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Meteorological Development Laboratory

The MOS Technique: General Information

For more specific information, please visit the following pages:

Training Material

Slide presentations suitable for use in teaching students, forecasters, and general users:

General MOS Background

Model Output Statistics (MOS) relates observed weather elements to appropriate variables (predictors) via a statistical approach. These predictors are:
  • NWP Model Forecast
  • Prior Obersvations
  • Geoclimatic Data
  • Statistical Method: Multiple Linear Regression

What MOS Does

  • Objectively interprets NWP Model based on historical sample
  • Predicts events forced by synoptic-scale systems
  • Corrects for certain systematic NWP model biases
  • Mimics conceptual forecast models
  • Quantifies uncertainty in NWP model forecasts
  • Accounts for deterioration NWP model skill with increasing forecast projection
  • Accounts for some local effects
  • Incorporates climatic considerations

What MOS Does Not Do

  • Account for forecaster excitement factor
  • Predict events forced by mesoscale features
  • Correct for systematic NWP model errors related to map type or synoptic situation
  • Correct for certain deficiencies in NWP model physics, analysis schemes, or parameterizations
  • Account for changes to NWP model components
  • Account for EVERY local effect
  • Account for unusual climatic conditions

Last Updated April 28, 2003

National Weather Service
Office Of Science and Technology
Meteorological Development Laboratory
Statistical Modeling Branch
1325 East West Highway
Silver Spring, MD 20910
Page Author: MOS Web Team
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Page last Modified: Thursday, 02 October 2008 17:13 UTC