Updated Friday, Sept. 25, 3:30 PM ET. Source: National Weather Service Boston/Norton (3:03 PM discussion), with WBZ-TV, NBC Boston and Boston 25.

The storm is arriving. A strong nor'easter — not a tropical storm — will affect the whole state through Sunday, with the worst winds Friday night through Saturday and the bulk of heavier rain Saturday afternoon through Monday.

Timing
Northeast winds are rising this afternoon. Per the latest NWS Boston discussion (3:03 PM ET), rain reaches the Cape and Islands late this afternoon and evening. Near and northwest of the I-95 corridor, the first overnight rain may stay scattered and showery, with more widespread rain for Greater Boston Saturday. Peak winds hit the Cape and Islands later tonight, then lift west Saturday into early Sunday as the storm track shifts southwest. Saturday remains very windy with on-and-off rain. The heaviest rain for most places runs Saturday afternoon through Monday. Wind eases Sunday; Monday stays wet and unsettled, with one more unsettled day Tuesday before a warming, drying trend midweek.

What to expect
NWS now expects rainfall totals of 2 to 4 inches, with localized 5 to 6 inches possible near the coast and over hills with upslope northeast flow. Street flooding in poorly drained areas is the main inland flood risk; no Flood Watch is in effect because the rain is spread over several days.

On the coast and on Cape Cod and the Islands, NWS calls for northeast gusts of 45 to 60 mph under a High Wind Warning (alert text: 50 to 60 mph gusts). Inland eastern and central Massachusetts are under a Wind Advisory, with NWS now expecting gusts of 35 to 50 mph — a bit stronger inland than earlier today as the strongest winds shift west. Power outages are a concern across eastern Massachusetts, Rhode Island and Connecticut because trees still have their leaves. Eversource and National Grid have extra crews staged.

Low-lying coastal areas could see up to about one foot of inundation at high tide from 5 PM Friday through 8 PM Sunday, with a storm surge on the order of 1 to 2 feet (briefly near 2.5 feet possible) and pockets of moderate flooding south of Boston and onto the Cape and Islands. Boston Harbor high tide is around 11:13 PM Friday. Breaking waves of 6 to 13 feet are forecast in the surf zone, with severe beach erosion. All MBTA ferry service is cancelled Saturday and Sunday; Lynn, Winthrop and Quincy ferries are also cancelled Friday.

Who is most affected
Cape Cod, the Islands, the South Shore and the coast south of Boston will be hit hardest. Boston and the North Shore should expect strong gusts and flooding at high tide; Mayor Wu has a city coastal storm warning through Sunday. Worcester, MetroWest and the Springfield area remain under a Wind Advisory with stronger inland gust potential than earlier forecasts. The Berkshires will see lighter wind but soaking rain Saturday through Monday.

Official alerts in effect (updated late afternoon Friday)
High Wind Warning for the east coast, southeastern Massachusetts and the Cape and Islands until 8 AM Sunday.
Wind Advisory for inland eastern and central Massachusetts, including Middlesex and Worcester counties, until 8 AM Sunday.
Coastal Flood Warning for the Essex coast, Boston, the South Shore and the Cape and Islands from 5 PM Friday to 8 PM Sunday.
Coastal Flood Advisory for the South Coast (southern Bristol and southern Plymouth) from 5 PM Friday to 8 PM Sunday.
High Surf Advisory for the east coast and the Cape and Islands until 8 PM Sunday.

Be ready
Charge phones and power banks tonight. Secure outdoor furniture, bins and decorations. Check on elderly neighbors and relatives. Before heading to Jumu'ah or other masjid programs, check with your masjid for any changes, and never drive through flooded roads.

For the latest forecast, visit weather.gov/box. We will keep this post updated through the weekend.