Region Lower 48
The readings under the map are for the whole map, not only the part shown.
Surface pressure (hPa) and 6-hour averaged precip rate (in/h)
GEM · Run 12Z 30 Sep · +6 h · Valid Wed 18Z 30 Sep
Surface pressure (hPa) and 6-hour averaged precip rate (in/h)
Heaviest 6-hour mean 0.243 in/h, near 38.1N 105.0W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.453 in/h, near 22.05N 79.95W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.789 in/h, near 22.65N 105.6W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.662 in/h, near 31.65N 99.0W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.645 in/h, near 29.1N 99.15W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.425 in/h, near 25.8N 100.2W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 1.049 in/h, near 25.2N 99.9W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.711 in/h, near 27.45N 99.0W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.735 in/h, near 21.9N 99.0W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.772 in/h, near 21.3N 89.7W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.736 in/h, near 31.2N 82.05W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 1.091 in/h, near 20.1N 112.5W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.916 in/h, near 20.25N 112.8W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.763 in/h, near 20.85N 90.6W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.634 in/h, near 21.15N 114.3W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.697 in/h, near 21.0N 105.45W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.826 in/h, near 28.05N 92.85W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.543 in/h, near 20.4N 116.55W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.443 in/h, near 32.25N 81.0W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.452 in/h, near 20.1N 119.1W · unshaded ground is where the model has under 0.01 in/h falling
One GEM run — issued 12Z 30 Sep — played forward 6 hours at a time, from 6 hours out to 120 hours out.
Methodology
Step forward and the pressure pattern moves, and the precipitation under it moves with it: that motion is the weather this run forecasts, not the forecast changing — Forecast Evolution is the film for that. Same chart grammar as the surface analysis: the same reduction, the same 4 hPa interval, the same frame; only the forecast hour varies. Six-hourly to 120 hours. GEM forecasts out to 240 hours; this film stops at 120. The frames past the one shown load on demand. GEM publishes no precipitation rate, so the shading here is the 6-hour mean rate — the run's total precipitation at each frame less the total 6 hours before, over 6 — on the same scale as the instant the other models shade with. A mean over 6 hours is smoother and weaker than an instant, so its heavy bands light less often on the same weather; and because no 6-hour bucket ends at the analysis, this film opens at +6 h rather than showing one frame with no rain under it.
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 Environment and Climate Change Canada. 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
- Environment and Climate Change Canada: GEM, from the MSC Datamart. Data Source: Environment and Climate Change Canada, under its Data Services End-use Licence.
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.