Codes Employed

The software packages used in the HWRF pre-implementations tests (and baselines) were developed at NCEP EMC and DTC. DTC modified Thompson and RRTMG schemes to test promising innovations (dubbed as HDT6).

The code repositories are:
• HWRF (scripts and namelists): https://svn-dtc-hwrf.cgd.ucar.edu/branches/dtc_physics_2015
• WRF: https://svn-wrf-model.cgd.ucar.edu/branches/dtc_physics_2015 r: 9034
• WPS: https://svn-wrf-wps.cgd.ucar.edu/tags/HWRF-20151113-h216-prep-control r: 925
• UPP: https://svn-dtc-unifiedpostproc.cgd.ucar.edu/tags/HWRF-20151113-h216-prep-control r: 728
• GSI: https://svnemc.ncep.noaa.gov/projects/gsi/tags/HWRF-20151113-h216-prep-control r: 64789
• HWRF-utilities: https://svn-dtc-hwrf-utilities.cgd.ucar.edu r: 1238
• MPIPOM-TC: https://svn-dtc-pomtc.cgd.ucar.edu/tags/HWRF-20151113-h216-prep-control r: 334
• NCEP Coupler: https://svn-dtc-ncep-coupler.cgd.ucar.edu/tags/HWRF-20151113-h216-prep-control r: 212
• GFDL Vortex Tracker: https://svn-dtc-gfdl-vortextracker.cgd.ucar.edu/tags/HWRF-20151113-h216-prep-control r: 249

HWRF Control: H16A Configuration

EMC conducted the H16A code using https://svn-dtc-hwrf.cgd.ucar.edu/branches/h216-prep-control-quasitag/. This code was used as part of the 2016 pre-implementation tests, and differed in a few ways from the 2015 operational model, such as retention of the non-hydrostatic state when the nest moves, and bug fixes.

• Model Time step 38 4/7 s
• Physics Time step 231.4 s
• Partial cloudiness bugfix included
• Retention of the non-hydrostatic state when the nest moves

HWRF Experimental Model: HDT6 Configuration

Configuration is similar to the H16A. Modifications include:

• Upgrades to Thompson microphysics
• Upgrades to RRTMG radiation
• Time step 30 s
• Physics Time step 60 s

Domain Configuration

The HWRF domain configuration for the H16A experiment consists of a parent with one set of storm-following nests. The parent grid covered an 75 x75 degrees area with approximately 18 km horizontal grid spacing. The d02 domain covers an area of approximately 12 x 12 degrees with 6 km grid spacing centered on the storm, while d03 domain covers 7.1 x 7.1 degree area with 2 km grid spacing.

The location of the parent and nests as well as the pole of the projection varied from run to run and were dictated by the location of the storm at the time of initialization in all experiments.

As with the operational configuration, HWRF was run coupled to the three-dimensional MPIPOM-TC model, which used approximately 9 km grid spacing. The Atlantic or Eastern North Pacific domain of the POM-TC model was chosen depending on which basin the storm was in.

Track and Intensity Verification

Track, Intensity, and Absolute intensity errors were computed relative to the NHC Best Track out to 120 hours using MET-TC software.

Large Scale Verification

Verification of large scale meteorological fields was computed with MET. The forecasts from HWRF's parent domain were first interpolated to a 0.25 deg latitude-longitude grid that is fixed for the entire experiment. Since the HWRF parent domain is in a different location at each forecast lead time, the sample size for verification is larger at the center of the fixed domain than at the edges. Verification was computed by comparing the HWRF forecasts against the HWRF analyses valid at forecast time for daily lead times out to 5 days. The fields include geopotential height, temperature, relative humidity and winds at selected isobaric levels.