| A | B |
|---|
| cold front | strong cold air mass advances on warm less dense air mass |
| warm front | warm air mass advancing on a cool denser air mass |
| frost | forms like dew but dewtemp is below freezing |
| global pressure belts | (polar high+low 90*north+south) (subpolar low and high 60*S+N) (subtropical high+low 30*N+S) (equatorial low 5*N–5*S) |
| westerlies | 35*north-55* north; surface winds flowing from the polar portions of the subtropical highs, carrying fronts, storms and variable weather conditions from west to east through the middle latitudes |
| polar easterlies | easterly surface winds that move out from the polar highs toward the subpolar lows; 90*north- 60*north |
| tropical easterlies (trade winds): | winds that blow from the east in tropical regions |
| trade winds (tropical easterlies): | 5*north-25*north; consistent surface winds blowing in low latitudes from the subtropical highs toward the intertropical convergence zone; labeled northeast trades in the Northern Hemisphere and southeast trades in the southern hemisphere. |
| hail | condensation freezing then falling |
| Horse latitudes | no consistent wind flow |
| humidity | amount of water vapor found in an air mass at a given time |
| Hurricane/typhoon | severe tropical cyclone of great size with nearly concentric isobars. Its torrential rains and high velocity winds create unusually high seas and extensive coastal flooding |
| Hydrological cycle | water cycle |
| Icelandic low | northern Atlantic branch of the sub polar low |
| instablilty | condition of air when it is warmer than the surrounding atmosphere and is buoyant with a tendency to rise; the lapse rate of the surrounding atmosphere is greater than that of unstable air. |
| Intertropical convergence zone (ITCZ) | zone of low pressure and calms along the equator, where air carried by the trade winds from both sides of the equator converges and is forced to rise |
| isobar | a line that connects points of equal atmospheric pressure |
| jet stream | high velocity upper-air current with speeds of 120-640 kilometers per hour (75-250mph) |
| Katabatic/drainage winds | downslope flow of cold, dense air that has accumulated in a high mountain valley or over an elevated plateau or ice cap |
| Lake effect precipitation | forms when cold dry air mass moves across relatively warm body of water saturate and drops copious amounts of precipitation |
