Region Lower 48
The readings under the map are for the whole map, not only the part shown.
ECMWF · Run 18Z 30 Sep · +0 h · Valid Wed 18Z 30 Sep
One ECMWF run — issued 18Z 30 Sep — played forward 6 hours at a time, from its analysis to 144 hours out.
Methodology
Nights and days pass as you step this run: that motion is the weather the run forecasts, not the forecast changing. Forecast Evolution is the other film — it holds one moment still and steps the runs, so the only thing that moves there is the model's mind. The colour scale is fitted to the whole run at once, so the same moment reads with more bands here than on the static ECMWF map; the field is identical. Six-hourly to 144 hours. ECMWF's 00Z and 12Z runs forecast out to 360 hours, its 06Z and 18Z runs to 144. The frames past the one shown load on demand.
This map is drawn from model output we store ourselves, not from anyone's picture of it, and is based on data and products of the European Centre for Medium-Range Weather Forecasts (ECMWF). The per-city read of the same day — which cities the models are fighting about, and what the discussion makes of it — is on the national page.
Sources and licences
- ECMWF: IFS, from ECMWF's open data. This service is based on data and products of the European Centre for Medium-Range Weather Forecasts (ECMWF). Source: www.ecmwf.int. This ECMWF data is published under a Creative Commons Attribution 4.0 International (CC BY 4.0). ECMWF does not accept any liability whatsoever for any error or omission in the data, their availability, or for any loss or damage arising from their use.
What we change: each field is cropped to the frame these maps share when we download it, and each map then smooths, contours, differences or ranks those numbers as its Methodology says. These are our maps of the providers' numbers, not their products, and none of them has reviewed or endorsed this site.
Coastlines, borders, lakes and place names: Natural Earth, public domain.