NAME	WIND SPEED	DESCRIPTION
Tropical Disturbance	Below 23 mph	A amass of storms with relatively low wind speeds, out of which hurricanes sometimes develop
Tropical  Depression	23 to 38 mph	A more organized cluster of storms
Tropical Storm	39 to 73	A well-organized storm system
Hurricane	74 mph and up	A storm system with counter clockwise winds in the Atlantic or eastern Pacific.
Typhoon	74 mph and up	A tropical cyclone arising in the western Pacific
Cyclone	74 mph and up	A tropical cyclone arising in the Indian Ocean

Global Winds

Surface winds are often described by the direction from which they originate: easterlies move from east to west, westerlies move from west to east.  Trade winds typically travel from subtropical, high pressure zones to areas of low pressure near the equator.  Jet streams are narrow bands of wind that move rapidly high up in the atmosphere (generally from west to east) over midlatitudes.