Arctic Meteorology and Oceanography

• Aug 04, 2000
  • Dutch Harbor
  • Limits
  • Planning
    • Question
  • Climatology
    • Question
  • Current Weather
• Aug 05, 2000
  • Near St. Paul Island
  • Fog
    • Question
  • Vessel Icing
    • Question
• Aug 06, 2000
  • West of Nunivak Island
  • Current Weather
    • Question
  • Forecast Considerations for 07 August
  • Short-Term Forecast
• Aug 07, 2000
  • Today's Plan
  • The Forecast
    • Question
  • Sea Ice
    • Question
  • Reporting Weather Observations
• Aug 08, 2000
  • Bering Strait
    • Question
  • Weather Analysis
• Aug 09, 2000
  • Point Lay
  • Morning Weather Briefing - Surface
  • Morning Weather Briefing - 500 mb
  • Weather Update
• Aug 10, 2000
  • Storm
• Aug 11, 2000
  • Analysis
• Aug 12, 2000

• Switch to Narrated

Aug 05, 2000 » Fog Question

Question

Fog, low stratus, and reduced visibility are common forecast problems throughout the Arctic. This sounding comes from nearby St. Paul Island. Which of the following features indicate fog? (Choose all that apply.)

a) Dewpoint nearly equal to temperature near the surface

b) Inversion just above the surface at 950 mb

c) Inversion at 650 mb capped by dry air

d) Tropopause at 280 mb.

The correct answers are a) and b).

Fog is characterized by a saturated layer near the surface where the dewpoint equals the temperature. This moist layer is kept from mixing with drier air aloft by an inversion near the fog top.