-level SRH in the Birmingham metro area that is concerning.


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The Vertically Integrated Graupel is designed to show storm cores (possibly of supercells) that have increased lightning/hail potential. Isolated storm cores exhibit deep VIG and probably signify very strong storm cores.


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This algorithm (an enhancement of the BRN) is designed to show Storm Mode. While initially favoring Disorganize/Pulse storms earlier on Sunday, as the event progresses, a strong tendency towards (potentially tornado-producing) discrete supercells occurs, with a narrow corridor of multicellular activity along the front boundary.




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The latest creation of mine is the Tornado Risk Index. It gives a score from 0 to 10 of the overall Tornado Risk in an area. It factors in STP (fixed layer version), SCP, SRH, EBWD shear, the LCL, and CIN (if present), and is normalized to go from 0 to 10. STP has the most weight. In cases where conditions are conducive to significant tornadoes (STP > 2, SRH > 200, EBWD > 25, and LCL < 1000, simultaneously), a hatch is applied to the plot.

The Tornado Risk looks largest Monday morning, probably in the predawn hours, and is maximized near the Birmingham metro area with around a 7 out of 10 on the scale, and a hatch.

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Hopefully this high-res 2k zoom in on the Alabama area is helpful/useful! I still think the situation favors a discrete cell situation, and tornadoes I'd like to believe would be isolated, but those that do form could be strong. Interesting setup, especially coming in the early AM hours.
 
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