STEELE COUNTY
SKYWARN
29-Jun-2010

July 21 Newsletter

SKYWARN Meeting
The next SKYWARN meeting is 20-Jul @ 7:00 PM, the third Tuesday of the month.

Activation
17-June From Dave KCUVY

We had a total of 34 volunteers and involved in the activation. This allowed us to fully staff the EOC and team up several groups of spotters in the field. Initially it appeared that the primary threat was going to be from the west. But the storms built very rapidly on the southern end of the line, so instead, we had a total of three tornados enter the county in the southern row of townships. Each of the tornados tracked approximately 6 miles into the county before they became rain-wrapped and died.

No cities were impacted directly, but there was a significant amount of structural damage including several homes which were completely destroyed. Initial damage assessments rate the tornados as EF-3 (Ellendale), EF-1 (Steele Center), and EF-3 (Blooming Prairie). Further results are still pending.

My thanks to all who participated in the activation. I don't think it is exaggerating to say that people are alive today because of your dedication.

The NWS is summarizing details along with graphics and radar loops. This can be viewed at http://www.crh.noaa.gov/mpx/?n=10june17.

25-June From Chris NCPG
EOC activation was made on the advice of NWS Chanhassen at 1850 CDT. At the time, the line of storms was crossing Mankato. The storms had a history of persistent rotation and there were reports of funnels near New Ulm. Weather had potential impacts on Medford Days and Owatonna street dance.

Steele County SKYWARN responded with 25 volunteers in the field and at the EOC. Storms initially appeared to be headed to the northern half of the county. There were problems with GRLevel3 and no radar data was received after 1926. Attempted to use Lacrosse and Des Moines radar and used Channel 6 TV. The main cell then moved directly toward Albert Lea. LEC dispatch sounded the sirens for the entire county. The effected portion of the tornado warning was for the southern 1/3 of the county (including Ellendale and Blooming Prairie). Tornado warning was cancelled for 2036. Spotters were returned to base and all accounted for. EOC was closed at 2100.

26-June From Chris NCPG
EOC activation was made at 2100 CDT. At the time, a Severe Thunderstorm Warning was being issued for the NW corner of Steele County. The line of storms was producing straight-line winds in excess of 65 mph. Amateur Radio Field Day activities were interrupted due to the storm, and many of the participants switched to storm spotting. A total of 21 volunteers responded to the activation call.

A line of storms built through the evening stretching from the Wright County through Faribault County. The southern portion of the line had a history of rotation. Straight line winds, large hail, and heavy downpours were also common. 105 machine was down, Chris was unaware of the problem until Tom and Dale arrived (I knew something was wrongit was too quiet on the radio!) Problems with GRLevel3 continued and no radar data was received after 2133. Attempted to use Lacrosse and Des Moines radar. Used Channel 6 TV, Wunderground still images, and spotter reports to track the line across the county. Two tornado warnings were issued for Steele County. The first tornado warning was posted for the northern 1/3 of the county at 2138 (radar indicated). The second tornado warning was posted for the southern 1/3 of the county at 2147 (Spotter indicated tornado 5 mi from Winnebego).

First tornado warning was cancelled for 2207. Second tornado warning was cancelled at 2214. Several spotters reported 35-40 mph measured winds and heavy rain. FJP reported localized street flooding on S Cedar Ave (South Federated Complex). UOW reported branches down at Lemond and 62nd Ave SW. Severe Thunderstorm Warnings cancelled at 2243. Spotters were returned to base and all accounted for. EOC was closed at 2251.

June Tornado History From Multiple Sources
As this is being written, the the NWS confirmed 20 tornado reports on 17-Jun. The previous one day record was 22 tornnadoes on 16-Jun-1992. After that, the number of tornadoes reported on a signle day drop significantly:

  • 18 tornadoes on 01-Jul-1997.
  • 16 tornadoes on 11-Jun-2001 and 13-Jun-2001.
  • June 28, 1979: 15 tornadoes on 28-Jun-1979 and 24-Jun-2003.
  • July 21, 1995: 14 tornadoes on 21-Jul-1995, 26-Oct-1996, 29-Mar-1998, and 25-Jul-2000.
Historical data indicates that June is the most active month for tornadoes, with about 25% of the tornadoes.

Web Site Updates
Brian KBDD updated the county map to include the "sweet spots" for spotting. The Spotter Report was updated as a pdf.

Mayfly Hatch From NOAA
The Doppler radar at La Crosse picked up an unusual return pattern in late May, shown at the right. The high density being returned were Mayflies hatching along the Mississippi River. Mayflies survive for just one day as an adult. To ensure they find a partner, their emergence from their aquatic, larval stage is somehow synchronized. The bugs hatched and were carried in the winds for 15 minutes or so.

SE MN SKYWARN Net
A SKYWARN net is conducted on Rochester's 147.255 machine on the first and third Monday of each month. The net begins at 9PM. The repeater has a 100.0 PL and can be accessed through EchoLink as node 420993.

Term For The Month From Minnesota WeatherTalk
Acclimatization Thermal Strain Index (ATSI)
Travel to distant places where the climate is different to that at home involves a period of short-term acclimatization adjustment following arrival. A traveler making a significant change in climate might experience thermally-induced physiological strain. ASTI assesses the health impact of such recreational travel by calculating the respiratory heat losses. A comparison is made between the home environment and the travel destination. Researchers found that summertime travel produces a larger shift than the coldeer months.



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Steele County SKYWARN
Owatonna, MN