The MOS Technique: General Information

For more specific information, please visit the following pages:

• Details of recent updates to the MOS Guidance
• MOS Frequently Asked Questions.
• MOS Frequently Used Acronyms.
• Join our Mailing List to receive updates!
• Short-Range Guidance & Development: 6-72 hour forecast projections.
• Medium-Range Guidance & Development: 24-192 hour forecast projections.

Training Material

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

• University of Maryland, 2003 Presentation
• University of Maryland, 2004 Presentation - COREL Presentation File (.shw), open locally - html version coming soon
• Millersville University, 2003 Presentation

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