Gouge – Navy slang for the bare essential knowledge to get by

History L.F. Richardson, 1922 Computers – a curiosity looking for a purpose Jule Charney – ( ) 1948, the postdoc to end all postdocs produces Q-G Theory and filtered, usable equations, provided the newfangled computer a purpose And the race was on… Get the fastest computer More resolution Better Physics (Like Primitive Equations) Iterate above

Types (Deterministic) Global (usually Spectral) Resolution represented by T (triangular truncation – basically the number of terms in the series), and by number of levels. T can be roughly compared to a grid point spacing (e.g. T213 ~ 80 km) Run for the longest time periods, 180+ Regional (usually Finite Difference) Grid point models, forced at boundaries by Global models. Focused on a region like N. Am. or Europe. Sometimes higher resolution, but … Becoming non-hydrostatic Data Assimilation Schemes Vary (e.g. 3D VAR – variational) Particularly for satellite soundings Model Physics and Parameterizations Vary Big one – how do you get convection in - Run Frequency also varies (1, 2, 4x a day or more)

NWP Centers NCEP (NOAA/NWS) – formerly “NMC” Mostly in Maryland, Camp Springs, Silver Springs, Suitland FNMOC – U.S. Navy, Monterey, CA UK Met Office (sometimes referred to as Bracknell, but they aren’t there anymore) ECMWF – The Long Rangers, Huge Budget, Focused Problem CMC (EC) - Canadian Meteorological Centre

NCEP Operational Models NAM - North American Meso, formerly the ETA, 12 km, 60 levels, has 4 km nests (Conus, AK, HI) Note: This is a now a special version of the WRF, known also as the NMM-B - Weather Research and Forecasting (Community Model), Non-Hysdrostatic Mesoscale Model, recently replaced WRF-NMM GFS - Global Forecast System (Global Spectral Model) - formerly the AVN/MRF, T574 to F192 (~28 km), 64 layers RAP (Rapid Refresh), analysis every hour, short range, aviation support, 13 km, 50 levels Replaced RUC – Rapid Update Cycle,

Other Good Models FNMOC NOGAPS – Global Spectral, T319 (~44 km), 42 Levels, Soon: NAVGEM – should be state-of-the-science COAMPS – High-res nested regional, run everywhere DOD has high interest at whatever resolution is required, non hydrostatic. UKMET - “Unified Global”, 40km, 50 levels and gridpoint CMC – Global Environmental Multiscale GEM Global, 33km, 58 levels, Grid Point, Tau 144/240 (12Z, 00Z) GEM Regional, 15 km MM5 – Common model developed by NCAR and run by various incl. USAF

An attempt to have up-to-date info, Comet’s Operational Models Matrix:

Ensemble Models (Stochastic) Another Day

Tropical Models Another Day

MOS