Storm Chase // 16 April 2024 // Southeast Iowa Tornadic Supercell

 I chased southern Iowa on April 16th and was rewarded with an intense EF2 producing tornadic supercell west of Burlington, IA. I departed Fort Wayne at around 1AM, took a brief nap near the Illinois border, and then reached my target of Albia, IA by late morning. Storms developed near Kansas City and advanced northeast across my region during the next few hours. Other convection was ongoing north and east as well, all due to the early arrival of an upper jet streak spreading across the area. I moved east with the storms coming up from the south, and they took on a QLCS structure. This didn't bode well for tornadoes, but there was a quasi-discrete cell along the southern end of the line, which I decided to target as it approached far southeast Iowa. This storm quickly matured into a supercell as it reached my location, with classic wall cloud structure, strongly rotating rain currents, and a well exposed updraft that showed clear signs of midlevel rotation. I moved north with the storm as the wall cloud lowered to the ground and displayed increasing rotation. And then just as it went tornadic, rain wrapped around the low-level meso and my view of the tornado was cut off. The road network was also becoming complex as I approached the MS river, so I let the rain-wrapped tornadic storm go as it drifted north, and then intercepted several cells to my south. They displayed some interesting structure, but also seemed to ingest cooler more stable air from the storm to the north, and thus failed to produce tornadoes. All in all a good chase day...images and weather data posted below, including a NAMNEST sounding/hodograph that yielded a predicted tornado pathlength of 78 km and tornado longevity of 61 minutes, which were slightly larger than the observed pathlength of 44 km and duration of 39 minutes associated with the EF2 tornado. Video will be posted soon.

Strong updraft rotation and swirling rain curtains adjacent to a rain free base viewed from highway 218 southwest of Burlington, IA.

Developing wall cloud and rotating rain curtains.

Low-level rotation becoming intense as the wall cloud lowers toward the ground.

Another view of a strongly rotating wall cloud.

Storm is going tornadic at this point with a rain filled RFD just about to wrap around the low-level mesocyclone.

Another cell coming up from the south. It possessed a large rain free base.

Strongly diffluent flow at 250 mb located within the left exit region of a 100+ kt jet streak arrived early across the region and led to widespread convection that may have precluded a more significant tornado outbreak.

A cold core 500 mb low centered over SD/NE/IA/MN border region focused low-topped tornadic storms near the bent-back occluded surface low.

700 mb objective analysis valid 00Z 17 April 2024.

850 mb objective analysis valid 00Z 17 April 2024.

Subjectively analyzed surface map valid 21Z 16 April 2024.

KDVN base reflectivity valid during the time of significant tornado activity in southeast Iowa.

KDVN 0.5 degree SRV valid during the time of sigtor activity in southeast Iowa. The velocity signature seems to be consistent with an EF2 strength tornado.

A NAMNEST sounding valid 21Z 16 April 2024 at Burlington, IA. The sounding may be located within the cool side of a subtle warm-frontal zone which might explain the slightly stable boundary layer profile. Otherwise, strong shear and sufficient CAPE were present for rotating storms and possible tornadoes.

A NAMNEST hodograph derived from the sounding above. Predicted tornado pathlength and longevity are displayed within the inset. Those values were slightly larger than what was observed with the EF2 tornado that occurred west of Burlington, IA.

4/2/2024 Storm Chase: Southeastern Indiana/Far Northern Kentucky

 I drove from Fort Wayne, Indiana south to southeastern Indiana on 4/2/2024 and managed to position myself east of a cluster of messy pseudo-cellular supercellular activity. I targeted a storm that appeared to be anchored to a theta-e gradient that materialized as a result of morning thunderstorm activity. That morning activity really worked over the thermodynamic environment, and probably aided in storm under-performance, as the shear profiles were very supportive of updraft rotation and possible tornadoes. The people of Indiana, Kentucky, and Ohio were undoubtedly grateful for the low tornado count that occurred during this event. Otherwise, I followed several supercells east to the Cincinnati airport, and then dropped south along an interstate in order to position for the passage of a strongly rotating storm. That cell yielded rotating rain currents as the RFD blasted across the interstate, but I didn't observe a tornado. It then moved east into unchaseable terrain, with other nearby cells going on to produce several tornadoes just east of my location, including an EF-1 with a 12.8 km pathlength and duration of 11 minutes. I'm continuing to test a tornado pathlength/duration algorithm, and output using a 22Z RAP sounding from the Cincinnati airport yielded a predicted pathlength of 27.6 km and duration of 22.9 minutes. Perhaps the worked over airmass reduced the potential for longer pathlengths?

0.5-deg reflectivity from the KILN radar showing messy supercells advancing east-northeast across northern Kentucky into southern Ohio.

250 mb valid 00 UTC on 03 April 2024. The left exit region of a diffluent 140+ kt jet streak overspread the region of tornadic activity during the afternoon and evening hours.

500 mb valid 00 UTC 03 April 2024. A midlevel shortwave trough with 70+ kt midlevel southwesterly flow spread east/northeast across the Ohio Valley region during the tornado event.

850 mb valid 00 UTC 03 April 2024. A deep low-level cyclone was present centered over lake Michigan, with fairly robust 40-50 kt south-southwesterlies at 850 mb aiding in moist advection and enhanced low-level vertical wind shear across the Ohio Valley region.

WPC surface analysis valid 00 UTC 03 April 2024. Storms initiated off of a cold front, and it was the activity that occurred along and south of a strong east-west gradient in theta-e that posed the greatest tornado threat from roughly the Ohio river southward.

RAP sounding valid 22 UTC 02 April 2024 near the Cincinnati airport. Thermodynamics were characterized by generally weak to moderate CAPE as well as generally low CIN and minimal near-surface stable layers.

RAP hodograph valid 22 UTC 02 April 2024 near the Cincinnati airport. A favorable wind profile was in place for supercells and short to medium pathlength tornadoes, though the veer-back characteristics of the shear vectors going from 0-5 km AGL and then 5-10 km AGL might have led to messy storm interactions.

Deadly Ohio Tornado: 14 March 2024

 A tornadic supercell initiated off of a cold front in western Ohio during the evening of 14 March 2024 and caused EF3 damage as well as three fatalities. The tornado had a pathlength of 49.9 km, a duration of 47 minutes, and a width of 1000 yards. The large-scale environment was characterized by a minor shortwave trough moving east across the Great Lakes region and Ohio Valley, with westerly flow dominating at all levels above 850 mb. From 850 mb to the surface, flow was slightly backed to southerly, which may be in response to the passing shortwave, as well as cooler more stable air modified by outflow due to a morning QLCS passage. Otherwise, dewpoints were near 60F during the time of significant tornadogenesis, and temperatures were near 70F, with steep lapse rates aiding in MLCAPE values from 500 to 1000 J/kg per RAP forecast soundings. The tornado pathlength/duration algorithms I am evaluating produced a max predicted pathlength forecast of 44.3 km and max duration of 31.2 minutes, which were around 5 km and 16 minutes lower than what was observed, but still useful guidance in my opinion, especially considering that the RAP sounding used to calculate those values was 10's of km south of the tornadic storm.

Radar reflectivity of the killer tornadic storm in western Ohio that occurred during the evening of 14 March 2024.

Base velocity of the killer tornadic circulation that occurred in western Ohio during the evening of 14 March 2024.

250 mb wind and streamlines valid 00Z 15 March 2024.

Surface observations with 60F dewpoint contour in green, frontal boundary in blue, and surface low pressure in red valid during the time of the killer tornadic storm in western Ohio. Data is courtesy of the SPC.

RAP model forecast sounding valid at Dayton, Ohio during the time of the killer tornadic storm.

RAP model forecast hodograph with tornado pathlength and duration output provided in the bottom left during the time of the killer tornadic storm. RAP point sounding is taken from Dayton, Ohio.

Late February Tornadoes Across the Midwest

 I ventured out to the Illinois/Northwest Indiana border during the late afternoon of February 27th, 2024 to see if thunderstorm initiation could take place near the warm sector of a deepening surface cyclone. Shear profiles would be more than favorable for tornadoes if storms did form near my location, but no storms formed, likely due to neutral to slightly anticyclonically curved mid/upper level flow spreading across Indiana which prevented the cap from fully eroding. Meanwhile, strong low-level convergence developed in the vicinity of a surface low pressure center over northern Illinois, which aided in surface based thunderstorm development. I had considered chasing that area, but model forecast soundings showed a consistent near-surface stable layer that prevented me from committing to that target. Plus, storms would drift east into the Chicago metro area with time, which I found to be a horrible chase scenario. 

Otherwise, a supercell formed during late afternoon very close to the previously mentioned surface low near the Iowa/Illinois border and produced a 4.5 km pathlength tornado with a duration of 8 minutes. With input from a RAP analysis sounding, the algorithms I'm testing yielded a predicted tornado pathlength for that area of 10 km with a 9.9 minute duration. Additional tornadic storms formed downstream from the surface low, just west of Chicago, with the maximum observed pathlength being 13 km and a duration of 10 minutes. The max predicted pathlength via RAP analysis soundings was 25 km with a duration of 25 minutes...a slight over-prediction compared to observations. Much later in the night, a QLCS advanced into western Ohio and produced a tornado with a pathlength of 22 km and duration of 14 minutes. My algorithms predicted 29.7 km and a duration of 23.6 minutes. Additional data and analysis is provided below.

KLOT base reflectivity during the time of max tornado development. Storms would quickly congeal into a bow echo after this time.

KLOT base velocity during the time of max tornado development.

250 mb analysis valid at 00 UTC 28 February 2024. Streamlines were neutral to slightly anticyclonically curved across much of the Midwest, which likely aided in suppressing storm development across much of the warm sector.

A crude subjective surface analysis with frontal boundaries, isotherms, and surface streamlines analyzed. Late afternoon/early evening severe storm development occurred very close to the region of strongest low-level convergence which aided in offsetting initially marginal large-scale ascent.

RAP analysis sounding valid near the time of the first tornado near the Iowa/Illinois border.

RAP analysis sounding valid near the time of tornado activity occurring in the vicinity of the Chicago suburbs.

RAP analysis sounding valid near the time of QLCS tornadoes in western Ohio.

Tornado pathlength and longevity guidance at the time of tornado activity near the Iowa/Illinois border. For reference, observed tornado pathlength and duration was 4.5 km and 8 minutes.

Tornado pathlength and longevity guidance at the time of tornado activity near the Chicago suburbs. For reference, max observed pathlength and duration was 13 km and 10 minutes.

Tornado pathlength and longevity guidance at the time of QLCS tornado activity in western Ohio. For reference, max observed pathlength and duration was 22 km and 14 minutes.

Sedona Hikes and Scrambles YouTube Video

 I added an iphone generated movie of my recent hiking experiences in Sedona, Arizona to my YouTube channel. Check it out here [https://www.youtube.com/watch?v=-AqjX1x5rxE].

Sedona Red Rock Caves

I had the chance to explore a series of caves etched into the red rock buttes surrounding Sedona, AZ during January 2024. In terms of cave epicness, the Subway Cave was at the top of my list. The cave requires a couple of miles of easy hiking starting from the Boynton Canyon Trailhead. Upon arrival, you have the option to scramble up a slick slab of rock that takes you into the heart of the cave, or you can bypass the scramble and walk along the side of a cliff that also gives access to the interior portion of the cave. I did the slick rock scramble up, which was easy, and then did the downclimb, which was not so easy. Nevertheless, I had the full Subway Cave experience, which included adjacent ancient cliff dwellings etched into the side of steep canyon walls. View the map location for the Subway Cave here.

Second on my list was Soldiers Pass Cave, which involved an easier hike and scramble. The cave itself consisted of a long chamber that was slit down the middle by a giant vertical crack. It was neat, and I appreciated the small natural window that gave a view of the outside surrounding terrain. The last cave I visited was the Birthing Cave. Not much to say about this one. Pretty unremarkable, but still a nice hike and good view of the surrounding desert.

Sedona Sunrise Followed by a Scramble up Bell Rock

 I was treated to a glorious color-filled sunrise in Sedona, AZ during early 2024. Views to the south at the Sedona Airport vista were filled with reds and orange, while the buttes to the east and north glowed in warming pre-day light. I captured a couple of landscape images during the sunrise experience, and then headed over to Bell Rock with Amy Schreiber. We hiked to the base of the Bell, and then began a fun red-rock scramble up short platforms of rock, occasional cracks and slots, additional smooth rock, and then a short class 5 climb. The class 5 climb required a 15 foot ascent up a crack, then a stretch across a void in order to acquire easy rock that then led to the top of the Bell Rock hike. We soaked in views, Amy obtained another 20 feet up a pillar of exposed rocks, and then we headed down. The down climb on the short class 5 section was briefly sketchy, but the sketch was short and sweet and we were cruising back to our car in no time. Bell Rock is definitely a Sedona classic that should not be missed...map can be viewed here.