UKMET - A medium-range numerical weather prediction model
operated by the United Kingdom METeorological Agency.
Updraft - A small-scale current of rising air. If the air is
sufficiently moist, then the moisture condenses to become a cumulus
cloud or an individual tower of a towering cumulus or Cb.
Updraft Base - Alternate term for a rain-free base.
Upper Level System - A general term for any large-scale or mesoscale disturbance capable of producing upward motion (lift) in
the middle or upper parts of the atmosphere. This term sometimes is
used interchangeably with impulse or shortwave.
Upslope Flow - Air that flows toward higher terrain, and
hence is forced to rise. The added lift often results in widespread
low cloudiness and stratiform precipitation if the air is stable, or
an increased chance of thunderstorm development if the air is
Upstream - Toward the source of the flow, or located in the
area from which the flow is coming.
UVM (or UVV) - Upward Vertical Motion (or Velocity).