2019-05-20 EVENT: TX/OK/KS

[chrisbray]

BTW, I'm going to start tooting the shit out of my own horn here, because I feel reasonably vindicated with just about every post I made in this thread. But the one quoted above is most prominent to me, and it's one I want everyone to pay attention to.

I know most of you here are not degreed meteorologists and are not researchers and thus are not totally informed as to all the tools out there. Thus it makes sense that so many of you seem to live and die by the HRRR, since it is arguably the most prominent CAM (and, in fairness, it does tend to provide a lot of helpful information and value for forecasting over non-convection-allowing models). However, it is not the only CAM out there, and is not even the only operational CAM. Those of you not already familiar with the HREF need to become familiar with it. Start here: SPC HREF viewer site

The 3 km NAM is a member, as is the HRRR. The HREF gave a lot of clues that this event may not turn into a massive tornado outbreak all the way from when the first members had this event in range.

While non-operational, the NCAR ensemble is running for the next few weeks as part of the HWT spring forecasting experiment in Norman. This happens every year. NCAR Realtime Ensemble Forecasts

Also, the HRRR has an ensemble component: HRRRE viewer site

Familiarize yourself with these other CAMs and CAM ensembles, because many of them will stick around, and one of them is bound to eventually supersede the HREF as it currently exists.

It would be unwise to cherry pick the HRRR or wishcast off of it. The most sensible thing you can do as a forecaster/chaser is to collect all the information you can and make a decision based off of the consensus of that information, not just the sexiest voice.

Hi Jeff,
I always appreciate the knowledge you bring. I saw on the discord that the 4/27/11 BMX sounding had a nearly identical thermal profile as OUN yesterday. Why would deep saturation hurt yesterday while not hurting 4/27/11?

 

[Brian McKibben]

Hi Jeff,
I always appreciate the knowledge you bring. I saw on the discord that the 4/27/11 BMX sounding had a nearly identical thermal profile as OUN yesterday. Why would deep saturation hurt yesterday while not hurting 4/27/11?

Same thing Jeff on the 00z Lamont sounding for the 4/14/12 outbreak. The 4/14 storms all formed along the dryline so they had a forcing mechanism to get them going. And once tapped into the deep surface theta-e air they were able to be fully maximized. Not too sure on the BMX sounding. I would like to see what the 00z sounding looked like. SO here it is:

Notice the warm temps/cap at 700 hPa has dissapated by 00z. Also, the moisture depth doesn't go all the way up to 700 hPa like it did on the 18z. So I think comparing 18z BMX and 00z OUN isn't fair.

Here is the 18z BMX sounding:

 

[Jeff Duda]

Hi Jeff,
I always appreciate the knowledge you bring. I saw on the discord that the 4/27/11 BMX sounding had a nearly identical thermal profile as OUN yesterday. Why would deep saturation hurt yesterday while not hurting 4/27/11?

I don't honestly know these answers. This is a lot of science-based speculation that has yet to be tested or verified with obs or even models.

Other things to consider are that storms never even really got going in S/C OK, yet they were prevalent on 4/27/11. Differences in wave timing, cloud cover (similar cloud cover seemed evident on 4/27/11, but it's hard to quantify this in a detailed sense) could have also helped. There also wasn't much in the way of synoptic scale convergence in the surface flow yesterday.

When it comes down to it, deep moist convection is very sensitive to thermodynamic changes. It could possibly be that temps were a mere few tenths of a degree too cool at the surface or too warm somewhere aloft that was just enough to keep a plume from going nuts. It's pretty hard to say without more extensive testing.