Forecast for May 30

Memorial Day. It's last year on this day that we caught a beauty.

This year looks like an okay setup for supercells, although tornadoes may be a little more elusive than last year.

Here's the rundown.

Moisture: copious. Not a concern, with surface dews around 20C likely to pool and moisture plentiful and deep.


Instability: plentiful. MLCAPEs are likely to be above 2000 J/kg all over the place.



Lift: should be good, with a surface low and fronts galore.

Shear: I have left this one to last, as it's the most telling. The shear is mostly linear, leading to a) linear (i.e. non-discrete) storms, and b) fast-moving storms. This could be a problem.

All that being said, if I could chase, I would begin by targeting Fargo, ND (assuming the NAM is right and actually, the GEM-REG is quite a bit farther north with this system) and going from there.

Day 7: bonus day

We hadn't really counted on chasing today, but it looks really good just to our east. We're currently north of Kansas City, which has a tornado warning out. Doppler looks good.

Anyhow, we're going to target the area of north-central Missouri (I know, not great territory) to western Illinois. Things are lining up there, and it's just a matter of whether or not we'll get lucky.

Day 6 recap

In a word, ugh.

We set out of OKC in the morning and targeted El Reno and points west.

We had lunch in El Reno and watched the dryline bubble up and start deep moist convection. Because of the shear involved, we figured any storm that went up big would be a long-lasting, prolific tornado producer.

Wow, were we wrong.

Just as we lost data coverage (thank you very much, western Oklahoma), the storm fell apart. Problem is, we couldn't see that because of the haze. So we were following along based on tornado warnings relayed by local radio stations.

When we finally got data coverage back, it was obvious we were behind a barely-broken line of potentially tornadic supercells and in no position to catch them.

What hurt, though, was not only that there were damaging (deadly, actually) tornadoes, but also the fact that just about every other chaser, it seems, caught at least one photogenic tornado. Including the storm of the day, which hit El Reno, where we had had lunch.

Ouch.

Day 6 forecast: outbreak?

If there's no other day you can watch, watch tomorrow.

I forecast that Tuesday, May 24, 2011 will be a big day for severe weather and likely tornadoes in Kansas and Oklahoma.

This time I will go with the full run-up.

Moisture - surface dewpoints in the low 70s F (20C+), and 850 dewpoints 15C and higher.


Instability - SBCAPEs and MLCAPEs over 3000 J/kg.


Shear - 0-6 km shear should be 50 knots or higher.



Trigger - Dryline. Weak cap. Need I say more?

We will be targeting Wichita first, then likely refine to points west for initiation, then move east with the storms. As the afternoon and evening wear on, the low-level jet will really get going, making for tremendous low-level shear.

Cons that I can think of include a slight lack of wind at 250 mb, which might not allow for updraft evacuation as efficient as I would like; this would lead to more HP supercells rather than classic.

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I must be missing something, but I can't think of it right now. Here are a couple of forecast soundings for the area.


We will have to be careful tomorrow, as storms will be more dangerous than just about anything I've ever been on. Follow along if you can.

Day 5 recap

We got to western Oklahoma, we were there for initiation, we got onto the right storm.

And still it barely produced. We got a short-lived funnel cloud that may have touched the ground, but if it did it lasted only a few minutes.

I can live with today. We didn't fail at all; the storms didn't produce, is all.

Tomorrow looks wicked...

Day 5: try try again

We're sitting in Perry, Oklahoma, north of OKC. It looks like things are going to fire along a composite warm front/outflow boundary just to our north, but we're also in place if things go on the dryline sitting to our west.

Moisture, instability, shear, trigger: they're all there. Now we play the waiting game. Will we catch our big storm today? Time will tell.

Day 4 recap

So many emotions today. We started off going toward Tulsa, expecting storms to initiate along the dryline and move east.

The dryline did its thing to our north, and once again we were playing catch-up. Mad and frustrated. We expected storms to go all the way down the line, but that wasn't the way it was to go. So we forayed into southeast Kansas, and could never catch up with the storm. Exasperated and vexed. We were close for a long time but it kept accelerating.

We got to the outskirts of Joplin, MO, about 2 miles behind the tornado. We couldn't see it but a) it looked scary on Doppler, and b) we would have to go through a bunch of large hail to catch it. So we bailed south. Terrified at times.




After much south driving, we got to a storm that was gathering strength but we couldn't get to it because of the terrain and lack of roads. Sad and mad.

Then there was another storm we could sort of get to, and we watched it produce a tornado after sunset--we barely saw it. Longing.

We stopped for some lightning pictures along the way. Happiness.

On the way back to the hotel, now, we're hearing reports of major damage and deaths in Joplin. Horrified.

What an exhausting day.