September 2008 Newsletter

The next SKYWARN meeting is 21-Oct @ 7:00 PM, the third Tuesday of the month.

About 9 members attended the 19-Aug meeting. Topics discussed included:

  • Reviewed the 7/31 deployment. Looked at radar images and photos from spotters.
  • Several people noted that they did NOT receive the CityWatch callout on 7/31.
  • Show and tell Tiger Roads in GRLevel3. Members asked to have the files (and instructions for using them in GRLevel3) posted on the website.
  • APRS experiments continue. We also continue to look at alternatives to APRS for non-HAMs.

Activation From Dave KCUVY
Steele County SKYWARN was activated on the morning of 31-Jul. The system moved into our area almost 45 minutes ahead of schedule. The system had a very strong bow echo (indicative of extreme surface winds). The gust front pushes into the unstable air in front of the system causing it to spawn new storms before the main system arrives. A tornado warning was issued for NE Steele and SE Rice counties at 8:50 based on radar indicators. To the best of my knowledge there were no actual sightings to confirm that. Several counties, including Steele were caught off guard. Combine that with the time of day, and we were able to get just 4 spotters in the field before the system reached Steele County. A couple of screen shots from the GRLevel3 are below.

It became apparent very quickly that there had been significant damage. Spotters quickly became damage assessment teams answering numerous questions for Chanhassen. There appear to have been two wind cores. The smaller struck Owatonna in a line from West Hills to the intersection of Highways 14 and 218. Along that path trees and limbs as large as 20 inches were snapped, taking down power, damaging homes, and even breaking a gas line.

The worst damage was related to the Medford storm. The damage path began in Le Sueur county and stretched to south of Rochester. While not long enough to qualify as a derecho, it showed many similar symptoms. Along this path trees as large as 24" diameter were snapped or uprooted.

We also continue to look at alternatives to APRS for non-HAMs. GpsGate is one such alternative. Dave KCUVY is running an experimental iGate at Technology Navigators. It can interface with many GPS enabled mobile phones and automatically update SpotterNetwork.
Speaking of, if you dont already have a free account, please signup for one. As mentioned, it is free. You can select Member Networks and associate yourself with Steele County SKYWARN.

Spotter ID
See Dave KCUVY for free bumper stickers and window decals. Magnetic signs cost $12 each. Official Steele County SKYWARN clothing, including vests, windbreakers, polo shirts and hats are available at Court Sports in Owatonna. The clothing is highly visible to help keep you safe while spotting. It is very nominally priced. Samples of the clothing may be seen at:

Owatonna Plane Crash
Dave KCUVY was featured as part of as article in the 02-Aug edition of the Owatonna Peoples Press. Dave discussed flying and landing as part of the bigger story on the plane crash at Owatonna Degner Regional Airport.

Garage Doors From Several Sources
When high winds, especially tornado winds, hit a typical suburban house, the failure of many garage doors to withstand the force can become the first link in a disastrous chain reaction. The garage door is often the first thing to go. Minnesota recently required that newly constructed residential garage doors must be able to withstand a 90-mile-per-hour gust for three seconds. The old standard had been 80 mph. Although the move put Minnesota in line with most non-coastal states, 90 mph hardly holds up to 167 mph winds from the Hugo tornado in May.

Aurora Borealis From USA Today
When is the best time and where is the best place to see the aurora borealis in the USA? Observations from Yerkes Observatory in Wisconsin during a 55-year period spanning five sunspot cycles confirm that January and July the least likely. March and September are the best months of the year, for several reasons:

  • Earth's orbit is in a zone of maximum solar activity during these months.
  • The months of March and September combine sufficiently dark skies. During the summer the sky is not dark enough to see the Aurora Borealis.
  • Another factor in choosing a best time of year has to be comfort for the viewer. In the winter you can see the Aurora Borealis but in temperatures of -40F you may freeze trying.
Most solar activity comes from regions of the sun outside the solar equatorial band plus or minus 10 to either side of the solar equator. The Earth in its orbit is inside this equatorial band during January and July, and when it is at it maximum heliographic latitudes in September and March, the Earth is in the zone of maximum solar activity.

The aurora borealis results from an interaction between solar particles and the Earth's geomagnetic field. This field is strongest at the poles, so best viewing is available in Alaska, followed by northern tier states such as Minnesota and North Dakota.

Oceanography Satellite From Science Daily
A new NASA-French space agency oceanography satellite, OSTM/Jason 2, was launched June 20. Its mission is to continue charting sea level, a vital indicator of global climate change. Measurements of sea-surface height, or ocean surface topography, reveal the speed and direction of ocean currents and tell scientists how much of the sun's energy is stored by the ocean. Combining ocean current and heat storage data is key to understanding global climate variations. The original satellite, Jason 1, remains operating in 1,336-kilometer (830-mile) orbital altitude. For six months, Jason 2 will orbit about 60 seconds behind Jason 1 for cross calibration. Once cross-calibration is complete, Jason 1 will alter course. By adjusting the orbit of Jason 1, its ground tracks will slightly overlap OSTM/Jason 2 and double the global data coverage.

Lightning Safety From USA Today
Learn more about lightning safety on this USA TODAY chat. John Jensenius is a lightning expert and meteorologist with the National Weather Service. The Institute of Electrical and Electronics Engineers publish a guide, How to Protect Your House and Its Contents from Lightning.

Ask An Astronaut
NASA has set up a page that allows you to submit questions to astronaut Greg Chamitoff, who is currently working and living at the International Space Station. Questions will be submitted to the station (220 miles above the Earth) by Mission Control each week. To improve the probability that your question will be answered:
-- Try to avoid asking a question answered often on previous missions.
-- Normally the questions most often answered are those more specific to the current crew and mission.
-- Review information about the station and current activities.

Word For The Month From Minnesota WeatherTalk
von Karman vortices
Named for the Founder of the NASA Jet Propulsion Laboratory, Dr. Theodore von Karman, this feature of the atmosphere is very recognizable in satellite images and photos of cloud forms taken from aircraft. When the air flow across the ocean is disturbed by an island, the downstream effect produces two oppositely rotating eddies of air. When cloud forms are present you can see the rotating motions in the form of cloud streets. More information is available from NASA. A wonderful recent cloud image of a von Karman vortex over the coast of Alaska is available on the Cloud Appreciation Society web page.

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Steele County SKYWARN
Owatonna, MN