DATASTREME DAILY SUMMARY

Tuesday, 21 November 2000


This week is Thanksgiving Week recess. This DataStreme Daily Summary contains the Historical Weather Events for this date. Current weather data are available on the homepage as usual. The Week 10 Activity files will remain available through this week. If you are looking for an alternative description of daily weather, you could try

http://www.usatoday.com/weather/ wlead.htm


CONCEPT FOR THE DAY - WINTER STORMS

NOTE: This Concept for the Day is a repeat of that which appeared in the previous week's Tuesday Weather Summary.

Has winter arrived yet? The answer depends upon whom you ask. Most of us would say no, since the popular definition of winter would require us to wait until the winter solstice, in about five weeks. A climatologist would say that winter would begin on 1 December, two weeks from today. We have already seen several storms move into the Pacific Northwest and across the Rockies during the last several weeks that have produced considerable snowfall and freezing rain.

A winter storm is a widespread set of weather conditions with winter-type precipitation - snow, ice pellets or freezing rain - often accompanied by strong winds and cold temperatures. They may form any time from late autumn through spring and affect, not just the northern states, but everywhere from the West to the Gulf Coast. They can range from a minor annoyance to the "Storm of the Century" that paralyzed the Gulf and East Coast in March 1993. In 1997, the year with the most recent reliable statistics, 141 deaths across the United States and territories were attributed to winter weather (84 winter storms, 6 ice storms, 51 cold-related deaths). The 90 deaths due to winter storms (snow and blizzards) and ice storms were second that year to the 118 lives lost due to floods. Winter storms also caused 573 injuries, second only to tornadoes (1,033 injuries).

Low pressure systems in the cooler season of the year may include precipitation that can fall as snow, often heavy, that is accompanied by high winds and wind-chill equivalent temperatures cold enough to be life-threatening. The winds and falling or blowing snow may produce blizzards with poor visibility. Hazards range from roof collapses to transportation gridlock. Slightly warmer temperature patterns may bring rain that freezes after contacting cold surfaces (freezing rain or drizzle). The build-up of ice during freezing rain can paralyze impacted areas for days from loss of power, communications disruptions and blocked roadways.

For a description of the terminology used in the official statements issued by the National Weather Service to inform the public of adverse winter weather conditions, please read the Tuesday optional electronic Supplemental Information.

QUESTIONS:

To be submitted on the lines for Tuesday on the Study Guide, Part B, Applications, Week 10 Chapter Progress Response Form, under section B. Daily Summary.

  1. Winter storms [(are) (are not)] limited to the Northern States.
  2. The weather conditions associated with winter storms may include [(freezing rain) (cold temperatures) (heavy snow) (all of the above)].

HISTORICAL WEATHER EVENTS - 21 November

From the files of the Aviation Weather Center, Kansas City, MO and Intellicast


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URL Address: datastreme/learn/t_sum.html
Prepared by Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 2000, The American Meteorological Society.