a cooling of the ocean current along the coasts of Peru and Ecuador. See El Niño for the opposite effect.
a wind blowing from the surface of a large lake onto the shores during the afternoon
a tornado that does not form in an organized storm-scale rotation; a non-supercell tornado. Landspouts are typically observed under cumulonimbus or towering cumulus clouds and are the land-based equivalents of waterspouts, which are also tornadoes.
the rate of change of temperature with height
the location north or south in reference to the equator (0°). Lines of latitude are parallel to the equator and circle the globe. The North and South poles are at 90 degrees North and South latitude.
local/locally or see Lifting Condensation Level
the side of an object (e.g., mountain) that is sheltered from the wind
see Longwave Trough
see Latent Heat
see Lifted Index
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 LI value, the more unstable the air is and the stronger the updrafts are likely to be with any developing thunderstorms.
sends a light beam (usually in the form of a laser) out and detects the reflected signal. Similar to a radar, but uses light instead of radiowaves. LIDAR may be used to measure the speed of winds and to obtain turbulence and wind shear data.
any visible electrical discharge produced by thunderstorms
a bulge in a thunderstorm line that produces 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.
see Low-Level Jet
low-level wind shear
a sounding characterized by extreme instability, but containing a cap. If the cap can be weakened or if the air below is heated sufficiently to overcome the cap, explosive thunderstorm development can be expected.
a product issued by local NWS offices to inform users of reports of severe and/or significant weather-related events
winds that blow over a small area at a speed or in a direction generally different from those that are appropriate to the general pressure distribution of the region (the general wind flow). Examples include sea and land breeze, Santa Ana wind, foehn winds, outflow from thunderstorms, etc.
the location east or west in reference to the Prime Meridian, which is designated as 0° longitude. The distance between lines of longitude are greater at the equator and smaller at the higher latitudes, intersecting at the earth's North and South Poles. Time zones are marked by longitude lines.
a trough in the prevailing westerly flow aloft that is characterized by a large length and (usually) long duration. The longwave trough may stay fairly stationary over an area as shortwave troughs rotate through it.
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).
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.