Not Tricking You With This Treat

With weather conditions more like Mother's Day (61 degrees F, 50 degree dew point, 68% humidity and 7 mph southerly winds) than Halloween on Tuesday, October 30, 2018, an unexpected strong storm cell formed from a clear afternoon sky. A small cluster of cells began to materialize around Cedar Rapids, Iowa about 12:30 pm CDT, and by 1:18 pm they had merged to the point where the congealed storm's updraft sported a pileus cap (above and below). Both iPhone 6 Plus cellphone camera images look SSE from Progress Drive at Martha's Way in Hiawatha. The most intense part of the storm was located about 15 miles distant, near the Interstate 380 bridge over the Iowa River in Johnson County. The image below is a panorama capture.

This radar screen capture corresponds to the above photographs. The target icon is my position, with the black arrow pointing to the photograph's updraft. White arrows indicate storm movement. From here the storm moved into northern Illinois and southern Wisconsin before breaking up into rain showers.

RadarScope capture of the storm cell around 1:30 pm.

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Unecessarily Awoken

I was awoken from sleep by my bedside weather radio around 10:30 pm CDT, Monday, October 8, 2018. A storm cell in Benton County, Iowa had intensified to become severe-warned, and was moving toward home in Cedar Rapids on its northeast track. Above is a view looking west from Bowman Woods Park in Cedar Rapids at 11:04 pm CDT. Clouds from the line of storms can be seen over the trees. Also visible is the bright (0.00 magnitude) star Vega in the constellation Lyra at right center. Image is a 25-second exposure at f/4.5, ISO 250 and 18mm focal length. Just after this image was captured the storm began to weaken and quickly dissipated. The next day, however, would bring longer-lived tornadic storms in nearly the same location. Nikon D7200 DSLR camera.

Radar image capture of the time corresponding to the photograph. My position is shown by the target icon. Note the storm track. Even if the storm had held together it might have still slid west of me and was on this night a false alarm.

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Wall-to-Wall Wall Clouds

Unseasonable amounts of moisture and instability were present in the state of Iowa on Tuesday, October 9, 2018. It felt more like May than October. This, and other factors prompted the Storm Prediction Center to post the convective (left) and tornado outlooks at 12:25 pm CDT.

An SPC Mesoscale Discussion (1550) at 12:59 pm further added the 80% probability of a tornado watch issuance, and indeed it was posted at 1:45 pm (Tornado Watch 404, above). Storm clusters began forming in south-central and south-east Iowa shortly thereafter, moving in a less normal NNE track. The first tornado-warned storm cell appeared in southern Marion and Mahaska counties at 2:20 pm, which prompted me to leave work a half-hour early to get ready for a possible intercept.

After quickly securing my photography and communication equipment, it was time to set out for the intercept. The image above, captured at 3:27 pm CDT while southbound on the Interstate 380 S-curve in downtown Cedar Rapids, Iowa, looks southwest toward a new tornado-warned cell, located about 25 miles distant, in northern Iowa County and southern Benton County.

Radar screen capture and our location for 3:30 pm.

3:38 pm CDT. Westbound on US Highway 30, just west of Fairfax, Iowa. The first of several wall clouds is beginning to come into view at our 10 o'clock position.

3:45 pm. Approaching the wall cloud with inflow tail cloud, about a half-mile east of 28th Avenue, and south of the town of Newhall, in Benton County. Wall cloud is about six miles to the southwest.

Radar screen capture and our location for 3:48 pm.

3:49 pm. We are stationary now, located on 27th Avenue at US Highway 30, south of Newhall in Benton County. This classic low-hanging wall cloud sported a rapidly rising right side. A confirmed EF0 tornado touchdown occurred southeast of the nearby town of Blairstown at 3:48 pm. I made a spotter report to the National Weather Service in the Quad Cities (DVN) at 3:50 pm.

3:54 pm. Same wall cloud looking due west from US Highway 30. This storm was moving left-to-right in the image. The wall cloud exhibited dynamic movement.

3:55 pm. A panoramic capture of the wall cloud with much of the storm structure included, from 27th Avenue at US Highway 30. A laminar shelf cloud can be seen at left.

3:57 pm. A zoomed-in shot of the wall cloud, which is quickly moving north (right). At this time we made the decision to return to our vehicle and follow its track.

Radar reflectivity (left) and velocity captures corresponding to 3:55 pm. The white target icons indicate our position.

4:01 pm. Northbound on 1st Avenue (W14), just south of the town of Newhall. Panorama image of wall cloud and shelf cloud, located about 1.8 miles to the northwest.

4:01 pm. Closeup of the wall cloud.

4:05 pm. Northbound on 27th Avenue north of Newhall. The wall cloud now has a tighter appearance and includes a inflow tail cloud. Weather conditions at this time was: 82 degrees F, 75 degree dew point, 79% humidity, wind at SE at 5 mph.

4:09 pm. Stationary again and on 27th Avenue (W14), about 3.1 miles north of Newhall. Looking northwest at the wall cloud and tail cloud.

Video frame capture from 27th Avenue (W14), about 3.1 miles north of Newhall and about .6-mile south of 67th Street in Benton County. Top image from 4:11 pm, bottom at 4:14 pm. The storm was moving toward the upper right of the images (NNE). The bottom image includes an apparent horizontal vortex, rotating around the storm. A slight grazing of rain briefly fell on us here as the storm moved away.

4:10 pm radar screen capture, showing our stationary position (target icon). Black arrow indicates most intense area of the tornadic storm, white arrows show storm movement.

4:15 pm. Lowering in northeast sky on the eastern flank of the storm, over 67th Street. The sun was beginning to emerge from behind the camera, providing excellent photographic contrast.

4:18 pm. Billy Gant photographs the storm in this panoramic view looking north-northeast from 27th Avenue (W14), about .6-mile south of 67th Street in Benton County. At extreme lower left of this image is the hood of a watchful Benton County Sheriff.

4:19 pm. Black and white version of the storm. B&W conversion created by Nik Collection/Silver Efex Pro 2.

4:58 pm. Stationary at Van Horn Chevrolet car dealership along US Highway 30 in Benton County. The image looks south beyond 28th Avenue toward a funnel cloud.

5:03 pm. Backlit rotation from same location. A steady rain was falling.

Radar screen capture and our location (upper left) for 5:08 pm.

5:12 pm. The storm cell has now passed to the east of the car dealership. The wall cloud is exhibiting a laminar structure, and is moving right-to-left in image.

5:22 pm. Stationary and looking northeast from 72nd Street at 28th Avenue, about one mile southeast of Newhall. Funnel in background was located about 9 miles distant. Sirens were sounding at this moment, probably due to another tornado-warned cell located near Fairfax, Iowa, 6.5 miles to the southeast (see 5:08 pm radar image above).

5:47 pm. Northbound on I-380 near H Avenue, following another wall cloud to the north. I would make a ham radio report of this wall cloud minutes later.

5:55 pm. Looking northeast from County Home Road just east of I-380. The wall cloud has a tight, bell-shaped appearance.

6:01 pm. Looking north from County Home Road, toward the town of Alburnett, in Linn County. Though the storm was significantly weakening at this time, a classic wall cloud persisted. Filtered setting sunlight created this beautifully colorful look. Despite the dynamic nature of this day's tornadic event, we experienced minimal amounts of lightning and wind and zero amounts of hail. Nikon D7200 DSLR camera.

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