04/15/06 Storm Report

My target for yesterday verified nicely even in my absence, with a number of tornado reports from just south of Beatrice, Nebraska in the late afternoon. Per the SPC Storm Reports for this date, there were three tornado reports between 2133 and 2152Z (4:33-4:52pm CDT) in Gage County, NE. Several chasers were on these storms and captured nice photographs and video that have already appeared on several media outlets. I would expect the Omaha/Valley NWS WFO to be putting out a preliminary storm assessment sometime Monday.
Here in KS, the show came a bit later. We spent the afternoon tree-shopping at a local greenhouse/nursery. After making our selections, we waited while the owners loaded our purchases into a truck for immediate delivery and it was then that I began to get a bit restless, observing a growing cell to our southwest(!). Upon arriving at home around 6pm, I immediately checked radar and confirmed that storms were now firing ahead of the dryline, forming a broken line along I-335 from Topeka SW to Emporia around 6:30pm. At this time, the storms were still 30-40 miles (and 1-1.5 hours) away from KTGX, yet a gorgeous anvil and its mammatus hung over KTGX for much of the early evening hours. Below is a photo of a swarm of gnats hanging out over the weather station…and oh yeah, some mammatus in the background at 6:25pm CDT:

One highlight of the pre-storm environment was the significant inflow from the SSE. Winds were blowing all afternoon, regularly sustained into the upper-20s to 30s, with gusts I’d estimate to the mid-40s. Similar conditions were observed from Topeka to Lawrence, with the Lawrence ASOS reporting a 51mph gust at 6:52pm CDT.

The storm finally pushed into Leavenworth county just before 8pm. KTGX was impacted by the storm at the southern end of a small sequence of cells. At 8:05pm, the only tornado report to come from the area was logged on the SPC storm reports, a brief touchdown 4 miles south of Tonganoxie at 8:05pm as reported by “broadcast media”. By this time, the rain was falling at rates easily exceeding 2″/hour here in KTGX and I dared not venture out of the house. Some minor hail was also included, although the headline was really the wind and the rain. A neighborhood weather station located on a rooftop just a few houses to our south that reports conditions online recorded a 69 mph wind gust during this time.

At 8:15pm, just as the wind and rain were beginning to subside as the cell slid to our NE, the KC NWS office issued a tornado warning for Wyandotte and southern Leavenworth counties (including KTGX). Since the sirens have not been fully functional this spring, the local police drove through local neighborhoods with sirens blaring while repeating the tornado warning text over their loudspeakers. At 8:16pm, I captured this image of a suspicious lowering of the cloud base directly to the south of our location:

No rapid rotation was evident, although upward motion and movement from W to E was apparent. I do not consider this feature to be any sort of funnel and whether or not it was the feature that was part of the tornado report from 11 minutes prior is unknown.

A total of 1.05″ of much-needed rain was recorded and a temp drop from near-80 to 56 degrees occurred during the storm, with temps rebounding into the mid 60s immediately following the storm’s passage as the southerly flow returned nearly immediately - the frontal passage had not yet occurred. Around 8:20pm, the core of the cell passed to our NE and was still growing (as shown in the photo at the top of this post).

By around 8:25pm, clear blue sky was visible to the west and south and a spectacular light show was in progress to the N and E with frequent anvil crawlers extending directly overhead. I played with the manual exposure settings on the new camera but wasn’t able to zero in on the appropriate settings until it was too late. But I know now for next time…