Atmospheric and Oceanic Sciences degree from UW-Madison: 1998. Former broadcast Meteorologist for NewsRadio 1310 WIBA in Madison. NWS Storm Spotter.
By: HaleStorm , 12:59 PM GMT on June 27, 2008
After the last few days of mostly dry weather, today we're going to be in for something different. A mostly cloudy sky this morning will turn darker as a line of showers and thunderstorms, currently just west of the Mississippi River, moves eastward into Wisconsin. Heavy rainfall is a good possibility, and the Storm Prediction Center in Norman, Oklahoma has placed us under the slight risk for severe weather today, mostly for the threat of large hail and damaging winds. Temperatures will stay mild today as a warm front moves though, but a trailing cold front will bring another chance of showers and thunderstorms to Wisconsin tomorrow, then wraparound moisture behind the low pressure system could make for a cloudy, cooler and drizzly day on Sunday.
Today’s Forecast Grade: B-
Today: Mostly cloudy this morning. Showers and thunderstorms developing this afternoon and this evening. Heavy rainfall is possible along with the slight risk of the storms becoming severe. High of 82. Chance of rain 70%.
Tonight: Cloudy and breezy with scattered showers and thunderstorms a good bet. Lows lower 60s. Chance of rain 80%.
Saturday: Mostly cloudy, breezy and a little cooler with more scattered showers and thunderstorms expected, although they probably will not reach severe levels. Highs mid- 70s. Chance of rain 60%.
Sunday: Mostly cloudy, still a little breezy and cooler with light rain showers or drizzle passing through from time to time. Highs near 70. Chance of rain 40%.
Monday: Partly sunny, highs 71-76.
Tuesday: Partly sunny, maybe an evening thundershower north, highs 73-78.
Wednesday: Partly sunny, highs 76-81.
Other City Forecasts:
This Weekend in Minneapolis/St. Paul, Minnesota: Scattered storms today and tomorrow, isolated showers on Sunday. Highs near 80 today, lower 70s tomorrow, then mid- 70s on Sunday.
This Weekend in Evansville, Indiana: Scattered showers and thunderstorms through Sunday afternoon, highs upper 80s to near 90 today and tomorrow and lower 80s on Sunday.
This Weekend in League City and Pearland, Texas: Scattered showers and thunderstorms, highs upper 80s to lower 90s.
This Weekend in Hilton Head Island, South Carolina: Scattered showers and thunderstorms, highs mid- to upper 80s.
This Weekend in Las Vegas, Nevada: Sunshine, hot, highs around 105.
This Weekend in Davenport, Florida: Numerous afternoon and evening showers and thunderstorms each day. Go figure. Highs lower 90s.
Weather in the News:
Typhoon toll in Philippines could pass 1,000
* NEW: Death toll has risen to more than 500 people killed and could go much higher
* NEW: Over 900 people still listed as missing, including 669 passengers from a ferry
* NEW: Of ferry's 849 passengers, 124 are confirmed dead, 56 have been found alive
* U.S. military has sent naval craft to assist in relief and search-and-rescue efforts
North Pole could be ice-free this summer, scientists say
* Ice retreated to a record level last fall when the Northwest Passage opened briefly
* Weather patterns will determine whether the ice cover melts completely this summer
* Scientists say the Arctic meltdown is not part of a historic cycle
...National lightning safety awareness week is June 22-28...
...Today's topic...the science of lightning...
---at any given moment...there are 1,800 thunderstorms in progress
somewhere on the Earth. This amounts to 16 million storms each
year! No wonder lightning has fascinated and frightened people.
---The formation of ice in a cloud appears to be a very important
element in the development of lightning...and those storms that fail
to produce quantities of ice may also fail to produce lightning. In
a storm...the ice particles vary in size from small ice crystals to
larger hail-stones...but in the rising and sinking motions within the
storm there are a lot of collisions between the particles. This
causes a separation of electrical charges. Positively charged ice
crystals rise to the top of the thunderstorm...and negatively
charged ice particles and hail-stones drop to the middle and lower
parts of the storm. Enormous charge differences...or electrical
---A moving thunderstorm gathers another pool of positively charged
particles along the ground that travel with the storm. As the
differences in charges continue to increase...positively charged
particles rise up taller objects such as trees...houses...and
telephone poles. Have you ever been under a storm and had your hair
stand up? Yes...the particles also can move up your body! This is
one of nature/S warning signs that says you are in the wrong
place... and you may be a lightning target!
---The negatively charged area in the storm will send out a charge
toward the ground called a stepped Leader. It is invisible to the
human eye...and moves in steps in less than a second toward the
ground. When it gets close to the ground...it is attracted by all
these positively charged objects...and a channel develops. You see
the electrical Transfer in this channel as lightning. There may be
several return strokes of electricity within the established channel
that you will see as flickering lightning.
---The lightning channel heats rapidly to 30,000 degrees. The rapid
expansion of heated air causes the thunder. Since light travels
faster than sound in the atmosphere...the sound will be heard
after the lightning. If you are ever in a storm when you see the
lightning and hear the thunder at the same time...that lightning is
in your neighborhood!
---Not all lightning forms in the negatively charged area low in the
thunderstorm cloud. Some lightning originates in the cirrus anvil
at the top of the thunderstorm. This area carries a large positive
charge, and lightning from this area is called positive lightning.
This type is particularly dangerous for several reasons. It
frequently strikes away from the rain core...either ahead or behind
the thunderstorm. It can strike as far as 5 or 10 miles from the
storm...in areas that most people do not consider to be a lightning
risk area. The other problem with positive lightning is it typically
has a longer duration...so fires are more easily ignited. Positive
lightning usually carries a High Peak electrical current...which
increases the lightning risk to an individual.
For additional information about lightning or lightning safety...
visit noaa's lightning safety awareness web site at:
Http://www.Lightningsafety.NOAA.Gov /lower case letters/
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