Severe Weather Comparison: Nor'easters and Hurricanes

Nor'easters Overview

• Definition: Low-pressure centers located near the New England area in the northeastern United States.
• Formation: Different from hurricanes; they form through strong frontal systems with cyclonic (counterclockwise) circulation in the Northern Hemisphere.
• Impacts: Can cause significant snowstorms, storm surges, and coastal damage, similar to smaller hurricanes.
• Key Characteristics:
  • Often called cold core storms due to their formation in colder areas.
  • Low-pressure does not reach the extreme levels seen in hurricanes.
  • Can impact larger areas from Canada to the Caribbean.
  • Onshore flow of winds can lead to flooding and storm damage.

Ash Wednesday Storm

• Date: A famous nor'easter that impacted 700 miles of the Atlantic coastline.
• Damage: Waves reached 30 ft, causing significant property damage.
• Comparison to Hurricanes: Similar in damage appearance but different in formation.

Superstorm Sandy

• Event: Combined characteristics of a nor'easter and tropical storm.
• Path: Traveled north, combining with a nor'easter setup.
• Impact: Major flooding in New York, New Jersey, and surrounding areas.

Comparison: Nor'easters vs Hurricanes

Similarities:

• Both can cause flooding, coastal damage, and storm surges.
• Impact large, populous areas, leading to extensive damage.

Differences:

• Formation:
  • Hurricanes: Form in tropical areas, require warm water (80°F or higher).
  • Nor'easters: Form through frontal systems, more common in the northeastern US.
• Pressure:
  • Hurricanes: Can have extremely low pressures (<920 mbars for Cat 5).
  • Nor'easters: Do not reach such low pressures but cover larger areas.
• Temperature:
  • Hurricanes: Warm core.
  • Nor'easters: Cold core.
• Wind and Circulation:
  • Hurricanes: Weak upper-level winds; strong winds at the surface.
  • Nor'easters: Strong upper-level winds; cyclonic circulation.
  • Strongest quadrant of impact differs: Left front for nor'easters vs right front for hurricanes.

Exam Preparation

• Topics to Review:
  • Differences in size, formation, duration, and frequency of events (hurricanes, tornadoes, thunderstorms, etc.).
  • How frontal systems (strong upper-level winds) interact differently with hurricanes and mid-latitude cyclones.
  • Key characteristics and formation differences between hurricanes and mid-latitude wave cyclones.
  • Impact and damage comparison: Force, pressure, winds, and associated weather phenomena.

Next Lecture

• Topic: Flooding
• Importance: Covers the last part needed for Exam 3.
• Action: Review lecture on flooding before the exam to cover all aspects of severe weather.