Weather Ms. Susinno Part 2: Air pressure Weather station model Winds Air masses and Fronts Cyclogenesis Weather maps Ms. Susinno

Air Pressure EXPLAIN!

can be measured in millibars Air Pressure can be measured in millibars Or inches... Torricelli

Air Pressure Centers http://www.mesoscale.iastate.edu/agron206/animations/12_CycAntiCyc.swf http://esminfo.prenhall.com/science/geoanimations/animations/26_NinoNina.html

PRESSURE CENTERS IN THE NORTHERN HEMISPHERE: Cool Dense Diverging Sinking Clockwise igh and dry L Warm Less Dense Converging Rising Counter-Clockwise ow and lousy

WIND Most US weather maps use millibars L ISOBARS – connect points of equal air pressure. L Where the isobars are close together, there is a great air pressure gradient. This results in faster/stronger energy flow from High to Low air pressure or WIND H

Find the pressure centers. Are they H or L? Evidence?

Weather Station Model Encoding Air Pressure Air pressure is normally between 950 and 1050 mb

Describe the weather variables at this station: Draw the Weather Station Model for the station below Which station (A or B) has the likeliest chance for precipitation? Provide evidence.

How does energy flow? Planetary Winds and Moisture Belts Jet streams are fast flowing, narrow air currents found in the upper troposphere. In meteorology, the polar front is the boundary between the polar cell and the Ferrel cell in each hemisphere. At this boundary a sharp gradient in temperature occurs between these two air masses, each at very different temperatures. The polar front arises as a result of cold polar air meeting warm tropical air. Polar Front Jet Stream H L H L H L H How does energy flow?

Planetary Winds L Winds are named after where they come FROM The wind system of the Earth’s troposphere exists because of the unequal intensity of solar radiation (because of Earth’s curved surface) and direction to the rotation of the Earth. Coriolis deflects winds to the right in Northern Hemisphere and to the left in the southern Hemisphere. Winds are named after where they come FROM L You are here We live in the Prevailing Southwesterlies Weather systems and pressure centers are usually pushed from the Southwest to the North East because they are driven by the prevailing southwesterlies

US weather systems generally travel from West to East – driven by the Jet streams and the South Westerlies.

Local Wind How does energy flow? Warm Less Dense Rising Cool Dense Sinking How does energy flow? Cool Dense Sinking Warm Less Dense Rising http://oceanservice.noaa.gov/education/pd/oceans_weather_climate/media/sea_and_land_breeze.swf

Local Wind Winds around High pressure centers and Low pressure centers, and the locations of fronts can change the way local winds blow from day to day L

An Air Mass is large volume of air in the troposphere that is mostly uniform in temperature and moisture. Air masses can extend thousands of kilometers across the surface of the Earth, and can reach from ground level to the stratosphere—16 kilometers (10 miles) into the atmosphere.

Front the leading edge of an air mass.

Air mass = army behind the front Warm Air mass FRONT= Drummer and Flag people Warm Front

cP mT

Warm Front A

Cold Front B

Describe each front: http://www.phschool.com/atschool/phsciexp/active_art/weather_fronts/

CYCLOGENISIS- The development of a mid-latitude cyclone (Low pressure center -storm)

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