Image sequence copyrighted by Fernando Caracena, 1997.
This is the beginning phase of a wet microburst when the precipitation
has not yet reached the ground (virga). However, unlike the dry
microburst where the falling hydrometeors remain virga, in the wet
microburst, a gush of rain reaches the surface with high winds, and
produces a brief, surface pressure spike called a pressure nose.

This downward bulge of heavy virga preceeding a severe microburst
was observed at Dallas Ft. Worth International Airport just before
an aircraft was downed by an encounter with the ensuing microburst
(Caracena et al., 1987a).

(To go to the next phase, click on the image.)
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