Weather Fronts and Frontal Boundaries

Introduction

• Front: Boundary where two or more unlike air masses meet
  • Results in temperature and humidity differences
  • Causes density differences, e.g., one air mass moves up, another moves down

Identifying Fronts on Weather Maps

• Temperature differences on each side of the front
• Differences in dew point and humidity
• Wind direction changes
  • Example: Gulf air mass (southeasterly winds) vs. Canadian air mass (north/northwesterly winds)
• Fronts on maps:
  • Cold front: Blue with triangles pointing direction of movement

Cold Fronts

• Characteristics
  • Colder air replaces warmer air
  • Fast-moving with steep front
  • Associated with severe weather (thunderstorms, cumulonimbus clouds)
• Weather Changes
  • Significant temperature drop behind the front
  • Low pressure along the frontal boundary
  • Wind direction changes (southerly flow ahead, northerly flow behind)
  • Clear skies and high pressure behind the front

Warm Fronts

• Characteristics
  • Warm air replaces colder air
  • Gradual and slower movement
  • More likely to form stratus and nimbostratus clouds
• Weather Changes
  • Steady rain with less intense storms
  • Increased humidity and dew point behind the front
  • Potential for mixed precipitation types in winter

Occluded Fronts

• Form when a cold front overtakes a warm front, lifting the warm air between them
• Types
  • Cold-type: Coldest air mass is behind
  • Warm-type: Coldest air mass is in front
• Weather Effects
  • Intense rainfall and storms along boundaries
  • Various precipitation types in winter

Stationary Fronts

• Occur when neither air mass is strong enough to move the other
• Characteristics
  • Persistent boundary with ongoing precipitation
  • Can lead to significant rainfall and regional flooding

Dry Line

• Relevant in regions like Texas
• Boundary between warm, dry air from the southwest and warm, moist air from the Gulf of Mexico
• Leads to significant weather events (thunderstorms, tornadoes)
• Visible on weather maps as a sudden change in dew points

Conclusion

• Understanding fronts is essential for predicting weather patterns and identifying severe weather risks.
  • Cold, warm, occluded, stationary, and dry lines are all significant in weather forecasting.
  • Special attention needed for regions with unique weather phenomena, such as tornadoes and hurricanes.