Last Updated: Wednesday 4 September 2002

Beginning with the 12Z forecast on Monday 9 September 2002,
2002090912, we will begin forecasting a new 4-km domain configuration
for the Pacific Northwest MM5 Weather Forecasts.

This new configuration will include:
<ul>
<li> larger 4 km domain extending into Idaho. See <a
href="/mm5rt/ter_aug02_d3.gif">terrain</a> and <a
href="/mm5rt/land_aug02_d3.gif">land use</a>.
<li> extending the 4 km domain forecasts from hours 9 to 48 (old was
     12 to 36)
<li> extending the forecast for the outer domains out to 72 hours.
<li> switching from our 30-processor Sun E6500 SMP machine to a
     32-processor Athlon powered Linux cluster running MM5 MPP code.
<li> initialization of most fields from NCEP's GFS (formerly known as
     the AVN) at 1-degree resolution.  The 36-km and 12-km domains
     will continue to be initialized with surface temperature, soil
     temperatures and moisture, and snow cover using the higher
     resolution ETA 221 grids (roughly 40-km resolution). 
<li>     <B>NOTE:</B>  We will run an additional forecast of the 36-km and
     12-km domains using only ETA 221 grids (as was done prior to
     2002090912).  A <a href="/mm5rt/etainit.html">separate Web page</a> will be available for viewing
     graphics from the different initialized runs.
<li> switch to version 3.5 of the MM5 model and preprocessing code
<li> temporary (?) end to cloud-water initialization for the outer
domains -- running MM5 with MPP code across clusters of Linux machines 
produces CFL errors with the cloud-water fields initialized.
</ul>

The terrain.deck file for this new configuration can be found <a href="/mm5rt/terrain.deck.aug02.txt">here</a>.

We are continuing to evaluate the Land Surface Model (LSM), more
complicated ice physics, and the RRTM radiation scheme.  A change
including some combination of these may occur sometime in Fall 2002.