January 2009 Newsletter

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

Activation From Dave KCUVY
Steele County SKYWARN was not activated in December.

Spotter Training
As mentioned in the December Newsletter, the Spotter Training Class is scheduled for 7:00 PM on Tuesday, 10-Mar. Training is planned for the Owatonna Fire Station. Spotters must attend a training class at least once every two years to remain certified. The number of participants last year stressed the space available in the training room.

We encourage everyone to pre-register by calling
Bonnie at the Owatonna Fire Station at 507-444-2454.

Winter Weather Terms From USA Today
Ever get confused by the terms used for watches, warnings, and advisories? USA Today has a nice listing of definitions.

Pole of Cold From Minnesota WeatherTalk
Coldest temperatures in the northern hemisphere have not been measured at the North Pole. The town of Tomtor in northeastern Siberia is about 100-200 miles south. Colder air held near the land surface under astrong "Siberian High Pressure" system in winter contributes the colder temperatures. It was -96 F therein 1926. The tourism industry has acknowledged the uniqueness ofthis area and each winter between late November and March, there are package vacation deals offered to tour the Pole of Cold region. Air and rail systems can get you to the region, then you will travel to Tomtor via 4WD Jeep, each equipped with up to three extra heaters for comfort and safety. In the town of Tomtor, you are greeted by the mayor, visit the Pole of Cold Monument, and are given a certificate for framing that verifies your wintertime presence there.

Lake Delton From USA Today
You may remember the news from Wisconsin when Lake Delton drained due to a breach in the dam. A series of storms flooded much of southern Wisconsin and the Midwest for weeks. Swelling waters ate away at a section of sandy shoreline between the lake and the river. The water eventually washed the earth away, creating a 700-foot channel. After nearly six months of hurry-up engineering and construction work, state officials say they're ready to start refilling the lake. Officials plan to close the Mirror Lake and Lake Delton dams to trap carp in standing ponds on Lake Delton's basin. They will apply a toxic chemical to the fish, wiping them out so more desirable species will have a better chance to survive when they're restocked this summer. Then they will open the Mirror Lake dam, but keep the Lake Delton dam closed, allowing Dell Creek to again fill Lake Delton.

Sunset vs. Shortest Day From Earth Skyy
At middle latitudes in the U.S. and throughout the northern hemisphere the earliest sunset of the year comes around mid-December. In the northern hemisphere, the shortest day and the longest night occur on the December 21 winter solstice. So why isnt the earliest sunset on the winter solstice? Its because of the discrepancy between the clock and the sun. The clock presumes exactly 24 hours lapse from noon to noon. However, days as measured from solar noon to solar noon rarely equal 24 hours exactly. Solar noon (midday) refers to that instant when the sun reaches its highest point for the day. At this time of year, the time period from one solar noon to the next is actually 1/2 minute longer than 24 hours long. On the day of the earliest sunset, the sun may reach its noontime position at 11:52 a.m. On the winter solstice, the sun will reach its noontime position at 11:59 a.m. Thats 7 minutes later than today. The later clock time for solar noon also means a later clock time for sunrise and sunset.

Lake Effect Snow From USA Today
We are fortunate not to have to deal with lake effect snow in Steele County. It iss not uncommon for some locations downwind of the Great Lakes to have snowfall averages more than 120 inches annually. When the difference in temperature between the surface air and air aloft reaches a threshold value, typically between 18 and 23 degrees in the Great Lakes, lake-effect snow becomes possible. In addition to the temperature differential, cold air must travel over at least 60 miles of relatively warmer open water.

As cold air flows over the warm water, the lake warms and moistens the air. Since warm, moist air is less dense than cold air, the heated air rises. Rising air cools and water vapor condenses into cloud droplets. These clouds can produce snow over the lake, but the efficiency of snow production increases when the wind pushes the clouds over land. Friction with the ground causes air to pile up. This frictional convergence creates lift and enhances snowfall. The lifting produced when moisture-laden clouds run into the windward slopes of inland hills and mountains further enhances the lifting and snow production.

It is important that the lake not freeze in order to maintain the open water required for lake-effect snow formation. Lake Erie is the shallowest and has the smallest volume of the Great Lakes. Because of its shallowness, it is the warmest of the Great Lakes, which means that it can generate impressive snows early in the winter. However, it cools rapidly during the course of the winter and is the only Great Lake prone to freezing over. Lake Ontario is smaller in surface area than Lake Erie but greater in volume. It generally remains unfrozen and lake-effect snows can continue into March.

Word For The Month From Minnesota WeatherTalk
Buys-Ballot's Law
This empirical law in meteorology, sometimes called the baric wind law, relates the horizontal wind field to the atmospheric pressure pattern. It was formulated in 1857 by Christoph H.D. Buys Ballot (pronounced Bowis-Ball-ott), then head of the Dutch Meteorological Services. Basically the law states that with your back to the wind, the pressure to your left is lower than the pressure to your right. This law is based on the known wind fields which circulate around low pressure and high pressure systems in the northern hemisphere. It is exactly reversed in the southern hemisphere. In the absence of any weather forecast, you can at least ascertain the direction of low pressure, where frontal activity such as precipitation may be occurring. If you place your back to the wind and are facing north, then low pressure and frontal activity is to the west and likely to be passing your way in the future. Conversely, if you find that you are facing south with your back to the wind, then low pressure is to the east and active weather systems are probably already heading away from you.

Copyright 2008
All Rights Reserved
Steele County SKYWARN
Owatonna, MN