Metro-03
Meteorology Review
a.
Description and composition
(1) Intense and localized downburst of air that
descends from a thunderstorm and, upon
reaching the ground, spreads horizontally
(2) Usually found beneath thunderstorms with
visible rain or virga
(3) Usually 1 to 2 miles in diameter; wind
speeds can exceed 100 kts (10,000 fpm)
and be accompanied by rain or other
obscuring phenomena; usually last less
than 10 minutes
(4) Intense horizontal outflows at low altitudes
result in extreme head wind to tail wind
differentials that have been recorded in
excess of 200 kts
(5) Experience has shown that microbursts are
not isolated but usually occur in groups
b.
Indications
(1) Blowing dust, dust devils, and gust fronts
(downbursts will occasionally generate
distinctive circular dust patterns)
(2) Thunderstorms in vicinity with visible areas
of downdrafts indicated by rain or virga
(3) Sudden and unexplained increase in
airspeed as noted on airspeed indicator
accompanied by increased AOA—
indicative of rolling outflow
(4) Sudden increase in rate of descent accom-
panied by a lower AOA--indicative of entry
into microburst core
(5) Extreme variations in wind velocity and
direction in short time
(7-97) Original
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