Midlatitude Cyclones Storms Extratropical cyclone or wave cyclone

Midlatitude Cyclones (Storms) • Extratropical cyclone or wave cyclone or frontogenesis or storm • Low pressure area with counter-clockwise circulation. • Atmosphere collects water as water vapor in evaporation from oceans, lakes. • It is returned via precipitation, often caused by storms.

Storms Center of intense low pressure with cyclonic circulation and resultant precipitation. • • Midlatitude Cyclone Hurricane Tornadoes Not thunderstorms, no cyclonic motion.

Cyclogenesis in Action: Mid-latitude (extratropical) cyclones

Air Masses Definition: volume of air with same temperature and humidity characteristics Source Regions: where air masses come from. Classification: warm or cold, moist or dry

Air Masses Affecting North America

Frontogenesis

Occluded Front: The Death of a Storm

Occluded Front

Weather Maps

Today’s Weather Maps

Storm Tracks: North America Storms (Storm Tracks) generally travel from West to East in North America all year They shift North in summer & South in Winter Actual Average Storm Tracks Moving(1991) West To East

Midlatitude Cyclone Characteristics Motion: these storms move across the midlatitudes at about 30 m. p. h. from west to east as they rotate once around a low pressure center. Size: roughly 1, 000 miles in diameter, the largest of storms Lifespan: 3 -6 days to develop, 3 -6 to dissipate Pressure: center roughly 990 -1000 mb (1 -2 % drop)