For almost a week, Tuesday October 4th was looking like a pretty exciting day, with the GFS forecasting an aggressive dryline (~30F DWPT gradient) to pass through OK/KS with the potential for some decent severe weather. It was somewhat forgotten about due to Hurricane Matthew – indeed, The Weather Channel could barely find time to dicuss the situation even on the morning of the 4th.
So, here’s a summary of my day. I chased with 3 of the other Reading students at OU.
The models firmed up over the previous day that we’d be looking at north Oklahoma/south Kansas for the majority of the storms, with the SPC issuing an ENHANCED risk for that area near the surface low track. Considering this, the morning sounding from Lamont, OK was exciting – with a 50kt LLJ just above the surface, a load of cyclonic shear and a low-to-mid-level zone of steep lapse rates.
The north looked an obvious target, with all the right conditions and latest HRRR and NAM runs suggesting a strong, quasi-linear system to develop in the late PM. However, the HRRR began to suggest an isolated supercell would develop SW of Norman/OKC. Despite the potential for this to be both severe and sexy, we deemed the probability lower, and headed north, whilst our American OU friends headed SW.
Leaving Norman at 12:30pm, our initial target was the Oklahoma-Kansas border. We steamed up I-35 and upon nearing Kansas headed northwest. The skies were clearing, wind was picking up (and the LLJ above very much visible in rapid cloud motion) and temperatures rising.
About 2:45pm we pulled over to check the latest data (yes, the car is very yellow).
The latest HRRR suggested between 3 and 4pm would be ‘kickoff’, with stuff initiating west and also rather too far to the north. We elected to head somewhere between these two zones and made our way straight to the dryline, which was lying just east of Pratt.
As we heard of the tornado watch issued for the area, the first supercells went up in the region to the north just as the HRRR had expected.
Then, west of Kingman, we got our first cell of the day right on the dryline. It grew rapidly before our eyes.
Knowing this was now an active region, we headed back towards Kingman – LTE was sparse in Kansas, so it also gave us a chance to check the radar and the latest HRRR. The storm became fairly high precip, with some small hail thrown in.
After getting drenched, we noted the HRRR had the most potent stuff near the border around 6pm, so with sunset in mind, we headed south along the dryline where we also saw a few other stormchasers. We passed through some more small hail, which was illuminated by the low sun angle.
Just north of Harper we stopped to take a breather. The wind was very much sweeping across the plains – I recorded 26mph on my handheld anemometer at head height. Convection was initiating to our SW, but we also had a beautiful storm to the NE heading towards Wichita.
It had a favourable radar signature and a strong inflow (left of image), with mammatus developing on the anvil. The moment it became severe warned was the fastest us four guys have ever moved. We made straight for it.
Approaching Norwich from the west, we glimpsed…something. Lots of excited noises. When the trees cleared on the horizon it turned out to just be deceptive scud (no rotation), but still made for a good view. The storm continued to have evidence of a hook, so we carried on.
We stopped north of Norwich in an open area, where we elected the storm was now too far north to chase given the setting sun and stuff developing to the south. We got a good view of the low wall cloud and hail core though!
Standing in the open plains of Kansas with this storm in the distance and huge rumbles of thunder filling the sky is an awe-inspiring feeling.
As the rain arrived, we headed south. The convection was now really going off in a line and we had to head right through some of it, which had hail mixed in. The radar screenshot below is just after the worst of it!
In Argonia we stopped to fuel up from a jerry can which took much longer than it should have thanks to a dodgy valve. The system we’d pushed through was now to our east and intensifying rapidly – it was quite the show whilst we faffed around with the car.
Fuelled up we headed due east, straight for the system. It was clearly now quite strong, but a lack of LTE data meant we were working with a 20 minute radar lag. Conditions rapidly deteriorated – southerly winds became very strong, with lashing sheets of rain and hail obscuring the sunset (which looked almost like the moon). Visibility was less than 10 feet. The car was struggling to go straight with the surface water. Then, the radar updated.
Realising the severity of the condition (the radar reflectivity doesn’t do the precip intensity justice), the track of the storm and the potential for a hook echo (sadly, I couldn’t load the velocities!), we quickly turned and drove the hell out of there. That was when the worst occurred. “Just keep going straight ahead”, was the best advice we had for Kieran, who was doing his best to keep driving.
Outside of that we took some time to reflect on what had just happened. Since winds were southerly throughout, we’ve concluded this was in no way tornadic but a strong downdraft region. It was the first time I’ve been properly scared by weather I was in.
From here, with light fading, we headed west then south with the line of storms out in front of us. This provided a fantastic lightning display once it had got dark, so we spent some time just standing outside in the plains, watching. I saw a few positive CG strikes, and a couple of what could have been blue jets – fleeting flashes out of the top of the Cb, much faster than the main lightning.
Kieran captured this fantastic photo of us watching the lightning. “This is my church, it’s a religious experience” was how I summed it up.
This marked the start of our journey home. Upon reaching N Oklahoma (by the way – the state sign on the KS border has been shot repeatedly, which is very amusing) we realised we had to drive back through the storms (our rapid retreat from the earlier encounter had left us the wrong side of everything). Given the region around I-35 wasn’t severe-warned, we continued on, though the rain was so bad we had to do 30-40mph for a good 5 minutes.
In the distance we could see the supercell that the HRRR forecast to develop near Norman had indeed formed, so those who did chase SW didn’t go home empty handed – and it too had a pretty significant hook…it just didn’t quite happen (thankfully, because Moore has suffered enough!).
We finally got back to Norman at midnight – a 12 hour chase, which I’ll never forget.
I can’t wait for the spring.