The Atmosphere in Motion: How do meteorologists predict the weather?

Weather refers to the present state of the atmosphere—air pressure, wind, temperature, and humidity. Meteorologists study weather by taking measurements of these conditions. The National Weather Service collects the measurements and records them on maps using a combination of symbols. These symbols form a station model which shows the weather conditions at one specific location.

Some conditions shown on a station model are: wind speed and direction, barometric pressure, change in barometric pressure in the last three hours, fraction of sky covered by clouds, dew point temperature, type of precipitation, and temperature.

With the information from a station model, meteorologists can predict the weather. For example, meteorologists know that high pressure is generally associated with fair weather and low pressure is usually associated with cloudy weather. If the barometric pressure is rising, weather is probably improving. The dew point indicates the temperature air is saturated and at which condensation occurs. These measurements, along with others, help meteorologists predict what kind of weather may be ahead.

In this Virtual Lab you will explore weather data collected over several days at stations in a certain region of the United States. Then you will make a prediction about the weather at those stations. When making your predictions, remember that weather systems generally move from west to east. Use the data from the westernmost station model in a region to predict the weather for the region's other stations.

Objective:

•Use station models to forecast conditions for weather stations in a region of the continental United States.

Procedure:1. Go to the Virtual Lab link:http://www.glencoe.com/sites/common_assets/science/virtual_labs/ES15/ES15.html2. Click on the Southwestern region on the U.S. map. 3. Each circle represents a weather station model. Examine the Station Model Key to see what each symbol in a station model means.4. Day 1: Explore the weather conditions at each station by clicking each station model. Record the conditions at each station. Predict the next day's weather.5. Day 2: Click the Next Day button to display the station models for Day 2 and check your weather predictions. Record the conditions at each station on the Day 2 Data Table. Look at the patterns from Day 1 to Day 2. Predict the next day's weather.6. Day 3: Click the Next Day button to display the station models for Day 3 and check your weather predictions. Record the conditions at each station on the Day 3 Data Table. Look at the patterns. Predict the next day's weather.7. Day 4: Click the Next Day button to display the region's possible weather stations for the 4th day. City A is done for you. From the weather stations pictured. Predict the weather for the region's other three stations for this day. Match the letter of the location to the weather prediction on your paper below the selected pictures on the line that says “P_________”. Put an “X” on any of the model that are not selected.8. Choose a station model from the five models on the right of the screen. Drag the station model to a station on the map. Repeat this step for each station in the region. 9. Click Check to verify your predictions. Record the correct station models on the line that says “Ans__________”. The correct answer will be shown in beige. It may or may not match your predictions. If the station model is not a correct answer put an “X” on the ‘Ans” line. 10. Repeat steps 4-9 using other regions of the United States.

Southwestern Region-Day 1

Temperature(C)

Wind Speed(knots)

Wind Direction

Barometric Pressure

(millibars)

Cloud Cover

amount

Type of precipitation

A. Oklahoma City, Oklahoma 18 8-12 SSE 242 clear none

B. Dallas-Forth Worth, Texas 20 3-7 ESE or SE 234 clear none

C. Houston, Texas 24 8-12 NNW 218 clear none

D. New Orleans, Louisiana 22 3-7 NE or ENE 197 clear none

Southwestern Region-Day 2

Temperature(C)

Wind Speed(knots)

Wind Direction

Barometric Pressure

(millibars)

Cloud Cover

amount

Type of precipitation

A. Oklahoma City, Oklahoma 25 23-27 S 118 clear none

B. Dallas-Forth Worth, Texas 25 18-22 S 148 clear none

C. Houston, Texas 24 8-12 SSE 186 ¾ or 75% none

D. New Orleans, Louisiana 22 13-17 S 171 ½ or 50% none

Western Region- Day 2

Temperature(C)

Wind Speed(knots)

Wind Direction

Barometric Pressure

(millibars)

Cloud Cover

amount

Type of precipitation

A. Sacramento, California 7 0 or none none or

N/A 150 ¾ or 75% fog

B. Reno, Nevada 12 13-17 WNW 125 ¼ or 25% none

C. Ely, Nevada 7 8-12 NNW 099 complete or 100% none

D. Salt Lake City, Utah 13 13-17 NNW or

NW 080 ¾ or 75% none

P_________

Ans__B____

P_________

Ans__C_____

P_________

Ans__D_____

P_________

Ans__X_____

P_________

Ans__X_____

Prediction answers will vary. There should be a label for B, C, and D then two models labeled X.

Southwestern Region-Day 3Temperature

(C)Wind Speed

(knots)Wind

DirectionBarometric

Pressure (millibars)

Cloud Cover

amount

Type of precipitation

A. Oklahoma City, Oklahoma 22 13-17 SW or

SSW 060 ¾ or 75% Thunderstorm and rain

B. Dallas-Forth Worth, Texas 24 23-27 SSW 082 ¾ or 75% none

C. Houston, Texas 25 13-17 SSE 128 ¾ or 75% rain

showersD. New Orleans, Louisiana 22 3-7 SSW 148 Overcast or

100% rain

Western Region- Day 1

Temperature(C)

Wind Speed(knots)

Wind Direction

Barometric Pressure

(millibars)

Cloud Cover

amount

Type of precipitation

A. Sacramento, California 14 3-7 ESE 043 complete

or 100% rain

B. Reno, Nevada 13 13-17 SW or

WSW 003 ½ or 50% none

C. Ely, Nevada 18 23-27 S 009 ¼ or 25% none

D. Salt Lake City, Utah 22 13-17 SE or SSE 031 ¾ or 75% none

Western Region- Day 3

Temperature(C)

Wind Speed(knots)

Wind Direction

Barometric Pressure

(millibars)

Cloud Cover

amount

Type of precipitation

A. Sacramento, California 8 8-12 NW or

WNW 175 none or 0% none

B. Reno, Nevada 13 8-12 NNW 164 ¼ or 25% none

C. Ely, Nevada 8 8-12 NW or WNW 156 ½ or 50% none

D. Salt Lake City, Utah 13 8-12 WNW or

NW 156 ¾ or 75% none

P_________

Ans__X_____

P_________

Ans___C____

P_________

Ans__X_____

P_________

Ans__D_____

P_________

Ans__B_____

Prediction answers will vary. There should be a label for B, C, and D then two models labeled X.

Midwestern Region-Day 1

Temperature(C)

Wind Speed(knots)

Wind Direction

Barometric Pressure

(millibars)

Cloud Cover

amount

Type of precipitation

A. Cedar Rapids, Iowa 3 8-12 ENE 286 ¼ or 25% none

B. Chicago, Illinois 5 3-7 E 257 none or 0% none

C. Indianapolis, Indiana 9 13-17 N or NNE 219 none or 0% none

D. Columbus, Ohio 2 13-17 NNE 180 ¾ or 75% snow

Midwestern Region-Day 2

Temperature(C)

Wind Speed(knots)

Wind Direction

Barometric Pressure

(millibars)

Cloud Cover

amount

Type of precipitation

A. Cedar Rapids, Iowa 16 13-17 SW or

SSW 103 none or 0% none

B. Chicago, Illinois 9 18-22 SSE 119 ½ or 50% rain

showersC. Indianapolis, Indiana 15 13-17 SSW 160 ½ or 50% none

D. Columbus, Ohio 9 3-7 SSW 193 ¼ or 25% none

P_________

Ans__D_____

P_________

Ans___B____

P_________

Ans__X_____

P_________

Ans___X____

P_________

Ans__C_____

Prediction answers will vary. There should be a label for B, C, and D then two models labeled X.

Prediction answers will vary. There should be a label for B, C, and D then two models labeled X.

Midwestern Region-Day 3

Temperature(C)

Wind Speed(knots)

Wind Direction

Barometric Pressure

(millibars)

Cloud Cover

amount

Type of precipitation

A. Cedar Rapids, Iowa 16 8-12 SSE 011 ½ or 50% rain

B. Chicago, Illinois 13 8-12 S or SSW 041 ½ or 50% fog

C. Indianapolis, Indiana 23 18-22 WSW 080 ½ or 50% none

D. Columbus, Ohio 21 18-22 WSW 089 ½ or 50% none

Southeastern Region- Day 1

Temperature(C)

Wind Speed(knots)

Wind Direction

Barometric Pressure

(millibars)

Cloud Cover

amount

Type of precipitation

A. Birmingham, Alabama 16 18-22 or

13-17 N 166 ¼ or 25% rain showers

B. Columbia. South Carolina 16 13-17 WSW 058 complete

or 100% rain

C. Atlanta, Georgia 9 13-17 NW or

WNW 123 complete or 100% fog

D. Knoxville, Tennessee 5 8-12 NNW 144 complete

or 100% rain

Southeastern Region- Day 2

Temperature(C)

Wind Speed(knots)

Wind Direction

Barometric Pressure

(millibars)

Cloud Cover

amount

Type of precipitation

A. Birmingham, Alabama 21 3-7 SSW 192 clear or

0% none

B. Columbia. South Carolina 19 3-7 NNW 167 clear or

0% none

C. Atlanta, Georgia 19 none none 198 clear or

0% none

D. Knoxville, Tennessee 13 3-7 NNE 198 clear or

0% none

Southeastern Region-Day 3

Temperature(C)

Wind Speed(knots)

Wind Direction

Barometric Pressure

(millibars)

Cloud Cover

amount

Type of precipitation

A. Birmingham, Alabama 25 8-12 S 161 ¾ or 75% none

B. Columbia. South Carolina 26 8-12 WSW or

SW 169 clear or 0% none

C. Atlanta, Georgia 24 3-7 SSW 192 clear or

0% none

D. Knoxville, Tennessee 22 13-17 WSW 153 clear or

0% none

Northeastern Region-Day 2

Temperature(C)

Wind Speed(knots)

Wind Direction

Barometric Pressure

(millibars)

Cloud Cover

amount

Type of precipitation

A. Pittsburgh, Pennsylvania 8 8-12 WSW 192 ¾ or 75% none

B. Philadelphia,Pennsylvania 11 18-22 NNW 117 clear or

0% none

C. Baltimore, Maryland 11 18-22 WNW or

NW 141 clear or 0% none

D. New York,New York 10 8-12 N 090 clear or

0% none

Northeastern Region-Day 3

Temperature(C)

Wind Speed(knots)

Wind Direction

Barometric Pressure

(millibars)

Cloud Cover

amount

Type of precipitation

A. Pittsburgh, Pennsylvania 21 8-12 WSW or

SW 092 3/4/ or 75% none

B. Philadelphia,Pennsylvania 17 8-12 WSW or

SW 102 clear or 0% none

C. Baltimore, Maryland 19 3-7 WSW or

SW 112 ¼ or 25% none

D. New York,New York 15 8-12 NNW 095 ¼ or 25% none

P_________

Ans__X_____

P_________

Ans__D_____

P_________

Ans__B_____

P_________

Ans__C_____

P_________

Ans__X_____

Prediction answers will vary. There should be a label for B, C, and D then two models labeled X.

Northeastern Region-Day 1

Temperature(C)

Wind Speed(knots)

Wind Direction

Barometric Pressure

(millibars)

Cloud Cover

amount

Type of precipitation

A. Pittsburgh, Pennsylvania 3 18-22 or

13-17 NNW 139 complete or 100% snow

B. Philadelphia,Pennsylvania

10 8-12 ENE or NE 088 complete or 100% rain

C. Baltimore, Maryland 10 8-12 ENE or NE 073 complete

or 100% rain showers

D. New York,New York 10 3-7 ENE or NE 112 complete

or 100%rain

thunderstorms

Journal Questions1. How did your Day 4 predictions compare with the actual weather conditions, as shown on the beige station models?

_______Answers will vary ___________________________________________________

_________________________________________________________________________

2. What observations and weather attributes did you find most helpful in predicting the weather conditions? Why?

Example: The change in barometric pressure is a helpful indicator of change in weather conditions. (the change in the last 3 hours can be most helpful) A drop in pressure, to lower pressure means that there is an increase for the chance of precipitation and cloudier conditions. Rising pressure means a decrease in rain chances and lower cloud cover. If the temperature is dropping also, then there may be a higher chance for drastic weather changes or severe whether if a cold front connects with a warm front.

3. Meteorologists have predicted the following weather for OKC for the next three days: