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EMC > HWRF > IMPLEMENTATION INFO
Hurricane Weather Research and Forecast System

IMPLEMENTATION INFORMATION

Highlights for HWRF's FY2015 implementation:

  1. HWRF Infrastructure/Resolution Upgrades : The NMM core of the operational HWRF model will be upgraded to latest community version referred to as V3.6.1. With the availability of additional computational resources on WCOSS Phase 2, atmospheric component of the HWRF model will be upgraded from 27/9/3 km resolution to a higher resolution operating at 18/6/2 km resolution. This will allow the model to better resolve the fine scales of hurricane inner core structure and provide improved intensity, size and structure forecasts.
  2. HWRF Physics Upgrades : HWRF physics will undergo major upgrades which include RRTM-G with parameterized subgrid-scale clouds for radiation, advanced Ferrier-Aligo Microphysics, improved PBL with wind-speed dependent vertical mixing coefficient, modified GFDL surface physics with improved specification of drag coefficient for momentum, and an advanced land surface model (NOAH LSM). Radiation upgrades will improve the cloud-radiation interactions with better representation of cloud top cooling and cloud base warming. The proposed microphysics upgrades will enhance representation of the storm structure and provide more realistic distribution of hydrometeors, especially ice concentration and fall speeds. The PBL and surface physics upgrades are aimed at improved representation of hurricane surface and boundary layer structures at high wind speeds. For the first time, a 4-level NOAH land surface model will be introduced into HWRF as a replacement of the GFDL slab model. NOAH LSM upgrades will address the cold land surface temperature bias noted in the current HWRF model forecasts, and will also provide the required surface runoff and base flow variables for landfall related downstream applications of river routing model and hydrology models.
  3. HWRF Initialization Upgrades : Vortex initialization is modified with further improvements to the storm size correction and resizing the filter domain, to be consistent with the increased resolution of both HWRF model and the parent model (GFS) that provides initial and boundary conditions.
  4. HWRF Data Assimilation System (HDAS) Upgrades : Upgrade to the latest EMC GSI v5.0.0, enlarge d2 (6km) and d3 (2km) analysis domains to address discontinuity in the initial condition  between forecast domains, and for the first time, assimilate the MSLP data from tcvitals along with dropsonde data from all available aircraft recon missions including NOAA P3, GIV, AF C-130 and Global Hawkand. For non-TDR cases, use the 80-member global ensemble based one-way hybrid EnKF-3DVAR 6h forecast fields to calculate the covariance; run GSI on d2 analysis domain and add analysis increment to d3; no satellite DA on d3 analysis domain due to pronounced negative impact. And for TDR cases, run 40-member HWRF ensembles for 6h to provide more accurate, flow-dependent, vortex-dependent data assimilation covariance; run GSI on both d2 and d3 analysis domains. The GSI system will be further tuned to improve the initial analysis for all HWRF domains.
  5. HWRF Post-Processing and Product Upgrades : HWRF post processing upgrades will include additional simulated synthetic imagery from different satellite sensors.
  6. HWRF Script Enhancements and Procedural Upgrades : Operational HWRF scripts will be converted to full python based scripts, following successful implementation of hybrid ksh-Python system implemented in 2014. Operational HWRF will remain in the vertical structure and will be known as hwrf.v9.0.0 on WCOSS.
  7. Expanding HWRF Model Guidance for all Global Tropical Ocean Basins : With support from NOAA HFIP and using dedicated HFIP computational resources, starting in 2012, HWRF team at EMC has been providing JTWC with experimental real-time forecasts for the WPAC basin. By January 2014, HWRF forecasts are extended to all global tropical oceanic basins (including NIO, SIO and SP). HWRF team at EMC is responsible for determining the priority and setting up the real-time model runs based on tcvitals provided by JTWC. Although graphical HWRF products are made available to JTWC through EMC HWRF web server, there is no mechanism for disseminating forecast products to the WFOs and to the public through official NCEP channels. Following recent requests from NWS Pacific Region and JTWC to make the experimental HWRF model runs operational for WPAC, NIO, SIO and SP basins; NCEP operational HWRF will be designed to provide real-time 126-hr HWRF forecasts four times a day, for a maximum of 7 storms covering all global tropical cyclones during their entire life cycle, and will be run throughout the year. (Previous capability is limited to a maximum of 5 storms in the ATL/EPAC basins).

Highlights for HWRF's FY2014 implementation:

  1. HWRF Infrastructure/Resolution Upgrades : The NMM core of the operational HWRF model will be upgraded to latest community version ref erred to as V3.6a. Due to computational constraints, FY13 HWRF was run with a coarse vertical resolution of 42 levels with model top extending only up to 50 hPa. Proposed FY14 HWRF will have vertical resolution increased to 61 levels with model top extending up to 2 hPa. This will al low the model to have the much desired higher resolution in PBL, and resolve the upper atmosphere more accurately. Extending the model top to 2 hPa will allow the HWRF Data Assimilation System to ingest more satellite radiance data which usually peaks above 50 hPa. The nest domain si zes will be increased by 20% for the 9km domain and by 10% for the 3km domain to allow the high-resolution nests capture larger storm regions w ithin the moving domains.
  2. HWRF Physics Upgrades : HWRF physics will undergo major upgrades which include RRTM-G for radiation, modified Ferrier Microphysics w ith advection of individual hydrometeors and an advanced land surface model (NOAH LSM). Radiation upgrades will improve the cloud-radiation in teractions with better representation of cloud top cooling and cloud base warming. The proposed microphysics upgrades will enhance representati on of the storm structure and provide more realistic distribution of hydrometeors, especially ice concentration and fall speeds. For the first time, a 4-level NOAH land surface model will be introduced into HWRF as a replacement of the GFDL slab model. NOAH LSM upgrades will address the cold land surface temperature bias noted in the current HWRF model forecasts, and will also provide the required surface runoff and base fl ow variables for landfall related downstream applications of river routing model and hydrology models.
  3. HWRF Initialization Upgrades : Vortex initialization is modified with further improvements to the storm size correction and resizing the filter domain, and will better align the filtered vortex and the environment. For the first time, we will be continuously cycling the vort ex from unnamed depressions (invests) when they transition into numbered/named storms, eliminating the cold starts for tropical storms.
  4. HWRF Data Assimilation System (HDAS) Upgrades : The 80-member global ensembles based one-way hybrid EnKF-3DVAR data assimilation sys tem for HWRF will further be upgraded to include more satellite data sets and aircraft recon data sets along with the NOAA-P3 Tail Doppler Rada r data. The GSI system will be further tuned to improve the initial analysis for all HWRF domains.
  5. HWRF Ocean Upgrades : Ocean model component of HWRF will be upgraded to multi-processor MPI-POM-TC with single trans-Atlantic domain and for the first time, a 3D ocean for Eastern Pacific basin instead of the current 1-D POM. The ocean model resolution will increase from 1/ 6o to 1/12o and will have a modified feature based initialization suitable for the MPI POM-TC model.
  6. HWRF Coupler Upgrade : The single processor NCEP coupler in HWRF model will be upgraded to run on multiple processors to enable fast er communications between the atmosphere and ocean components. This is required due to increased resolution.
  7. HWRF Post-Processing and Product Upgrades : HWRF post processing upgrades will include additional simulated synthetic imagery from d ifferent satellite sensors, and will have new products requested by SPC (tornadic potential fields) and for downstream applications including H urricane Wave Model. For the first time, FY14 operational HWRF will now have complete GRIB2 support, eliminating all GRIB1 products from opera tional suite.
  8. HWRF Script Enhancements and Procedural Upgrades : Operational HWRF scripts will undergo major enhancements with better exception ha ndling features and efficiency. The new python based scripts will eliminate lot of duplication and will greatly reduce the length of HWRF scri pts in operations. They also provide for the first time the opportunity to unify various versions of the scripts used by the community and dev elopers. They also have the flexibility to add features that can be utilized for graphics and automation. Operational HWRF will remain in the v ertical structure and will be known as hwrf.v8.0.0 on WCOSS.