Air Masses

Definition Large body of air having similar temperature and moisture Air masses extend several miles up and cover lots of “ground” There can be several different air masses over the US at any given time

Source Region Geographic Region where the air mass originated Continental = _____________ Maritime = _______________ Tropical = __________________ Polar = ____________________ Arctic = _________________ Over land, dry Over water, wet Lower latitudes, warm Mid to upper latitudes, cool Upper latitudes, cold

Air Masses Characteristics mT = maritime tropical = ___________ mP = _____________ = ___________ Warm and moist Maritime polarCool and moist

Air Mass Characteristics cT = _________________ = ____________ cP = _________________ = ____________ cA = _________________ = ____________ Continental tropicalDry and warm Continental polarDry and cool Continental ArcticDry and Cold ESRT Page 13

mP cP mP mT cT mT

Tools Meteorologists Use

1. Station Models How the weather is plotted on a surface map ESRT page 13

Station Models Temperature Dew Point Visibility Present Weather Cloud Cover Barometric Pressure Has to be converted Precipitation past 6 hours Wind Direction and Wind Speed

ESRT Page 13

Converting the air pressure for the station model If the air pressure is mb  drop the 9 and the decimal and put 868 on your station model If the air pressure is  drop the 10 and the decimal and put 098 on your station model

Examples = _______ = _______

Reading the air pressure from the station model Look at your station model number, if its greater than 500, add a 9 and put a decimal between the last 2 numbers Look at your station model number, if its less than 500, add a 10 and put a decimal between the last 2 numbers

Examples 678 = ________ 002 = ________

2. Surface maps Station models are plotted and then analyzed- Usually for isotherms and isobars, high and low pressure, fronts, precipitation, etc. Isotherms: Lines of equal _________________________ Isobars: Lines of equal ______________________ = isobars close on a weather map mean the wind speed is __________(higher pressure gradient) temperature isobars higher

Isobars – connect points of equal pressure