Tuesday May 16th Tornado Forecast

051517 Forecast map

I’m going to keep it fairly short tonight because I don’t have a lot to add and I want to chill out for a bit before bed since I’ll be on the road for god knows how many hours tomorrow. My plan right now is to leave Wichita between 11 and noon. I’m planning on heading towards Laverne, Oklahoma initially. There are roads going every direction out of there so I’ll probably check data there and make my final adjustments. Storm motions are going to be pretty god damn fast tomorrow, so I am not keen on hugging the dryline. I’m going to position a fair ways downstream to make sure I have a good enough lead to pick the right storm and stay ahead of it until I think the tornado threat is ramping up. I haven’t seen any chasers talking about the storm motions, but 45-50mph is nothing to sneeze at. In fact, I think 40mph is about the cutoff for where you can realistically keep up. Storms are likely to exceed that speed threshold tomorrow, so I want to stay downstream at least initially.

When storms will fire tomorrow and the extent of storms is a big question mark still. The models have been all over the place with both. I am still looking at data so I don’t have any strong opinions yet, but my guess is we’ll get storms firing along the dryline from SW Kansas down through the Texas panhandle between 4-5. That’s pretty much a guess. I pray to god they don’t go early because the conditions don’t become real favorable for tornadoes until closer to 7pm and it is key that storms are discrete during that 6-9pm window for the tornado potential to be realized. I think that screwed up the tornado potential on Wednesday of last week with that OFB triple point storm in north Texas. It fired too early and then by the time the parameters became supportive later in the day, the storm had already turned into a clustered mess of competing cells that went outflow dominant. The same concern exists for tomorrow. The parameters over most of the warm sector will not be very favorable for tornadoes until later in the day. Once low level shear ramps up around 7pm though, hodographs are fairly impressive, especially over the central portions of the area I boxed in red on the above map. If storms fire at the right time so there are discrete supecells tracking through that area later in the day when low level shear increases, then I think there’s a chance for a strong tornado.

I am still just getting into my forecasting, but I did start to glance at moisture. The moisture coming on shore in SW Texas right now is what is forecast to advect into the target area through the day tomorrow. Dewpoints are in the upper mid and upper 60’s over the southern part of Texas right now. The moisture wasn’t really all that deep with the Corpus Christi sounding (about to 900mb), but I think moisture can only be a mitigating factor tomorrow, not a deal breaker.

Another concern is the slight S shape to hodographs after 00Z, but I’m not terribly worried about that either. It’s not the real pronounced backing in the mid levels that can really screw things up for tornado potential so I think we’ll be alright. Again like moisture I think it’s more of a mitigating factor than any sort of potential deal breaker. The timing and extent of convection are my biggest concerns with tornado potential getting ruined tomorrow. CAM guidance in the morning should provide a lot more light on that.

Alright, enough for tonight. I think SPC will hold with the enhanced tomorrow, but if things come together right I could see probabilities getting upgraded to more like 10% hatched for tornadoes for portions of the area I boxed in red on the map. Good luck if you’re going out. I’ll update regularly through the day tomorrow so check back if you’re interested.

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