Week 2 (bottom) still has a huge area of much above normal temperatures, but as the forecast period increases, so does the uncertainty, thus the lessened intensity of the temperature forecasts. However, Alaska still remains much below normal.
Alaskan Vortex could be replaced by a ridge, thus lower temperatures in the US. But this is not reflected in the US, meaning that some other indices may be influencing the pattern to disprove the possible below normal temps and keep them above normal.
The same situation exists in week 4.