A quick update on the storm that will pass southeast of Nantucket this weekend - this post update's yesterday's full post.
TIMING: Still some significant differences on the track, intensity and therefore timing of the storm, but I like a scenario that develops precipitation on the western periphery of the storm path, bringing showers and rain into Eastern New England Saturday morning, ramping up through midday and continuing through the afternoon and night. Cold air will become increasingly involved, meaning precipitation will change from rain to snow for some (more below).
Map of precipitation expected between 11 AM and 2 PM Saturday - the idea is that rain ramps up late morning to midday:
RAIN VS. SNOW: With ample cold air available in Southern Canada, and the storm center strengthening southeast of New England, inducing a strengthening north-northeast wind, this will allow for colder air to become entrained into the system. The result will be a change to snow for some. In Central and Southern New England, this likely occurs Saturday night, as the precipitation is ready to shut down - in Maine, and particularly Eastern Maine, a storm track into Nova Scotia is likely to keep precipitation falling long after a change to snow. The end result should be a snow pattern like the one I've been airing on NECN Thursday morning, and seen below - the broad area of "an inch or two possible," I am essentially couching for the potential that cold air streams in quickly enough, or moisture extends far enough northwest, to allow this scenario to play out...still a necessary admission of uncertainty at the current timeframe and with lingering varied solutions:
WIND: As the storm center strengthens over the waters east of New England, air will rush into its center, creating a broad corridor of strong, gusty wind. As referenced yesterday, a large area of 40 knot winds just 2200 feet off the ground - that area now looks as though it may be closer to 45 knots along the Eastern New England coast, meaning some gusts to 50 mph will be possible. This would be enough for some widely scattered wind damage along the Eastern New England coastal plain, within about 30-40 miles of the coast.
COLD AIR: The combination of wind gusts to 50 mph, sustained wind of 20-30 mph, and high temperatures only in the 40s (30s north) on Sunday will produce wintry wind chill values of only 30° to 35° for a large chunk of New England, even on Sunday afternoon! The map below shows apparent ("feels like") temperature forecasts for Sunday at 1 PM:
WAVES: Eventually, by late Sunday, waves build to 15 feet offshore of New England's coastline. By that point, however, a northwest wind is blowing and directing most of the energy from these waves offshore. Therefore, the time of greatest wave impact will likely be to Outer Cape Cod on Sunday morning, with a morning high tide about 6:50 AM - near the time when this wave height and direction forecast, below, is valid, raising the potential for some minor Outer Cape beach erosion Sunday morning.
Of course, I'll update the forecast again, and with latest details and fine tuning, Friday morning from 5 to 10 AM on NECN.