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Weather Lab 6-8 / Week 08 / Station Day
6/6
Week 08 · Air Masses and Fronts

Station Day

Station Day: Front hunters
// Where weather changes come from
⏱ about 20 min

Station Day: Front Hunters

Saturday morning is bright and brisk, and the flag on Station Rooftop points steadily toward the southeast.

"Northwest wind," Rocket says, reading it backward. "The cold front came through last night, just like the forecast said."

Raven lays the week's log on the table. "What do you notice about the pressure reading?"

"It dropped before the front and climbed after," Rocket says. "The barometer saw it coming."

Nova projects a checklist for the family. "A front leaves fingerprints," she says. "Temperature, wind, sky and pressure. Find all four."

Rocket is already pulling on a sweater. "Front hunters, move out."

  1. An air mass is a large body of air with uniform temperature and humidity, taken from the surface where it formed.
  2. Two letters name an air mass. The first, c or m, says land or sea. The second, A, P or T, says how far from the equator.
  3. A front is the boundary between two air masses. Cold fronts are blue with triangles, warm fronts red with half circles.
  4. When a front passes, the sky, temperature and wind direction change, often within hours.
  5. A probability of precipitation is the percent chance of at least 0.01 inch at your spot.
◇ FRONT HUNTERS
Together, read the last seven days of the weather log. Look for a day when the temperature changed a lot.
Check whether the wind direction changed on the same day, and whether the sky changed from cloudy to clear or back.
If you found all three fingerprints, you found a front. Decide together whether it was a warm front or a cold front.
Go outside and read the flag, the thermometer and the sky right now. Write a one-line forecast for tomorrow.
Tomorrow, check your forecast. Celebrate what you got right and talk about what surprised you.
For a grown-up
The forecast for your area on weather.gov names the fronts and the percent chance of rain. Reading it together is the best check on today's hunt.
If a thunderstorm is in the forecast, the outdoor part of the hunt waits until it has passed.
HUNTER CHECK
  • Read the question.
  • Tap your answer.
Which three things change when a front passes?
The air behind a cold front is usually what?
Which forecast word goes with a 30 to 50 percent probability?
A cold front is drawn in which color?
A warm front is drawn in which color?
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