Reanalysis time machine

Scrub to any day since 1950 and read off the state of every major teleconnection — ENSO, the MJO, PNA, AO, NAO, EPO, WPO, QBO, PDO, SOI. Use the date picker, the ◀ ▶ buttons, the ← → keys (hold Shift for ±30 days), or Play to animate. Toggle the map between that day’s 24-hour precipitation and the 500 hPa upper-air pattern.

About the time machine

The time machine lines up every major teleconnection index on a single day, from 1950 to the present: ENSO (RONI), the Madden-Julian Oscillation phase and amplitude, the PNA, AO and NAO, the EPO and WPO, the QBO at 50 hPa, the PDO and the SOI. Alongside the indices, a map shows that day's 24-hour precipitation or the 500 hPa upper-air pattern from ERA5 reanalysis.

Daily indices (PNA, AO, NAO and the MJO) come from NOAA's Climate Prediction Center and the Wheeler-Hendon RMM record, which begins in 1974. Monthly and seasonal indices are held constant across their month or season. Where an index does not exist yet, such as the QBO before 1979, the timeline reads “no data.” Use it to revisit a big storm, a drought winter or a record snow year and see what the large-scale drivers were doing at the time.

To ask the question the other way around, what a given driver state tends to bring, use the Pattern Heatmaps, Snowfall Explorer or Analog Builder.