|Local forecast by
3-Month - Consecutive three-month periods
A - Used on climate outlooks to indicate areas that are likely to be above normal.
Above Normal - One of the outlook categories that are based on the 1981-2010 climatological normal. During this 30 year reference period, average three-month temperature was observed in Above Normal category (10 warmest years) 1/3 (33.3%) of the time.
Anomaly - The deviation of a measurable unit, (e.g., temperature or precipitation) in a given region over a specified period from the long-term average, often the thirty year mean, for the same region.
B - Is used on climate outlooks to indicate areas that will likely be below normal.
Below Normal - One of the outlook categories that are based on the 1981-2010 climatological normal. During this 30 year reference period, average three-month temperature was observed in Below Normal category (10 coolest years) 1/3 (33.3%) of the time.
Climate - Prevailing set of weather conditions at a place over a period of years.
Climate Change - A non-random change in climate that is measured over several decades or longer. The change may be due to natural or human-induced causes.
Climate Model - Mathematical model for quantitatively describing, simulating, and analyzing the interactions between the atmosphere and underlying surface (e.g., ocean, land, and ice).
Climate Outlook - Aa future estimate of climate. A NWS climate outlook provides expected chance for the average climate variable to occur within a specified period of time.
Climate Prediction Center (CPC) - This Center is one of several centers under the National Centers for Environmental Prediction (NCEP) part of the National Weather Service (NWS) in the National Oceanic and Atmospheric Administration (NOAA). The Center serves the public by assessing and forecasting the impacts of short-term climate variability, emphasizing enhanced risks of weather-related extreme events, for use in mitigating losses and maximizing economic gains. CPC produces operational predictions for 6-10-, 8-14-days, monthly and seasonal time frames. (See http://www.cpc.ncep.noaa.gov)
Climate Variable - Qualitative classification of a weather element (e.g., temperature, precipitation, wind, humidity, etc.) at a place over a period of time
Climatological Normal - The prevailing set of weather conditions calculated over a 30-year period, presently 1981-2010. Note that the climatological normal taken over different periods of time (30 years, 1000 years) may be different.
Climatology - (1) The description and scientific study of climate. (2) A quantitative description of climate showing the characteristic values of climate variables over a region. (3) The 30-year average of a variable, like temperature, at a given location and time of year.
Confidence Intervals - Upper and lower limits on a climate variable scale, within which you might have a stated level of confidence that the true mean of the climate variable lies. For example, these are usually quoted as 95% intervals, which are constructed so that you are 95% confident that the true mean lies between the limits.
Confidence Limits - The lower and upper boundaries (values) of a confidence interval, that is, the values which define the range of a confidence interval.
CONUS - Conterminous United States
COOP ID - Cooperative Station Identification
Correlation Coefficient - A number that indicates the strength of the relationship between two climate variables or the same climate variable at different locations. The number varies between -1 to +1. Zero indicates absolutely independent relationship. 1 (plus and minus) indicates the strongest (perfect) relationship.
Decadal - A consecutive ten year period.
EC - Equal Chances - The probability of the most likely category cannot be determined and the expected likelihoods of Above-, Near- and Below- Normal do not differ from their climatological odds of 33.33...% each.
EC (Equal Chance) - An abbreviation used on climate outlook maps to indicate areas where equal chances of experiencing below-normal, normal, or above-normal conditions are possible, based on 1981-2010 climatological normal.
Experimental Product - The NWS product 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.
Forecasts (Synonymous with predictions and outlooks) - A forecast, or prediction, is an estimation based on special knowledge of the future state of the atmosphere with respect to a particular weather element (e.g., temperature, precipitation, wind).
Local - Reference to a site specific location.
Local 3-Month Temperature Outlook - A forecast product extended from the three-month climate outlook that NOAA's Climate Prediction Center (CPC) produces on the third Thursday of each month.
Mean - (1) The arithmetic average of observation; (2) expected value of a forecast distribution.
Median - The middle value of a variable sample sorted into ascending order. The median value means that during a period of sample time, half of the time (50%) the variable was greater than the median and in the other half (50%) less than that.
National Centers for Environmental Prediction (NCEP) - The National Centers for Environmental Prediction (NCEP), an arm of the NOAA's National Weather Service (NWS) provides national and international weather and climate guidance products to National Weather Service field offices, government agencies, emergency managers, private sector meteorologists, and meteorological organizations and societies throughout the world. The nine centers are: Aviation Weather Center, Climate Prediction Center, Environmental Modeling Center, Hydrometeorological Prediction Center, Marine Prediction Center, NCEP Central Operations, Space Environment Center, Storm Prediction Center and Tropical Prediction Center (formerly the National Hurricane Center). (See http://www.ncep.noaa.gov)
National Climatic Data Center (NCDC) - NCDC maintains the world's largest active archive of weather data. NCDC produces numerous climate publications and responds to data requests from all over the world. (See http://lwf.ncdc.noaa.gov)
National Oceanic and Atmospheric Administration (NOAA) - NOAA's historical role has been to predict environmental changes, protect life and property, provide decision makers with reliable scientific information, and foster global environmental stewardship. Today NOAA's mission remains unchanged as it describes and predicts changes in the Earth's environment, and conserves and wisely manages the Nation's coastal and marine resources. (See http://www.noaa.gov)
National Weather Service (NWS) - The National Weather Service (NWS) - provides weather, hydrologic, and climate forecasts and warnings for the United States, its territories, adjacent waters and ocean areas, for the protection of life and property and the enhancement of the national economy. NWS data and products form a national information database and infrastructure which can be used by other governmental agencies, the private sector, the public, and the global community. (See http://www.nws.noaa.gov)
NCEP - National Centers for Environmental Prediction
Near Normal - One of the outlook categories that are based on the 1981-2010 climatological normal. During this 30 year reference period, average three-month climate variable was observed in Near Normal category (the 10 years between the 10 warmest and the 10 coolest years) 1/3 (33.3%) of the time.
NOAA - National Oceanic and Atmospheric Administration
Normal - Aka Climatological Normal. The prevailing set of weather conditions calculated over a 30-year period, presently 1981-2010. Note that the climatological normal taken over different periods of time (30 years, 1000 years) may be different.
NWS - National Weather Service
Operational Products - Products and data that have been fully tested and evaluated that are produced on a regular and ongoing basis.
Percentile - Percentiles are values that divide a sample of data into hundredths containing equal numbers of observations. For example, 30% of the data values lie below the 30th percentile.
Pie chart - A graphical summary of categorical data. It is a circle, representing a whole, divided into segments, representing the categories as parts of the whole.
Probability - A chance, or likelihood, that a certain event might happen; expressed as a percentage between 0% (impossibility) and 100% (certainty).
Probability of Exceedance - The expected chance of the average climate variable to exceed (i.e. be higher than) a particular climate variable value.
Probability of Exceedance Graph/Curve - A graphical expression of Probability of Exceedance. Usually it is an x-y plot showing Probability of Exceedance Percentiles on one axis and corresponding to those climate variable values on the other axis.
Probability of Non-Exceedance - The expected chance of the average climate variable to non exceed (i.e. be lower than) a particular climate variable value.
Probability of Non-Exceedance Graph - A graphical expression of Probability of Non-Exceedance. Usually it is an x-y plot showing Probability of Non-Exceedance Percentiles on one axis and corresponding to those climate variable values on the other axis.
R - Correlation Coefficient
Seasonal - Referring to consecutive three-month periods.
Signal - That part of the variation of the environment which corresponds to a real - physical phenomenon. When the signal is large, its signature stands out above the remainder to the variation of the environment, the latter is called the noise. Some signals (e.g., ENSO) are predictable. Noise is not. The relationship between signal and noise is expressed as a number, called the signal-to-noise ratio or s/n. When s/n is greater than 1, signal is larger than noise, and the signature of the disturbance causing the signal can be seen. When s/n is less than 1 we have no hope of seeing or predicting the disturbance.
Standard deviation - A measure of the spread or dispersion of a set of data. The more widely the values are spread out, the larger the standard deviation. It is calculated by taking the square root of the variance.
Statistical predictions - Predictions based mainly on large observational data sets. CCA, OCN, SMLR, CAS, CA are examples of these.
Statistics - The analysis and interpretation of numeric data.
StDev - Abbreviation used to denote standard deviation.
TEMP - Abbreviation for temperature, given in Fahrenheit for CPC products.
Terciles - Values that partition a set of data, arranged in order, into three groups. Each group contains one-third of the total number of the data. For example, the lowest 1/3 of the data set lies below the lower tercile.
Three (3) Month Temperature - Temperature averaged over a consecutive three-month period.
Trend - An increasing or decreasing tendency in a climate variable behavior over specific period of time at a given place. An increasing (decreasing) tendency is called a positive (negative) trend.
Variance - A measure of the average distance between each data point and the data mean value; equal to the sum of the squares of the difference between each point value and the data mean.
XML - (EXtensible Markup Language) An open standard for describing data. It is used for defining data elements on Web page documents. XML uses a similar tag structure as HTML; however, whereas HTML defines how elements are displayed, XML defines what those elements contain.
* Sources for definitions include: The American Heritage Dictionary, The New York Times Weather Report, American Meteorological Society's Glossary of Meteorology (2000), CPC, and the Internet.