STEELE COUNTY
SKYWARN
30-May-2010

June 21 Newsletter

SKYWARN Meeting
The next SKYWARN meeting is 15-Jun @ 7:00 PM, the third Tuesday of the month.

WX Radio Event From Deuel NSL
Steele County SKYWARN hosted a WX radio event at the Faribault Hy-Vee in May. Helping with the event was Larry KRK, Mike KDDKC, Deuel NSL, and Delores P.

Badges
Most individuals that requested badges had new badges available at the May meeting. The new badges are designed to be used by SKYWARN, CERT, and RACES. The new badges have a yellow area at the bottom indicating what groups you are part of and have an expiration date on the back. The logo for the primary group you belong to is at the top. You must turn in any badges you were previously issued before getting a new one. We are also asking volunteers to sign a "Hold Harmless" document. This is to help ensure volunteers understand risks and protections.

If you indicated SKYWARN as your primary organization, Dave P has your badge. If you indicated CERT as your primary organization, Shirley W has your badge. If you indicated RACES as your primary organization, Tom K has your badge. Older badges do not have the yellow area at the bottom and do not have an expiration date on the back. All older badges will be replaced in the near future.

Seasonal Outlook From Multiple Sources
Minnesota may hold a new record for the warmest spring. Average temperatures for March, April, and May were 6-9 degrees above normal. The current record for the warmest spring is 1977. On the other hand, the NOAA Climate Prediction Center released seasonal climate outlooks. Minnesota is predicted to have a higher than normal chance of below normal temperatures over the coming months. Rainfall should be near normal.

Rain Gauges From USA Today
How much rain did we get? It would seem the size of the rain gauge opening would impact how much water is collected. The standard rain gauge used by many observers has an 8-inch diameter, while National Weather Service gauges have either 8-inch or 12-inch diameters. While the collection diameter is large, the rain gets funneled into a smaller measuring tube. This exaggerates the depth of the collected water so that more precise rainfall measurements can be made. Some examples of rain gauges are shown at these NOAA web sites: OutReach, ASOS, and COOP.

El Nio, La Nia, and Tornadoes From Science Daily
Meteorologists found connections between the sea surface temperature in the tropical Pacific Ocean and the occurrence of tornadoes in unlikely parts of the North American continent. During El Nio events, when the winter sea surface temperature is warmer than usual, tornadoes are more likely to occur in the states bordering the Gulf of Mexico and in central Florida. During La Nia events, when the temperatures are cooler, tornadoes are more likely to occur in southeastern Texas and the upper Midwest. This new discovery addresses tornado patterns during El Nio or La Nia events -- although predicting when either will develop is tricky.

Sky Watching
If you have an astronomy interest, you can check out the daily features of the night sky Earth Sky.

Tornado Alleys? From MSNBC
A university of Akron researcher suggests there are multiple zones across the US that might be defined as "Tornado Alley". The analysis looked at tornadoes greater than F2 with a track longer than 20 miles. Over a 50+ year period, 3,000 cells qualified. The result suggest there are four regions: Dixie Alley, Tornado Alley, Hoosier Alley and Carolina Alley. Southeast Minnesota still falls into the traditional "Tornado Alley", but the "Dixie Alley" may be more active. "Dixie Alley" is made up of Arkansas, Mississippi, northern Louisiana, northern Alabama, and southwest Tennessee.

Cloud Holes From USA Today
Clouds that have a hole in the center are aptly named "hole-punch clouds." They are ypically found in a layer of high-altitude cirrus clouds. The key to the formation of the hole is the growth of ice crystals at the expense of nearby microscopic cloud droplets, resulting in a circular void of clouds with a mass of ice crystals in the center. The National Weather Service office in Mobile/Pensacola has a nice case study of a hole-punch cloud event from December 2003.

Why Water Does Not Freeze in the Clouds From Science Daily
Supercooling was identified as far back as the 1700s. It is a state where liquids do not change into solids below their normal freezing point. Supercooling is seen in clouds. Ice may form if the water droplets were also contaminated with something that caused crystals to form. The reason water droplets do not freeze without some impurity has never been fully understood. Recent research suggest the water molecules may be formed into a pentagon shape, which prevents crystals from repeating. Think about trying to fill a sheet of paper with pentagons, rather than triangles, squares, or hexagons. Those shapes can fill a sheet completely.

Rainfall Trend From USA Today
The U.S. Global Change Research Program concludes that overall precipitaion in the US has increased 5% over the past half century. When looking at heavy precipitation events, the increase is 9% in the Southwest and gradually increases to 67% in the Northeast. The Midwest data falls into the mid-range 31%.

Laser Clouds From Multiple Sources
Cloud seeding with iodide crystals is the typical method used for helping rain fall from the sky. It appears that a laser could be used as an alternative. Firing short pulses of laser light into water-saturated air can form clouds similar to the contrails formed by jets flying at high altitudes. Initial tests did not produce clouds formations visible to the naked eye. A change in the density and size of water droplets was detected using LIDAR. Continued research will evaluate various factors in the laser pulse, such as wavelength, pulse duration, and focus.

Alerts via Car Horn From Science Daily
German researchers are proposing that cars horns could be used as a warning device. Vehicles would be equipped with a radio receiver that would activate the horns of parked cars. This proposal would be part of a planned system named eCall. Similar to the GM OnStar system, eCall sends a message from a vehicle in case of an accident. Extensive coverage of Germany could be achieved if just 14% of the registered vehicles are equipped.

Term For the Month From USA Today
Isotherms and Isodrosotherms
Isotherms are lines of constant temperature drawn on weather maps. These isotherms can be used to locate fronts, especially cold fronts, as the contrast between cold and warm air is indicated by packing of the isotherms. Since cold fronts can often trigger thunderstorms, locations with packed isotherms would be a logical place to look for stormy weather.

Isodrosotherms are lines of equal dew point meaning that they indicate where the air has an equal amount of water vapor. Again, this can also be useful for locating especially moist air. Moist air transported by the low-level jet can sometimes be spotted on by isodrosotherms on a surface or 850 mb chart and can give an indication of the potential for nocturnal thunderstorms.



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Steele County SKYWARN
Owatonna, MN