FORECASTING WEATHER USING WIND-BAROMETRIC TABLES

KEY CONCEPTS

  1. By interpreting wind direction and air pressure and other weather conditions, local weather forecasts can be made over a short period of time.
 

MATERIALS
 
 

PROCEDURE

  
 
 

Activity

  1. Familiarize students with the weather station equipment. Refer to "Establishing a Weather Station" activity. Click here to see an animation that shows a weather station in "action."
  2. Arrange students into teams with specific assignments for daily weather logging.
  3. Enter data onto weather data sheets, which can be down loaded or printed daily for each team.
  4. Refer to the Forecast Chart for possible correlation between wind direction and changing air pressure to make forecasts.
  5. Compare student forecasts with actual weather conditions. If actual weather reports confirm student predictions, then the weather data and forecast models are reliable for that locale. If, however, actual weather reports contradict student predictions, check the points at which the report and prediction failed to coincide. What modifications should be made for future weather forecasting? What factors are contributing to the errors?
 
 

Assessment Ideas

  • Have students work in pairs and try to forecast local weather based only on the use of wind speed and barometric pressure. After analyzing the predictions, exchange forecast and have students write an explanation as to why the forecast was incorrect or correct. Use satellite information and actual weather conditions a guiding framework.
  
 
 

CROSS-CURRICULAR IDEAS

  • History (Research topic): What was the lowest barometric pressure ever recorded? What does this mean in terms of local weather?
  • Technology/Mathematics: Use electronic probes to measure barometric pressure versus other factors such as temperature, humidity, amount of sunlight. Construct graphs and explain the relationships.
  
 

VOCABULARY

  • atmospheric (air) pressure: the weight of air exerting pressure on a unit area upon the earthıs surface
  
 

SOURCE

  • "Winds of Change" educational CD-ROM, Copyright Caltech and NASA/Jet Propulsion Laboratory
  

WEATHER DATA SHEET

Date:__________________ Time:________

Current Weather Conditions: ________________________________________________________________

___________________________________________________________________________________________
temperature
 
wind speed  
wind direction  
relative humidity
 
precipitation  
cloud form  
air pressure  
rising / falling  
Student Comments: ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________
FORECAST CHART
WIND DIRECTION: AIR PRESSURE AT SEA LEVEL: EXPECTED WEATHER:
SW To NW 30.10 to 30.20, steady Fair with little temp. change for 2 days
SW To NW 30.10 to 30.20, rising fast Fair followed by rain in 2 days
SW To NW 30.20 or above, steady Continued fair with little temp. change
SW To NW 30.20 or above, falling slowly Slowly rising temp; fair for 2 days
S To SE 30.10 to 30.20, falling slowly Rain within 24 hours
S To SE 30.10 to 30.20, falling fast Wind rising in force; rain in 12 - 24 hours
SE To NE 30.10 to 30.20, falling slowly Rain in 12 - 18 hours
SE To NE 30.10 to 30.20, falling fast Wind rising; rain within 12 hours
E To NE 30.10 or above, falling slowly Rain (snow) within 24 hours in winter
E To NE 30.10 or below, falling fast Rain (snow), wind
SE To NE 30.00 or below, falling slowly Steady rain for 1 - 2 days
SE To NE 30.00 or below, falling fast Rain and high wind clearing in 36 hours
S to SW 30.00 or below, rising slowly Clearing within a few hours then fair
S to E 29.80 or below, falling fast Severe storm imminent, clearing in 24 hrs
E to N 29.80 or below, falling fast Severe northeast gale, rain (snow)
Going to W 29.80 or below, rising fast Clearing and colder