Regents Earth Science HIGH AND LOW PRESSURE SYSTEMS WEATHER SYSTEMS UNIT By the end of this class, you will be able to: *Compare and contrast high and low pressure systems *Identify areas of high and low pressure on a weather map
Mar 19, 2016
Regents Earth Science
HIGH AND LOW PRESSURE SYSTEMSWEATHER SYSTEMS UNIT
By the end of this class, you will be able to:*Compare and contrast high and low pressure systems
*Identify areas of high and low pressure on a weather map
DO NOW: What’s in a letter?
Take a moment to think about what each letter stands for when used on a weather map
High Pressure Low PressureType of phenomenon Weather systemDetermined by… Changes in air pressureDensity of air Higher Lower
Representation on a map H (typically blue) L (typically red)
Motion of air Clockwise, air sinks Counterclockwise, air rises
Also known as… Anticyclone Cyclone
Stability of atmosphere Stable Unstable
Compare/Contrast ChartHigh and Low Pressure
High Pressure
LOW PRESSURE
Thumbs up for high, Thumbs down for low
Identify one center of high pressure and one center of low pressure using the letters on the map below. Be able to briefly explain your answer.
FRONTSFront: The leading edge of an air mass-branch from low pressure systems
Fronts are shown by lines with symbols that show the type of front and the direction of movement
Fronts- ESRT page 13
Warm front: an area where a warm air mass is replacing a cooler air mass
What to ExpectBefore the front: A.cool or cold tempsB.falling barometerC.increasing & thickening cloudsD.light-to-moderate precipE.winds from the e-se, F.Temp and dp get closer together/higher humidity
After the front: A. Warmer and more humid weather conditions
B. clearing cloudsC. a brief rise in pressure D. winds from the s-swE. Temp and dp are close/high humidity
Cold Front
Cold front: an area where a cold air mass is replacing a warmer air mass
What to ExpectBefore the Front: A.winds from the s-swB.warm tempsC.a falling barometer (dropping pressure)
D.an increase in cloudsE.a short period of precip F.Temp/dp are close; high humidity
Cold FrontAfter the Front:A.winds from the w-nwB.a drop in tempsC.a rise in pressureD.showers followed by clearing skiesE.Temp and DP get farther apart/ lower humidity
Stationary Front
Stationary Fronts: a boundary between air masses that are not moving
What to expect: a noticeable change in wind direction or temperature when crossing from one side of the front to the other
Occluded Fronts
Occluded Front: occur when warm air is pushed above Earth’s surface by cooler air that is closing in from both sides
DO NOT WRITEA developing cyclone usually has a warm front and a faster moving cold front that wraps around the storm.
An occluded front forms when cold air behind the cold front catches up to the warm front, which is stuck behind the cool air already in place
What to expect: A change in temp., dewpoint or wind direction is possible
Occluded Front DevelopmentPhase 1: Phase 2
Animation of Fronts <3Animation of Fronts
Movement of Weather RevisitedMost of the tracks (paths) follow a southwest to northeast pattern because of the United States’ location in the prevailing southwest wind belt
Video: Tying it Together!: Jet Streams, Pressure Systems and Fronts