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<br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br />. <br /> <br />Low Level Jetstream: A band of strong winds at an atmospheric level well below the high <br />troposphere as contrasted with the jet streams of the upper troposphere. <br /> <br />Mass curve: Curve of cumulative values of precipitation through time. <br /> <br />Mid-latitude frontal system: An assemblage of fronts as they appear on a synoptic chart north <br />of the tropics and south of the polar latitudes. This term is used for a continuous front and its <br />characteristics along its entire extent, its variations of intensity, and any frontal cyclones along it. <br /> <br />Moisture maximization: The process of adjusting observed precipitation amounts upward based <br />upon the hypothesis of increased moisture inflow to the storm, <br /> <br />Observational day: The 24-hour time period between daily observation times for two <br />consecutive days at cooperative stations, e.g., 6:00PM to 6:00PM. <br /> <br />One-hundred year rainfall event: The point rainfall amount that has a one-percent probability <br />of occurrence in any year. <br /> <br />Precipitable water: The total atmospheric water vapor contained in a vertical colwnn of unit <br />cross-sectional area extending between any two specified levels in the atmosphere; commonly <br />expressed in terms of the height to which the liquid water would stand if the vapor were <br />completely condensed and collected in a vessel of the same unit cross-section. The total <br />precipitable water in the atmosphere at a location is that contained in a column or unit cross- <br />section extending from the earth's surface all the way to the "top" of the atmosphere. The 300- <br />mb level is considered the top of the atmosphere in this study, <br /> <br />Persisting dew point: The dew point value at a station that has been equaled or exceeded <br />throughout a period, Commonly durations of 12 or 24 hours are used, though other durations <br />may be used at times, <br /> <br />Probable maximum precipitation (PMP): Theoretically, the greatest depth of precipitation for <br />a given duration that is physically possible over a given size storm area at a particular <br />geographic location at a certain time of the year. <br /> <br />Rain shadow: The region, on the lee side of a mountain or mountain range, where the <br />precipitation is noticeably less than on the windward side. <br /> <br />Saturation: Upper limit of water vapor content in a given space; solely a function of <br />temperature. <br /> <br />Storm transposition: The hypothetical transfer or relocation of storms from the location where <br />they occurred to other areas where they could occur, The transfer and the mathematical <br />adjustment of storm rainfall amounts from the storm site to another location is termed "explicit <br /> <br />XIX <br />