Region Lower 48
United States
Europe
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 00Z 4 Oct · +6 h · Valid Sun 06Z 4 Oct
Surface pressure (hPa) and 6-hour averaged precip rate (in/h)
Heaviest 6-hour mean 0.573 in/h, near 29.85N 81.9W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.942 in/h, near 28.65N 87.6W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.844 in/h, near 28.95N 94.05W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.939 in/h, near 28.5N 93.0W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.754 in/h, near 20.1N 114.9W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.786 in/h, near 20.1N 115.35W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.539 in/h, near 20.1N 95.4W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.63 in/h, near 21.0N 95.55W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.631 in/h, near 20.1N 117.3W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.929 in/h, near 21.3N 105.3W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.798 in/h, near 20.1N 118.5W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.558 in/h, near 28.95N 85.05W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.436 in/h, near 21.45N 77.4W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.839 in/h, near 20.25N 96.45W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.862 in/h, near 20.55N 96.9W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.493 in/h, near 20.25N 122.55W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.71 in/h, near 21.0N 123.3W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.853 in/h, near 24.6N 106.8W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.409 in/h, near 21.15N 95.25W · unshaded ground is where the model has under 0.01 in/h falling
Heaviest 6-hour mean 0.372 in/h, near 20.55N 89.25W · unshaded ground is where the model has under 0.01 in/h falling
One GEM run — issued 00Z 4 Oct — 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. Every model's full forecast for any of these cities, or anywhere else, is in the beta: request an invite; it's free during the beta.
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.