Maritime and Marine Marine Weather and Meteorology 1 — Questions and Answers
Question 1: What does a rapidly falling barometer (pressure drop of more than 0.06 inches per hour) indicate?
- An approaching storm or rapidly deteriorating weather conditions (Correct answer)
- Fair weather moving in from the west
- Fog formation expected within 12 hours
- A slow-moving high pressure system passing overhead
Correct answer: An approaching storm or rapidly deteriorating weather conditions
A rapid barometric pressure drop signals an approaching low pressure system, usually associated with storms, strong winds, and rough seas.
Question 2: What is a 'small craft advisory' issued by NOAA?
- Wind speeds of 21-33 knots or hazardous wave conditions for small boats (Correct answer)
- Wind speeds over 48 knots posing danger to all vessels
- Visibility below 1 mile creating navigation hazard
- Water temperatures below 50°F requiring cold water protection
Correct answer: Wind speeds of 21-33 knots or hazardous wave conditions for small boats
NOAA issues a Small Craft Advisory when winds of 21-33 knots (25-38 mph) are forecast, or when wave conditions are hazardous to small vessels.
Question 3: What causes sea fog (advection fog) common along the US coasts?
- Warm moist air moving over cooler water, cooling to its dew point (Correct answer)
- Cold arctic air moving over warm tropical water
- Strong onshore winds pushing moisture against coastal mountains
- Overnight radiative cooling of the sea surface
Correct answer: Warm moist air moving over cooler water, cooling to its dew point
Advection fog forms when warm, moist air flows over cooler water and is cooled to its dew point, causing condensation near the surface.
Question 4: What is the Beaufort scale used for in marine meteorology?
- Describing wind speed based on observable sea and land conditions (Correct answer)
- Measuring wave height in open ocean conditions
- Rating hurricane intensity from Category 1-5
- Estimating visibility in nautical miles
Correct answer: Describing wind speed based on observable sea and land conditions
The Beaufort scale (0-12) estimates wind speed by observing sea state conditions like ripples, whitecaps, and spray.
Question 5: Which NOAA weather radio channel should US mariners monitor for marine forecasts?
- WX1 through WX7 on dedicated NOAA Weather Radio frequencies (Correct answer)
- VHF Channel 16 for all marine weather broadcasts
- AM 1630 kHz for coastal marine forecasts only
- VHF Channel 22A for US Coast Guard weather broadcasts
Correct answer: WX1 through WX7 on dedicated NOAA Weather Radio frequencies
NOAA Weather Radio broadcasts continuous weather on 7 dedicated frequencies (WX1-WX7) receivable on most VHF marine radios.
Question 6: What does the term 'fetch' mean in weather and wave forecasting?
- The distance over which wind blows across open water to build waves (Correct answer)
- The time between successive wave crests
- The height difference between wave crest and trough
- The speed at which a storm system moves across the ocean
Correct answer: The distance over which wind blows across open water to build waves
Fetch is the unobstructed distance over open water that wind has blown; longer fetch allows larger waves to develop.
Maritime and Marine Marine Weather and Meteorology 1
What does a rapidly falling barometer (pressure drop of more than 0.06 inches per hour) indicate?