Vanishing Act

An SPC Moderate Risk was posted for the southern two-thirds of the state of Missouri on this day, Saturday, May 27, 2017. A Slight Risk extended up into the extreme southern and southeastern part of Iowa. Above, a small cell (arrow) begins to form between New Sharon and What Cheer, Iowa around 3:00 pm. It would become a "Tail-end Charlie" of a comma-shaped line of lesser storms forming in Mahaska County and moved in a generally easterly direction. At 3:20 pm I decided to depart Cedar Rapids in an attempt to intercept this cell, and hoped it would continue to hold its strength. On my way south on Interstate 380/US Highway 218, the storm became severe-warned at 4:00 pm, and I found my spotting position--a favorite spot in Washington County on Yucca Avenue, about 1 mile east of US Highway 218 and about 2 miles east of Ainsworth, Iowa.

This image shows my vehicle's severe weather equipment as I waited at 4:48 pm on Yucca Avenue, facing west. The approaching storm cell had become tornado-warned just minutes before.

The radar capture above shows the tornado-warned storm at 5:04 pm. Its most intense core was located about 32 miles distant, between the towns of Sigourney and Harper. My spotting position is the blue target at far right.

5:18 pm (above) and the most intense area has now moved east over the Harper, Iowa area.

Two minutes later. A funnel had been reported by other spotters with this storm. Its impressive structure began to materialize along the horizon to my west. I felt I was in perfect position here--if the cell stayed on its current track its southern edge would pass to the east just north of me. Temperature at this time was 73 degrees F, dew point 63 degrees, 69% humidity and the winds were out of the SSE.

5:25 pm. The structure is looking better than ever, and I was filled with anticipation. I had no reason to believe the storm would not maintain its current strength. Nikon D7200 DSLR camera.

By 5:30 pm my weather radio announced the storm had weakened and the tornado warning had been lifted (radar capture above). From 5:30-5:50 pm the cell went from tornado-warned to an area of mere light rain! An astounding and frustrating vanishing act, probably brought on by its entry into very stable air. It was time to return home.

Read more...

Colorful Gaps In May 15 Storm

Gaps in severe weather clouds allowed brief and vivid color glimpses in Eastern Iowa on the evening of Monday, May 15, 2017. Above, a view looking northwest from Noelridge Park in Cedar Rapids at 8:05 pm CDT, shows the sun peaking out of clouds whose severe-warned center was located about 60 miles to the northeast (right), about 10 miles northwest of Dubuque.

A zoomed-in view of the same area less than five minutes later.

8:25 pm, looking northwest over Noelridge Christian Church in Cedar Rapids. The most intense part of the severe storm was now located just north of Dubuque, about 65 miles distant.

A vertically-oriented version of the same image.

A minute later at a nearby vantage point. Some of the storm's striated lower clouds (that extended well out of the image to the right ) can be seen at right. Nikon D7200 DSLR camera.

Read more...

Gonna Get Wet

These GoProHero4 video frame captures from Wednesday, May 17, 2017 in Benton County Iowa show a fast approaching gust front and blasting wind and rain. The time sequence was from about 5:50-5:53 pm CDT. The images look southwest from the grounds of the Youngville Cafe on US Highway 30, about 3.6 miles southwest of the town of Newhall. Pea-size hail and an estimated 60-70 mph straight line winds accompanied the storm, whose rain shafts resembled a wedge tornado.

Read more...

May 17 Iowa Severe Weather Threat

An Enhanced Risk severe weather potential for the state of Iowa was posted by the SPC on Wednesday, May 17, 2017. Tornado Watch 231 (above, left) was issued for the west two-thirds of Iowa at 12:05 pm CDT; then Tornado Watch 233 for NE Iowa (above, right) at 3:10 pm. I was on the road less than a half-hour later and selected a severe cell moving south-to-north in Johnson County (below).

My position for the photo--seen below at 4:30 pm--is shown in the radar image above at upper right. The lighter area of the storm cell in the image below is in the area of the arrow shown above.

The severe cell passed to my west (above) as I found a spotting position at 4:45 pm. My location was on 540th Street SW, a half-mile west of Observatory Avenue, and about 1.5 miles southwest of Hills, Iowa. The cell, which appeared to sport a funnel-like appendage, was about 10 miles distant.

When the Johnson County cell weakened below severe limits, I decided to head back north on US Highway 218/Interstate 380 to get into position to intercept a new line of severe storms to the west in Iowa County before 5:00 pm. This line had a NNE track. I then decided to travel west on US Highway 30, and as the storms neared, selected the driveway at the Youngville Cafe along Highway 30 in Benton County. The historic cafe is located just east of 24th Avenue, and about 3.6 miles southwest of the town of Newhall. The above image looks south at the approaching storm from behind the cafe at 5:48 pm. The fast moving storm was about 10 miles distant at this moment.

This panoramic image in the same location, but closer to the highway, distorts the actual much wider shelf cloud, giving it a wedge tornado-like appearance. At this moment--5:50 pm--the storm had neared to only 5 miles away. Less than ten minutes later, the storm blew over me, with winds estimated briefly at 60-70 mph. Pea-size hail and blinding rain followed. Returning home, I noticed a couple of utility poles askew and intermittent areas of small debris on the road. Nikon D7200 DSLR camera.

The radar image above corresponds to the panoramic image above it. The target symbol is my position, with the black arrow pointing toward the storm. White arrows indicate storm movement.

Read more...

Big Serving Of Altocumulus

Much of the sky was taken up here by large formations of altocumulus clouds during the morning hours of Sunday, May 7, 2017. This panoramic image looks west at 10:56 am CDT from the grounds at Noelridge Christian Church in Cedar Rapids, Iowa. These cloud types typically exist from 6,500-20,000 feet above the ground. Nikon D7200 DSLR camera.

Read more...