Technical Tornadoes

When it comes to tallying tornado sightings, I've landed on two categories -- legit tornadoes and technical tornadoes. Those latter ones come up when I scour and enhance my video and still photos later, pair them up with confirmed tornado reports and imagery and notice that I managed to catch either funnel or debris in my footage. I've also lumped in a couple cases where I've spotted funnels that I suspected at the time I was seeing them, but wrote them off, only to find out later they actually had been tornadic. These are three from this past chase season.

May 1: Chester, KS tornado
I picked up the funnel for a couple minutes on the dash cam without realizing it. In the moment, I was more concerned with staying out of the hook as we cruised down I-70 and wasn't noticing the new circulation handing off further east. Only after seeing the report and checking vs. my time stamps did I notice it on the video.

May 1: Tescott, KS tornado
I was in a great spot to see at least the first minute or so of this one if I had just waited. But I got anxious that the storm was going to get away from us and wanted to get in a better intercept location near Bennington. So I wound up jumping back on I-70 about 30-60 seconds before it touched down. I had my window-mounted video camera recording the wall cloud, but the hills were way more of an issue than I realized they'd be. I got a few frames where the dark edges of the wedge were visible between hills, beneath the wall cloud.

May 27: Federal, WY tornado
Just after catching a beautiful rope tornado north of Cheyenne, I was about to reposition when I noticed the new wall cloud had a fang dropping down on its leading edge. I started tearing cameras out of the car and got crooked video of it just as it was at its pointiest, and a still photo just as it was degenerating. I figured it was probably just a scary looking scud tag at the time and disregarded it. Reports, photos and time stamp comparisons later identified it as being tornadic.

With those, my count for 2018 is:

  • 3 tornado days
  • 8 legit tornadoes
  • 3 technical tornadoes :)

I've also got a what-the-heck-nado from May 2nd, but that's a story for another time.

We had an excellent sky combo over Flagstaff last night. The full moon was blasting a halo into thin cirrus, and a lenticular cloud was blooming to the east of the Peaks. I started on Route 66 east of town a little after midnight to get some shots. The halo was really intense at that point.

180 degrees in the other direction, the lenticular cloud was looking nice and marshmallowy in the moonlight.

For a couple minutes I wondered if I should try shooting and stitching a massive panorama to capture the halo and lenticular together. I decided that would be really frustrating to compose decently and a lot of hard work later. So I moved on up Highway 89 between Sunset Crater and Wupatki. That managed to get both of them both features paired up with the Peaks.

The FGZ sounding from about 7 hours earlier shows a stable air mass with strong, unidirectional wind out of the west and a moist layer up at 350mb. The slight inversion on that sounding is a bit below the moist layer — not sure what that means, since it’s been above the moist layer in a couple previous cases.

Lenticular Cloud Forecasting

This morning, I got treated to this tubular breadstick-of-a-lenticular-cloud. Almost always seems I'm in a hurry to get somewhere when I spot these. I had to stop for at least a few minutes to grab some shots.

It finally got me thinking how I could attempt to forecast these in advance. They tend to form downwind of the San Franciso Peaks in advance of an approaching trough...but not reliably. Seems to me that it probably isn't as straightforward as 'moist, stable air flowing over a mountain'. I pulled up this morning's sounding and plotted soundings for a couple previous days when I had photographed them.

What stood out to me so far were some common traits:

  • Elevated terrain feature - to generate eddies
  • Upper level winds around 40-50 kts with 15-25kts near terrain feature - sufficient wind speed to convert horizontal terrain interaction into sufficient vertical motion. The San Francisco Peaks reach to about the 650mb level, so I'd watch for winds beginning to pick up around that level.
  • Roughly uniderectional upper winds - to support laminar flow
  • Stable air mass - to avoid mixing and further support laminar flow
  • Dew points within 5°C of saturation at one more points in the upper air mass - to allow air to condense when it is lifted from terrain eddies
  • Dry air in lower levels - to allow clear visibility to lenticular cloud features
  • [edit 31 March 2018: a couple additional bullets added below, courtesy of feedback from John Sirlin]
  • Shallow inversion above mountain - seems I did see this on a couple soundings, so I'll be watching for that too.
  • Orientation of flow to terrain feature - For terrain that is elongated, look for greater likelihood when flow is perpendicular to this feature. I haven't watched for this with the San Francisco Peaks since they're fairly symmetrical, but should be something evident with flow lofting over the Mogollon Rim.

I want to play with those options when I get the chance now, to see how repeatable I can get with seeing that combo of elements leading to lenticular clouds. Is there a limit to how slow flow can be at the terrain feature? Does flow at 650mb even matter for the Peaks or does it still get captured if 500mb flow is strong while winds below are weak? If upper level wind direction varies by more than say 30 degrees, does it wreck the effect? What if there is a tiny bit of elevated instability - at what point does it start to interfere? How far from saturation can dew points be and still be expected to condense into lenticular clouds?

With those options in mind, I pulled a NAM forecast sounding for this Saturday afternoon. If that forecast pans out, it could make for some lenticular action that afternoon with perhaps a cloud cap just above the mountaintop and possibly a high altitude wave off to the east-northeast. I'll keep an eye out and see how wrong I am.

I'll update with how that goes

Randall the Wandering Gartersnake

Three months ago, we found a garter snake roaming the rose bushes in front of our house. I was really surprised. It’s been a long time since I’ve seen one in the wild, but I can only recall ever seeing them near creeks and other healthy water sources. With all the cats and cars around in town, I figured he was a really lucky critter. He musked when I first picked him up, but never bit, and that was the only time he ever tried to skunk me or anyone else.

First sighting beneath our rose bushes

Doing a little research after that, I ID’d him as a Wandering Garter Snake — Thamnophis elegans vagrans. He’s about 24 inches long and I’m guessing male because the tail after the cloaca doesn’t quite seem to taper for about an inch or so.

I haven’t had a pet garter since I was a kid and had forgotten how awesome they are. He’s just an exceptionally beautiful snake. Bright eyed with a slight olive green tint up top and pastel bluish green gastrosteges beneath—and glossy like a moving ceramic sculpture. We handle him regularly and he is completely comfortable with that—always on the move, exploring and flicking, never snippy or skittish.

He spent the first few weeks in a small 7-ish gallon tank, but is now set up in a better 20 gallon tank with trimmings to hopefully make it as pleasant for him to live in as it is for us to watch. We’ve had friends through the years that have had milk snakes, boas and kings, but I haven’t yet seen any that compare to watching a garter just constantly moving and grooving, stretching and reaching around their environment.

We have some extra faux-vine leaves and a climbing rock that we bring out and set on the table a couple times a week to let him crawl around and explore different layouts. Sometimes one of us will sit there and play or work on the laptop while he takes an extended tour. That’s where I had been feeding him too—big earthworm on a paper towel in the middle of a temporary table garden. A little vitamin dusting on the worm once every couple weeks. He was ravenous the first couple months and at times would scarf his meal before I even had a chance to put him down.

He shed twice in the first two months, but what I feared has now happened. He stopped eating in September, and has gone into enhanced exploration mode, so I figure he’s hunting for a good brumation spot. I’m afraid he’ll lose too much weight if I try to avoid brumating until it’s too late. So I picked up a thermostat and separate heat mat to set him up in the smaller tank, out in the garage for I guess a couple months to reset the belly clock.

Randall checking out the freshly assembled brumation hideout

I’m really afraid we could lose him to that process. But definitely don’t want him starving himself at higher metabolism in our indoor temperatures either. I wish I could be confident that after a couple months of not eating and warm temperatures I could be sure he’d figure it out and start chowing down again…but as far as I know, he could get sick and die of malnutrition first. So I guess I’m giving brumation a shot. The cage is covered in foil to keep it dark, thermostat programmed for 50 degrees F, water dish and cover added, and snake in residence. We’re starting with two or three days indoors to start the dark. Then out to the garage for cooler temps. We’re going to miss watching him roam and flounce around for a couple months.

US Storm Chase Map - 2017 Update

So this update is kind of late for the 2017 season, but I wanted to get it out there anyway. This adds info for the remainder of the western and eastern US. I also got permission from the Reddit user WestCoastBestCoast94 to include the road image he generated, so that underlayer has been included. This mostly shows up as gray patchiness at lower resolutions.

The map is based on my visual assessment of the road network. So there's a fair amount of subjectivity in there. At a variety of points, I'm positive people could find things that aren't spot on. Texas was questionable in a lot of places, because of how often the road grid there is rotated 45°. At available resolution I couldn't visually tell if those networks were truly gridded or not, so they got knocked down in quality due to uncertainty. Mainly, I tried to err on the side of pessimism if I couldn't tell for sure how well gridded the network was.

Despite that, I've been pretty satisfied with how it's held up in areas where I've chased. The area in northwest Oklahoma/Barber County Kansas definitely checks out as sketchy. There are some tough road choices too in the less networked area in north Texas along the Red River; but then some pretty decent zones in the Mississippi flood plain. The map gave me confidence with a setup that looked like it could produce in that flood plain and I caught a tornado near Grady, Arkansas last year because of it. Some day, North Dakota shall call, and I will answer. Original detailed discussion about the map and process for creating it is found here: 2015 US Storm Chase Map Project

Links to high-res versions are included with the low-res images below:

US Storm Chase Map - with forested areas
1600 x 1067px | 1920 x 1280px | 3840 x 2560px

US Chase Map 11 June 2017 - with forest

US Storm Chase Map - without forested areas
1600 x 1067px | 1920 x 1280px | 3840 x 2560px

US Chase Map 11 June 2017 - with forest

The maps may be distributed/reposted for non-commercial purposes. Please preserve the watermark, and I'd be grateful a link back to this site if possible. If you would like a full-resolution copy (13,500px x 9,000px), please get in touch at the email address in the header of this page.

I hadn’t been forecasting this day to death…not even close. I was pretty much keeping a lazy eye on it for any option for strong storms as low pressure worked its way into southern Arizona. SPC had marked out southeast Arizona and southwest New Mexico for marginal severe probabilities, but a quick check of HRRR this morning hinted at some fun further north in the Little Colorado River Valley.

Six overlapping runs of HRRR helicity swaths

Several runs were pretty consistently bringing up to 750 j/kg SBCAPE, 20-40 knots of 6km shear, low 50 degree dew points up into the LCRV. Those runs were also consistently laying down decent helicity swaths across I40 between Winslow and Holbrook. As the day wore on, dew points looked like they might cross the 50 degree threshold. By 2PM, convection was starting to strengthen south of Holbrook, so I took off to sample the goods.

And what goods there were.

As I headed east, one cell took over and picked up a very nice, cyclonic velocity couplet as it drifted north-northwest.

Reflectivity/Velocity Radar at 3:19PM (2219Z)

By the time I was within 50 miles, I could start to make out a couple layers of bell-shaped lowerings sweeping beneath the lurking darkness of the storm. As good as the couplet looked, I was pretty sure the storm was peaking and I’d probably missed the best.

Distant view of the storm base looking east from I-40 (2246Z)

Looking southeast during a quick stop at Hibbard Rd. before continuing east (2302Z)

About 10 miles east of Winslow, I exited at Jackrabbit road, trying to position a couple miles east of where I thought the storm would cross. I haven't scouted this area before, and got stuck with some pretty bland landscape options…shooting perpendicular across railroad tracks makes me sad. But the storm…the storm was incredible. The RFD gust front had scooped up a gigantic cowcatcher shelf cloud as it loomed closer. After snagging a few still photos, I set both cameras up to catch both wide and tight video as it moved in.

Five-frame stitched pano looking south at the approaching supercell from 10 miles east of Winslow (2315Z)

Close up of the leading edge of the RFD shelf (2319Z)


Within a few minutes, my phone belted out a warning alarm, and there I was smack dab in the middle of a tornado warning polygon. Although there was broad rotation, I didn’t notice anything tightening up apart from some fun eddies underneath the gust front.

Finding myself in the center of a tornado warning polygon (2321Z)


Both cameras shooting video (2326Z)

Road options were no good once it crossed the interstate and I headed back west to Winslow to take Highway 87 north. From there I watched a trailing cell try to make good on whatever was left to chew on.

Looking southeast at the weakening remains of a trailing cell from a few miles north of Winslow (0006Z)

…and the very important rainbow shot (0016Z)

So, yeah, it feels great to finally have been on a tornado-warned Arizona supercell!

Tornado Warned Supercell—Joseph City, Arizona—3 November 2016 from Jeremy Perez on Vimeo.

11 August

Nocturnal storms moving in from the southwest sent me up to Sunset Crater National Monument for a try at some shots. CGs were very reluctant as the storms weakened on approach. I still wound up with some rim lighting on the cloud base as a consolation.

Nocturnal lightning display at Sunset Crater National Monument - 0908Z

21 August

No storm chasing going on here, just spontaneous German Shepherds in the sky.

Convection or dog with a stick from east Flagstaff - 0152Z

26 August

Another day of southwest flow had me out at the Winona/I-40 exit shooting some time lapse photography. As a strong storm set up over Flagstaff. This one picked up a weak (~14 mph radial velocity), pulsey velocity couplet through 4 slices for about 20 minutes. Not enough to qualify as even a minimal mesocyclone. Structure, as far as Flagstaff storms go, was pretty nice and it covered the San Francisco Peaks in a white cap of hail. I drove further east to Buffalo Range Road and got a look at a pretty nice shelf moving in. It was interesting to watch the time lapse on that as a northbound gust front interacted with it and sent a cool whirl along the shelf.

Sheared convection east of Flagstaff looking north from Winona/I-40 exit - 2002Z

Storm building over Flagstaff looking west from Winona/I-40 exit - 2010Z


Shelf cloud looking west from Buffalo Range Road/I-40 exit - 2103Z

Hail on the San Francisco Peaks from Hwy 180 west of Flagstaff - 0035Z

2 September

One more southwest flow day back out at Twin Arrows to watch for the occasional shelf or lowering near Merrill Crater. As convection filled in southward, a building gust front loaded up with meshing gears of vorticity to wrap up the time lapse.

Convection and lowering north of Twin Arrows/I-40 exit - 1833Z

No landspouts, just galaxy cores overhead - 1958Z

Passing convection and gust front looking northeast from Twin Arrows/I-40 exit - 1904Z


A few days in early August gave me opportunities to intercept monsoon thunderstorms along the Mogollon Rim Convergence Zone during southwest flow. The 5th, 6th and 10th of the month served up some nice ones. I’m not getting too detailed with these, or else I’ll never get around to posting the pics.

5 August

Around noon, I followed a strong cell east out of Flagstaff as it drifted along north of I-40. I managed some time lapses south of the Twin Arrows/I-40 exit as it was draping a shaggy shelf cloud around its core. I paced it further east to Buffalo Range Road where it ran into a boundary being laid down by another line of north-south convection to the east. The interaction worked some beautiful structure into the updraft of the original cell before it merged, mushed and gusted out. I tried for some more convection further north on the AZ-87 toward Dilkon. Nothing strong materialized, but the landscape was stunning against the tattered sky.

Flaring shelf cloud north of Twin Arrows - 1924Z



Debris clouds east of Twin Arrows - 1937Z

Northbound convection looking east from Buffalo Range Road & I-40 - 1954Z

Eastbound convection looking north from Buffalo Range Road & I-40 - 1954Z


Gust fronts beginning to merge - 1958Z



Enhanced structure as interaction strengthens eastbound cell - 2011Z


Disorganized convection southeast of Dilkon - 2113Z






6 August

Another noon chase, and another cell drifting east out of Flagstaff. This one was over Doney Park with a severe warning when I first got on it. The warning soon dropped off and I ran some more time lapse ops on the structure at Twin Arrows again. Later that evening while visiting friends, a pair of cells popped up north of the San Francisco Peaks. The sun was setting and casting a mellow light on the anvil and updrafts as lightning moved around their innards. A few bolts snuck a peek outside the clouds, but I only caught a couple while shooting the time lapse sequence.

Severe-warned storm over Doney Park as seen from Winona & I-40 - 1903Z

Looking north from Twin Arrows & I-40 - 1936Z


Twilight storms north of the San Francisco Peaks from Doney Park - 0239Z


10 August

Some tropical storm moisture and a Pacific low overlapped a bit over northern Arizona, and I headed east once again for a look. My first view was from east Flagstaff of a cell to the southwest over Kachina Village. Although the base was strung out, it was still decent by Arizona standards as it played at displaying some tail cloud characteristics. After that dissipated, I got east on I-40 and hung out at Homolovi State Park for a while, grabbing time lapse as a new cell got going southwest of Winslow. This one sported some more beautiful structure as the orange landscape reflected up onto the base of the storm. Bryan Snider and his wife Monika showed up and we shot some time lapses together as the storm grew a lowering and grumbled at us. We got ahead of it as the rain moved in and watched from Hibbard Road as it withered and sheared away. Later that night, another round of convection slowly moved up from Verde Valley and gave an opportunity for some nighttime lightning photography at Sunset Crater National Monument. Not a lot of nearby CG activity as the storms weakened by this point, but still some good under-cloud illumination against the cinder hills and ponderosas.

Cell over Kachina Village as seen looking southwest from east Flagstaff - 2010Z


Lowering on a new cell over Winslow as seen from Homolovi State Park - 2302Z





Sheared convection looking west from Hibbard Road & I-40 - 2331Z



Monsoon storms got an early start on July 2nd. The night before, the HRRR model was trending toward an MCS rolling out of southern Nevada and into Flagstaff by around 6 AM. I set my alarm for 5 and sure enough she was right on schedule just west of town. I quickly threw myself and everything else in the car and headed out on east Route 66 to watch it plow through town. I love watching Arizona storm clouds when they’re in high-speed mode.

Storms towering over Flagstaff as seen from east Route 66 - 1226Z

Gust front making its way out of town - 1230Z

A nice eddy sculpts the gust front as it rushes by the south side of Mt. Elden - 1231Z

Since it looked like it might stay interesting, I headed east to Twin Arrows—and was reminded how much I disliked the view from that exit. So I headed a bit further east to the Buffalo Range Road exit—no real foreground elements to speak of, but at least it wan’t fences, power lines and dumpsters. As the gust front moved in, a northern stretch of it lunged out and sculpted an amazing, terraced shelf.

Beautifully sculpted shelf cloud between Twin Arrows and Two Guns - 1302Z

I jumped further east to Two Guns and composed some shots of the ghost town structures with the heavy morning sky. I’ve snagged a few photo ops with the stone structures in the area, but this was my first time working with the buildings on the east side.

Moody sunrise over Two Guns - 1313Z

Insane graffiti and advancing storms at Two Guns - 1317Z

After that, I raced ahead to Holbrook and then southeast on Hwy 180. The line of storms was messier at this point but still had some moments of shelfy goodness to offer.

Fangy, embedded shelf cloud southeast of Holbrook - 1451Z

Tantalizing scud photographed on the move, southeast of Holbrook - 1458Z

As that line weakened and moved off to the east, I had a look at the models again. Indications were that the morning cirrus shield would move on, the atmosphere would recover, and more storms would fire, despite subsidence in the wake of the morning MCS. So I headed back west and decided to explore Homolovi State Park for a little bit while convection slowly got going again.

Receding convection and windmill on Hwy 180, southeast of Holbrook - 1612Z

A Loggerhead Shrike keeping an eye on parking spaces at the entrance to Homolovi State Park

Pottery shards gathered on stone platforms at the Homolovi II Archeological Site

Cumulus bubbling south of Homolovi State Park - 1957Z

Convection strengthening over the San Francisco Volcanic Field - 2016Z

Collared Lizard showing off its colors at Homolovi State Park

Storms continued firing west of Leupp while tracking along and north of I-40, so I headed over to Rt 99 northwest of Winslow, then the Meteor Crater Road exit, and then back to Rt 99 south of Winslow. Storms were not as sculpted as they were that morning, but still enjoyable viewing on desolate roads.

Convection south of Leupp from Rt 99 - 2147Z

Lightning strike from north of Meteor Crater Road - 2246Z

Transient structure at the I-40/Rt 99 offramp - 2306Z

Storms forming along an intersection of outflow boundaries south of Winslow on Rt 99 - 2348Z

A hangnail of vorticity and a sunbeam along Rt 99 - 0007Z

I wrapped it up with a time lapse near Clear Creek as distant storms pulsed along a southward moving outflow boundary.

Convection and anvils along a receding outflow boundary from near Clear Creek - 0048Z

A short sequence of time lapses from the day.

I had a nice local storm chase today. I headed west, past Wiliams, to catch storms as they started firing and hopefully ride them east with some road network testing along the way.

A little after noon, I took an exit at Welch Road a few miles east of Ash Fork to get some shots as convection was developing to the west. Somebody had kindly donated* a sofa. It was facing the wrong way, but I was not tempted by its mysterious comforts.

Furniture spotting on Welch Road east of Ash Fork - 1950Z

A couple other angles as it dared me to take a load off.

As cells blew eastward, I cruised up to Williams and took Rt. 64 north to see what would pop up next on the outflow. I stopped a bit south of Valle to watch a transient lowering, as one does when trying to randomly spot landspouts. While I was there, another chaser, Jonathan Triggs, from Grand Canyon Village stopped to say hi before making his way toward Flagstaff. Convection at this point was pretty laid back, wimpy and grungy as I circled back southeast on Hwy 180.

A momentarily interesting updraft east of Valle - 2031Z

Tendrils of rain that kept reflexively catching the corner of my eye - 2052Z

Made a stop at Red Mountain for a quick look around—I need to hike this cinder cone some day - 2119Z

Although I’d been hoping for a chance of a developing cell drawing up some vorticity as the gust front passed the San Francisco Peaks, it seemed pretty unlikely at this point. So I decided to run an audit of one of the forest service roads, north of the Peaks in the no-man’s-land between Hwy 180 and 89.

I got about three miles in, before the likelihood of getting stuck and busting my car in the rocky, cratered road became too great. I stopped and found a spot to hike up a hill to get some shots of a pretty decent cell popping up north of the Peaks by that time. Lots of terrain mostly blocked the view as it continued eastward and joined a strong line of storms that moved off onto the Navajo and Hopi Reservations.

Looking east at a cell developing north of the San Francisco Peaks - 2159Z

Some wildflowers in the area starting to like the recent rain - 2203Z

Rain core getting established - 2207Z

After shooting a few angles, I made my way back down toward Hwy 180 and did a bit of Coconino Cow Spotting before calling it a day.

Gate guardians

Bossy momma


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