Transcript NWWeatherWorkshop2012.ppt

Update on the Northwest
Regional Modeling System 2012
Cliff Mass and David Ovens
University of Washington
http://www.atmos.washington.edu/mm5rt/
NW High Resolution Regional
Prediction
• Supported by NW Modeling Consortium-a
collection of local, state, and Federal Agencies
AND the private sector (Iberdrola Energy, King5)
• Currently runs with 36, 12, 4, and 1.3 km grid
spacing using the WRF (Weather Research and
Forecasting) ARW model twice a day at 0000
and 1200 UTC (5 AM and 5 PM PDT)
• One of the highest resolution numerical
weather prediction efforts in the U.S.
Major Changes in Domain
October 2011
36 km
12
km
4 km
1.33 km
High-Resolution WRF Forecasts
• Forecast Periods:
– 36-12-4 km out to 84h
– 36-12 out to 180 h
– 1.33 km out to 48h
• Initialization and boundary conditions from
the National Weather Service GFS model
• Graphics available on the web and grids
available to contributing consortium members
Before
After
Still running the old MM5 model initialized with the NWS
NAM model for a quick-look prediction twice a day
36-12 km
only
Structural Change With Resolution
24-h snowfall ending 00UTC Wed
Feb 20
12 km
4-km
1.3 km
2-m temperature
12km
4 km
1.3 km
In general, verifications look
favorable for the 1.3 km—but
there are real issues in verifying
Behind the Scenes: Hardware
• Added more Intel Newhalem 8 and 12-cpu
servers
• Using 136 processors for the UW highresolution runs.
• Excellent parallelization—many processors
working together.
• Connected with high-bandwidth Infiniband
networking (40 Gb per second).
• Mirrored RAID disk arrays for dependability
But what about vertical resolution?
• Do we need more vertical resolution—more
vertical levels– in the new 4/3 km domain?
• Testing is now going on….
• Will more vertical levels will help with a
significant problem we see– an inability to
maintain shallow cold air layers.
Adding ten more levels below 200
meters (12 UTC 20 January
38 levels
48 levels
Observed
48
38
48
38
Regional Data Assimilation and
Forecasting
The Long Term Future of the UW
Modeling Effort
• Based on a large (64 member) ensemble of
forecasts at 36 and 4 km grid spacing. WRF
model and DART Ensemble Kalman Filter (EnKF)
System
• Every three hours assimilate a wide range of
observations to create 64 different analyses.
• Then we forecast forward for 3 hours and then
assimilate new observations.
• Thus, we have a continuous cycle of probabilistic
analyses.
EnKF Ensemble Forecasting System
• We can run ensemble of forecasts forward to
give us probabilistic forecasts for any period
we want. Now doing 24h ahead, four times a
day.
• Planning to go to a 1-hr cycle and to use more
observations (e.g., more surface pressure
obs).
• More next year.
Mean and Spread of Analyses
4 km analyses
On-The-Fly Graphics
How many are looking?
KING TV
PPM Energy
The End