User:Obrk/sandbox

[...] The predictors are typically forecasts from a numerical weather prediction (NWP) model, climatic data, and, if applicable, recent surface observations. These predictors are used as inputs into MOS equations for specific weather elements and location--such as tonight's temperatures at a nearby airport. Since the NWP model's surface grid points often do not coincide with cities and airports, the MOS technique effectively 'downscales' NWP model output to these desired locations. In addition to post-processing quantities directly from the NWP model, MOS can provide information not forecasted directly by the model, such as probabilities of precipitation (e.g. "chance of rain is 60% this evening") or the likelihood of dense fog tomorrow morning. Thus, ....

Background
Output directly from the NWP model's lowest layer(s) generally is not used by forecasters because the actual physical processes that occur within the Earth's boundary layer are crudely approximated in the model....

Description of MOS Technique
The technique used to develop MOS guidance is actually quite simple to illustrate and is based on the statistical procedure known as linear, least-squares regression. This technique seeks to find the relationship between one or more input variables, the predictors, to a response variable. In the case of a single input variable, the result of least-square regression is a straight line such that the sum of the squared errors is minimized. In the case of a temperature forecast for Minneapolis-St. Paul International Airport as shown on the right, the 'fit' between the variables as measured quantitatively by R2 is very good. Further increase in R2 would be obtained by adding more input variables in an attempt to 'explain' the remaining variability.

MOS History
MOS was conceived and planning for its use began within the U.S. National Weather Service’s (NWS’s) Techniques Development Laboratory (TDL) in 1965 and forecasts first issued from it in 1968.[6] Since then, TDL, ....

National Weather Service
Currently there are eight sets of MOS guidance available from MDL, operational and experimental, covering the span ...

MOS Guidance Suite
Currently ..... United States.