Forecasting the Weather

Station Model Shows a summary of current weather

conditions at a particular weather station

Isotherms lines connected areas of the same

temperature

Isobars: lines connecting areas of the same

air pressure

Pressure Centers when isobars form circles they

designate the center of high or low pressure, labeled with an H or L

Weather Instruments Thermometer – measures

temperature Barometers – measures air pressure Anemometer – measures wind speed Wind Vane – measures wind direction

Doppler Radar uses reflected radio waves to

determine the velocity and location of objects, can detect the precise location, movement, intensity of precipitation, wind patterns, and severity of the storm

Pressure Centers: Move from high pressure to low

pressurea) High Pressure – sunny calm weatherb) Low Pressure – can mean

storminess, fronts extend from them

Air Masses: move by global winds and the jet

streama) Arctic/Polar – typically move to the

South and Westb) Tropical – moves to the North and

Eastc) Bring characteristics of where they

formed, the longer they are stationary the more they exhibit the characteristics of that region, they change as they move

Fronts: Cold Front – preceded by strong thunder and

snow storms, after it passes temperatures drop sharply and pressure rises rapidly

Warm Front – thick, low level clouds, wide spread precipitation

Stationary Front – similar results as a warm front, just over longer period of time

Occluded Front – large scale precipitation and widespread rain and thunderstorm

Dew Point The higher the dew point, the more

water in the air, thus higher chance of precipitation

Air Pressure: If air pressure is dropping, a storm

could be on the way

Isobars: Wind follows the isobars, the closer

they are together, the stronger the winds due to the larger pressure gradient

Jet Stream: High altitude, narrow bands of wind

that typically go west to east, dictate weather pattern and air mass movement, stronger during winter due to larger temperature differences between poles and equator

General Patterns: Generally weather patterns move

from west to east due to global winds (prevailing westerlies)