Subj : Wx Terms (E)(3) To : All From : Daryl Stout Date : Sun Aug 06 2017 12:06 am Eruptive In solar-terrestrial terms, solar activity levels with at least one radio event (10 cm) and several chromospheric events per day (Class C Flares). Eruptive Prominence on Limb (EPL) In solar-terrestrial terms, a solar prominence that becomes activated and is seen to ascend from the sun. ESP Extended Streamflow Prediction EST Eastern Standard Time Estuary In hydrologic terms, the thin zone along a coastline where freshwater systems and rivers meet and mix with a salty ocean (such as a bay, mouth of a river, salt marsh, lagoon). Esturine waters In hydrologic terms, deepwater tidal habitats and tidal wetlands that are usually enclosed by land but have access to the ocean and are at least occasionally diluted by freshwater runoff from the land (such as bays, mouths of rivers, salt marshes, lagoons). Esturine Zone In hydrologic terms, the area near the coastline that consists of esturaries and coastal saltwater wetlands. ETA 1. The Eta Model, now referred to as North Amercian Meso (NAM) an 84-hour numerical model of the atmosphere run four times daily by NCEP. This is one of the main forecast models used for short-term weather prediction in the United States. 2. Estimated Time of Arrival Eta Model Now referred to as North Amercian Meso (NAM) is one of the operational numerical forecast models run at NCEP. The Eta is run four times daily, with forecast output out to 84 hours. Evaporation The process of a liquid changing into a vapor or gas, usually water in meteorology. Evaporation Pan In hydrologic terms, a pan used to hold water during observations for the determination of the quantity of evaporation at a given location. Such pans are of varying sizes and shapes, the most commonly used being circular or square. Evaporation Rate In hydrologic terms, the quantity of water, expressed in terms of depth of liquid water, which is evaporated from a given surface per unit of time. It is usually expressed in inches depth, per day, month, or year. Evaporation-mixing Fog Fog that forms when the evaporation of water raises the dew point of the adjacent air. Evaporimeter In hydrologic terms, an instrument which measures the evaporation rate of water into the atmosphere. Evapotranspiration Combination of evaporation from free water surfaces and transpiration of water from plant surfaces to the atmosphere. EVE Evening EWD Eastward EWW Extreme Wind Warning (EWW) inform the public of the need to take immediate shelter in an interior portion of a well-built structure due to the onset of extreme tropical cyclone winds. An EWW for extreme tropical cyclone winds should be issued when both of the following criteria are met: a. Tropical cyclone is a category 3 or greater on the Saffir Simpson hurricane scale as designated by NHC, CPHC or JTWC. b. Sustained tropical cyclone surface winds of 100 knots (115 mph) or greater are occurring or are expected to occur in a WFO's county warning area within one hour. Excess Rain In hydrologic terms, effective rainfall in excess of infiltration capacity. Excessive Heat Excessive heat occurs from a combination of high temperatures (significantly above normal) and high humidities. At certain levels, the human body cannot maintain proper internal temperatures and may experience heat stroke. The "Heat Index" is a measure of the effect of the combined elements on the body. Excessive Heat Outlook This CPC product, a combination of temperature and humidity over a certain number of days, is designed to provide an indication of areas of the country where people and animals may need to take precautions against the heat during May to November. Excessive Heat Warning Issued within 12 hours of the onset of the following criteria: heat index of at least 105øF for more than 3 hours per day for 2 consecutive days, or heat index more than 115øF for any period of time. Excessive Heat Watch Issued by the National Weather Service when heat indices in excess of 105øF (41øC) during the day combined with nighttime low temperatures of 80øF (27øC) or higher are forecast to occur for two consecutive days. EXCLD Exclude Exclusive Flood Control Storage Capacity In hydrologic terms, the space in a reservoir reserved for the sole purpose of regulating flood inflows to abate flood damage. Exit Region The region downstream from a wind speed maximum in a jet stream (jet max), in which air is moving away from the region of maximum winds, and therefore is decelerating. This deceleration results in divergence in the upper-level winds in the left half of the exit region (as would be viewed looking along the direction of flow). This divergence results in upward motion of air in the left front quadrant (or left exit region) of the jet max. Severe weather potential sometimes increases in this area as a result. See also entrance region, right entrance region. Exosphere The upper most layer of the earth's atmosphere; the only layer where atmospheric gases can escape into outer space. Experimental Product An experimental product is in the final stages of testing and evaluation. If the product proves accurate and valuable to users then the next step is to make it an operational product. Explosive Deepening A decrease in the minimum sea-level pressure of a tropical cyclone of 2.5 mb/hr for at least 12 hours or 5 mb/hr for at least six hours. EXTD Extend/Extended Extended Forecast Discussion This discussion is issued once a day around 2 PM EST (3 PM EDT) and is primarily intended to provide insight into guidance forecasts for the 3 to 5 day forecast period. The geographic focus of this discussion is on the United States (including Alaska and Hawaii). Although portions of this narrative will parallel the Hemispheric Map Discussion, a much greater effort is made to routinely relate the model forecasts and necessary modifications to weather forecasts, mainly in terms of temperature and precipitation. Extraterrestrial Radiation The theoretically-calculated radiation flux from the sun at the top of the atmosphere, before losses by atmospheric absorption. Extratropical A term used in advisories and tropical summaries to indicate that a cyclone has lost its "tropical" characteristics. The term implies both poleward displacement of the cyclone and the conversion of the cyclone's primary energy source from the release of latent heat of condensation to baroclinic (the temperature contrast between warm and cold air masses) processes. It is important to note that cyclones can become extratropical and still retain winds of hurricane or tropical storm force. Extratropical Cyclone A cyclone in the middle and high latitudes often being 2000 kilometers in diameter and usually containing a cold front that extends toward the equator for hundreds of kilometers. Extratropical Low A low pressure center which refers to a migratory frontal cyclone of middle and higher latitudes. Tropical cyclones occasionally evolve into extratropical lows losing tropical characteristics and become associated with frontal discontinuity. --- þ Synchronet þ The Thunderbolt BBS - wx1der.dyndns.org .