A shortwave trough will dig from Ontario Saturday night into
the eastern Great Lakes by Sunday morning. The shortwave will
keep digging southeastward through Sunday. There is some
uncertainty in this window and heading into early next week. The
operational GFS/ECMWF and GEFS/EPS retrograde a cutoff low into
the Gulf of Maine/Nova Scotia. This will have implications on
temperatures and sensible weather in this timeframe, but there
is a lot of spread amongst guidance in how far west the system
retrogrades. The GEFS and operational GFS are much further east
than the EPS an operational ECWMF.
Who's do we believe?