Big Changes in Pattern Likely Part 2

The ECMWF 168 hour 500 mb forecast, valid at the same time as the GFS forecast below is quite different. It predicts a strong cutoff still lingering over the Southwest while the digging S/W is further off the northwest coast. So, the two models indicate a change to an amplified pattern but with the weather outcomes for next Friday being considerably different for much of the country. The ECMWF has been fairly consistent the last two forecast cycles but was much different than the GFS in yesterday morning's forecasts. So, the question is what's causing this large, longer term variance in the two models. See Part 3 above for some possiblities.