- 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, stepped three-hourly from T+12 h to T+72 h — on the model's own 9 km domain, and on the wider GFS fields that force it.
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9 km domain
WRF Synoptic Overview
Mean sea-level pressure, 10 m wind, dew point and 6-hourly precipitation, over 500 hPa geopotential height and vorticity and the 850 hPa wind and relative humidity.
Open the overview ↗ -
GFS 0.25 deg · 10W-65E, 48S-15N
GFS Large-Scale Overview
The same surface and upper-air layout as the WRF overview, rendered from the raw NCEP GFS boundary-forcing data across the wider region the model sits inside.
Open the overview ↗
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 34 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 |
|---|---|---|---|---|
| d02 Outer domain |
9 km | 214 x 200 | 14.7-36.1E, 20.5-36.9S | South Africa, Lesotho and Eswatini Forced directly from GFS at the lateral boundary; cumulus parameterised |
| d03 Convection-permitting nest |
3 km | 246 x 156 | 21.9-29.4E, 23.6-27.9S | North West and Gauteng Cumulus scheme off - convection resolved explicitly |
The two domains are two-way nested. The 9 km domain takes its lateral boundary conditions directly from GFS; both are published.
Configuration
| Dynamical core | WRF-ARW v4.8.0, non-hydrostatic |
|---|---|
| Map projection | Lambert Conformal (true latitudes -23.7 and -34.0) |
| Microphysics | Thompson (mp_physics = 6) |
| Cumulus | Kain-Fritsch on 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 |