I don't know if I'll chase today. Probably will. It looks like the front placement may split the difference between the NAM and GFS, and that leads to an interesting thought. Just wanted to mention something that's floating around in the realm of possibilities.
- Mid-afternoon: Convection initiates on the dryline not too far south of the triple point in NW TX.
- Strongly backed low-level flow carries the developing updraft almost due north (this is why I think nothing initiated by the front will survive).
- Late afternoon: The storm strengthens and turns to the northeast in the ideal environment just south of the front, in SW OK.
- With a continued right turn, the supercell's motion approaches the SW-NE boundary orientation.
- Early evening: Motion becomes parallel to the boundary at exactly the time the storm reaches it.
- Through late evening: LLJ arrives in force and the rogue boundary-riding supercell drops a string of significant tornadoes across OK.
- Front begins advancing southeastward again, finally undercutting the storm.
As a low-probability (storm has to fire in precisely the right place), high-impact (could produce tors along a 100+ mile path) event, is that far-fetched?
More likely, we'll see a couple nice supercells around Snyder-Wichita Falls-Walters-Lawton. These would easily be capable of producing significant tornadoes. Convection along the front stands no chance of becoming established before moving northward into colder air, so this may limit severe potential in much of Oklahoma. RAP's orientation of the front in NE OK may, however, allow a few storms to get into the warm sector in NE OK/SE KS/SW MO. This would mean a second tornado hotspot up there, where hodographs are just obscene. For now, I think the only major tornado threat to central OK is as described above, with a storm from the dryline rooting on, or even turning eastward from, the frontal boundary. No matter what happens, it's time for me to get sleep now.
Preliminary target: Grandfield, OK
Wednesday, April 17, 2013
Tuesday, April 16, 2013
The supercell drought ends
Storms? What are those? It's been so long since the Southern Plains has seen convection worth a drive that I almost forgot what it was like. Today was a marginal day, with SPC extending, then removing, then extending again a slight risk area from E OK down through N TX. I got into the first few problems of math homework early in the afternoon, took care of a couple other things, and noticed short-range models continuing to insist on a few storms along the stalled front. With 2000-3000 J/kg CAPE and 40+ kt shear, these would probably be supercells. I started rolling south on I-35. While the unbroken pattern of cloud streets in E and SE OK suggested strong capping persisted in that area, well-defined Cu lined the frontal boundary in N TX. A mesoscale discussion came out from the SPC, followed in short order by a tornado watch box. I initially pegged Madill, OK, as a target, but got lost in Ardmore after taking the wrong exit. Might've been for the best, as I returned to I-35 instead of pressing east to Madill. A quick stop on the south side of Ardmore combined gas, water, and weather radio battery resupply. About that time, KFWS radar finally came back into service after being down for a while. Seeing a cluster of storms approaching Bowie, TX, I was pretty sure I could intercept in Texas.
Maneuvering around Gainesville on I-35 at 4:30 was an adventure in itself, with what appeared to be exit ramps on the map never materializing. I finally found a frontage road and stayed on it into Valley View, where I headed west on two-lane back roads with the nowcasting guidance of a friend back in Norman. I caught a glimpse of the lead cell, dominant at the time, in a rural area between Decatur and Gainesville.
This marginally severe supercell became less impressive as it tracked just north of my location. I edged northwestward--road options forced a northwesterly or southwesterly path--to position for another supercell at the back of the cluster as it became dominant. Many miles in the distance, I noticed an interesting feature under its updraft. It looked to be scud, but persisted for a while with noticeable motion. I stopped on a gravel spot along the shoulder, but was immediately met by a local resident coming home. He was pretty touchy when I tried to talk to him. It turned out that one of the gravel roads that rolled over the hill from that pull-off spot was his driveway. I was a couple feet off the roadway, well outside his fence. There was no house anywhere to be seen. But rural Texans own guns, and if they say you're violating their privacy on the shoulder of a public road, you don't stand there in your crimson OU hat and argue the point. I apologized and rolled on, catching a couple quick shots of the feature of interest. Other chasers claim it as a funnel, but nobody seems to have been close enough to verify that.
I came into Forestburg, TX, and stopped for a couple more structure shots across a football field in disrepair.
This supercell was peaking as I left Forestburg; it was just about to dump 1"+ hail on Sunset, TX, to the southwest. I wanted to get to Alvord, TX, just to the southeast of Sunset. I missed the turn for Alvord, and found myself headed for Sunset. I turned around, went back, and got on the right road. Flying solo screws you up sometimes. As I headed southwestward toward Alvord, the supercell's structure became otherworldly.
I pulled off the road at an oil or natural gas facility after passing numerous chasers. They had the right idea. Even with my wide-angle camera, which is usually a pain because the subject of the photo isn't big enough, I couldn't capture the full structure. Still, being alone under this mothership-style LP storm, watching the striated front side of the thing stream northward into the updraft, was incredible.
Maneuvering around Gainesville on I-35 at 4:30 was an adventure in itself, with what appeared to be exit ramps on the map never materializing. I finally found a frontage road and stayed on it into Valley View, where I headed west on two-lane back roads with the nowcasting guidance of a friend back in Norman. I caught a glimpse of the lead cell, dominant at the time, in a rural area between Decatur and Gainesville.
This marginally severe supercell became less impressive as it tracked just north of my location. I edged northwestward--road options forced a northwesterly or southwesterly path--to position for another supercell at the back of the cluster as it became dominant. Many miles in the distance, I noticed an interesting feature under its updraft. It looked to be scud, but persisted for a while with noticeable motion. I stopped on a gravel spot along the shoulder, but was immediately met by a local resident coming home. He was pretty touchy when I tried to talk to him. It turned out that one of the gravel roads that rolled over the hill from that pull-off spot was his driveway. I was a couple feet off the roadway, well outside his fence. There was no house anywhere to be seen. But rural Texans own guns, and if they say you're violating their privacy on the shoulder of a public road, you don't stand there in your crimson OU hat and argue the point. I apologized and rolled on, catching a couple quick shots of the feature of interest. Other chasers claim it as a funnel, but nobody seems to have been close enough to verify that.
I pulled off the road at an oil or natural gas facility after passing numerous chasers. They had the right idea. Even with my wide-angle camera, which is usually a pain because the subject of the photo isn't big enough, I couldn't capture the full structure. Still, being alone under this mothership-style LP storm, watching the striated front side of the thing stream northward into the updraft, was incredible.
And that's really all that's worth seeing. The storm went through some contortions as it decayed, dying out with the decline of surface heating. Is it worth driving to rural northern Texas to experience a few minutes of epic storm structure? Of course!
On a side note, as I finished writing this, central Oklahoma felt a preliminary magnitude 4.3 earthquake. Here's hoping this apartment complex makes it through the night.
Monday, April 1, 2013
Spring!
It may finally be springtime on the plains of Oklahoma. I chased a dying hailstorm near El Reno, OK, on 3/29, then showed up late to the Medicine Park-Walters hailer the following day with a couple friends from SoM. Not a lot to show from either day. Norman got run over by a beast of a severe thunderstorm about 4 a.m. on Easter morning, 3/31. Our apartment complex got plenty of hail, quarters and smaller, while golf balls fell farther south. Video:
The GFS and ECMWF are in agreement that an upper trough will dig into the Southwest early next week. As is often the case, the Euro slows things down a bit. The latest GFS (00z 4/2) is the fifth consecutive run to indicate a significant severe weather event in W OK and/or NW TX on Monday, April 8. It has the highest potential of any run yet, with 3000 J/kg CAPE, 50-60 kt shear, and the enormous sickle-shaped hodographs of a violent tornado outbreak. I don't like to trust models at this range, but these last several runs are hard to ignore. Based on the consistency of the GFS, even with some doubts about exact timing and location, I wouldn't be surprised to see a Day 7 area highlighted in the SPC's next Day 4-8 outlook.
Even less certain is the setup for the following day, Tuesday, April 10. A couple older GFS runs hinted at a major event in AR. The most recent has 3000-3500 J/kg CAPE across most of E/C TX, with tantalizing wind profiles up around the DFW metro. The Euro solution might lend itself even more to multiple days of severe weather in the Southern Plains if the system stalls. I think it's safe to say Monday and Tuesday are worth watching...and I'll be wrapping up homework by this weekend. I wasn't in the TX Panhandle for today's surprise tornado, in part because I was doing Matlab at 3:30 in the morning and couldn't consider making a 3+ hour one-way drive. That isn't going to happen again!
The GFS and ECMWF are in agreement that an upper trough will dig into the Southwest early next week. As is often the case, the Euro slows things down a bit. The latest GFS (00z 4/2) is the fifth consecutive run to indicate a significant severe weather event in W OK and/or NW TX on Monday, April 8. It has the highest potential of any run yet, with 3000 J/kg CAPE, 50-60 kt shear, and the enormous sickle-shaped hodographs of a violent tornado outbreak. I don't like to trust models at this range, but these last several runs are hard to ignore. Based on the consistency of the GFS, even with some doubts about exact timing and location, I wouldn't be surprised to see a Day 7 area highlighted in the SPC's next Day 4-8 outlook.
Even less certain is the setup for the following day, Tuesday, April 10. A couple older GFS runs hinted at a major event in AR. The most recent has 3000-3500 J/kg CAPE across most of E/C TX, with tantalizing wind profiles up around the DFW metro. The Euro solution might lend itself even more to multiple days of severe weather in the Southern Plains if the system stalls. I think it's safe to say Monday and Tuesday are worth watching...and I'll be wrapping up homework by this weekend. I wasn't in the TX Panhandle for today's surprise tornado, in part because I was doing Matlab at 3:30 in the morning and couldn't consider making a 3+ hour one-way drive. That isn't going to happen again!
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