Subj : Wx Terms (M)(5) To : All From : Daryl Stout Date : Tue Nov 14 2017 12:05 am Moisture Ridge An axis of relatively high dew point values. This axis is sometimes referred to as a 'moist tongue'. Molecule The smallest particle of a substance that retains the properties of the substance and is composed of one or more atoms. Monitor Stage The stage which, when reached by a rising stream, represents the level where appropriate officials (e.g., county sheriff, civil defense officials, or bypass gate operators) are notified of the threat of possible flooding. (Used if different from action stage, and at the discretion of the WFO or river forecast center [RFC].) The term "alert stage" is to be used instead of warning stage. Monitor stage or caution stage may be used instead of alert stage in some parts of the country. Monostatic Radar A radar that uses a common antenna for both transmitting and receiving. Monsoon A thermally driven wind arising from differential heating between a land mass and the adjacent ocean that reverses its direction seasonally. Monthly Climatological Report This climatological product is issued once a month by each National Weather Service office. It is a mix of tabular and narrative information. It is organized so that similar items are grouped together (i.e., temperature, precipitation, wind, heating/cooling degree information, etc.). Morning Glory An elongated cloud band, visually similar to a roll cloud, usually appearing in the morning hours, when the atmosphere is relatively stable. Morning glories result from perturbations related to gravitational waves in a stable boundary layer. They are similar to ripples on a water surface; several parallel morning glories often can be seen propagating in the same direction. MOS Model Output Statistics - the Hydrometeorological Center (HPC) produces a short range (6 to 60 hours) MOS guidance package generated from the NGM, GFS, and ETA models for over 300 individual stations in the continental United States. These alphanumeric messages are made available at approximately 0400 and 1600 UTC for the 0000 and 1200 UTC forecast cycles, respectively. Model Output Statistics are a set of statistical equations that use model output to forecast the probability of precipitation, high and low temperature, cloud cover, and precipitation amount for many cities across the USA. The statistical equations were specifically tailored for each location, taking into account factors such as each location's climate. Mostly Clear When the predominant/average sky condition is covered 1/8 to 2/8 with opaque (not transparent) clouds. Sometimes referred to as Mostly Sunny if this condition is present during daylight hours. Mostly Cloudy When the predominant/average sky condition is covered by more than half, but not completely covered by opaque (not transparent) clouds. In other words, 5/8 to 7/8 of the sky is covered by opaque clouds. Same as Considerable Cloudiness. Mostly Sunny Same as Mostly Clear, except only applicable during daylight hours; when the predominant/average sky condition is covered 1/8 to 2/8 with opaque (not transparent) clouds. Mount Wilson Magnetic Classifications In solar-terrestrial terms, a classification system for sunspots: Alpha: Denotes a unipolar sunspot group. Beta: A sunspot group having both positive and negative magnetic polarities, with a simple and distinct division between the polarities. Beta-Gamma: A sunspot group that is bipolar but in which no continuous line can be drawn separating spots of opposite polarities. Delta: A complex magnetic configuration of a solar sunspot group consisting of opposite polarity umbrae within the same penumbra. Gamma: A complex active region in which the positive and negative polarities are so irregularly distributed as to prevent classification as a bipolar group. Mountain Wave The wavelike effect, characterized by updrafts and downdrafts, that occurs above and behind a mountain range when rapidly flowing air encounters the mountain range's steep front. Mountain Wind System The system of diurnal winds that forms in a complex terrain area, consisting of mountain-plain, along-valley, cross-valley and slope wind systems. Mountain-Plain Wind System A closed, large-scale, thermally driven circulation between the mountains and the surrounding plain. The mountain-to-plain flow making up the lower branch of the closed circulation usually occurs during nighttime, while the plain-to-mountain flow occurs during daytime. Mountainado A vertical-axis eddy produced in a downslope windstorm by the vertical stretching of horizontal roll vortices produced near the ground by vertical wind shear. Mountainadoes, when carried by the mean wind, can produce strong horizontal shears and wind gusts that are much more damaging than the general prevailing wind speeds. MOV Move Movable Bed In hydrologic terms, a stream bed made up of materials readily transportable by the stream flow. MOVG moving MR more MRF Medium Range Forecast model, the medium-range computer model run by the United States (NOAA). The output from this model is part of what is now known as the GFS model, so the term MRF is no longer widely used. MRGL Marginal MRNG Morning MSG Message MSL (Mean Sea Level) - The arithmetic mean of hourly water elevations observed over a specific 19-year tidal epoch. MSLP Mean sea level pressure MST Mountain Standard Time MSTLY Mostly MSTR Moisture MT 1) Mountain 2) Montana MTN Mountain MTNS Mountains MTS Mountains Mud Slide Fast moving soil, rocks and water that flow down mountain slopes and canyons during a heavy downpour of rain. Muggy A subjective term for warm and excessively humid conditions. MULI Most Unstable Lifted Index - Lifted Index (LI) calculated using a parcel from the pressure level that results in the Most Unstable value (lowest value) of LI possible. Multicell Thunderstorm These thunderstorms are organized in clusters of at least 2-4 short-lived cells. Each cell generates a cold air outflow and these individual outflows combine to form a large gust front. Convergence along the gust front causes new cells to develop every 5 to 15 minutes. The cells move roughly with the mean wind. However, the area (storm) motion usually deviates significantly from the mean wind due to discrete propagation (new cell development) along the gust front. The multicellular nature of the storm is usually apparent on radar with multiple reflectivity cores and maximum tops. Multiple Doppler Analysis The use of more than one radar (and hence more than one look angle) to reconstruct spatial distributions of the 2D or 3D wind field, which cannot be measured from a single radar alone. Includes dual Doppler, triple Doppler, and overdetermined multiple Doppler analysis. --- þ Synchronet þ The Thunderbolt BBS - wx1der.dyndns.org .