Because of an oversight, there are two sign errors in Eq. (2) of Becker et al. (2013). The correct equation is shown below as it should have appeared:

 
formula

We regret any inconvenience these errors may have caused.

REFERENCE

REFERENCE
Becker
,
E. J.
,
H.
van den Dool
, and
M.
Peña
,
2013
:
Short-term climate extremes: Prediction skill and predictability
.
J. Climate
,
26
,
512
531
, doi:10.1175/JCLI-D-12-00177.1.