Altocumulus Clouds

Altocumulus Clouds

Mid-Level Puffy Clouds ☁️

Altitude

6,500 - 20,000 feet (2 - 6 km)

Mid-level clouds

Appearance

Small puffy clouds in rows

"Mackerel sky" patterns

Weather Sign

Weather changing

Instability approaching

What Are Altocumulus Clouds?

Altocumulus clouds are mid-level puffy clouds that form in layers or patches. They are smaller than cumulus clouds below them and often appear in patterns or waves. Altocumulus clouds frequently indicate that weather will change within 12-24 hours, often with thunderstorm potential developing.

Characteristics & Patterns

Key Characteristics

  • ✓ Size: Smaller than cumulus (0.5-1 km)
  • ✓ Color: White with gray shading
  • ✓ Base: Relatively flat and aligned
  • ✓ Pattern: Often organized in rows
  • ✓ Transparency: Can see sun through gaps
  • ✓ Movement: Drifts with mid-level winds

Patterns & Variations

Altocumulus Castellanus: Towers with cauliflower appearance, indicates instability

Altocumulus Lenticularis: Lens-shaped clouds near mountains from wind flow

Altocumulus Floccus: Ragged, tufty appearance, often with virga below

Mackerel Sky: Regular wave patterns resembling fish scales

What Altocumulus Means

Altocumulus clouds are strong indicators of changing weather patterns. Their appearance often precedes significant weather changes.

Weather Change Signs

  • • Indicates atmospheric instability
  • • Thunderstorms possible within 24 hours
  • • Temperature may rise before cooling
  • • Wind patterns changing at mid-level

Observation Tips

  • • Look at mid-day sky
  • • Watch for orderly patterns
  • • Note size compared to clouds
  • • Regular spacing indicates waves