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hailg

hailg is a meteorological metric used in storm-scale research to quantify the potential growth of hail within convective storms. The term is short for hail growth gauge (or hail growth index) and is used in various forms in the literature. In its broad sense, hailg represents a dimensionless or scaled quantity that correlates with the likelihood of hailstone production and the possible size distribution of hailstones.

In practice, hailg is derived from numerical weather prediction outputs or cloud-resolving simulations. It combines dynamic

Applications include comparing environmental potential across storms, evaluating sensitivity to microphysics schemes, and supporting research in

See also: hail, convective storm, microphysics, cloud-resolving model, updraft.

fields
such
as
updraft
velocity
(w)
with
microphysical
variables
including
the
mass
of
supercooled
liquid
water
and
the
characteristics
of
ice-phase
hydrometeors,
under
the
influence
of
the
ambient
temperature
and
pressure
profile.
The
exact
formulation
varies
by
model,
but
common
interpretations
interpret
hailg
as
proportional
to
the
product
of
updraft
strength
and
available
hail-favorable
liquid
water,
adjusted
for
thermodynamic
conditions.
Values
are
typically
normalized
(for
example,
0
to
1)
in
comparative
studies,
though
some
implementations
report
unnormalized
scores.
nowcasting
and
hazard
assessment.
Hailg
is
not
a
direct
forecast
and
is
sensitive
to
model
parameterizations,
initialization,
and
data
quality.
It
remains
a
research-oriented
metric,
with
ongoing
work
to
standardize
definitions
and
improve
interpretability
across
modeling
platforms.