Lake
Breeze - a wind blowing from the
surface of a large lake onto the shores during the afternoon
Land
Breeze - a breeze from land to sea, caused by the temperature
difference when the sea surface is warmer than the adjacent land
Lapse
Rate - the rate of change of temperature
with height
Latent
Heat - the heat
released or absorbed by a substance during a phase change
Lee
Side - the side of an object (e.g., mountain) that is sheltered
from the wind
Left
Mover - a thunderstorm which
moves to the left relative to the steering winds, and to other nearby
thunderstorms; often the northern part of a splitting
storm
LEWP
(Line Echo Wave Pattern) - a bulge
in a thunderstorm line producing a wave-shaped
"kink" in the line. The potential for strong outflow and damaging straight-line
winds increases near the bulge, which often resembles a bow
echo. Severe weather potential also is increased with storms near
the crest of a LEWP.
Lifted
Index (or LI) - a common measure of atmospheric instability;
its value is obtained by computing the temperature
that air near the ground would have if it were lifted to some higher level
(around 18,000 feet, usually) and comparing that computed temperature
to the actual temperature at that level. Negative values indicate instability;
the more negative, the more unstable the air is and the stronger the updrafts
are likely to be with any developing thunderstorms.
Lifting
Condensation Level (LCL) - the level in the atmosphere
at which an unsaturated air parcel lifted
dry adiabatically would become saturated.
See convective condensation level (CCL).
Lightning
- any visible electrical discharge produced by thunderstorms
Liquid
- one of the basic three phases of matter; characterized by
free movement of the constituent molecules among themselves but without
the tendency to separate
Liquid
Water Equivalent - the amount of water estimated from a reflectivity
signature on a radar. The liquid water equivalent
is computed using an empirical mathematical equation.
Local
Winds - winds which blow over a small
area at a speed or in a direction generally different from those which
are appropriate to the general pressure distribution of the region
Longwave
Radiation - in meteorology, radiation
having a wavelength greater than that of visible light
Low
- in meteorology, an region
of low pressure; see also cyclone
Low-Level
Jet (abbreviated LLJ) - a region of relatively strong winds
in the lower part of the atmosphere. Specifically,
it often refers to a southerly wind maximum in the boundary
layer, common over the Plains states at night during the warm season
(spring and summer).
LP
Storm (or LP Supercell) - Low -Precipitation
storm (or Low -Precipitation supercell); a supercell
thunderstorm characterized by a relative lack of visible precipitation;
visually similar to a classic supercell, except without the heavy precipitation
core. LP storms almost always occur on or near the dry
line, and thus are sometimes referred to as dry line storms.
LSR
(Local Storm Report) - a product issued by
local NWS offices to inform users of reports
of severe and/or significant weather-related events
Luminance
- a measure of the brightness of a surface; See radiance
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