Forecast Tools

Computer models are simulations of the atmosphere that utilize the most powerful supercomputers in the world. Also called Numerical Weather Prediction, or NWP, these supercomputers solve equations dealing with fluid dynamics and thermodynamics to predict the conditions of the atmosphere at different altitudes over a period of time. Some computer models are global in their scale, while some are regional, or "limited area" models.

In the weather business, we spend a lot of time doing analysis on maps that tell us different things about how the atmosphere behaves. Some maps and charts tell us different things depending on what level of the atmosphere they are representing (temperatures, winds, vorticity, humidity, etc.). We break these maps and charts down into two categories: "upper air" charts that deal with the atmosphere away from the surface of the Earth (broken down by pressure levels: 850 mb, 700 mb, 500 mb , 300 mb, and 250 mb being the main ones), and "surface" charts that deal with what is going on here on the ground (which includes rainfall, wind, and temperature forecasts among other things). Soundings are a profile of the atmosphere obtained by weather balloons when they are released twice a day. They contain temperature, dewpoint, and wind data from the surface to the top of the troposphere, and are essential in severe weather forecasting.

Global Scale Models:

GFS - Global Forecast System, developed by NOAA

NOGAPS - Developed by the US Navy

ECMWF - Model run by the European Center for Medium Range Weather Forecasts

UKMET - Developed by the United Kingdom's national weather service

JMA - Developed by the Japanese Meteorological Agency

Limited Area Models:

NAM - North American Mesoscale Model, run by the National Center for Environmental Prediction

WRF - Weather Research and Forecasting model

GEMS - Developed by the Meteorological Service of Canada for Canada and North America

Computer Models

Understanding Computer Models: