Ensembles work by perturbing the intensity and location of features to account for errors and uncertainty. At D7-8, it’s perfectly normal to have a much broader area of low pressure than what will ultimately occur. Plus, always be a little more skeptical when a model suite’s solutions are playing up its biases:
1. Progressive bias for GFS
2. over amplified bias for Euro
3. wonky 2m temps for GGEM