History-WX

The Dam Breaks

Pressure systems as 3D towers: the blocking high (amber) dams the arctic air while the jet stream (cyan surface, flowing particles at 250 hPa) buckles. Sea-level isobars on the ground. Jan 25 – Feb 22, 2021, ERA5. Keys: S cities · D draw · 1/2/3 color · C clear · L Deutsch.

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Geopotential anomaly vs. zonal mean · 1000–200 hPa

1×

Feb 1 · Blocking Feb 6 · Jet buckles Feb 13 · Uri

Objects

Ridge / blocking high

Trough / low

Jet stream > 45 m/s

Sea-level isobars