New England Border Supercells Gear Up for Tornadoes, Tennis-Ball Hail — SevereWX

Storms intensifying near the Canadian border could spawn supercells packing serious hazards across western Maine, northern New Hampshire, and Vermont.

The Storm Prediction Center's Mesoscale Discussion 1613 flags a mesoscale convective vortex pushing east-southeast from near Greenville, Maine. While earlier activity fizzles, fresh thunderstorms are firing along a key outflow boundary extending into southwestern Quebec.

Rich moisture (70°F dewpoints) and CAPE over 2000 J/kg fuel this renewal, especially as a capping elevated mixed-layer erodes southward by 4-6 PM EDT. Strong shear could organize these into supercells spreading into the U.S. border region through 8 PM EDT.

Key threats:

• Large hail: 1.50-2.50 inches (golfball to tennis ball size)
• Damaging winds: 65-80 mph gusts
• Tornadoes: 1-2 possible, most probable peak intensity 120-145 mph (EF2-EF3)

Watch issuance odds sit at 60%, with storms eyeing parts of western Maine, northern New Hampshire, and Vermont. Peak timing aligns with evening rush—stay vigilant.

Preparedness tip: Monitor radar closely, have a severe weather plan ready, and heed any watches or warnings from NWS offices like Caribou (CAR), Gray (GYX), and Burlington (BTV). Know your safe spot indoors.

Stay tuned to SevereWX.net for updates as this evolves.