Boston air quality is being affected by wildfire smoke even as Maine faces a 10% severe weather risk on Tuesday, with damaging wind, large hail and an isolated tornado possible. NOAA's Storm Prediction Center issued the rare outlook as a very strong cold front is expected to drive thunderstorms into the state by evening.
The highest chance for numerous severe thunderstorms is across the mountains and northern New Hampshire, but northern Franklin and Somerset counties could see showers and thunderstorms as early as 1 PM. The main event is expected after 5 PM and last through midnight, with flooding also possible if storms strengthen.
Maine Tuesday storm window
Showers and thunderstorms are expected over the mountains around 4 to 7 PM, then spread into the broader severe weather window later in the evening. The storms that turn strong to severe carry the main threat of damaging wind and large hail, with an isolated tornado also on the table.
Heat advisories remain in effect until 8 p.m. on Tuesday, even though incoming wildfire smoke is limiting how hot the area gets. Dew points will run in the 60s, so the air stays muggy while the front approaches.
NOAA's Storm Prediction Center outlook
A 10% risk from NOAA's Storm Prediction Center is the kind of outlook usually reserved for places where severe storms are possible but not routine. In practical terms, it tells readers in Maine to expect enough instability for damaging weather, not just ordinary rain.
Campers in the mountains and people in northern Franklin and Somerset counties face the tightest timing. By Wednesday, lower humidity is expected as refreshing air rushes in, but the storms before midnight remain the part of Tuesday that matters most.
