SMN WRF Argentina 4 km

GribStream Code: smnwrf

Forecasts and available historical runs from 1 January 2022. Parameter coverage changes with date; source gaps remain.

• 4 km grid with 1,247,751 locations across southern South America.
• Forecasts through 72 hours, initialized at 00, 06, 12 and 18 UTC.
• 14 weather variables and 15 parameter/statistic combinations, including 10-minute precipitation.

A regional forecast built by Argentina’s national weather service

SMN WRF is the deterministic regional forecast from Argentina’s Servicio Meteorológico Nacional. Its domain covers Argentina, Chile, Uruguay and Paraguay, parts of Bolivia and Brazil, and adjacent Pacific and Atlantic waters. The 4 km grid provides a regional view of weather across the Andes, Pampas, Patagonia and Río de la Plata.

The science behind the forecast

SMN documents a WRF-ARW 4.0 configuration with 45 atmospheric levels and a model top at 10 hPa. Initial and boundary conditions come from NOAA’s 0.25° GFS. Convection is represented explicitly: the model can develop storm-scale circulations on its grid, while smaller-scale cloud processes still require physical parameterizations. The published setup uses WSM6 cloud microphysics, MYJ boundary-layer physics, RRTM longwave radiation, Dudhia shortwave radiation and the four-layer Noah land-surface model. SMN model configuration.

A 4 km grid can represent terrain and local contrasts more finely than the driving global model. It does not make a forecast exact at an individual field or guarantee the location and timing of a thunderstorm. This is one deterministic forecast; it does not supply ensemble probabilities.

Weather variables and practical uses

• Agriculture: combine 2 m temperature and humidity, rainfall, and temperature and moisture in the upper 0–10 cm of soil to plan fieldwork and assess near-term water demand. Daily temperature extrema support frost and heat screening; crop thresholds and local observations remain necessary.
• Rainfall and catchments: hourly and 10-minute precipitation help examine the timing of forecast rain. Ten-minute values are accumulated amounts for the preceding ten minutes, not observations or a radar nowcast.
• Energy: downward shortwave radiation and temperature provide inputs for solar-generation models. Wind speed and direction are supplied at 10 m, so wind-power applications need a separate hub-height treatment.
• Mountain and transport planning: freezing-level altitude, rain, temperature and surface wind provide a common regional forecast for routes through changing terrain.

Units and time intervals that matter

Temperature is in °C, wind speed in m/s, precipitation in mm and surface pressure in hPa. Radiation variables are energy accumulated since the forecast began, in J/m²; differences between successive values divided by elapsed seconds give interval-mean W/m². SMN supplies calibrated temperature and wind products when available.

Daily Tmin covers 00–12 UTC and Tmax covers 12–24 UTC. Their date label is midnight UTC, rather than the end of the interval. These are not local-calendar-day extrema. See the official variable definitions and the complete selector inventory below.

Forecast history and attribution

The source archive begins on 1 January 2022. Radiation, soil variables and 10-minute precipitation were added in January 2023; 06/18 UTC runs in June; freezing level in September. Historical parameter coverage therefore changes with date. Historical runs from January 2022 are available through GribStream; missing source periods and fields remain gaps. SMN product history.

Weather data: Servicio Meteorológico Nacional, CC BY 2.5 Argentina. Retain attribution and the licence link, and identify changes when redistributing derived material. Compare the regional forecast with GFS for the larger-scale weather pattern, or use the API documentation to request locations and variables.

• Archive begins: 2022-01-01

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