I think dews that are too low is another bias of the long range NAM, maybe the NAM in general. Sometimes it gets it right but I think it often is too low; sometimes way too low. Still, add a few degrees to this map and many would still be in a good place; I mean single digits from CAE to AHN!
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Maybe a met could chime in, but this really looks like the NAM is in the process of trying to ramp this thing up big time; if it went a few more frames. The convection near the gulf and the orientation of the transition line looks like a process of amplification; much like a bow echo radar in summer thunderstorms. If that is the case, we would not want that East of there.
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