<s>
A	O
hail	B-Algorithm
spike	I-Algorithm
or	O
three	B-Algorithm
body	I-Algorithm
scatter	I-Algorithm
spike	I-Algorithm
(	O
TBSS	B-Algorithm
)	O
is	O
an	O
artifact	O
on	O
a	O
weather	B-Application
radar	I-Application
display	O
indicative	O
of	O
large	O
hail	O
.	O
</s>
<s>
Generally	O
known	O
as	O
hail	B-Algorithm
spikes	I-Algorithm
,	O
these	O
are	O
the	O
result	O
of	O
energy	O
from	O
the	O
radar	O
hitting	O
hail	O
,	O
or	O
very	O
heavy	O
rain	O
,	O
and	O
being	O
reflected	O
to	O
the	O
ground	O
,	O
where	O
they	O
reflect	O
back	O
to	O
the	O
hail	O
and	O
then	O
to	O
the	O
radar	O
as	O
in	O
the	O
image	O
on	O
the	O
left	O
.	O
</s>
<s>
The	O
hail	B-Algorithm
spike	I-Algorithm
region	O
has	O
thus	O
comparatively	O
quite	O
weaker	O
echoes	O
than	O
the	O
echoes	O
directly	O
from	O
the	O
hail	O
or	O
heavy	O
rain	O
core	O
.	O
</s>
<s>
Since	O
hail	O
cores	O
are	O
most	O
intense	O
at	O
higher	O
elevations	O
,	O
hail	B-Algorithm
spikes	I-Algorithm
usually	O
appear	O
at	O
the	O
levels	O
aloft	O
that	O
accompany	O
the	O
most	O
intense	O
hail	O
.	O
</s>
<s>
Because	O
of	O
this	O
,	O
hail	B-Algorithm
spikes	I-Algorithm
are	O
usually	O
not	O
seen	O
at	O
lower	O
elevations	O
.	O
</s>
<s>
In	O
rare	O
cases	O
more	O
than	O
one	O
hail	B-Algorithm
spike	I-Algorithm
has	O
been	O
documented	O
with	O
a	O
single	O
storm	O
in	O
one	O
volume	O
scan	O
.	O
</s>
<s>
Because	O
of	O
their	O
observed	O
accuracy	O
in	O
indicating	O
large	O
hail	O
aloft	O
,	O
TBSS	B-Algorithm
's	O
are	O
used	O
operationally	O
by	O
the	O
National	O
Weather	O
Service	O
to	O
identify	O
thunderstorms	O
that	O
could	O
likely	O
produce	O
large	O
,	O
severe	O
hail	O
.	O
</s>
<s>
This	O
would	O
warrant	O
the	O
issuance	O
of	O
a	O
severe	O
thunderstorm	O
warning	O
or	O
mention	O
of	O
large	O
hail	O
in	O
a	O
tornado	B-Language
warning	O
.	O
</s>
