The Storm Prediction Center, located in Norman, Oklahoma, is part of the National Centers for Environmental Prediction (NCEP), operating under the control of the National Weather Service, which in turn is part of the National Oceanic and Atmospheric Administration (NOAA) of the U.S. government. Until October 1995, the SPC was known as the National Severe Storms Forecast Center (NSSFC). Image File history File links Storm Prediction Center logo File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Bizzel Library, University of Oklahoma Norman is a major city located in Cleveland County, Oklahoma and is part of the Oklahoma City Metropolitan Area. ... The US National Centers for Environmental Prediction delivers national and global weather, water, climate and space weather guidance, forecasts, warnings and analyses to its Partners and External User Communities. ... The National Oceanic and Atmospheric Administration (NOAA) is an agency of the United States Department of Commerce. ... The National Oceanic and Atmospheric Administration (NOAA) is a scientific agency of the United States Department of Commerce focused on the conditions of the oceans and the atmosphere. ... ...

Overview

The SPC is responsible for identifying the risk of severe weather caused by severe convective storms and winter weather. It does so primarily by issuing severe thunderstorm watches, tornado watches, and mesoscale discussions. The SPC also issues severe weather forecasts for up to two days in advance. Watches issued by the SPC are generally no less than 50,000 square miles in area and are normally preceded by a mesoscale discussion. NOAA scientists observe severe weather using a mobile doppler radar and a helicopter (in the distance) Severe weather phenomena are weather conditions that are hazardous. ...

Severe weather outlooks

Several times daily, the SPC issues categorical and probability forecasts. They are labelled and issued by day. Day 1 outlooks refer to the current day and include graphics relating the probability of tornadoes, hail, wind, and severe weather in general. Day 2 outlooks refer to tomorrow's weather and only include a general overview with a probability graph. Finally, Day 3 outlooks refer to the day after tomorrow, and include the same "break outs" as the Day 2 outlook.

Critical areas (often referred to as "hatched areas" because of their representation on Day 1 outlooks) refer to an increased or imminent threat of severe weather. For example, a critical area on the "Hail" graphic would be hatched to indicate an imminent threat of large hail within that region.

Local forecast offices of the National Weather Service, radio and television stations, and emergency planners often use the forecasts to gauge the potential severe weather threats to their areas.

Mesoscale discussions

Mesoscale discussions (or "MD"s) generally precede a tornado watch or severe thunderstorm watch. They're designed to give forecasters an update on a region that is becoming a severe weather threat. (However, it's important to note that these discussions are often associated with other events such as blizzards or freezing rain.)

The discussions generally break down a smaller area for review than is given in the severe weather outlook. If a mesoscale discussion is issued and the weather trend for that area continues, a weather watch is generally issued in one to three hours for roughly the same area.

External links

• SPC