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The Lemon technique is a method used by meteorologists using weather radar to determine the relative strength of
thunderstorm A thunderstorm, also known as an electrical storm or a lightning storm, is a storm characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere, known as thunder. Relatively weak thunderstorms are somet ...
cells in a vertically sheared environment. It is named for
Leslie R. Lemon __NOTOC__ Leslie R. Lemon (January 19, 1947 – May 29, 2020) was an American meteorologist bridging research and forecasting with expertise in weather radar, particularly regarding severe convective storms. Lemon was, along with Charles A. Dos ...
, the co-creator of the current conceptual model of a
supercell A supercell is a thunderstorm characterized by the presence of a mesocyclone: a deep, persistently rotating updraft. Due to this, these storms are sometimes referred to as rotating thunderstorms. Of the four classifications of thunderstorms ...
. The Lemon technique is largely a continuation of work by Keith A. Browning, who first identified and named the supercell.; The method focuses on updrafts and uses
weather radar Weather radar, also called weather surveillance radar (WSR) and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, and estimate its type (rain, snow, hail etc.). Modern weather radars are mostly puls ...
to measure quantities such as height (''echo tops''), reflectivity (such as morphology and gradient), and location to show features and trends described by Lemon. These features include: * ''Updraft tilt'' - The
tilted updraft A tilted updraft (also known as a tilted storm) is a thunderstorm which is not vertically erect. This happens as a result of unidirectional wind shear, or a change in wind speed with height. In such an environment, the top of the updraft is pu ...
(vertical orientation) of the main updraft is an indication of the strength of the updraft, with nearly vertical tilts indicating stronger updrafts. * ''Echo overhang'' - In intense thunderstorms, an area of very strong reflectivity atop the weak echo region and on the low-level inflow inside side of the storm. * ''Weak echo region'' (WER) - An area of markedly lower reflectivity, resulting from an increase in updraft strength. * ''
Bounded weak echo region The bounded weak echo region, also known as a BWER or a vault, is a radar signature within a thunderstorm characterized by a local minimum in radar reflectivity at low levels which extends upward into, and is surrounded by, higher reflectivitie ...
'' (BWER) - Another area of markedly lower reflectivity, now bounded by an area of high reflectivity. This is observed as a "hole" in reflectivity, and is caused by an updraft powerful enough to prevent ice and liquid from reaching the ground. This powerful updraft is often an indication of, or is facilitated by, a mesocyclone. A mesocyclone is not strictly necessary for BWER development. Storm rotation can be reliably detected by the Doppler velocities of a
weather radar Weather radar, also called weather surveillance radar (WSR) and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, and estimate its type (rain, snow, hail etc.). Modern weather radars are mostly puls ...
.


See also

*
Convective storm detection Convective storm detection is the meteorological observation, and short-term prediction, of deep moist convection (DMC). DMC describes atmospheric conditions producing single or clusters of large vertical extension clouds ranging from cumulus c ...


References

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External links


Paul Sirvatka and Les Lemon ''The Lemon Technique'' – College of DuPage Meteorology

The Lemon Technique (LT) to determine updraft strength
(
University of Illinois The University of Illinois Urbana-Champaign (U of I, Illinois, University of Illinois, or UIUC) is a public land-grant research university in Illinois in the twin cities of Champaign and Urbana. It is the flagship institution of the Unive ...
) Severe weather and convection Radar meteorology