Subj : Wx Terms (U)(2) To : All From : Daryl Stout Date : Thu Jun 22 2017 12:04 am Upper-air Weather Chart Weather maps that are produced for the portion of the atmosphere above the lower troposphere, generally at and above 850 mb. Isolines on these maps usually represent the heights of a constant pressure surface, such as the 500 mb surface. UPR Upper Upslope Flow Same as Orographic Lifting; air that flows toward higher terrain, and hence is forced to rise. The added lift often results in widespread low cloudiness and stratiform precipitation if the air is stable, or an increased chance of thunderstorm development if the air is unstable. Upslope Fog A fog that forms when moist, stable air is carried up a mountain slope. UPSLP Upslope Upstream Towards the source of flow, or located in the area from which the flow is coming. Upstream Slope The part of the dam which is in contact with the reservoir water. On earthen dams, this slope must be protected from the erosive action of waves by rock riprap or concrete. UPSTRM Upstream Upwelling In ocean dynamics, the upward motion of sub-surface water toward the surface of the ocean. This is often a source of cold, nutrient-rich water. Strong upwelling occurs along the equator where easterly winds are present. Upwelling also can occur along coastlines, and is important to fisheries and birds in California and Peru. Urban and Small Stream Flood Advisory This advisory alerts the public to flooding which is generally only an inconvenience (not life-threatening) to those living in the affected area. Issued when heavy rain will cause flooding of streets and low-lying places in urban areas. Also used if small rural or urban streams are expected to reach or exceed bankfull. Some damage to homes or roads could occur. Urban and Small Stream Flooding Flooding of small streams, streets, and low-lying areas, such as railroad underpasses and urban storm drains. This type of flooding is mainly an inconvenience and is generally not life threatening nor is it significantly damaging to property. Urban Flash Flood Guidance A specific type of flash flood guidance which estimates the average amount of rain needed over an urban area during a specified period of time to initiate flooding on small, ungaged streams in the urban area. Urban Flooding Flooding of streets, underpasses, low lying areas, or storm drains. This type of flooding is mainly an inconvenience and is generally not life threatening. Urban Heat Island The increased air temperatures in urban areas in contrast to cooler surrounding rural areas. UTC By international agreement, the local time at the prime meridian, which passes through Greenwich, England. Prior to 1972, this time was called Greenwich Mean Time (GMT) but is now referred to as Coordinated Universal Time or Universal Time Coordinated (UTC). It is a coordinated time scale, maintained by the Bureau International des Poids et Mesures (BIPM). It is also known a "Z time" or "Zulu Time". More about UTC, and a table to convert UTC to your local time is posted at: http://www.srh.noaa.gov/jetstream/remote/radarfaq.htm#utc UV Index Ultraviolet Index This index provides important information to help you plan your outdoor activities in ways that prevent overexposure to the sun's rays. It was designed by the National Weather Service (NWS) and the Environmental Protection Agency (EPA). Unlike some countries' indices, the United States UV Index is not based upon surface observations. Rather, it is computed using forecasted ozone levels, a computer model that relates ozone levels to UV incidence on the ground, forecasted cloud amounts, and the elevation of the forecast cities. The calculation starts with measurements of current total ozone amounts for the entire globe, obtained via two satellites operated by the National Oceanic and Atmospheric Administration (NOAA). These data are then used to produce a forecast of ozone levels for the next day at various points around the country. Category UV Index Time to Burn Actions to Take Minimal 0 - 2 60 min. + Apply SPF sunscreen. Low 3 - 4 45 min. Apply SPF sunscreen, wear a hat. Moderate 5 - 6 30 min. Apply SPF 15, wear a hat. High 7 - 9 15 - 24 min. Apply SPF 15 to 30, wear a hat and sunglasses. Limit midday exposure. Very High 10+ 10 min. Apply SPF 30; wear a hat, sunglasses, and protective clothing; limit midday exposure. UVM Upward Vertical Motion (also known as Upward Vertical Velocity) UVV Upward Vertical Velocity (rising air) UWNDS Upper Winds --- þ Synchronet þ The Thunderbolt BBS - wx1der.dyndns.org .