9:30 PM - The National Weather Service has extended the blizzard warning until 10 PM, and issued a new coastal flood advisory through midnight. Tides could be as much as 2.5 feet higher than usual, flooding vulnerable basements and shore roads. Erosion is a concern for east-facing beaches on Cape Cod and Nantucket.
Eversource has restored power to many residents, but more than half of customers in Yarmouth - plus thousands more across the Cape and Islands - are still without electricity. Many school districts are already announcing closures or delays for Friday.
4:45 PM - Winds and heavy snow are causing widespread power outages across southeastern Massachusetts. Yarmouth has been particularly hard-hit, with more than 90% of customers without power. A quarter of Falmouth is without power. Here's the full picture:
National Grid is currently reporting 24 outages on Nantucket.
Both utilities say they have crews out and working to restore service.
12:45 PM - No, that rumbling wasn't an early snowplow. It was thunder. Thundersnow is unusual, but it's being reported around southeastern Massachusetts right now, and we've experienced it a few times in recent years. The Weather Channel explains that thundersnow storms are different than warmer weather thunder storms:
The latter are usually rather tall, narrow storms containing a rising updraft of warm, moist air that has risen in a layer from near the surface that may go upward to 40,000 feet or more. Temperatures at the surface are usually well above freezing.
Snowstorms, by contrast, are mostly associated with rather extensive layers of flat, relatively shallow cloud. Precipitation in the clouds is usually formed below 20,000 feet, as sketched in the first diagram on the right. Upward and downward motions in ordinary snowstorms are rather gentle.
Thundersnow typically develops when cloud bumps, or "turrets," rise up to 5,000 feet above the main cloud layer of the storm.
11:45 AM - The shift from rain to snow is underway in Plymouth and the Upper Cape, as this radar image from Weather Underground shows:
10:45 AM - Pilgrim Nuclear Power Station has shut down in preparation for today's storm. WCAI received this statement:
Pilgrim Station determined at 8:00 am this morning, based on updated National Weather Service forecast data and in accordance with station operating procedure, to preemptively shutdown ahead of today’s winter storm. Pilgrim has been operating at 30% power since Monday night when a small seawater leak was identified in one condenser tube and subsequently repaired. Pilgrim proactively decided to plug additional tubes to prevent this type of issue in the future. This work will continue while the plant is offline. A date and time of when Pilgrim will return to 100% power is considered business sensitive and we do not disclose that information.
9:30 AM - In anticipation of today's storm, Governor Baker has declared a snow emergency and the National Weather Service has issued a blizzard warning for Eastern Plymouth County, Cape Cod, Martha's Vineyard, Nantucket, and Block Island effective Thursday, 9am through 8pm. After a brief period of rain this morning, precipitation will turn to snow, with total accumulations of 12-16 inches. Snow will be heavy at times this afternoon, with limited visibility and northeast winds 30 to 40 mph, gusting up to 65 mph.
Minor coastal flooding is also a risk along east and northeast facing shorelines during, and following, this morning's high tide. This includes Plymouth, the Cape Cod Bay shoreline between Sandwich and Dennis, Chatham, Nantucket, and Martha's Vineyard.
Many state offices and schools are closed. Bus and ferry services in the region have been curtailed, and Governor Baker is asking residents to stay off the roads.
WCAI will be updating this post throughout the storm, and our storm guide has more resources for tracking conditions and closures.