2019 04/25 Meteotsunami

Much additional research will be needed before we can forecast the actual occurrence of a meteotsunami, however, there are some general conditions that can alert

forecasters to the possibility of such an event.

Springtime events occur in March, April and May. They occur north of a warm or stationary front and often occur out ahead of strong upper level troughs emerging from

the Rockies. The convection that produces them forms in the Plains states overnight and usually reaches Lake Michigan early in the morning to near midday. Summer

events usually occur with strong squall lines.

The thunderstorms, and an accompanying atmospheric pressure jump of at least 3 to 5 millibars in one minute, need to be moving at between 58 and 75 mph forward speed

across Lake Michigan to set up a resonance between the atmosphere and the lake, which creates the fast moving, long lasting wave. Slower thunderstorm movement or a

weaker pressure jump will not create a meteotsunami on Lake Michigan.

Since such an event cannot be well forecast, it is crucial for swimmers and boaters to pay very close attention to all NWS marine warnings and advisories, even if skies are

clear at the time.

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