Pacific Northwest MM5 Weather Forecasts: Information

For a description of our experimental WRF forecasts click here

General Information: The Department of Atmospheric Sciences at the University of Washington is now running the Penn State/NCAR mesoscale model version 3.7.3 (MM5 v3.7.3) twice a day in order to produce high resolution meteorological forecasts for the Pacific Northwest. This effort, supported by a consortium of local, state, and federal agencies, has several goals:

To provide high resolution meteorological fields for air quality applications, weather forecasting, and other needs.
To test the viability of local numerical weather forecasting completed on relatively low-cost workstations.
To provide a large number of mesoscale model forecasts to determine model strengths, weaknesses, and biases.
To improve mesoscale model physics and data assimilation approaches.
To test the potential of directly coupling an atmospheric forecast model to air quality and hydrological numerical models.

Change Log: For the latest information on our setup, please consult the Change Log for Pacific Northwest MM5 Numerical Forecasts

Model Configuration: The MM5 numerical forecasts currently feature an outer grid of 36 km horizontal resolution that covers much of western North America and the northeastern Pacific, a nested grid of 12 km resolution that covers Washington, Oregon, Idaho, western Montana, southern British Columbia, and northern sections of California, Nevada, and Utah and an inner 4 km resolution grid encompassing all of Washington and Oregon plus the western third of Idaho. The regions covered by each domain, showing topography and land use categories are shown in these plots:

New version
Compatible with WRF Old version
from TERRAIN

Terrain Land Use Terrain Land Use

36-km terrain 36-km land use 36-km terrain 36-km land use

12 km terrain 12 km land use 12 km terrain 12 km land use

4 km terrain 4 km land use 4 km terrain 4 km land use

A land use category color key is included in the links above, you may view it alone here.

A detailed description of the domain boundaries as well as the actual terrain.namelist are given here. Detailed land use information for each domain was derived from the 1-km USGS digital database, with some subjective modification using other data sources.

New version Compatible with WRF	Old version from TERRAIN
Terrain	Land Use	Terrain	Land Use
36-km terrain	36-km land use	36-km terrain	36-km land use
12 km terrain	12 km land use	12 km terrain	12 km land use
4 km terrain	4 km land use	4 km terrain	4 km land use

The model utilizes 38 vertical full-sigma levels see below, and is run in non-hydrostatic mode in order to limit pressure gradient force errors over the complex terrain. An upper-radiative boundary condition is used to allow gravity waves to radiate through the model top without being reflected. The following table describes the phyics options we are currently using:

Phyics Options:

Physics Comments

CCM2 Radiation We changed the effective ice radius as used in radcsw.F from the default 14.6 microns to 35 microns. We are using ICLOUD=1, using resolved clouds.

Reisner 2 Moist Physics Includes graupel.

Kain-Fritsch Cumulus As of 5 August 2004, we are using this on all domains.

MRF PBL Also known as the Hong-Pan PBL (Hong and Pan 1996).

5-layer Soil Model Dudhia scheme predicting temperature at approximately 1, 2, 4, 8, and 16 layers with a fixed substrate below.

Bucket Soil Model (IMOIAV=2) Used on all domains, with 36-km and 12-km domains initialized with 20-km RUC values of soil moisture. Begun with 2004081900 forecast. Note: As released, the MM5 code does not allow IMOIAV=2 and IFSNOW=1 at the same time; thus, we turn off IFSNOW with this option. (See also comparison.)

Here are the exact mmlif files that are used to run the model: 36/12 km mmlif and 4 km mmlif (these two links are updated with each model run.). NOTE: EXTFRQ and EICER are U.W. modifications and will not work with standard MM5 versions.
For more information on any of these options, see the MM5 chapter of the MM5 tutorial notes.

Physics	Comments
CCM2 Radiation	We changed the effective ice radius as used in radcsw.F from the default 14.6 microns to 35 microns. We are using ICLOUD=1, using resolved clouds.
Reisner 2 Moist Physics	Includes graupel.
Kain-Fritsch Cumulus	As of 5 August 2004, we are using this on all domains.
MRF PBL	Also known as the Hong-Pan PBL (Hong and Pan 1996).
5-layer Soil Model	Dudhia scheme predicting temperature at approximately 1, 2, 4, 8, and 16 layers with a fixed substrate below.
Bucket Soil Model (IMOIAV=2)	Used on all domains, with 36-km and 12-km domains initialized with 20-km RUC values of soil moisture. Begun with 2004081900 forecast. Note: As released, the MM5 code does not allow IMOIAV=2 and IFSNOW=1 at the same time; thus, we turn off IFSNOW with this option. (See also comparison.)

Initializations: Currently two model runs are performed. One utilizes initial and lateral boundary conditions for the MM5 that are generated by interpolation of the National Centers for Environmental Prediction (NCEP) "ETA" model analysis and forecast fields. This MM5-ETA run only includes the 36 and 12 km domains.
The second initialization uses NCEP's GFS model (formerly known as AVN or MRF) at 1-degree lat/lon resolution for nearly all fields. The exceptions are: 1) SST is from the 1/4 degree OTIS grids, 2) surface temperature is from the ETA 221 grids (40-km grid spacing), and 3) subsurface soil temperature and moisture are also from ETA 221 grids.

Forecast: Forecasts are computed as follows:

MM5-ETA: 24 processor SUN Microsystems Ultra Enterprise 6500 Server For increased speed, the SUN MM5 code is parallelized using Kuck & Associates' OpenMP compiler, Guide.
MM5-GFS: a 40-processor HP Xeon Beowolf cluster running Debian Linux.

Currently, the model is run for a 72 hour forecast period over the 36 and 12 km domains and up to 48 hours for the inner 4 km domain. The MM5-ETA finishes in roughly 3.0 hours of wallclock time, while the MM5-GFS finishes in roughly 4.5 hours of wallclock time.

Future Improvements: The modeling system is constantly being improved. Among the changes we hope to make in the near future are:

Improve initial analysis through reanalyses of eta initialization fields using regional surface, upper-air, and wind profiler observations.
Incorporate four-dimensional data assimilation by means of nudging the model during a 12-h pre-forecast spin-up period.

Full Vertical Sigma Levels

Sigma: 1.00, 0.995*, 0.99, 0.985*, 0.98, 0.97, 0.96, 0.95*, 0.94, 0.93*, 0.92, 0.91*, 0.90, 0.88, 0.86, 0.83, 0.80, 0.77, 0.74, 0.71, 0.68, 0.64, 0.60, 0.56, 0.52, 0.48, 0.44, 0.40, 0.36, 0.32, 0.28, 0.24, 0.20, 0.16, 0.12, 0.08, 0.04, 0. * = added 7/9/2001 Half-Sigma Levels

K-index	Sigma	K-index	Sigma	K-index	Sigma
1	0.02	2	0.06	3	0.10
4	0.14	5	0.18	6	0.22
7	0.26	8	0.30	9	0.34
10	0.38	11	0.42	12	0.46
13	0.50	14	0.54	15	0.58
16	0.62	17	0.66	18	0.695
19	0.725	20	0.755	21	0.785
22	0.815	23	0.845	24	0.87
25	0.89	26	0.905	27	0.915
28	0.925	29	0.935	30	0.945
31	0.955	32	0.965	33	0.975
34	0.9825	35	0.9875	36	0.9925
37	0.9975

Past Domain Configurations: This table provides all the necessary information about previous domain configurations.

Domain Name	Code Version	First Forecast	Last Forecast	36 km Domain			12 km Domain			4 km Domain			Terrain Setup File	Full TER.PLT NCGM File
Domain Name	Code Version	First Forecast	Last Forecast	Terrain	Land use	Lat, Lon, Elev and Domain Extents	Terrain	Land use	Lat, Lon, Elev and Domain Extents	Terrain	Land use	Lat, Lon, Elev and Domain Extents	Terrain Setup File	Full TER.PLT NCGM File
may06	3-7-3	2006051512	present	terrain	land use	text file	terrain	land use	text file	terrain	land use	text file	terrain.deck	TER.PLT
dec03	3-6-3	2004020912	2006051500	terrain	land use	text file	terrain	land use	text file	terrain	land use	text file	terrain.deck	TER.PLT
aug02	3-5-4	2002090912	2004020900	terrain	land use	text file	terrain	land use	text file	terrain	land use	text file	terrain.deck	TER.PLT
jun01	3-4	2001070912	2002090900	terrain	land use	text file	terrain	land use	text file	terrain	land use	text file	terrain.deck	TER.PLT
jul00	2-12	2000073112	2001070900	terrain	land use	text file	terrain	land use	text file	terrain	land use	text file	terrain.deck	TER.PLT
dec99	2-12	1999121300	2000073100	terrain	land use	text file	terrain	land use	text file	terrain	land use	text file	terrain.deck	TER.PLT
may99	2-12 and 2-7	1999051812	1999121212	terrain	land use	text file	terrain	land use	text file	terrain	land use	text file	terrain.deck	TER.PLT
mar98	2-7	1998031812	1999051800	terrain	land use	text file	terrain	land use	text file	terrain	land use	text file	terrain.deck	TER.PLT
sep97	??	1997092912	1998031800	terrain	land use	text file	terrain	land use	text file	terrain	land use	text file	terrain.deck	TER.PLT

Questions and Comments: We're always interested in feedback. Please direct any questions and comments you have to Mark Albright (marka@atmos.washington.edu) or Cliff Mass (cliff@atmos.washington.edu).