Weather intro Weather instruments Temperature Clouds Dewpoint Relative

Weather intro: Weather instruments, Temperature Clouds Dewpoint Relative humidity Ms. Susinno

Weather: The daily conditions of the troposphere in terms of temperature, atmospheric pressure, wind, and moisture. Weather Variables:

Weather Station Model Sometimes weather maps have the weather variables recorded on weather station models.

The most effective tool to detect precipitation is radar. Radar, which stands for RAdio Detection And Ranging, has been utilized to detect precipitation, and especially thunderstorms, since the 1940's. Radar enhancements have enabled NWS forecasters to examine storms with more precision. The radar used by the National Weather Service is called the WSR-88 D, which stands for Weather Surveillance Radar - 1988 Doppler (the prototype radar was built in 1988). As its name suggests, the WSR-88 D is a Doppler radar, meaning it can detect motions toward or away from the radar as well as the location of precipitation areas. This ability to detect motion has greatly improved the meteorologists’ ability to peer inside thunderstorms and determine if there is rotation in the cloud, often a precursor to the development of tornadoes. There are 155 WSR-88 D Doppler radar in the nation, including the U. S. Territory of Guam and the Commonwealth of Puerto Rico, operated by the National Weather Service and the Department of Defense.

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TEMPERATURE Base your answer on the temperature field map below. The map shows temperature readings (°C) recorded by students in a science classroom. The readings were taken at the same time at floor level. Temperature readings for points A and B are labeled on the map. 1. Draw the 18°C, 20°C, and 22°C isotherms 2. Find the temperature gradient between A and B?

Base your answer on the weather map below, which shows temperature readings at weather stations in the continental United States. On the weather map provided on your answer paper, draw three isotherms: the 40°F isotherm, the 50°F isotherm, and the 60°F isotherm.

TEMPERATURE CONVERSION But don’t worry. . . You have a HANDY DANDY ESRT!

Clouds

Cirrus

Cirrostratus

Cirrocumulus

Altocumulus

Altostratus

STRATUS

Nimbostratus

Cumulus

Cumulonimbus

What the hail?

Cloud Prefixes Nimbo- precipitation Cirro- very high-level clouds Alto-mid-level Stratus- low level

DEWPOINT the temperature to which a given parcel of air must be cooled, at constant barometric pressure, for water vapor to condense into water. The condensed water is called dew. The dewpoint is a saturation point. As altitude increases, temperature _____ Air temp = dewpoint

20 -15= 5ºC Sling psychrometer The Dewpoint is 12ºC This means that the air must be cooled to 12ºC for condensation to occur.

Expansion or adiabatic cooling Remember? Molecules further apart= less vibration Temperature = average kinetic energy cooler Molecules closer together= more vibration Temperature = average kinetic energy warmer

Let’s do the CLOUD DANCE!!!

Density Warm moist air rises Air temperature

Expands and cools y) all t ic ba d ia (a http: //www. harcourtschool. com/activity/science_up_close/610/deploy/610_HR_Clouds. swf https: //courseware. e-education. psu. edu/public/meteo 101 demo/Examples/Section 6 p 04. html

The air temperature meets the dewpoint

Condensation happens… on condensation nuclei

And when they get heavy enough, they fall.

Take a bow.

Humidity • The amount of water vapor in the air. As humidity increases, density of the air _______ As humidity increases, evaporation _________

RELATIVE HUMIDITY Relative humidity is the percent of water vapor in the air compared to how much the air can hold. • Metaphorically speaking, warmer air can “hold” more water vapor. • Dewpoint is a measure of how much water vapor is actually in the air. RH%= How humid the air FEELS Meteorologist’s view of how this is a very broad generalization: http: //www. ems. psu. edu/~fraser/Bad. Clouds. html

19 ºC

https: //www. youtube. com/watch? v=Oiej. HVHrd. Oo

Which weather station has the highest relative humidity? What is your evidence? B A

CLOUD BASE

Next up. . . Air Pressure Winds Weather Station Model Air Masses Fronts.