- 4.8.0WRF-ARW version
- 3 kmFinest nest
- 72 hForecast length
- 18ZDaily GFS cycle
An operational WRF-ARW configuration run in house each day and co-located with the Lekwena radar and the NWU station network for verification. Model documentation is maintained by the WRF user community.
Synoptic overview
Surface analysis with the two upper-air levels that drive it, on the Southern Africa domain. Stepped three-hourly from T+12 h to T+72 h.
Official warnings
Issued by the South African Weather Service.
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Official · SAWS
SAWS Severe Weather Warnings
Official impact-based warnings on a basemap, with validity period, severity, affected municipalities and expected impacts, filtered to the current forecast window.
Open the warnings ↗ -
Official · SAWS
Warnings map
The same warnings as an interactive map, on the 9 km domain.
Open the map ↗
Impact dashboards
Model output scored per location against storm, heat, frost, fire and agricultural decision thresholds.
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9 km domain
National Impact Dashboard
Thirty-two cities scored for convection, rainfall, wind, heat stress (Heat Index and WBGT), livestock heat load (THI), frost, fire danger, spray windows and irrigation scheduling.
Open dashboard ↗ -
3 km domain
NWU Campus Dashboard
Convection-permitting guidance for the Potchefstroom, Mahikeng and Vanderbijlpark (Vaal) campuses, with livestock heat load broken out by species.
Open dashboard ↗
Severe convective environment
How supportive the atmosphere would be for a storm that forms at each point, on a 0-100 scale, from instability aloft, wind shear, low-level moisture and freezing level, reduced where capping would suppress convection.
Gridded fields
Each field is published at both resolutions. The 3 km nest resolves convection explicitly and is the better guide to thunderstorm timing, placement and mode over the Highveld.
Vertical profiles for 48 locations are on the soundings page.
Interactive maps
Three of the fields above on an OpenStreetMap basemap, with a frame slider and an opacity control. 9 km only.
Model domains
| Domain | Resolution | Grid | Extent | Coverage |
|---|---|---|---|---|
| d01 Outer domain |
18 km | 279 x 219 | 0.4-49.6E, 5.4-40.3S | Southern Africa Lateral boundary forcing only - not published as gridded fields |
| d02 Regional domain |
9 km | 214 x 200 | 15.9-34.8E, 21.2-36.5S | South Africa, Lesotho and Eswatini Cumulus parameterised |
| d03 Convection-permitting nest |
3 km | 246 x 156 | 22.0-29.2E, 24.1-28.2S | North West and Gauteng Cumulus scheme off - convection resolved explicitly |
The domains are two-way nested. The outer domain supplies lateral boundary conditions only; its gridded fields are not published.
Configuration
| Dynamical core | WRF-ARW v4.8.0, non-hydrostatic |
|---|---|
| Microphysics | Thompson (mp_physics = 6) |
| Cumulus | Kain-Fritsch on d01/d02, off on d03 |
| Longwave radiation | RRTMG (ra_lw_physics = 3) |
| Shortwave radiation | RRTMG (ra_sw_physics = 3) |
| Planetary boundary layer | YSU (bl_pbl_physics = 1) |
| Surface layer | Revised MM5 Monin-Obukhov (sf_sfclay_physics = 1) |
| Land surface | Unified Noah LSM (sf_surface_physics = 2), 4 soil layers |
| Initial and boundary conditions | NCEP GFS 0.25 deg, 3-hourly |
| Forecast length | 72 h |
| Cycle | Daily, from the 18Z GFS cycle |