Another Expedited Intercept

At 4:35 pm CDT on Sunday, June 9, 2019 I was working on my computer, oblivious to the possibility of any kind of severe weather. The 8:40 am Storm Prediction Center (SPC) convective outlook maps for June 9 showed only the smallest probability for thunderstorms in my location (see target icons above). So when my wife approached me with the news she had heard from the radio at 4:34 pm: "There's a tornado warning," I was utterly confused. I thought she had meant for Texas or Oklahoma, and why would she be telling me that? Suddenly my home weather radio blared an alert, followed quickly by my cell phone notification. This setup was similar to the May 29 event, when there was very little time to prepare.

A line of storms had started forming around 3:00 pm in northeast Iowa, east of Decorah, and began moving southeastward with a track that would bring the southern segment just northeast of Cedar Rapids. The radar image above corresponds to the time of the tornado warning alert. The area of greatest intensity is circled, with arrows showing the storm's movement.

With the storm less than 20 miles away there was only time to pack my bare essential equipment for an intercept: my Nikon and GoPro cameras, and hand held weather and transceiver radios. The Radarscope frame capture above shows my mobile position to the tornado-warned storm at 4:54 pm.

The image above looks northeast at 5:00 pm while northbound on Highway 13 just south of County Home Road (E34). Billowing in the background is a cumulonimbus cloud spiking above 40,000 feet. The most intense part of the storm was located about 14 miles distant, about five miles northwest of Anamosa.

5:01 pm and eastbound on County Home Road (E34), just east of Highway 13 and northeast of Marion, Iowa. Zoomed-in shot of the anvil-topped cumulonimbus.

5:02 pm. Wide angle shot of the northeast sky while continuing east on County Home Road, about 3 miles west of Whittier, Iowa.

5:07 pm. Eastbound on County Home about 2 miles west of Viola, Iowa. A high precipitation core of the storm is seen at left.

5:08 pm. Now about one mile west of Viola. Heavy rain shafts are seen at right. The storm is moving from left-to-right in the image. Camera looks to the northwest.

5:09 pm. Eastbound on County Home Road at the western edge of Viola. A medium rotating wall cloud is seen above the background utility poles, with a possible forming funnel (lighter area) at center.

5:10 pm. At the intersection of County Home Road (E34) and Stone City Road in Viola. Rotating wall cloud can be seen low in the east, just above the tree line at right.

Radar frame capture for 5:15 pm as I was proceeding toward Anamosa on County Home Road. An arrow points toward the most intense part of this storm from my current mobile location (target icon). An EF0 tornado was occurring in this general area at this time.

5:16 pm. Eastbound on County Home Road (E34), about 1.5 miles southwest of Anamosa, Iowa, and .25-mile west of 223rd Avenue. The high precipitation area of the tornado-warned cell is just behind the tree line at left.

Base reflectivity (left) and velocity images corresponding to the time of the photograph above them. My location is shown with the white target icon. Arrows indicate the storm's track.

5:20 pm. At my stationary spotting position on 223rd Avenue in the Turkey Hollow II housing development, about 1.5 miles southwest of Anamosa. This image looks east. The storm sports a high precipitation core at left, a slowly rotating wall cloud at center and is moving away at around 35 mph toward the background at right.

5:27 pm. Panorama looking southeast from 223rd Avenue. Note the large precipitation area at left.

5:30 pm. Storm with a very impressive precipitation core.

5:32 pm. Looking southeast from 223rd Avenue at the departing storm. My eyes were probably deceiving me when I thought I saw faint debris rising from just above the tree line at left background and moving to the right; but it also could have been dirt kicked up by a truck driving through a construction area which was located in that direction. I could not report what I might have been imagining. (What was not imagination was the fact that three EF0 tornado touchdowns were confirmed on this day: 3:53 pm northeast of Winthrop, 4:24 near Prairieburg and 5:14-5:17 south of Anamosa.) With the passage of the storm from this position, it was soon time for me to "weigh anchor" and head for home.

5:47 pm. This image looks back east at the departing storm cell during a brief stop on a connecting intersection along US Highway 151 near Springville, Iowa. Nikon D7200 DSLR camera.

Read more...

June 5 Weather Elements

Impressive mammatus formations graced the southern skies at 8:56 am CDT as seen from Progressive Drive and Martha's Way in Hiawatha, Iowa on Wednesday, June 5, 2019. Weather conditions at this time: 64 degrees F, 63-degree dew points with 94% humidity.

Panorama of the scene moments later. East is left, south is at center. Mammatus clouds are a result from the sinking of moist air into dry air and often reside under the anvils of thunderstorms.

Radar frame capture corresponding to the above two iPhone 6 Plus photographs. The target icon at top shows my position in relation to the storm clouds. Arrows point to the white line, indicating approximately where the mammatus was residing at this time.

This east-facing panorama shows the departing storm at 9:34 am. It was about 35 miles distant. iPhone 6 Plus camera.

By afternoon, severe storms were located a considerable distance south from my location but were still observable. The above panorama image was captured from Alburnett Road and Flight Drive in the Bowman Meadows housing development in Marion, Iowa at 3:17 pm. The image spans from east (left) to west, with south at center. The left part of this line of storm clouds were in Illinois, the right, in Missouri. Nikon D7200 DSLR camera.

Radarscope frame capture graphic corresponding to the panorama image above it. Storm "A," near Kirksville, Missouri, was about 135 miles distant; storm "B" was located near Quincy, Illinois and was about 140 miles distant; "C" was about 165 miles distant and was located west of Springfield, Illinois.

Read more...

May 29 Iowa Tornadic Storm

I was not expecting any significant severe weather in eastern Iowa on the evening of Wednesday, May 29, 2019 as the Storm Prediction Center (SPC) had posted a lighter Marginal Risk (above). So much so that I was relaxing and watching TV when my nightstand weather radio squawked an alert at 6:15 pm. With heavy rains having occurred the past few days, I expected a flash flood warning when I checked the alert. Instead, I was amazed that it was a tornado warning! It was the only storm in the eastern two-thirds of the state, it was currently in eastern Poweshiek County (about 42 miles away) and it was heading directly for Cedar Rapids!

Teaming up with fellow spotter Billy Gant, we initially headed west on US Highway 30, but as the storm's track progressed it became obvious that in order to stay on its southeast flank (and out of the rain and hail) I needed to reverse direction. Our new target area was now Mount Vernon, Iowa. We would find an ideal location just off Highway 30, about 2.5 miles west of town, with an unobstructed view of the western and southern skies. Here we would stay during the rest of the spotting duration. In the panoramic image above, captured at 7:49 pm CDT, the growing tornadic storm is approaching from the southwest.

7:51 pm. Zoomed-in view of the storm.

8:01 pm. Skies to the northwest were ablaze with color. In the foreground Billy photographs the incoming storm beside our vehicle.

8:02 pm. Colorful sky--the calm before the storm.

8:26 pm. Beginning to form in the storm at left is a horseshoe-shaped updraft base.

Radarscope frame capture corresponding to the photograph above it. Note the three red tornado warning polygon boxes and the larger green flash flood warning box.

8:31 pm. Panorama looking southwest. The center of the storm is beginning to show a cake-layered appearance, with frequent lightning discharges.

8:35 pm. Incoming storm is progressing closer and now shows an inflow tail cloud low on the horizon at right. It is now about 9 miles distant.

Reflectivity radar screen capture corresponding to 8:35 pm. The target icon and black arrow show our position in relation to the most intense part of the tornadic cell. White arrows show storm movement.

8:38 pm. Close-up of storm, looking ominous and now about eight miles distant.

8:41 pm. Looking south across US Highway 30. The leading edge of the storm can be seen at right. In just minutes the storm would arrive, bringing heavy rain, dime size hail and estimated 60 mph winds...but no tornadoes. Eight weak tornadoes did spin up in various other parts of the state on this night. Nikon D7200 DSLR camera.

Read more...

Tales of Gilgamesh

With continuous heavy rain occurring in Cedar Rapids before I considered driving south to intercept severe storms in Henry County in southeast Iowa on the evening of Tuesday, May 28, 2019, I left with some trepidation. Flash flood talk was continuous on the radio, and I wondered if what I was going to do was in fact, foolish. Above, an Emergency Alert sounded on my iPhone at 5:36 pm CDT, while I was southbound on US Highway 218 in Washington County. Now I was spooked!

Upon arriving, and after a brief stay in Mount Pleasant where a benign line of storms passed through, more dire warnings of flash flooding was forecast from another approaching line of stronger storms. I finally decided for safety sake it was in my best interest to abort the storm intercept now and get out of "Dodge." In the Go Pro video frame capture image above, I am returning north in heavy rain on US Highway 218 about 2.5 miles north of Mount Pleasant in Henry County at 6:40 pm.

6:45 pm. Continuing north on US Highway 218, about one mile south of Swedesburg, Iowa in northern Henry County. The combination of waning daylight and blinding rain made for an increasingly stressful ride. Farm fields (background) were at this time about 50% inundated. Later, and despite reaching home safely, I regretted I ignored prudence and ever took this trip. A lesson learned! Nikon D7200 DSLR camera.

Read more...

Bust to Best

The Storm Prediction Center (SPC) Convective Outlook is shown above. The Weather Channel's (TWC) Dr. Greg Postel named two areas in the midsection of the U.S. where tornado formation was possible on this day, Friday, May 24, 2019. Postel's forecast was this: The Texas/Oklahoma area ("A" in the top graphic) would have more instability, but the Iowa/Illinois area ("B") contained more wind shear and therefore had a slightly better chance of tornado genesis. This would prove to be absolutely correct, although not initially without some doubt for several hours.

With conditions in Cedar Rapids, Iowa becoming more and more favorable as the morning passed, I activated my Spotter Network ID around 12:30 pm, but the watching and waiting game would last about another three hours. Around 3:30 pm the SPC posted a severe thunderstorm watch probability for the eastern half of Iowa. It was time to pick up my storm intercept partner and future son-in-law, Billy Gant. My target spot to await storm initiation was one of my favorites of recent times--a gravel road just under two miles east of Ainsworth, Iowa in Washington County. This location was prime if storms would form in all directions of the Slight Risk area and immediate relocation would be  necessary. Conditions there were indeed favorable: temperature of 81 degrees F, dew point 79 degrees, humidity 94% and wind out of the south to southeast.

5:11 pm CDT. In position on Yucca Avenue, .1-mile south of Highway 92 and 1.9 miles east of the town of Ainsworth. Some cloud formations and cumulus towers had begun to form but as time passed it was looking like maybe this wasn't going to happen after all.

For an hour curious passersby came and then drove on, chatting with us about the possibility of bad weather. All we could give them was "maybe." Just as it started to look like it might become a bust, we observed a storm cell to our northwest, growing more robustly than others. Above, I captured what was actually a forming supercell at 6:15 pm. The supercell was about 30 miles distant, located near North English, Iowa. Since this was beginning to look interesting, Billy and I agreed to set out and head toward it.

We had no sooner gotten into our car to move when our weather radio sounded a tornado warning. Above is an IEM radar image capture for 6:20 pm, the time this cell went tornado-warned.

As it turned out, we were actually in perfect position to intercept this storm. In short order we were back on US Highway 218 and northbound as this image from 6:22 pm shows. We were 1.5 miles north of Ainsworth and about 25 miles south of the storm, which was located just NW of Wellman, Iowa.

6:25 pm. A little closer to the supercell and it is growing bigger in size. Its cloud tops (echo tops) would eventually reach around 45,000 feet.

6:29 pm. Now it had become real--Emergency alerts on our cell phones were going off.

6:33 pm. This two-stitch panorama looks northeast while we continued northbound on US Highway 218. Low on the horizon was an inflow tail cloud, feeding into the storm toward the left of the image, a further indication of its strength.

6:34 pm. Now looking west. Not to disappoint, a large updraft with a wall cloud was beginning to blot out the sun. This supercell meant business now!

6:41 pm. We had minutes earlier pulled off the Hills, Iowa exit in Johnson County, and were negotiating Observatory Avenue, then 540th Street SW. A needle-thin funnel had now touched the ground and become a bonafide tornado.

6:41 pm. Zoomed-in image a short distance from the previous image.

6:44 pm. Go Pro video frame capture westbound on 540th Street SW west of Hills, Iowa, showing towering updraft and tornado.

6:45 pm. Stationary now on top of a hill on 540th Street SW, about 3.4 miles WSW of Hills. This Go Pro video frame capture looks northwest at the EF1 twister which is approaching, but passing about 2.5 miles to our north.

6:45 pm. Approaching stove pipe tornado to our northwest.

Radar frame capture corresponding to 6:45 pm, showing base reflectivity image of the storm. The target icon shows our position in relation to the tornado (black arrow). White arrows show storm track.

Base reflectivity and base velocity images for 6:46 pm.

6:48 pm. Go Pro video frame capture. Tornado is showing a spiraling horizontal tube. Some who were closer to the tornado at this time reported a loud "roar," but from our position it was inaudible.

Map and graphic showing the tornado's track in relation to our position. The tornado tracked a safe 2.5 miles to our north.

 6:49 pm. Go Pro video frame capture. Tornado to our north is now displaying multiple vortices.

6:50 pm. Tornado is beginning to lift.

As the tornado lifted, we decided to follow it. We were eastbound on Bayertown Road SW about 3.5 miles west of Hills, Iowa. The storm cell had seconds earlier possibly dropped to the ground an elephant trunk funnel. The above image shows the funnel retracting from its parent cloud at 7:04 pm.

7:57 pm. Preparing to call off the chase and head for home. This image looks east at the departing storm while southbound on Baker Avenue (X30), about 3 miles north of West Branch, Iowa. The storm is about 14 miles distant. An exhilarating afternoon/evening of storm intercept! This was Billy's first tornado, and it was the BEST kind: clear view, safe distance, breathtaking structure, track mostly through farmland, no hail, minimal property damage and no injuries or fatalities. Nikon D7200 DSLR camera.

Read more...

May 16 Fast Forming Severe Storm

This storm began forming near Story City in central Iowa about 6:50 pm CDT, Thursday, May 16, 2019. In just a half-hour it went severe-warned and was moving swiftly east. I gathered my staple spotting equipment and headed out. The above image looks west from Boyson Road in Cedar Rapids a short distance from home. The severe warned cell, with its most intense area now located near Marshalltown Iowa and about 70 miles distant, nearly covers the western horizon at 7:37 pm.

7:40 pm. At the intersection of Boyson Road and Council Street NE. The right edge of the storm cell is beginning to cover the setting sun.

7:43 pm. I drove northbound on Interstate 380 in order to capture a superior open area shot of the storm cell's impressive structure. This image is a two-stitch panorama.

Radar frame capture of the corresponding time to the image above it. The black arrow (right) shows my location and the white arrows show storm track.

With heavier activity to my south, I then reversed direction, despite waning light availability. This image of an approaching severe cell--a four second exposure at f/10, 320 ISO and 18mm focal length--was captured at 8:35 pm. My location was Herky Street at Penn Street, just west of I-380 and North Liberty, Iowa. I did not stay long here and headed home, which was a good choice as tremendous amounts of rain and hail would fall here.

Read more...