6/25 - 2:30pm - Watch Out This Weekend

Here's the latest severe outlook from the SPC:



(Day 4 is Saturday)

I just got some numbers in on instability for Saturday's hyped-up severe weather outbreak. Even though they're preliminary at this point, I'm already a little concerned. CAPE values (measures instability) are forecast to get near the 2000 J/KG mark, which is pretty unstable. Anything over 1000-1500 J/KG is high enough to support a severe weather outbreak, just as long as all the other elements come into place. The cap (layer of warm air just above the surface that acts as a "pressure cooker" to build up energy) looks like it will be around here until after noon on Saturday before completely getting blown off. This will allow sunlight to heat the surface and energy to build throughout the morning. During the afternoon when the cap disappears, this energy will allow air to rapidly lift upward (instability) and condense at high altitudes. The condensation of this air is what will form our severe storms.

We'll also have to see what happens with shear and surface winds as well on Saturday. I think shear will be adequate for an outbreak, but winds are still a question at the surface. Those will pretty much determine if we'll see a line of storms or separate super cells.

My best guess is that we'll see our standard setup: a few super cells in front of a MCS (mesoscale convective system) line of storms. It just doesn't seem likely that we'd have a tornado mess since we're pushing into July. Stranger things have happened though. Nobody, not even the SPC, can really tell you exactly what's going to happen until just hours before the outbreak. It's simply too far out to tell right now.

Until the rabble-rousing on Saturday, we'll see a small daily chance of thunderstorms and temperatures holding around 90. South winds will bring up moist air and push our humidity up quite a bit, with dew points in the mid to upper 60's (uncomfortable).