Numerical Weather Prediction (NWP) [ Resources | Exercises]

Lab Exercises

A. Forecast Centers

Describe the full title, geographic location, and some info about each of the following operational weather forecast centers. Also, answer any special questions indicated below for these forecast centers.

  1. NCEP .
    1. List the 9 centers that make up NCEP.
    2. What kind of computers ( international NWP , ) are used to make the operational forecasts ( EMC )?
  2. FNMOC .
  3. CMC
    1. List 3 branches of CMC.
    2. Describe the computers (see slides 17 & 18) used today at CMC to make the daily NWP forecasts. (also see top500 list )
  4. ECMWF .
  5. UKMET .

B. Some Operational Numerical Models

For this section, use the info described in the MedEd models matrix.  When you first access this Meteorological Education (MetEd) site, you will need to register.  It is free, so please set and remember your password for MetEd, so you can log into it any time.  

Then, under the MetEd Topics tab, select NWP (Modeling).  Then, at the top of the right window, click on the Operational Models Matrix.   

In that matrix, each column describes a different NWP model, and the rows describe its characteristics.  To do this exercise, first print a copy of this models grid from the link above. [If any of the Canadian model data is missing, see the old (Oct 2006) info about the CMC GEM model.]

What you will do here is create your own, abbreviated table:

  1. List the full name, and abbreviation, for each model, and indicate if it is a grid-point or a spectral model.
  2. List the country (and organization, if given) where each model is run operationally (i.e., to make official weather forecasts)
  3. On your printed table, in the "horizontal resolution" row, circle the highest and the lowest resolution.
  4. On your printed table, in the "vertical resolution" row, circle the highest and the lowest number of layers in the models.
  5. What aspects of the model physics are parameterized in the models (hint, see leftmost column labels under the "Physics" rows).
C. Research Numerical Models
Give the full title for these numerical models.  (Tip: If the links below don't work, try the MetEd Models Matrix from the previous section.):
  1. MM5 .
  2. MC2 ( see Table 1 and Table 2 , extracted from Benoit et al, 2002, BAMS) It is the Mesoscale Compressible Community model .
  3. RAMS .
  4. UW-NMS .
  5. ARPS .
  6. WRF -ARW.
D. Initial Data (the starting point for all numerical forecasts)
  1. What are the broad categories of observation data that are used to create the analyzes of initial conditions for a typical model? (Hint, in the Resources section from this web page on Input: Sources of Initial Data & Data Assimilation, look at the various "Data Coverage" maps)
  2. What is "data assimilation" and how does it work? See MetEd tutorial (In the left frame, work your way down thru each chapter listed, and don't forget to click on all the "pages" listed in the left frame under each chapter heading).

E. Other Forecast Topics

  1. What is MOS, and why is it useful (see MetEd on Statistical Guidance , don't forget to look at the multiple pages for each topic)? 

F. Ensemble Forecasts

  1. What is an ensemble forecast ( MetEd , NCEP tutorial , ECMWF intro , CMC , or WMO ) ?
  2. What is a
    1. spaghetti diagram ( NCEP tutorial , CMC tutorial , CMC products, or NCEP )?
    2. probability diagram or probability plots
  3. What other ways are used to present ensemble information?

G. Forecast Models Run at UBC, Vancouver, Canada.

  1. At what horizontal grid sizes are the NWP models run (WFRT) ? (Ask Stull for the username and password during class.   If WFRT doesn't work, try the back-up WFRT server.) Hint, look at the row labels in the forecast table.
  2. Compare and discuss the "coloured surface winds and convergence" forecasts for only the coarsest mesh and the finest mesh grids of the MC2 model, using the forecast map valid at the time you do this exercise. (If that wind map is not available, then use some other map, such as sea-level pressure and precipitation.)
  3. Access the ensemble meteogram (column = ENS, row = meteogram) for the site BC-VANCOUVER INTL ARPT (WS3) [EC] - KF . Print the "Combined Plots" pdf product, and discuss the accuracy of the ensemble-average forecast (dark blue line in center) and the range of the ensembles (red lines).

Updated Aug 2007 by Roland Stull

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Resources - Part 1: NWP Concept, Methods, & Activities

CAUTION:  The Resources links have not been updated for several year.  Some might not work.

Tutorials

Forecast Centers

Numerical Models

Input: Sources of Initial Data & Data Assimilation

Model Output Statistical Guidance (& MOS)

Ensemble Forecasts

Resources - part 2: Forecasts resulting from NWP

Real-time Weather Forecasts from Numerical Models

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Written by Roland Stull
Lab portion last upated 26 Aug 2007.
Copyright © 2007 by Roland Stull
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