1. Weather Instruments P

2. We need data to forecast the weather
Temperature
Air pressure
Humidity
Type of clouds
Level of precipitation
Wind direction and speed

3. Instruments used to gather the data
Lower Atmospheric Conditions
Temperature
Thermometer
Uses a liquid either mercury or alcohol sealed in a glass tube
Electrical thermometer
As temp rises the electrical current increases
A thermistor responds very quickly and is used where temps change quickly

4. Air pressure Barometer Aneroid (pictured) Mercury
fronts are usually indicated by a drop in air pressure

5. Wind Speed and direction
Anemometer
Wind speed
Wind vane
Wind direction

6. Rainfall
Rain gauge

7. Measuring Upper Atmospheric Conditions

8. Doppler image of a hurricane

9. Radar Doppler radar Stands for radio detection and ranging
Uses reflected radio waves
Doppler radar
Can indicate precise location, intensity of precip and extent of a storm
Shows wind patterns
Towards or away from the radar

10. Radiosonde
An instrument package that is carried by a helium-filled balloon
Radio sends info to ground
Determines direction and speed of high altitude winds

12. Skew-T Shows a vertical slice of the atmosphere Temperature on right
Dew point on left
Air pressure
Wind speed and direction

14. Weather Satellites Can measure visible Infrared Ocean conditions
temperature and flow of ocean currents and
height of ocean waves

15. Computers
Solve mathematical equations that describe the behavior of the atmosphere
Can store weather data
Can store weather records

16. This info is reported from stations
WMO World Meteorological Organization
10,000 land based stations and hundreds of ship-based stations
Weather satellites
GOES Global Orbiting Earth Satellite

17. Data from stations is compiled and analyzed to forecast
In the past this was done by hand
Now much is done by computer
But, different programs work better for different locations and types of weather
Often two or three computer models are consulted to make one forecast

18. Weather Station Symbols
Temperature is upper left corner
Barometric (air) pressure is upper right

19. Air pressure
represents the last three digits of the observed pressure reading in millibars (mb)
Like on previous labs

20. Dew point Dew Point is lower left corner
When the air temperature and the dew point are the same the air is saturated
Relative humidity can be inferred
High if temp and dp are close
Low if large difference between dp and temp

21. Relative Humidity can be inferred
When the air and dew point temperatures are very close, this indicates that the air has a high relative humidity.
The opposite is true when there is a large difference between air and dew point temperatures, which points to air with a low relative humidity.

22. Wind Speed and Direction
Wind stick points in the direction "from" which the wind is blowing
Which direction is the wind from?

23. Wind Speed May be measured in mph, km/hr or knots
The more barbs the windier it is
Each long barb is approx 10 knots

25. Cloud Cover

26. Precipitation Symbols

27. Worksheets Surface Weather Map Study the tables and the station model
Use the info to answer the questions
Transparency worksheets

28. Dry Line Note the sharp difference in dew points
The line that separates dry air from moist air

29. Isobars Lines that connect points with equal air pressure
Drawn at 4 mb (millibar) intervals

30. Pressure and Wind Relationships
Draw isobars
Use pencil
CI = 4
Mark high and
low pressure
Answer the questions

31. Methods of Forecasting
Persistence
Trend
Analog

32. Persistence
Persistence—based on continuity of a weather pattern—if it is raining now it will probably be raining tomorrow

33. Trend
Trend—based on the movement or trend of the weather system Ex. Cold front moving E at 20 Km/hr will affect weather 80 KM away in 4 hours

34. Happy Birthday, Hoang

35. Analog
compares present weather (cloud cover, wind, temperature, humidity, etc) with weather conditions produced by same features in the past
Others
Climatology—data accumulated through many years
4th of July is usually hot and dry
Numerical Weather Prediction—uses programs built by meteorologists
Not exact

36. Meteorologists
What high school courses are necessary to prepare for a career in meteorology?
Because meteorology is a science, a good background in mathematics and the sciences is mandatory. Knowledge of physics and chemistry is helpful toward a career in the atmospheric sciences.

37. OU is the Best for Meteorology

38. Weather Station Symbols
Temperature is upper left corner
Barometric (air) pressure is upper right

39. Lab Do isotherms in red (every 2) Do isobars in blue (Every4)
Do lightly in pencil first
Do isobars in blue (Every4)

40. Winds

41. Three causes of motion(recap)
WIND ALWAYS FLOWS
FROM HIGH TO LOW PRESSURE
1. Warm air rises and cool air sinks because of density
This is called a convection current
2.pressure differences in the atmosphere that are a result of temperature differences
Wind is horizontal air movement
3. The deflection of objects to the right in the northern hemisphere—called the Coriolis Effect
Due to rotation of the earth

42. Winds blow from high to low pressure.

43. Highs and Lows? Winds circle Clockwise around a high
Highs generally mean cold dry air that is sinking
High pressure usually = fair weather

44. Low Pressure Systems Winds circle counterclockwise around a low
Warmer air rises and cools and forms clouds and precipitation
Low pressure usually = rainy weather

45. Global Circulation Patterns
We are located in the Westerlies section
That means our weather moves from the west coast to the east coast

46. Overall movement is west to east
Local wind patterns can be from any direction

47. Recognizing fronts on a map
sharp temperature changes over relatively short distances
changes in the moisture content of the air (dew point)
shifts in wind direction
low pressure troughs and pressure changes
clouds and precipitation patterns

48. Types of fronts Named for the invader
Each type of front has a typical weather scenario

49. Cold Front
heavy cold air displaces lighter warm air, pushing it upward
Cumulus clouds form and usually grow into thunderstorms
Temperatures drop anywhere from 5 to 15.
Winds become gusty and erratic.
Rain, snow, sleet, and hail can occur with a cold front.

50. Warm Front
Warm fronts occur when warm air replaces cold air by sliding over it.
Altocumulus clouds form and may be associated with rain, snow, or sleet.
Temperatures may warm slightly.
Winds are usually gentle with this kind of front.

51. Stationary Front
neither warm nor cold air advances. The two air masses reach a stalemate.
That is what stationary means - that neither front is moving.
can last for days, producing nothing but Altocumulus clouds
Temperatures remain stagnant and winds are gentle to nil

52. Occluded Front
cold air is replacing cool air or vice versa at the surface, with warm air above.
Both types of fronts are usually associated with rain or snow and cumulus clouds.
Temperature fluctuations are small and winds are gentle.

53. Where are the fronts? Stationary front Change in wind direction
Can dump heavy rains

54. Warm Front
Marked temperature difference

55. Cold front
Cold temperatures are moving in

56. Wind and Pressure Relationship Lab

57. Remember Topographic Maps?

58. Same Concept—Different Use
Isotherm=equal temperature
Isobar=equal barometric pressure

59. contour interval (CI) The contour intervals vary
Isobars often have an interval of 4
Read the directions or look at examples to see the contour level

60. Iso therm Equal temperature
If a station reports the exact value the line will go through the station symbol
If it is not exactly on the value it will not

61. Points shown are reporting stations
Here, the stations reported pressure and temperature
The lines are drawn in different colors to help differentiate them
There may be areas that do not report or have no station

62. The closer contour lines are to one another, the higher the wind speed.

63. Where is the wind speed high? Where is it low?

64. Inside a series of closed contours (the contours make a circle) is a High or Low pressure

65. Describe the motion of the wind.

66. Wind Flow around Isobars
Winds flow roughly parallel to the isobars, as depicted in the schematic below

68. Current Weather Conditions

69. Current Weather Station Data

70. Source:University of Illinois

71. Metars
In a small group try to figure out what each set of numbers or letter mean
TYPEIDTIMEWINDVISWXSKYT/TDALTREMARKMETAR KORD Z 19020G26KT 6SM -SHRA BKN070 12/08 A3016 RMK AO2

72. Understanding Metars Activity
Brainstorm about what the numbers and letters may mean
Discuss as a class
Interpret metars and decode them

73. Zulu Time Used to be known as Greenwich Mean Time
Uses the military clock of 24 hours
For numbers above 13 subtract 12
Converting to KS time
For CST –6
For CDT -5

74. Upper Air Data
Shows

75. Become a meteorologist
OU is the best