How Do We Predict Weather? General Weather Information Clouds, rain, thunderstorms, etc. What is the National Weather Service??. Organizational Structure…. U. S. Department of Commerce (International Trade, US Business Growth, Aid in Technological Advancement)
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General Weather Information
Clouds, rain, thunderstorms, etc.
U. S. Department of Commerce
(International Trade, US Business Growth, Aid in Technological Advancement)
National Oceanic and Atmospheric
(Climate, Ocean Life, Satellites, Research)
National Weather Service
(Forecasts, Warnings, River Data, Weather Safety)
Produce Weather, Water and
Climate Forecasts and Warnings
-For All Americans
-To Protect Life and Property
-To Enhance the National Economy
Data and Products:
Weather and data are becoming more important to the economy and business decisions
Our Primary Mission:
The protection of lives and property
Watches, warnings, and advisories for:
Watch: Stay Alert!
Warning: Take Cover NOW!
Austin/San Antonio, TX
This problem has two parts . . .
Analyze: What’s going on right now?
Forecast: What’s going to happen?
Surface Observations . . .
mostly at airports . . .
can be taken by people
Or by machines such as the ASOS -
It can see father - with greater detail and more power than any other weather radar in the world!!
So sensitive . . . it can detect birds . . . bats . . . bugs and pollen in the air . . . and leaves rustling on nearby trees.
But observations are not limited to surface conditions. Aircraft reports of winds and weather are important.
And observations from upper air balloons launched twice a day at around 120 sites are the basis of upper air analysis.
Dozens of satellites keep a constant watch over the earth each day. Some are geosynchronous (stay in the same position over the earth) while others orbit around the earth.
FORECASTING each day. Some are geosynchronous (stay in the same position over the earth) while others orbit around the earth.
There are 3 basic methods of forecasting:
PERSISTENCE: each day. Some are geosynchronous (stay in the same position over the earth) while others orbit around the earth.
EXPERIENCE: each day. Some are geosynchronous (stay in the same position over the earth) while others orbit around the earth.
MODELS: each day. Some are geosynchronous (stay in the same position over the earth) while others orbit around the earth.
The Earth rotates on a tilted axis.
Due to the tilt, the equator is always heated more than either pole.
The Result . . . weather?
Part of Earth’s atmosphere is too cold and dense and part of the atmosphere is much too warm and light
Somehow . . . this must all be balanced out.
Air which stays over water for long periods of time absorbs some of the moisture through evaporation.
Cirrus Clouds weather?
Two basic ways precipitation forms:
Easier for water vapor to deposit directly onto ice crystals. Crystals then grow heavy enough to start falling.
In order to form, thunderstorms need:
Low-level moisture comes from the Gulf of Mexico.
Minimal Tornado weather?
- F0, F1
- 67% of S.C. TX Tornadoes
- Causes 5% of all deaths
- Life span 1 to 2 minutes
- Path length less than 1 mile
- Path width less than 100 yards
- Wind speeds up to 110 mph
Strong Tornado weather?
Violent Tornado weather?
- F4, F5
- 3% of S.C. TX Tornadoes
- Causes 65% of all deaths
- Life span to several hours
- Path length dozens of miles
- Path width to 1 1/ 2 miles
- Wind speeds over 300 mph
Jarrell, TX — May 27, 1997 weather?
For each foot of rising water, a car weighs weather?1500 pounds less!
As little as 18 inches of water can float a truck! It takes only 12 to 14 inches of water to float a car!
Tire 8” wide, weather?
floats 816 lbs
of car weight
Tire 12” wide,
floats 1225 lbs of car weight
For Current Weather Information: weather?
NOAA Weather Radio
Clickable map of the entire U.S.
NWS Austin/San Antonio’s Homepage
National Weather Service
2090 Airport Road
New Braunfels, TX 78130