Ensembles — 500 mb Height & Temperature Plumes
The four main global ensembles — GEFS, ECMWF IFS-ENS, AIFS-ENS and GEPS (CMC) — over the Northern Hemisphere, as a Day 0–15 lead-slider animation. 500 mb height anomalies are vs the 30-year ERA5 normal (1991–2020); black contours are the ensemble-mean height. Run-to-run change and the 48-hour trend compare the same valid time across cycles. Temperature plumes pool the members into a mega-ensemble for selected US cities.
500 mb Height
Drag the slider to step Day 0 → 15. Red = ridge (above normal), blue = trough.
All-Ensemble Mean — anomaly vs ERA5 1991–2020
The consensus 500 mb height anomaly: the four ensemble means averaged together, with the mean height field contoured. The cleanest single view of the large-scale pattern.
Four-Model Comparison — anomaly vs ERA5 1991–2020
The same anomaly, model by model, to eyeball agreement and spread. All shown as the ensemble mean: GEFS (31), ECMWF IFS-ENS (native mean), AIFS-ENS (50), GEPS (20).
Change vs Previous Run
How the forecast for each valid time shifted from the previous day's cycle — a quick read on model "trends." Red = run trended the height up, blue = down.
48-Hour Trend
The forecast for each valid time minus the run 48 h earlier — a longer-baseline view of how the solution is drifting.
Temperature Plumes
Pooled mega-ensemble 2 m temperature distribution for selected US cities (demo).
2 m Temperature — Mega-Ensemble Plumes
The GEFS + GEPS members pooled (~51) into one distribution per city, Day 0–15. Shaded bands are min–max, 10–90% and 25–75%; the dark line is the median. Spread widens with lead time as forecast uncertainty grows.
