Great Lakes waterspout season is here

The first waterspout of the summer was spotted offshore in St. Joseph over the weekend. It didn't cause any damage and stayed over the open water before dissipating. If you didn't get to witness it, you'll likely have additional chances over the next three months. That's because August, September and October are referred to as "waterspout season" in the Great Lakes! Yes, waterspouts have their own season. All of the Great Lakes can see waterspouts, and their development depends highly on the meteorological setup over and around the lake.

Because their formation depends on things like air temperature, wind speed and direction and relative humidity, meteorologists can issue Hazardous Weather Outlooks or Nearshore Marine Forecasts upwards of 12-24 hours ahead of time stating that they believe the conditions will be right for waterspout development. It's important to know that these waterspouts seen on the Great Lakes during the late summer and early fall months are called fair weather waterspouts. There is a huge difference between these fair weather waterspouts and tornadic waterspouts. Fair weather waterspouts like the one seen in St. Joseph over the weekend are small, thin, typically harmless, and form when cool air moves over the relatively warm lake waters when high humidity values are in place. They form on the surface of the water and climb skyward toward the clouds (usually some sort of cumulus).

Tornadic waterspouts, on the other hand, are less common, significantly more dangerous, and are associated with thunderstorms and severe weather. Tornadic waterspouts develop from the cloud and fill in on their way toward the water. They can become very strong and have the ability to move inland and sustain their strength. Fair weather waterspouts usually do not move onto land. If they do, they typically dissipate rather fast without causing any significant damage.

If you are hoping to snap a few photos of these picturesque waterspouts over Lake Michigan in the coming months, there are a few things to look for in the forecast:

  • Relatively warm water temperatures in the low and mid 70s
  • Cool air compared to the lake (temperatures in the 50s, 60s and low 70s)
  • A light to calm west or northwest wind 
  • High relative humidity (check and see if the air temperatures will be near or pretty much identical to the dew points)
  • Head to the lake during the morning or evening hours
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