<s>
The	O
Rapid	B-Architecture
Update	I-Architecture
Cycle	I-Architecture
(	O
RUC	O
)	O
was	O
an	O
American	O
atmospheric	O
prediction	O
system	O
that	O
consisted	O
primarily	O
of	O
a	O
numerical	B-General_Concept
forecast	I-General_Concept
model	I-General_Concept
and	O
an	O
analysis	O
system	O
to	O
initialize	O
the	O
model	O
.	O
</s>
<s>
Significant	O
weather	O
forecasting	O
problems	O
that	O
occur	O
in	O
the	O
0	O
-	O
to	O
12-hr	O
range	O
include	O
severe	O
weather	O
in	O
all	O
seasons	O
(	O
for	O
example	O
,	O
tornadoes	B-Language
,	O
thunderstorms	O
,	O
snow	O
,	O
and	O
ice	O
storms	O
)	O
and	O
hazards	O
to	O
aviation	O
(	O
for	O
example	O
,	O
clear	O
air	O
turbulence	O
,	O
icing	O
,	O
and	O
downbursts	O
)	O
.	O
</s>
<s>
The	O
RUC	O
was	O
decommissioned	O
on	O
May	O
1	O
,	O
2012	O
;	O
it	O
was	O
replaced	O
by	O
the	O
Rapid	B-Application
Refresh	I-Application
(	O
RR	O
or	O
RAP	O
)	O
model	O
,	O
based	O
on	O
the	O
WRF	B-Application
.	O
</s>
<s>
Like	O
the	O
RUC	O
,	O
the	O
Rapid	B-Application
Refresh	I-Application
model	O
also	O
runs	O
hourly	O
out	O
to	O
18	O
hours	O
on	O
a	O
grid	O
spacing	O
,	O
but	O
also	O
covers	O
a	O
wider	O
area	O
.	O
</s>
<s>
An	O
experimental	O
High	B-Application
Resolution	I-Application
Rapid	I-Application
Refresh	I-Application
(	O
HRRR	B-Application
)	O
ran	O
by	O
the	O
Earth	O
System	O
Research	O
Laboratory	O
(	O
ESRL	O
)	O
offers	O
resolution	O
at	O
15-minute	O
intervals	O
.	O
</s>
