Detailed Notes on Hurricanes and Air Masses

Hurricane Overview

• Lecture continues from previous discussions on hurricanes and their impacts.
• Transitioning to Chapter 9 covering air masses, general circulation, and more on climate.

Hurricane Impacts

• Key impacts include storm surge and precipitation.
• Storm Surge:
  • Caused by high wind speeds pushing water onto shore.
  • Historically the primary cause of damage and mortality.
• Precipitation Events:
  • Increasingly significant in recent hurricanes (e.g., Hurricane Harvey).
  • Damaging effects on inland areas, not just coastal regions.

Storm Surge Dynamics

• Relative wind speed depends on hurricane movement and location.
• Example: Hurricane Katrina and Louisiana; wind speeds can add up.
• Directionality of the hurricane affects storm surge:
• Eastern side experiences onshore flow (high surge) while western side may have offshore flow (low tide).

Factors Influencing Hurricane Movement

• Track influenced by larger atmospheric patterns.
• Coriolis force causes hurricanes to curve to the right in the Northern Hemisphere leading to specific tracks towards the northeast.

Hurricane Examples

• Hurricane Katrina (2005):
• Major catastrophic impact; rapid intensification to Category 5.
• Resulted in significant fatalities and damages.
• Hurricane Sandy (2012):
• Hit NYC; lower intensity but caused widespread flooding due to track and conditions.
• Hurricane Harvey (2017):
• Historical rain events resulting in extensive flooding, particularly in Houston.

Precipitation vs. Storm Surge

• Harvey underscored the damage from precipitation; emphasizing the changing dynamics of hurricane impacts.

2024 Hurricane Season Summary

• Predicted to be active; early formation of hurricanes indicated a dynamic atmosphere.
• The return to a more active season due to transitioning climate conditions (El Nino to La Nina).

Air Masses Introduction

• Air masses: large regions of air with uniform properties regarding temperature and humidity.
• Classified by source region (cold vs. warm) and moisture content (maritime vs. continental).
• Types of Air Masses:
  • Continental Polar (CP), Continental Tropical (CT), Maritime Polar (MP), Maritime Tropical (MT).

Characteristics of Air Masses

• Air masses undergo changes as they move; retain characteristics, impacting weather conditions in new regions.
• Cold air masses can bring unusual weather to warmer areas.

Frontogenesis and Weather Systems

• Fronts are the boundaries between different air masses, leading to weather changes.
• Interaction of warm and cold air results in significant weather events.

Jet Stream & Circulation Patterns

• Jet streams: fast-moving air currents, influenced by temperature differences; important for weather forecasting.
• Coriolis effect and atmospheric conditions lead to undulations and wave patterns (Rossby waves) in jet streams affecting weather dynamics.