How a nor’easter forms

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?️ How a nor’easter forms

1️⃣ Cold air from Canada moves south

A big area of cold, dry air drops down from Canada into the northeastern U.S.

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2️⃣ Warm, moist air is sitting over the ocean

Over the , the air is much warmer and full of moisture.

This temperature contrast is very important.

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3️⃣ A storm forms along the coast

When that cold land air meets the warm ocean air, a low-pressure system starts to develop near the East Coast.

This setup is exactly what the looks for when forecasting a nor’easter.

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4️⃣ The storm feeds on ocean moisture

As the storm moves along the coastline, it pulls in warm, wet air from the ocean.

That gives the storm:

• heavier snow (or rain),
• stronger winds,
• and a wider impact area.

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5️⃣ Winds come from the northeast

Because of how the air circulates around the low-pressure center, the wind blows from the northeast toward the land.

That’s why it’s called a nor’easter.

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✅ In short (plain English)

A nor’easter forms when:

➡️ cold air from the north
meets
➡️ warm, wet air from the ocean
right along the East Coast
and a strong coastal storm spins up.

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? Why Marshfield and Plymouth County get hit so often

You’re right on the coast, so when these storms track just offshore, towns like Marshfield and the South Shore sit right in the:

• strong northeast winds
• heavy precipitation
• and sometimes coastal flooding zone.