Pretty short and sweet this morning as we've got some good news on Danny. Some slightly surprising (not shockingly unexpected, but not really predicted to occur) developments over the past 24 hours are going to make Danny pretty much a non-issue. In fact, I wouldn't even bother posting an update today except that after yesterday forecast with much more significant impact expected, it seems important to get out here and advertise the changes. But, with little impact expected, I'll keep this diary short - for a change.
The unexpected changes over the last day are two-fold and both work together to minimize Danny's impact. One change is Danny's failure to intensify. Wind shear, which rips apart tropical systems, was expected to diminish yesterday afternoon and overnight. It hasn't. This is what Danny looks like this morning:
...the deep reds indicate strong convection. Impressive, right? The only problem is, the center of Danny is west of all the convection. For tropical development the convection needs to be over the storm center. It isn't. The convection is being blown (or sheared) off to the east of the storm center. This is precluding any development. In fact, Danny has weakened to a minimal tropical storm.
And as for intensity expectations, Danny has little opportunity to develop. The best chance the storm has to intensify is as a hybrid (part tropical, part non-tropical), when it gets non-tropical energy injected into it late tonight as it passes Cape Hatteras. But, being non-tropical, it will not likely be something that allows Danny to form an inner core (which would allow winds to spin up). So, this will likely only result in a small increase in winds out on the east side of the storm.
The other minor surprise is the eastward shift in the model tracks. I'm still not entirely sold on them being correct (Danny right now appears to be on the western edge of the guidance). But they are tightly clustered and it's a very short term forecast, so there's just so much I'd dare vary from those models. Here's what they're showing:
...they are tightly clustered offshore. I would lean west a bit, as I said. But all this does is allow the center of Danny to perhaps nip Cape Cod. All of the strongest winds and heaviest rains will be on the east side of Danny, and Danny will be weak. So, this means that no one in New England, not even Cape Cod, is likely to see tropical storm force winds. Maybe, maybe the Outer Cape - Provincetown to Chatham - can clock a couple of gusts to 40mph, but that's it... nothing damaging, nothing impressive. As for rainfall, as Danny goes subtropical, some rain should wrap around the center, so all of southeastern Mass is likely to see some heavy rain, but this will likely only yield localized, brief flooding of low lying areas (and sandy-soiled coastal areas resist this type of flooding due to the ver porous soil).
The National Hurricane Center also expects no tropical storm force winds anywhere. Here's their tropical storm force winds swath prediction:
...the yellow shade is the 30% probability demarcation. No one exceeds a 30% chance. A slightly more western track, as I expect, could push Cape Cod and the Islands to 40%, but it's still less than a 50-50 shot.
And as for the Canadian Maritimes, Danny will be extratropical by then. So, he'll simply provide that region with a breezy rain storm.
Bottom line, New Englanders (esp. those in SE MA) still need to watch Danny, but all indications are that the only effect will be some heavy rains in southeastern Massachusetts Saturday afternoon/evening. That's it.