Weather

Air Masses

• Differences in air pressure are caused by unequal heating of Earth’s surface–creates wind

patterns–Deflects in a curved

path because of the Coriolis effect

Review

• Along the surface, air moves from areas of high pressure to areas of low pressure– Poles to Equator

• At high altitudes, air moves from the equator to the poles

•When air is stationary, or moves slowly, the air takes on the temperature and humidity of a region

Target #9- I can describe how air masses form

• Air Mass: a large body of air throughout which temperature and moisture content are similar

Target #10- I can define air mass

Target #11- I can describe how air masses are classified

• Air masses are classified according to their source regions–Source region: determine temperature and humidity of an air mass• Polar areas produce cold and dry air masses• Tropical areas produce warm moist air masses

• Continental: air masses that form over land–Form over large

land masses–Low humidity–Brings dry weather– Continental Polar- cold

and dry• Symbol: cP

– Continental tropical- warm and dry• Symbol: cT

Target #12 I can differentiate between continental and maritime air masses

• Maritime: air masses that form over oceans– Form over large bodies of

water– Higher humidity than

continental air– Commonly bring

precipitation when travelling over land

– Maritime polar- moist and cold• Symbol mP

– Maritime tropical- moist and warm• Symbol mT

Target #13- I can identify North American air masses on a map

• North American Air Masses– Continental Tropical

• Form in the southwestern U.S.• Brings hot, dry weather

– Maritime Tropical• Form over the Atlantic Ocean• Brings humid weather to eastern U.S.

– Continental Polar• Form in Canada• Bring cool dry weather to northern U.S.

– Maritime Polar• Forms in northern Pacific & Atlantic Oceans• Brings rain, snow, and fog to the Pacific Northwest and

New England

• New Jersey is about halfway between the equator and the North Pole–Geographic location results in highly variable daily weather

Target #14- I can summarize how the air masses over New England influence New Jersey weather

• The Garden State is 166 miles long, and is 65 miles at its widest point– There is a marked

difference in climate between Wildwood and Ocean City in the south and High Point and Stokes State Forest in the north

• The prevailing winds in NJ travel west to east– A part of the westerlies

wind belt– Can shift north or south

which influences the weather• If shifting south,

continental polar air brings colder temperatures with potential for snow

• If shifting north, maritime tropical air bring hot humid weather and potential for rain

• Current Satellite Maps

• In northern NJ:– Average annual precipitation: ~51in– Snowfall season: Oct to April– Precipitation comes from storms coming

from the Mississippi Valley, Great Lakes, and from southern Canada.

– The mountains also influence the formation of precipitation

– The heat retained by the city also influences the types of weather produced

Analysis Question

• How do temperature and humidity change when a maritime tropical air mass is replaced by a continental polar air mass?