The weather models overnight have NOT flipped back to the colder / possible Frost solution that they were depicting on Monday and Tuesday. The problem remains that the weather models are not handling the interaction between the main jet stream and his large upper low centered over the central Plains next week.
As I stated earlier this week it is the interaction between the main jet stream and this system which produces the deep trough and allows the cold air to flow southward. The models earlier in the week were taking this upper low phasing it were merging it with the main jet stream into a large low pressure area over the eastern Great Lakes and moved up into eastern Canada. Behind that low the cold air according to the models earlier in the week would flow southward and we would get the early season .
However the models over the last 24 hours have moved away from that idea. The European model of yesterday was holding back the large Upper Low and was NOT making a major storm over the eastern Great Lakes. It had some cold air getting into the Dakotas Minnesota and Wisconsin on the morning of the 25th in the 26th but nothing major.
The model data overnight on the GFS and the European continue to not develop the Big Low for the eastern Great Lakes. The Models keep the large Upper Low over the Plains and the main Jet stream stream does NOT phase or merge with it. So there is No big Low over the eastern Great Lakes.
As a result there is a lot more Uncertainty in the forecast regarding the Frost threat.
It should be note that the Canadian model however continues to show a serious frost threat because it does develop a major low on the cold front which moves up through the eastern Great Lakes... and sends the colder southward a couple days later.
I am not yet convinced that the entire Frost threat is completely off the table but honestly the odds and the weather models are clearly moving against that direction. I am concerned that the weather models are handling how these two features-- the main jet stream and a large upper low over the central Plains - are going to interact. As we get closer to the event-- Sunday and Monday --we could see the models show a significant change. Weather models are notoriously famous in the weather business for mishandling large slow-moving Upper Low-pressure areas in the jet stream. But at this time I think it is fair to say that while the weather models could suddenly flip over the weekend or Monday the odds of that happening are Not good . Possible but not good.