Most of the day was dry for St. Patrick’s Day parades today, with a springlike Boston reaching 69 degrees and several inland areas hitting 70. But Sunday night is when the weather drama begins as the edge of a storm system that has been unleashing deadly severe weather across the South will bring heavy rain, possible thunderstorms and strong gusty winds to New England later in the evening — beginning well after sunset for Boston and around dinnertime for Western Mass.
The pressure gradient has tightened as the storm nears, strengthening the southerly flow to draw in warmer and moist air into the region.
The heavy rains arrive in the evening and persist through the overnight hours. There could be some thunderstorms embedded in the storm line that pushes through. As the storm moves in, winds will ramp up closer to 40 to 50 miles an hour in the evening and overnight hours. A wind advisory is in effect from tonight through Monday for the northern Berkshires and in parts of New Hampshire and Vermont.
About 1 to 2 inches of rain are forecast across a good chunk of Southern New England, with a few areas across Southern New England seeing higher totals. The heaviest rain is forecast overnight and take place across the South Shore, southeastern Mass. and Rhode Island.
The heavy precipitation could lead to some minor flooding across Southern New England. However, a flood watch has been issued for parts of Vermont Sunday and Monday with the rain and the rapid snowmelt potentially causing some rivers and streams to overflow. Up to 3 inches of additional runoff could occur across the Green Mountain State. Isolated flood warnings have been issued for rivers in New Hampshire and Maine.
The cold front will likely stall and slow down due to a blocking high pressure over the northern Atlantic, meaning light to steady rain is expected to linger across the eastern portions of New England through the morning commute. Be mindful of ponding on the roads in the morning.
Greater Boston: Windy on Sunday under mostly cloudy skies. Highs build to the mid-60s with gusty winds before heavy rain arrives later Sunday night. Up to 2 inches expected.
Central/Western Mass.: A spot shower during the day will lead to heavy rain arriving Sunday evening and continue through the overnight with gusty winds.
Cape and Islands: Sunday brings warm temperatures to the mid-50s with a strong wind developing. Heavy rain arrives Sunday night with up to 2 inches of rain forecast.
Rhode Island: Sunday sees overcast skies with temperatures pushing into the low 60s, upper 50s around Newport. A sprinkle possible during the day before strong winds and rain arrive later in the evening. Up to 2 inches of rain are possible.
New Hampshire: Seeing partly cloudy skies on Sunday with building wind to 10 to 15 mph. Rain arrives Sunday evening with gusts pushing higher.
Rest of New England: Sunday brings overcast skies with temperatures building to the upper 50s and low 60s. A spot shower is possible during the day, but rain arrives to Vermont around late afternoon with Maine seeing steady to heavy rain fall later in the overnight.
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Ken Mahan can be reached at ken.mahan@globe.com. Follow him on Instagram @kenmahantheweatherman.
