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Weather Instruments P 611-614 We need data to forecast the weather Temperature Air pressure Humidity Type of clouds Level of precipitation Wind direction.

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Presentation on theme: "Weather Instruments P 611-614 We need data to forecast the weather Temperature Air pressure Humidity Type of clouds Level of precipitation Wind direction."— Presentation transcript:


2 Weather Instruments P

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

4 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

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

6 Wind Speed and direction Anemometer Wind speed Wind vane Wind direction

7 Rainfall Rain gauge

8 Measuring Upper Atmospheric Conditions

9 Doppler image of a hurricane

10 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

11 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


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


15 Weather SatellitesSatellites Can measure visible Infrared Ocean conditions temperature and flow of ocean currents and height of ocean waves

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

17 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

18 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

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

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

21 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

22 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.

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

24 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


26 Cloud Cover

27 Precipitation Symbols

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

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

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

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

32 Methods of ForecastingForecasting Persistence Trend Analog

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

34 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


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

37 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.

38 OU is the Best for Meteorology

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

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

41 Winds

42 Three causes of motion (recap) 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

43 Winds blow from high to low pressure.

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

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

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

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

48 Recognizing fronts on a map 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

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

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

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

52 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 Altocumulus Temperatures remain stagnant and winds are gentle to nil Temperatures

53 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.rain or snow cumulus Temperature fluctuations are small and winds are gentle. Temperaturewinds

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

55 Warm Front Marked temperature difference

56 Cold front Cold temperatures are moving in

57 Wind and Pressure Relationship Lab

58 Remember Topographic Maps?

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

60 contour interval (CI) 1. The contour intervals vary 2. Isobars often have an interval of 4 3. Read the directions or look at examples to see the contour level

61 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

62 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

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

64 Where is the wind speed high ? Where is it low ?

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

66 Describe the motion of the wind.

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


69 Current Weather Conditions

70 Current Weather Station Data Weather Station

71 Source:University of Illinois /home.rxml /home.rxml

72 Metars In a small group try to figure out what each set of numbers or letter mean TYPEIDTIMEWINDVISWXSKYT/TDALTREMARK METAR KORD Z 19020G26KT 6SM - SHRA BKN070 12/08 A3016 RMK AO2 METARKORD041656Z19020G26KT6SM- SHRABKN07012/08A3016RMK AO2

73 Understanding MetarsMetars Activity Brainstorm about what the numbers and letters may mean Discuss as a class Interpret metars and decode them

74 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

75 Upper Air Data Shows

76 Become a meteorologist OU is the best OU


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