The Hunter’s Moon officially becomes full at 1:23 a.m. Eastern on Saturday but will appear full as long as it is visible throughout the weekend.
In most of the eastern United States, moonrise Friday night is just after 6 p.m. (6:12 p.m. in Washington, D.C.) and moonset is just before 8 a.m. (7:50 a.m.) Saturday morning, but local times will vary some.
Sky conditions should generally promote good viewing in the Northeast and Southeast as well as the Southern Plains and Southern Rockies, but the moon may be obscured by clouds in the Pacific Northwest and much of the north central United States. In the Mid-Atlantic, including Washington, some clouds may be around, but there should be enough breaks to catch a glimpse.
EarthSky.org writes this moon is the year’s second biggest. This is because the moon is near perigee, when it is closest to Earth in its orbit. When a full moon occurs right at perigee, it is known as a supermoon. This month’s moon doesn’t quite meet that criteria, but December’s “Cold Moon” will.
The moon’s gravitational tug on the ocean will raise water levels at the coast. South Florida is bracing for its latest encounter with “king tides,” which lead to inundation in certain flood-prone, low-lying areas. Last month, because of a combination of the king tide and onshore winds and rain, parts of coastal Miami experienced heavy flooding.
“The total water level will almost certainly be less than what was observed during October’s full moon, because it coincided with strong onshore winds,” notes Brian McNoldy, Capital Weather Gang’s tropical weather expert. Nevertheless, some minor flooding is possible.
Other parts of the East Coast will be affected by elevated tides as well. “With a full moon on Saturday and a prolonged onshore flow this weekend, several rounds of minor flooding may occur, especially during the morning high tides and particularly Saturday morning,” the National Weather Service office serving the southern New Jersey shore said.
In the Washington area, the National Weather Service said tides would be about 0.75 feet above normal, just below coastal flood advisory levels for the tidal Potomac and Chesapeake Bay.
Because of climate-change-induced sea-level rise, coastal flooding during these astronomically high tides is predicted to increase substantially in future decades. Already, large increases in “nuisance flooding” have been observed along the East Coast.