Tuesday Daily Summary

DATASTREME ATMOSPHERE DAILY SUMMARY

Tuesday, 16 March 2010

This week is Spring vacation week for DataStreme Atmosphere. This DataStreme Atmosphere Daily Summary contains Historical Weather Events for this date. In addition, new items appear in the Weekly Weather and Climate News. The Investigation and Supplemental Information…In Greater Depth files from last week will remain on the DataStreme Atmosphere Homepage and the Concepts of the Day for Tuesday and Thursday will be repeated for those who may have been on spring break. If you have questions, check with your mentor. Current weather data are available on the homepage as usual. Current weather data are available on the homepage as usual. If you are looking for an alternative description of daily weather, you could try:

http://www.usatoday.com/weather/default.htm (USA Today)
or
http://www.weather.com/newscenter/nationalforecast/index.html (The Weather Channel)

The usual DataStreme Atmosphere Daily Summaries and Investigation files will return next week, beginning on Monday, 22 March 2010.

CONCEPT FOR THE DAY - SATURATION

Note: This Concept and accompanying questions represent a repeat of the Concepts and questions that were posted last Tuesday, 9 March 2010.

The chemical compound that we call water is a unique substance in that it can exist in three phases within the ranges of temperatures and pressures found in the atmosphere. At very cold temperatures, water is a solid, ice, which covers our lakes and puddles. Warm it some and it melts to liquid that covers almost two-thirds of the Earth and falls from clouds above. At all typical temperatures, some water exists in the invisible vapor phase. The transition between these forms is crucial to the conditions we associate with "weather". A volume, even without air in it, has a maximum capacity for vapor that depends on the temperature. As the temperature rises, more ice can sublimate or water can evaporate to provide additional vapor for the volume. As the temperature falls, some vapor must condense back to the liquid or solid form. The maximum amount of vapor in the volume at its associated temperature produces the condition called saturation.

Normally a volume of air is not saturated, meaning that less than the maximum possible vapor is present. Saturation can occur in one of two ways. More vapor can be added to the volume to reach the maximum. This addition is seen just above the spout of a boiling teakettle, or with so-called steam fog, a version of your breath on a cold day. Generally the atmosphere creates saturation a second way, by cooling the air volume to reach saturation with the amount of vapor originally present. Cooling to saturation can be by one of two processes. Rising air cools as it expands into lower surrounding pressures at higher altitudes. Saturation and clouds can result. Overnight radiational cooling near the ground may create fog.

For more information describing the global hydrological cycle, you may consult the optional material in Tuesday's Supplemental Information…In Greater Depth.

QUESTIONS:

To be submitted on the lines for Tuesday on the Investigations Manual, Week 6 Chapter Progress Response Form, under section B. Daily Summary.

As the temperature changes, the amount of water vapor in a volume at saturation [(changes) (is constant )].
Clouds [(are) (are not)] usually formed by air being cooled by expansion.

HISTORICAL WEATHER EVENTS - 16 March

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

...1843...A great Northeast snowstorm swept from the Gulf of Mexico to Maine. In Tennessee, Natchez received 4 inches and Shelbyville received 21 inches. Philadelphia and New York City each received 12 inches , and Concord, NH recorded 8 inches. (Intellicast)
...1942...A widespread outbreak of tornadoes occurred across Mississippi, Alabama , Tennessee, Kentucky, Illinois, and Indiana. As many as 25 tornadoes were of F2 intensity or greater. Seventy-five fatalities occurred in Mississippi. Baldwyn, MS was hit by two tornadoes (one F4 and the other F3) only 35 minutes apart. A violent (F5) tornado tore through Peoria and Marshall counties in Illinois, killing 7 and injuring 70. (David Ludlum) (Intellicast)
...1975...A single storm brought 119 inches of snow to Crater Lake, OR establishing a state record . (The Weather Channel)
...1986...A small but rare tornado touched down perilously close to Disneyland in Anaheim, CA. (Storm Data)
...1987...Softball size hail (4.5 inches in diameter) caused millions of dollars damage to automobiles at Del Rio, TX. Three persons were injured when hailstones crashed through a shopping mall skylight. (The National Weather Summary) (Storm Data) (The Weather Channel)
...1988...A winter storm produced heavy snow in the Central Rockies. Winds gusted to 80 mph at Centerville, UT. Eighteen cities in the southeastern U.S. reported new record low temperatures for the date, including Tallahassee, FL with a reading of 24 degrees. (The National Weather Summary)
...1989...A winter storm brought heavy snow and high winds to the southwestern U.S. Winds gusted to 60 mph at Lovelock, NV, Salt Lake City, UT, and Fort Carson, CO. Snow fell at a rate of three inches per hour in the Lake Tahoe area of Nevada. (The National Weather Summary) (Storm Data)
...1990...Thunderstorms developing ahead of a cold front produced large hail and damaging winds from northwest Florida to western South Carolina. Thunderstorm winds gusted to 75 mph at Floridatown, FL. Sixteen cities across the northeastern quarter of the nation reported record high temperatures for the date. The afternoon high of 78 degrees at Burlington, VT smashed their previous record for the date by 23 degrees. New York City reported a record high of 82 degrees. (The National Weather Summary) (Storm Data)

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