Metro-02
Meteorology and Flight Planning
7.
Convective SIGMETs (WST) at 55 minutes past the
Sg 3, fr 12
hour (H+55) 1.1.1.11.2
Fig 16: Convective
SIGMET (WST)
a.
Issued hourly
(1) As thunderstorms are likely to be accom-
panied by severe or greater turbulence,
severe icing, and low-level wind shear,
these conditions shall not be specified in
the advisory
(2) "NONE" shall be used as the text if
appropriate
(3) Valid for up to 2 hrs or until superseded by
the next hourly issuance
(4) Special WSTs as required
(5) Three bulletins issued for eastern (E),
central (C), and western (W) regions
(a) Boundaries at 87 and 107 degrees
west
b.
WSTs shall be issued when either of the
following occurs and/or is forecast to occur for
more than 30 minutes of the valid period,
regardless of the size of the area affected
(i.e., including isolated)
(1) Severe thunderstorms
(a) May include specific information on
tornadoes and/or hail 3/4-inch or
greater and/or wind gusts of 50 kts or
greater
(2) Embedded thunderstorms
(a) Occurring within and obscured by
haze, stratiform clouds, or precipitation
from stratiform clouds
(7-97) Original
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