Since we look to be under a very high severe risk today, this column post will be mainly focused on us and what we can expect later on tonight through early tomorrow morning. There will be a brief update on the Joplin situation near the end of the article though. First and foremost however, here is some of the data the models are painting for us as far as severe parameters go.
The 06z NAM is showing these conditions for us early tomorrow morning:
- CAPE (Convective Avaliable Potential Energy): 1500-2000; now what CAPE tells us is the instability in the atmosphere. The higher these values go…the more instability we have. For a May time event 1500-2000 is plenty to sustain severe storms.
- LI’s (Lifted Indices): -5 to -6; if these numbers are above -4…that tells us that severe weather is very probable at the surface due to the lifting avaliable.
- EHI (Energy-Helicity Index): 3-4; this is measured by a storms rotation, it takes the values CAPE and helicity to get this number. The NAM is showing values of 3-4…which indicates that we could potentially have an environment for rotating thunderstorms.
- Helicity: 250-300; anytime these values get above 250…that indicates a favorable environment for tornadoes in supercells. So while these numbers aren’t “off the charts”, they are still dangerous and in that area of concern.
- Shear: 40-50 kts; shear is the twist in the atmosphere at different layers, these values are very sufficient for severe storms and for severe storms to be maintained as they move into our region.
The GFS models paints a slightly weaker atmosphere for severe storms, so we will have to wait for the RUC to come into play and see what it shows as this event gets closer. Point still being, it does seem we could have a long night on our hands with severe weather. Have those weather radioes near by!
It is still looking like the main player will be a squall line with embedded supercells, but a discrete supercell (with an enhanced tornado/hail threat) could move into our area late tonight before the squall line moves through. The SPC does have us on the fringe of the MDT (Moderate) risk category, do not be surprised if we see a HIGH risk issued for areas NW of us and we be put into that MDT risk zone. If the NAM is correct it would be warranted.
Now for an update on Joplin, sadly the death toll has risen to 125 per http://www.cnn.com/ and is continuing to rise by the day. As of last evening over 1,500 people were unaccounted for though, fortunately, emergency officials believe many of those are people who left town and just have no way to contact family members due to communications in the area being completely shut down.
There was a severe storm that hit Joplin last night with winds of 60 mph, thankfully no new injuries or deaths came from that storm. It seems they will, finally, enjoy a rest from Mother Nature for a few days and be able to do more clean-up with the hinderance of severe storms forecasted for their area…we all know they need that break.