So Danny weakened even more last night and is barely a tropical storm at this moment. Danny will have a slim window to strengthen as it approaches us from the south but the National Hurricane Center keeps Danny a tropical storm for the remainder of its tropical life.
The core of Danny will pass by tomorrow evening but out ahead of the storm is where most of the action will be. This is going to turn into a huge rainmaker for Southern New England...upper level dynamics, a cool dry airmass near the surface with Danny's warm tropical air being thrown northward sliding over it leads to rain amounts that will likely be between 2-5". As I talked about yesterday in my blogs, the flash flood threshold is around 3.5", so, I do expect some flash flooding...street flooding and poor drainage flooding is likely but also the streams and rivers will be rising rapidly during this event and river gauges will be monitored closely tomorrow!
As far as wind goes...interestingly, the strongest winds in Boston will likely occur well out ahead of the storm...again, due to the pressure gradient from tthe departing high and the approaching storm. Winds will be sustained near 20 mph with gusts to around 30 mph. The damaging wind threat remains confined to SE Mass, at this time. The track will likely take it near or over Nantucket, there is still a possibility that it goes a little west of there too. Therefore some winds from the core could impact the area. Not only that, but those areas will be very close to the tropical air, in fact it may actually get to the surface so while some interior locals in New England won't see 70 degrees tomorrow, the Cape and Islands may pop well into the 70s! That would promote stronger winds working down to the surface so gusts over 40 mph are possible if not likely at this point which could lead to scattered power outages. Again, boat owners should secure moorings and boats at this time!
The storm, while currently creeping along to the north, will pick up forward speed later today and race through to the Gulf of Maine by tomorrow evening...so conditions will greatly improve by tomorrow evening.
More as it comes in...
