Since my previous update on Wednesday, Grace made landfall on the Yucatan Peninsula as expected, weakened to a tropical storm, then regained hurricane intensity over the Bay of Campeche on Friday morning. Henri is centered east of northern Florida but is forecast to make a right turn and head toward New England.
Grace is a Category 1 hurricane again, and will make a second landfall on Mexico later tonight. It is likely to strengthen more over the very warm water and in minimal wind shear, but time is running out for it. *IF* if maintains at least tropical depression status across Mexico and reforms in the East Pacific, it would keep the name Grace; but if it dissipates and then reforms, it would take the next name in the East Pacific list: Marty.
Henri is very close to becoming the season's third hurricane, which would be 19 days ahead of average if it happens today (other years in recent memory with three hurricanes by August 20 are 2012, 2005, 2004, 2003, 1996, 1995...). And while it has been facing moderately strong northerly wind shear, that shear is expected to relax starting today which would allow the anticipated strengthening to commence.
The large-scale steering pattern changes today as well, and Henri will start traveling north rather than west, and that is a really big problem for the mid-Atlantic and New England coasts over the next 2-3 days. Hurricane watches and storm surge watches are already in effect for much of the area from Long Island to Cape Cod. Keep in mind that the "cone of uncertainty" is constructed using the past five years of track errors and is designed to include the track of the storm 2/3 of the time... and it does NOT show where impacts will be experienced.
One of the hazards that will affect several states is storm surge and the resulting coastal flooding. It seems inevitable at this point that areas from Maryland to Maine will see elevated water levels and heavy surf, with the worst expected on Sunday from Long Island to Cape Cod. Henri does not even need to make landfall to generate this, as strong onshore winds will impact the area regardless.
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| Tracks of the 16 hurricanes to make landfall from Long Island NY to Cape Cod MA since 1851. |
In terms of ACE (Accumulated Cyclone Energy), and with one advisory remaining, the season is at 154% of the average of the past 50 years. The 2021 season has been above average since it began on June 1.
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