This morning's sounding showed classic conditions for strong microburst winds with an "inverted V" profile created by the temperature (red) and dewpoint (green) traces above the shallow surface-based nocturnal inversion.
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| Source: SPC |
Microbursts are are sudden strong winds caused by downdrafts induced by precipitation and may be "wet" or "dry", with the latter occurring when the precipitation evaporates before reaching the ground.
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| Source: Wikipedia |
One measure of the potential for strong downdrafts and microburst winds is what is known as the downward convective available potential energy or DCAPE. DCAPE is maximum energy available for a negatively buoyant parcel of air cooled by evaporation assuming no mixing with the environment. Values above 1000 Joules/kg are considered high and significant. This morning, the DCAPE at Salt Lake City international airport was 1223 Joules/kg.
Not surprisingly, we've had some strong winds in northern Utah. This morning, I observed a modest microburst drive an impressive "pollen front" into the Avenues (sorry, no pictures, but I did sneeze). Subsequently, several valley locations have reported microburst wind gusts in excess of 60 mph including the Kennecott Tailings Pile (61), Lake Point (63), Vernon Hill/Tooele Valley (65), Syracuse (66), and Pleasant Grove (68).
The biggest gust so far was recorded on Fremont Island in the Great Salt Lake, with a gust of 91 mph. The NWS just tweeted that there is wind damage on nearby Antelope Island.
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