2013-03-30 FCST: OK

[James Gustina]

Marginal looking day in terms of any appreciable threat for supercellular/isolated storms but still worth looking at.

12Z NAM placed significant instability on the order of 2000 j/kg+ of MLCAPE over north-central Oklahoma along with pretty decent moisture with dewpoints around 60F. The biggest problem with this one is the NAM, GFS and SREF are all showing very weak upper-level support with NW flow at 30-40 knots and a poor kinematic environment with very little veering with height/lack of appreciable deep-layer shear with the SREF shooting under 30 kts. The dryline that the NAM was hinting at in western Oklahoma also looked diffuse along with a rapidly advancing cold front out of Kansas. Besides the poor shear though, everything else should be ok with a considerably unstable environment for this time of year along with the great moisture and forcing possibly coming in advance of the cold front. As opposed to the last few setups on the southern plains, the moisture is already in place a full day in advance making the possibility for rapid moisture transport the day of with heavy cloud cover pretty unlikely. I've heard some other people talk about this as well, but if there's ongoing convection overnight in Oklahoma and Texas, there's the possibility for an outflow boundary to hang around in northern Oklahoma and maybe put up something a bit more substantial than the multicell clusters that look likely otherwise. Thoughts?

 

[Jeff Duda]

I see what you're saying. Yeah, it appears the low level flow is just all sorts of whacked out, so there just isnt' much organized, widespread low-level shear. There is decent shear between 850 mb and 500 mb, but it's still quite marginal. Instability appears to be best farther south and east. The 4 km NAM shows preferential development over the high plains of W TX, E CO, W KS generally after 00Z, so it looks like one of those events where the sufficient shear, instability, and forcing generally don't overlap.

 

[James Gustina]

Its looking like the OFB scenario might not be that unlikely given that an MCS will probably train over the Red River at some point tonight/in the early morning. Considering lapse rates will be over 8.5 C/km along with some improved upper level flow may help organize things a bit better. 4KM WRF and HRRR both seem to be handling it badly because there isn't a classic shortwave with a 110 knot jet streak rounding the base of the trough, but we'll see what happens.

 

[Greg McLaughlin]

30-40kt flow is plenty to get it done. The storms today were gorgeous, and we nearly had tornadogenesis at least twice on the cell west of Guthrie. Many chasers including myself have seen great tornadoes in 30-40kt mid-level flow setups. Its about balance. Today we were just a little too stable at the surface. Tomorrow will be interesting, especially if we have any boundaries left over.

 

[Bob Hartig]

30-40kt flow is plenty to get it done. The storms today were gorgeous, and we nearly had tornadogenesis at least twice on the cell west of Guthrie. Many chasers including myself have seen great tornadoes in 30-40kt mid-level flow setups. Its about balance. Today we were just a little too stable at the surface. Tomorrow will be interesting, especially if we have any boundaries left over.

I was thinking about this. Last year here in Michigan on March 15, VAD profiles for GRR and DTX showed anemic mid-levels. I never expected a thing, so imagine my surprise when I saw big towers off to my east and a flying eagle on my radar. A tornado dropped near Ann Arbor and did EF-3 damage in the town of Dexter, and Nick Nolte scored some pretty video. The difference-maker was an outflow boundary that blew in from storms way down in Ohio. Tomorrow kind of reminds of that scenario, only with the advantage of actually expecting OFBs instead of getting caught by surprise.

 

[Marcus Diaz]

No doubt we'll see some storms today, question is what will they do? Plenty of instibility and good 0-3km lapse rates. Storms today should become good looking supercells too with that 30-40kt NW flow. My biggest concern throughout watching this setup was the lack of a good LLJ. Very meager 850s and 925s means these storms will need to explode and create their own SRH to get it done. Luckily I'm sure last night's convection spit out an OFB which is what I would pretty much latch onto during the day. Financially I couldn't go out today but I figure I'd throw my thoughts into the mix. If its anything I saw on radar yesterday, should be a decent day if all the pieces fall in together.