When to bring the Boro paddy in.

Method

How the state is computed

1. Pull the hourly rainfall forecast from api.open-meteo.com for nine grid points (four in the upper Meghna catchment, five in the haor basin), model ECMWF IFS 0.25 deg.
2. Aggregate to 24h cumulative rainfall per grid point per day.
3. Sum the next 72 hours of upstream rainfall (catchment mean across the Meghalaya points). This is the surge driver.
4. Map the 72h upstream total to a four-state ladder: green, watch, advisory, warning. Thresholds 60, 120, 200 mm.
5. During the Boro harvest window (April 15 to May 31), if local haor rainfall over the same window exceeds 25 mm, bump the state up one level. Local rain delays harvest labour.
6. Refresh four times daily via the BDPolicyLab collector scheduler.

Source: Open-Meteo ECMWF IFS 0.25 deg, free for non-commercial use, no API key. Code: app/collectors/haor_weather.py, app/analysis/haor_ews.py.

Caveats

Read this as harvest urgency

• This is a v0 heuristic, not a calibrated hydrological model. Upstream-rainfall thresholds are rules of thumb; replace with BWDB-station-calibrated routing in v1.
• Operational warnings should ride on FFWC and Google Flood Hub. This page is a complementary, haor-specific decision-support layer for upazila Krishi offices.
• Forecast skill at 72h is probabilistic, not deterministic. Treat the state as harvest urgency, not a flood guarantee.
• Open-Meteo's ECMWF IFS is the same operational model behind ECMWF's own forecasts, updated four times daily.