Mesoscale Branch Web Page Reference List

Table of Contents

1. NCEP OPERATIONAL MODEL FORECAST GRAPHICS

Web Page Models Displayed Forecast Length Forecast frequency Grids used Animation? Archive of past forecasts?
NAM FORECAST METEOGRAMS NAM 84-h ; displays last two NAM runs 1 hour 1300+ stations, use NAM model grid point nearest to station Not applicable No
NAM FORECAST PRECIPITATION TYPE METEOGRAMS AND REGIONAL PLOTS NAM 84-h (00Z/12Z runs only) 1 hour 1300+ stations, use NAM model grid point nearest to station Yes, for regional hourly plots of precipitation type No
RUC FORECAST METEOGRAMS RUC 12-h; displays latest RUC 3-h cycle 1 hour 500+ stations, use model grid point nearest to station Not applicable No
NAM MODEL FORECAST SOUNDINGS NAM 60-h (00Z/12Z), 48-h (06Z/18Z) 6 hours RAOB stations, use NAM model grid point nearest to station Yes No
NCEP Operational NAM 12km - CONUS Graphics NAM 84-h 6 hours #221 (32 km LCC) Yes No
NCEP Operational NAM 12km - Alaska Graphics NAM 84-h 6 hours #221 (32 km LCC) Yes No
NCEP Operational NAM 12km - Eastern Pacific Graphics NAM 84-h 6 hours #221 (32 km LCC) Yes No
NCEP Operational NAM 12km - Hawaii Graphics NAM 84-h 6 hours #209 (44 km LCC) Yes No
NCEP Operational NAM-12 : Enhanced CONUS/North America/Hawaii Graphics NAM 84-h 3 hours #221 (32 km LCC), #218 (12 km LCC) for precip, 2-m temps, 10-m wind Yes 3 days
NCEP Model Graphics NAM, GFS, NGM, NAM parallel (if running) 84-h (48-h for NGM) 6 hours #104 (90 km NPS for NAM, NGM) #3 (1 deg lat/lon for GFS), #218 for NAM precip Yes 7 days
NCEP Operational NAM-12 : Convective Forecasting Page for 00Z/12Z cycles NAM 66-h 3 hours #104 (90 km NPS), #215 (20 km LCC) for precip, 2-m temps, precip type Yes No
NCEP HiResWindow Forecast Page
  • East/Central US NMM and ARW (00Z,12Z) vs ops NAM
  • West/Central US NMM and ARW (06Z) vs ops NAM
  • Hawaii NMM and ARW (00/12Z) vs ops NAM, Hawaii RSM
  • Puerto Rico NMM and ARW (06/18Z) vs ops NAM
  • Alaska NMM and ARW (18Z) vs ops NAM
    		• 48-h 3 hours
  • NMM/ARW : 5 km output grids (LLC over CONUS, polar sterographic over Alaska, lat/lon over Hawaii/Puerto Rico)
  • NAM : #218 (12 km LLC over CONUS), #242 (12 km polar Sterographic over Alaska), 0.1 deg lat/lon grid (Hawaii/Puerto Rico
  • Hawaii RSM : 0.1 deg Mercator grid
    		• Yes No
    NCEP Operational RUC : Convective Forecasting Page RUC 12-h Hourly from 0-9h and 12-h #236 (40 km LCC) Yes 1 day
    NCEP Operational NAM, GFS - Forecast Trends over North America NAM, GFS 84-h (00Z/12Z cycles only) 12 hours #104 (90 km NPS for NAM) #3 (1 deg lat/lon for GFS), #218 for NAM precip No 2.5 days
    NCEP Short-range Ensemble Forecast (SREF) System 21 member SREF ensemble (5 Eta Model, 5 RSM, 5 Kain-Fritsch Eta, 3 WRF-NMM, 3 WRF-ARW) 87-h 3 hours #212 Yes 3 days
    NCEP Downscaled GFS by Eta Extension (DGEX) DGEX (CONUS at 06/18Z, Alaska at 00/12Z), GFS 84-192 h 6 hours #185 (12km LCC over CONUS), #186 (12km NPS over Alaska), #3 (1 deg lat/lon for GFS) Yes No
    NCEP Real-Time Mesoscale Analysis (RTMA) Hourly Operational RTMA, Hourly ops RUC2 and ops surface RUC analyses Yes 24 hours

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    2. PARALLEL/EXPERIMENTAL GRAPHICS

    Web Page Models Displayed Forecast Length Forecast frequency Grids used Animation? Archive of past forecasts?
    NCEP Parallel NAM run (NAMY) 00Z and 12Z Ops NAM, 12-km NAM parallel 84-h 3 hours #221 (32km LCC), #218 (12 km LCC) for precip, 10-m wind, 2-m temp Yes 3 days
    NCEP Parallel NAM runs (NAMY vs NAMX, 00z cycle)
    NCEP Parallel NAM runs (NAMY vs NAMX, 12z cycle)     		NAM parallels (NAMY vs NAMX) 84-h 3 hours #221, #218 for precip Yes 1 day
    4.5 km WRF-NMM Parallel - Eastern/Central U.S. domain 4.5 km WRF-NMM (Eastern/Central US domain) 36-h (00Z) 1 hour Yes No
    PARALLEL 12KM NAM FORECAST SOUNDINGS Operational NAM and various 12km NAM parallel runs, surface to 200 mb 48-h 12 hours RAOB stations, use NAM model grid point nearest to station Yes 4 weeks
    PARALLEL 12KM NAM FORECAST SOUNDINGS (PBL) Operational NAM and various 12km NAM parallel runs, surface to 600 mb 48-h 12 hours RAOB stations, use NAM model grid point nearest to station Yes 4 weeks
    Parallel NCEP Real-Time Mesoscale Analysis (RTMA) Hourly Operational RTMA, Parallel RTMA, hourly ops RUC2 and ops surface RUC analyses Yes 24 hours

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    3. VERIFICATION / DIAGNOSTICS

    Web Page Description Models Displayed Retention Period
    Daily Precipitation Verification Plots This site is an archive of model forecast precipitation vs. 24-h (12Z-12Z) observed precipitation analysis NAM, GFS, NGM, GFSX, CMC, CMC Global, UK Met, HiResWindow runs, various NAM parallels 10 months
    NCEP/EMC Precipitation Skill Scores for Operational Models Monthly equitable threat and bias scores for 24-h forecast precipitation versus observed precipitation NAM, GFS, NGM, HiResWindow runs, various international regional and global models 1995 - present
    NAM/GFS/NGM Forecast 500 Mb Height Differences This page shows the forecast height difference at 500 mb for the NCEP NAM, GFS, and NGM models, compared to the NCEP Final (GDAS) analysis. NAM, GFS, NGM 4-6 months
    Operational NAM-12 versus RTMA analysis comparison page (00Z, 12Z runs) This page is a comparison of the NAM forecast and the best available RTMA analyses valid at the same time. NAM, RTMA analyses 7 days
    INTERACTIVE NCEP MODEL VERIFICATION WEB PAGE Interactive web page tool for display of NCEP model verifications NAM, GFS, NGM, RUC January 2006 - present
    EMC MODEL FORECAST VERIFICATION STATS (Static Display) Verification (bias and RMS errors) of 06-84 h forecasts of 500 mb Height, 700 mb RH, 850 mb Temp, 250 MB Vector Wind vs. rawinsondes over the CONUS; 2-m temps / 10-m winds vs. surface observations NAM, GFS, NGM, RUC Past 30 days vs rawinsondes, past 8 days vs surface data
    NCEP/EMC Cyclogenesis Tracking Page This page shows the various model forecast tracks for tropical and extratropical cyclones NAM, GFS, GEFS, SREF, UKMET, NOGAPS, CMC Several months
    NAM-12 versus GFS 00-h analysis comparison page Comparison of NAM-12 vs GFS 00-h analysis to observations, with full fields (height/wind, temperature, specific humidity, total column precipitable water) and analysis/observation increments NAM, GFS analyses 7 days
    NAM 3DVAR observations monitoring page Plots of the distribution of most observation types used by the NDAS/NAM 3DVAR analysis over North America. Observation locations are color-coded to identify those reports which are rejected by various data quality control algorthims. NDAS / NAM 6 days
    EMC MODEL FORECAST VERIFICATION STATS - HI-RES WINDOW RUNS Verification (bias and RMS errors) of 06-48 h forecasts of 500 mb Height, 700 mb RH, 850, 700, 500, and 300 mb Temp, 250 MB Vector Wind vs. rawinsondes over the each HIRESW domain; 2-m temps / 10-m winds vs. surface observations Operational East US, West US, Alaska HIRESW (WRF-NMM and WRF-ARW) and vs Ops NAM Past 21 days vs raobs, past 10 days vs surface data
    Near-Surface Forecast Verification Statistics for operational NCEP models
  • Monthly (diurnal) composite of 00-hr to 84-hr forecast (0-48 h forecast for NGM) from the NAM, GFS, and NGM models verified against observations averaged by region and composited on a monthly basis for 00z and 12z cycles.
  • Annual time series of the bias in the 84-hr forecast (end point) from the NAM model verified against observations averaged by region for the given year
    		• NAM, GFS, NGM April 1998 - present
    Evaluation of NAM surface variables This page contains verification of NAM forecast surface meteograms and soundings as well as forecasts of fluxes and soil parameters for selected sites. NAM 2 years
    Monthly NDAS / NAM Preciptation / Water Budget plots This page contains monthly precipitation and water budget plots from the operational NDAS and NAM forecast NDAS, NAM 1999 - present
    NDAS/NAM Surface Radiation Budget Verification This page contains verifications of NDAS/NAM surface upward and downward radiation flux (monthly mean diurnal and daily mean diurnal cycle) against observations at SURFRAD sites. NDAS, NAM December 2003 - present
    PARALLEL NAM-12 FORECAST VERIFICATION STATS Verification (bias and RMS errors) of 12-84 h forecasts of 500 mb Height, 700 mb RH, 850 mb Temp, 250 MB Vector Wind vs. rawinsondes over the CONUS; 2-m temps / 10-m winds vs. surface observations Ops NAM-12 vs various 12km NAM parallels Past 21 days vs rawinsondes, past 8 days vs surface data
    Operational 12-km NDAS Surface Parameters 2-d graphics (animated) of NDAS surface fields (e.g., 12-h precip, soil temperature/moisture) 12 km Operational NDAS 120 hours
    NCEP NAM-12 SST analysis 2-d graphics (regional plots) of the most current SST analysis used by NAM model NAM 7 days
    NCEP NAM-12 Snow/Sea Ice analysis Plots of the most current Snow/Sea Ice analysis from NESDIS, USAF, and the analysis used as initial conditions in the NAM model NAM 7 days

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    4. ON-LINE DOCUMENTATION OF MESOSCALE BRANCH MODEL CHANGES (For a complete list of Eta/EDAS changes prior to March 2004, go to the Eta/EDAS production change log. For a more complete list of RUC changes, go to FSL's RUC change log)

    Date (link goes to on-line documentation) Contents/major changes
    22 April 2008
  • Begin assimilation of AIRS radiance data in NDAS/NAM GSI analysis. This was not implemented on 31 March 2008 as intended due to a script error.
    • 31 March 2008
  • Changes to the WRF-NMM forecast model running in the North American Mesoscale (NAM) Analysis and Forecast System and the DGEX:
    1. WRF-NMM Model changes:
      1. Run with WRF-NMM V2.2 code (August 2007 Repository version) with IJK array indexing
      2. Use gravity wave drag/mountain blocking. Run with SIGFAC=0: gravity wave drag responds only to ELEVMAX, the maximum elevation within the grid box only. No further inflation is done based on the standard deviation of the 30" heights in the grid box.
      3. Use new Unified (with NCAR) Land-Surface Physics module. This module now uses total soil moisture rather than liquid soil moisture (as in the previous NCEP/noahlsm) to determine bare-soil evaporation, which results in greater moisture fluxes (and thus higher near-surface dew point temperatures) over regions of frozen, bare soil with patchy or no snow cover.
      4. Use of new passive advection with the requirement for exact conservation of specific humidity, TKE, and cloud water relaxed in the advection step. The exact conservation is still required in the antifiltering step following the advection step.
      5. Stratospheric ozone fix in the computation of latitude: the error led to using climatological ozone values valid at the equator at all latitudes.
      6. Remove two modifications to longwave radiation made for the June 2006 WRF-in-NAM implementation
        1. Remove averaging of longwave temperature tendencies from the lowest two model layer
        2. Compute the upward LW at the surface was based on the ground (skin) temperature instead of the average of the skin and lowest model layer temperatures.
    2. GSI analysis changes:
      1. New (August 2007) version of GSI code
      2. Retuned background errors (gives improved obs fit to first guess)
      3. Use AIRS radiance data
      4. Use GOES 1X1 radiance data
      5. New SATWND data (eumetsat and modis)
      6. MESONET uv (winds with uselist)
    3. Use new terrain with "3x3" (smoothed-desmoothed) smoothing, a smaller (more realistic) Great Salt Lake, better depiction of the Channel Islands off the California coast, and spurious waterfalls removed; use climatological water temperatures for Lake Champlain.
    4. Use 12-36 h forecast precipitation from the 00z ops NAM run to fill in for the CONUS-based Stage II/IV analysis as a driver for NDAS soil moisture outside of the CONUS (OCONUS)
    • 12 December 2007
  • Changes to Short-range Ensemble Forecast System:
    1. Introduce bias correction scheme for basic meteorological fields (except QPF)
    2. Expand RSM domain to fully cover Alaska
    3. Add aviation-related ensemble products (icing, CAT, flight restriction, ceiling height)
    4. Add BUFR sounding output to the 6 WRF members
    • 11 December 2007
  • Mesoscale Modeling Branch 2007 Production Review
    • 11 September 2007
  • Changes to the NCEP HiResWindow Modeling System:
    1. WRF-NMM
      1. Upgrade from WRF version 1.3 to WRF version 2.2
      2. Increase resolution from 5.2 km to 4.0 km
    2. WRF-ARW
      1. Upgrade from WRF version 1.3 to WRF verison 2.2
      2. Increase resolution from 5.8 km to 5.1 km
    3. Expand large domains (Click here to see new HIRESW domains)
      1. Western and Eastern U.S. domains roughly doubled in size
      2. 3 CONUS nests reduced to 2 overlapping domains (West-Central & East-Central)
      3. New HIRESW schedule (see below) to run the new East/Central domain at 00z and 12z for NCEP's Storm Prediction Center
    4. New HIRESW run schedule:
      1. 0000Z : East/Central U.S., Hawaii
      2. 0600Z : West/Central U.S., Puerto Rico
      3. 1200Z : East/Central U.S., Hawaii
      4. 1800Z : Alaska, Puerto Rico
    5. The operational HIRESW forecasts are subject to cancellation by NCEP Central Operations (NCO) if the NCEP Hurricane model is running. This is the production HIRESW configuration when the NCEP hurricane model is running
      1. No hurricane runs : Both large and small NMM and ARW domains are run by NCO
      2. One hurricane run : Large domain ARW run cancelled by NCO
      3. Two or three hurricane runs : Both large domain NMM and ARW runs cancelled by NCO
      4. Four hurricane runs : All WRF HIRESW cancelled by NCO
    6. Due to computing resource constraints EMC will no longer run the cancelled HIRESW WRF-NMM forecast on the development computer at this time.
    • 19 June 2007
  • Changes to the WRF-NMM model running in the NAM and DGEX:
    1. Under stable conditions, modify roughness length for heat so that it is only a function of surface-layer bulk Richardson number, removing the dependence on surface elevation.
    2. The minimum canopy resistance was increased for evergreen needleleaf forest (doubled from 125.0 to 250.0, units of s/m) and for mixed forest (from 125.0 to 150.0).
    • 19 December 2006
  • Changes to the WRF-NMM forecast model running in the North American Mesoscale (NAM) Analysis and Forecast System and the DGEX:
    1. The divergence damping routine, which damps all gravity-inertia and external modes, is changed to increase damping of the external mode.
    2. During the NDAS, divergence damping is increased to 5x that used during the 84 hr NAM free forecast.
    3. Numerous changes are made to convective parameterization:
      1. Triggering of deep and shallow convection is considered only for grid points with positive cape throughout a parcel's ascent; the search for parcel instability is extended to include not only whether the most unstable (highest theta-e) parcel can support convection, but also whether parcels originating at higher levels become positively buoyant when lifted to their LCL. Convective adjustments are made with respect to the parcel associated with the greatest instability (largest CAPE)
      2. The search for the most unstable parcel is extended from the lowest twenty percent of the atmosphere to the lowest 40 percent of the atmosphere.
      3. Water loading effects are now included in assessing the buoyant instability of parcels from which a revised (lower) cloud top is determined to be at the highest level of positive buoyancy.
      4. The latent heat of vaporization used to calculate equivalent potential temperatures during model integration is made to be consistent with the value used in generating the initial lookup tables.
      5. When a grid point fails the entropy check for deep convection but still has positive CAPE, changes in temperature and moisture by shallow convection are then considered at these so-called "swap" points. The first-guess estimate for the top of shallow convection is based on the highest level where the parcel remains positively buoyant (this is more restrictive than positive CAPE), and the vertical extent of shallow convection is not to exceed 0.2 times the atmospheric pressure depth (e.g., 200 hPa for a surface pressure of 1000 hPa). A final adjustment is made to the top of shallow convection in which it can extend to higher altitudes if the mean ambient relative humidity (RH) in the cloud layer exceeds a threshold RH while remaining positively buoyant (i.e. CAPE greater than 0). The threshold RH is based on the RH at cloud base that is consistent with a deficit saturation pressure of 25 mb (usually near 90%). The maximum cloud top height for shallow convection is still limited to 450 hPa.
      6. The first-guess reference temperatures in the upper-half of shallow convective clouds are limited to be no more than 1 deg C colder than the ambient temperature.
    4. Three changes are made to the cloud microphysics:
      1. During melting precipitation ice particles are assumed to have the same mean diameter (1 mm) as at the freezing level.
      2. Two changes intended to increase the presence of supercooled liquid water and improve forecast products for use in aircraft icing algorithms:
        1. The temperature at which small amounts of supercooled liquid water, if present, are assumed to be glaciated to ice was lowered from -30C to -40C.
        2. The temperature at which ice nucleation is allowed to occur was lowered from -5C to -15C based on aircraft icing observations
    5. Allow horizontal diffusion between neighboring grid points with a slope of less than or equal to 54 m / 12 km (9x that in previous operational NAM).
    • 12 December 2006 (Powerpoint)
    12 December 2006 (PDF)
  • Mesoscale Modeling Branch 2006 Production Review
    • 5 September 2006
  • Changes to the North American Mesoscale (NAM) Analysis and Forecast System:
    1. Increased Smagorinsky constant for lateral diffusion from 0.27 to its maximum value of 0.4; this was inadvertently left out of the 8/15 changes for the NAM, it was implemented in the DGEX on 8/15
    2. Revert back to using the 1/2 degree RTG_SST analysis used in the NAM-Eta due to problems with a persistent cold bias in the hi-res (1/12th degree) RTG_SST analysis in and north of the Bering Strait and in Hudson's Bay.
    • 15 August 2006
  • Changes to the North American Mesoscale (NAM) Analysis and Forecast System and the DGEX:
    1. Remove any restrictions to horizontal diffusion between water points at different elevations (e.g., between erroneously sloping water points and water points at sea-level)
    2. Redefine roughness length z0=z0base (veg component) + z0land, removing terrain height component
    3. Code changes to allow horizontal diffusion at grid points along coastal/ice boundaries where the slope between neighboring grid points is > 6 m
    4. Increases Smagorinsky constant for lateral diffusion from 0.27 to its maximum value of 0.4
    5. Enhanced vertical diffusion
    6. Turned on assimilation of surface temperature data over land in the GSI analysis
    7. Modified the SST preprocessing job to use new climatological values for Great Salt Lake water temperatures from the University of Utah; a cosine fit to the bimonthly observational data from Saltair Boat harbor (from 1972-1989). From Steenburgh et al., 2000: Climatology of Lake-Effect Snowstorms of the Great Salt Lake. Monthly Weather Review, 128, 709-727.
    8. Modified the SST preprocessing job to use monthly climatological values of water temperature for the Salton Sea in southern California
    9. Modified the SST preprocessing job to use monthly climatological values of water temperature (obtained from the Army Corps of Engineers) for Fort Peck Reservoir in Montana
    • 6 August 2006
  • Operational implementation of the Real-time Mesoscale Analysis (RTMA).
    • 20 June 2006 (NCEP/EMC documentation, PDF format)
    20 June 2006 (COMET documentation)
  • Changes to the North American Mesoscale (NAM) Analysis and Forecast System:
    1. Eta step-mountain coordinate model replaced with the WRF version of the Non-hydrostatic Mesoscale (WRF-NMM) model in the NDAS, NAM, and DGEX; WRF-NMM model characteristics:
      1. Uses WRF common modeling infrastructure
      2. Non-hydrostatic dynamics
      3. Uses hybrid sigma-pressure vertical coordinate with model top pressure of 2 mb for NAM (DGEX has 30 mb model top)
      4. Refined advection, diffusion, numerics, and physics
    2. Eta 3D-Variational analysis replaced with the Gridpoint Statistical Interpolation (GSI) analysis:
      1. Unified 3D-Variational analysis adapted to WRF infrastructure
      2. Uses background errors based on WRF-NMM forecasts
      3. Uses new variable (normalized RH) for moisture analysis
      4. Uses tendency in constraint term
      5. Uses dynamically retuned observation error covariances
    3. Changes to model initialization:
      1. Use of new unified package to bring external fields (SST, snow, sea ice) into WRF-NMM forecast
      2. Begin use of high resolution (1/12th degree lat/lon) RTG_SST analysis
      3. Begin use of high resolution (NESDIS 4km) snow analysis
    4. Data assimilation changes:
      1. Turn off nudging of temperature, mositure and cloud during assimiltion of observed precipitation, but continue use of bias-corrected observed precipitation analysis to drive the WRF-NMM land-surface physics
      2. Begin use of new observation types: WSR-88D Level II radial wind data, GPS-Integrated Precipitable Water (IPW) data, and NOAA-18 radiances.
      3. Drop use of GOES and SSM/I Precipitable Water retrievals
    • 6 December 2005
  • Mesoscale Modeling Branch 2005 Production Review
    • 6 December 2005
  • Changes to Short-range Ensemble Forecast System:
    1. Added 6 new members:
      1. Three with 40km/50lev WRF-NMM w/EMC physics (control, n5, p5 perturbations)
      2. Three with 45km/35lev WRF-ARW w/NCAR physics (control, n1, p1 perturbations)
    2. Begin use of common ensemble product generator
    • 31 August 2005
  • Changes to Short-range Ensemble Forecast System:
    1. RSM: Updated and optimized version used. Domain now covers all of Alaska and Hawaii
    2. RSM resolution decreased from 40 to 45 km
    3. RSM Bufr sounding files now output for all 5 RSM members
    4. Implement WRF-POST: all derived fields will be based on model state variables in a common WRF model output format.
    5. SREF Forecast Length to be extended to 87 hours.
    6. LBCs: 3 hour old GFS ensemble forecasts now used for SREF member LBCS (instead of 9 hr old).
    7. New output grids: #216 (Alaska 45 km), #243 (Hawaii 0.4 deg lat/lon)
    • 28 June 2005
  • Resolution of WRF-NMM in HIRESW system changed from 8km/60levels to 5.1km/35 levels
  • Resolution of WRF-EM (ARW) in HIRESW system changed from 10km/50levels to 5.8km/35 levels
  • Convective parameterization turned off in both HIRESW NMM and ARW
    • 3 May 2005 (low-res version)
    3 May 2005 (Powerpoint file)
  • Changes to NAM/DGEX:
    1. Eta 3DVAR:
      1. Turned on use of on-time overland surface temperature observations in Eta 3DVAR using 2DVar with anisotropic covariance tied to terrain
      2. Use of Level II.5 (on-site derived superobs) WSR-88D radial velocity data
    2. Precipitation assimilation:
      1. Cease attempts to create precipitation when model precipitation is less than observed
      2. Continue to reduce latent heat and moisture fields when model precipitation is greater than observed
      3. Use observed precipitation directly in driving the land surface physics
    3. Eta Model : Land-surface model changes:
      1. Use high-resolution (1-km vs 1 deg) vegetation and soils data bases with more classes
      2. Retuned canopy conductance and other vegetation parameters - ops had been tuned to higher values to maintain reasonable evaporation rates given low soil moisture bias which is removed by new precipitation assimilation procedures
      3. Lowered roughness length for heat to reduce skin temperature, and hence lower diagnosed 2-m air temp
      4. Parameter changes over patchy snow cover (higher snow albedo, reduced snow sublimation, less snow depth for 100% cover)
      5. Surface emissivity over snow changed from 1.0 to 0.95
      6. In very stable conditions when PBL depth is diagnosed at the lowest Eta model level, impose lower limit on eddy diffusivity up to (and one level above) inversion height
    4. Eta Model : Clouds / radiation:
      1. Radiation scheme modified to "see" thicker clouds by removing the upper limit for cloud water mixing ratio when computing optical depths
      2. Modified cloud cover fraction formulation to allow for more partial cloudiness (had been too binary)
    • 25 January 2005
  • Operational Eta forecast system officially renamed North American Mesoscale (NAM) forecast system; Eta Data Assimilation System (EDAS) renamed NAM Data Assimilation System (NDAS).
    • 7 December 2004
  • Mesoscale Modeling Branch 2004 Production Review
    • 29 November 2004
  • Changes to WRF-NMM and WRF-ARW runs in HIRESW system:
    1. WRF-ARW:
      1. The "masked" horizontal interpolation of SST data was generating spurious 290K temperatures over parts of the Arctic Ocean, leading to unrealistically warm near-surface temperatures.
      2. Native-grid GRIB output from the HI and PR WRF-ARW runs were being labeled as Lambert Conformal, when the integration domain is actually Mercator. Improper hardwiring of the map type to a Lambert Conformal projection was removed from, and the problem that necessitated the hardwiring was eliminated.
      3. Made modifications so an initial snowcover would be properly defined within the WRF-ARW.
      4. Definition of sea-ice points are changed from water to land, and the Land-sfc physics can now handle sea-ice properly
    2. WRF-NMM:
      1. Modify vertical advection to use an off-centered Crank-Nicholson scheme, which remedied recent failures of the WRF-NMM over Alaska
      2. Divergence damping parameter CODAMP set back to 6.4 for all domains
      3. Removed faulty logic in generating the initial skin temperature
    3. WRF Post-processor:
      1. The reduced sea-level pressure in the WRF-ARW was in poor agreement with the initializing Eta model data at the initial time (up to 5 hPa too low relative to the Eta), and would continue to have a low bias through the forecast period. A moisture component of pressure that is subtracted out during initialization of the WRF-ARW was added back in the post.
      2. Fixes which ensure that output from both WRF cores will produce bit-identical answers regardless of the number of processors applied to the task.
      3. Modified two routines to process properly the snow and snowcover fields now coming out of the WRF-ARW.
    • 21 September 2004
  • Replace single run of NCEP Non-hydrostatic Meso Model (NMM) in the HiResWindow suite with two runs : 1) The WRF version of the NMM (WRF-NMM), and the WRF version of the Eulerian Mass core (WRF-ARW) with physics chosen by NCAR:

    WRF-NMM

    Physics module

    WRF-ARW

    Betts-Miller-Janjic

    Convection

    Kain-Fritsch

    Ferrier

    Microphysics

    Ferrier

    Mellor-Yamada-Janjic (Eta)

    PBL

    MRF scheme

    Monin-Obukhov (Janjic Eta) scheme

    Surface layer

    Monin-Obukhov

    OSU land-surface

    Land-surface

    OSU land-surface

    GFDL (Eta)

    Radiation

    Dudhia

  • The WRF version of the NMM has been upgraded with these changes to the model dynamic core:
    1. The Matsuno vertical advection scheme has been replaced with the neutral, unconditionally stable Crank-Nicholson scheme
    2. The Smagorinsky constant in the lateral diffusion is reduced by 70%
    3. The effect of horizontal shear of vertical velocity has been added to the lateral diffusion scheme.
    4. The fundamental time step has been reduced by 10%.
  • The NCEP physics for the WRF-NMM have these changes:
    1. Input data on surface conditions (soil and vegetation type) have been refined
    2. Soil heat capacity has been increased which results in larger ground fluxes
    3. The dependence of roughness length (z0) on the height of topography has been removed, significantly reducing z0 over elevated terrain
    4. The countergradient heat flux has been added to the turbulent kinetic energy (TKE) equation and in the vertical heat diffusion
    5. The diagnostic mixing length has been increased
    6. The floor values for TKE and mixing length have been significantly reduced
    7. Increased residual turbulent mixing has been introduced in case of strong stability between the top of the surface layer and the layer above the inversion
    8. The effect of entrainment has been incorporated into the procedure for finding convective cloud top pressure.
    9. The entropy change threshold for triggering deep convection has been reduced
    • 17 August 2004
  • Replace 48-km SREF (10 Eta members, 5 RSM members) with a 15-member Eta/RSM system at 32 km resolution with physics diversity:
    1. Eta, Betts-Miller-Janjic convection, ops Ferrier microphysics, control
    2. Eta, Kain-Fritsch convection, ops Ferrier microphysics, control
    3. Eta, Betts-Miller-Janjic convection, ops Ferrier microphysics, negative perturbation
    4. Eta, Betts-Miller-Janjic convection, ops Ferrier microphysics, positive perturbation
    5. Eta, Kain-Fritsch convection, ops Ferrier microphysics, negative perturbation
    6. Eta, Kain-Fritsch convection, ops Ferrier microphysics, positive perturbation
    7. Eta, Betts-Miller-Janjic convection w/saturated vapor pressure profiles, experimental Ferrier microphysics, negative perturbation
    8. Eta, Betts-Miller-Janjic convection w/saturated vapor pressure profiles, experimental Ferrier microphysics, positive perturbation
    9. Eta, Kain-Fritsch convection w/full cloud detrainment, experimental Ferrier microphysics, negative perturbation
    10. Eta, Kain-Fritsch convection w/full cloud detrainment, experimental Ferrier microphysics, positive perturbation
    11. RSM, simplified Arakawa-Schubert convection, Zhou GFS microphysics, control
    12. RSM, simplified Arakawa-Schubert convection, Zhou GFS microphysics, negative perturbation
    13. RSM, simplified Arakawa-Schubert convection, Zhou GFS microphysics, positive perturbation
    14. RSM, relaxed Arakawa-Schubert convection, Zhou GFS microphysics, negative perturbation
    15. RSM, relaxed Arakawa-Schubert convection, Zhou GFS microphysics, positive perturbation
    • 1 June 2004
  • Initial implementation of the Downscaled GFS with Eta Extension (DGEX) over the CONUS (06Z/18Z cycles) and Alaska (00Z/12Z cycles)
    • 16 March 2004
  • Use of daily gauge data for precipitation assimilation bias adjustment
  • Assimilation of GOES cloud top radiances
  • Eta Land-surface model precipitation type now based on model microphysics
  • Post-processing changes
    • 9 December 2003
  • Mesoscale Modeling Branch 2003 Production Review
    • 10 September 2003
  • To improve the quality of the Eta initial conditions: 1) surface temperatures over land are not used in the Eta 3DVAR analysis, and 2) all surface data that is not within 6 minutes of the analysis time is excluded.
    • 2 September 2003
  • SREF increased from 10 to 15 members with the addition of 5 Eta forecasts with Kain-Fritsch convective parameterization
    • 8 July 2003 (TPB)
    8 July 2003 (Powerpoint briefing)
  • Extension of the "off-time" (06/18Z) runs to 84 hours
  • Addition of hourly output on selected grids to 36 hours
  • Modifications to the cloud physics and radiation
  • Assimilation of GOES cloud top pressure, Stage IV precipitation data, and super-observations of NEXRAD radial wind data.
    • 27 May 2003
  • A 3-d variational (3DVAR) analysis was implemented replacing the previous optimal interpolation (OI) analysis in the 20 km RUC
    • 15 April 2002
  • Resolution of the RUC changed from 40km to 20km
  • Improved cloud microphysics, convection, land-surface physics
    • 22 February 2002
  • Eta land-surface physics changed to increase the thermal conductivity through snow; change lessened Eta forecast 2-m temperature bias over snow cover
  • Upgrade to the NCEP HiResWindow (HIRESW) runs with the Non-hydrostatic Meso Model (NMM)
    • 27 November 2001 (TPB)
    27 November 2001 (Powerpoint briefing)
  • Increased horizontal and vertical resolution from 22 km/50 levels to 12 km/60 levels
  • New cloud microphysics scheme
  • Improvements to the 3DVAR initialization
    • 24 July 2001 (TPB)
    24 July 2001 (Powerpoint briefing)
  • Eta 3DVAR analysis modified for improved mass-wind balance constraint
  • Assimilation of the 4-km NCEP National Precipitation Analysis (stage II) in the EDAS
  • Extensive modifications to the Eta model land-surface physics (NOAH LSM version 2.3
    • 5 June 2001
  • Initial implementation of NCEP Short-range Ensemble Forecasting System
    • 22 March 2001
  • Extension of 00z/12z Eta runs to 84-h
  • Introduction of nested Eta HiResWindow (HIRESW) runs
    • 26 September 2000 (TPB)
    26 September 2000 (Powerpoint briefing)
  • Eta model resolution increased to 22-km and 50 vertical levels
  • Improvements to Eta 3DVAR analysis
  • Vertical advection of cloud ice/water has been added, and slight modifications to the convective scheme
    • 29 March 2000
  • The 00Z and 12Z runs have been extended to 60 hours
  • The convective scheme has been modified to reduce the dry bias in the western U.S. and the moist bias along the Gulf and southeast U.S. coast
  • VAD winds are now being used a new quality control code
  • Balloon drift is now accounted for in the processing of radiosonde data
    • 15 March 2000
  • Nested Grid Model initialization changed to use the 00-h Eta analysis over North America and a 6-h GDAS forecast over the rest of the Northern Hemisphere in place of the Regional Data Assimilation System
    • 13 May 1999
  • Eta 3DVAR modified to improve mass/wind balance
    • 9 February 1998
  • Increase resolution from 48km/38levs to 32km/45levs
  • Replaced Eta OI analysis with Eta 3-d variational (3DVAR) analysis

    • Back to Table of Contents

    5. MISCELLANEOUS LINKS

    Contents of NDAS/NAM archive on HPSS

    Link to log of all operational NAM (formerly Eta) model changes since 1995

    Link to reference page and domain size graphics for NCEP output grids

    Link to Mesoscale Modeling Branch parallel log

    Link to NCEP Environmental Modeling Center Home Page

    Link to Mesoscale Modeling Branch Home Page

    Disclaimer

    Eric Rogers
    NCEP/EMC Mesoscale Modeling Branch
    Page Last Modified: 12 August 2008