OUPV Weather Interpretation and Forecasting 2 — Questions and Answers
Question 1: What type of cloud formation indicates potential thunderstorm development?
- Cirrus clouds
- Towering cumulonimbus clouds with an anvil top (Correct answer)
- Stratus clouds
- Fair-weather cumulus
Correct answer: Towering cumulonimbus clouds with an anvil top
Cumulonimbus clouds with vertical development and an anvil-shaped top indicate a mature thunderstorm.
Cumulonimbus (Cb) clouds are the thunderstorm cloud. They develop through strong convective updrafts, growing from near the surface to 40,000 feet or higher. The anvil top forms at the tropopause. A mature Cb can produce lightning, heavy rain, hail, microbursts, and waterspouts.
Question 2: What does a steady barometer reading typically indicate?
- A storm is imminent
- Continuation of current weather conditions (Correct answer)
- Rapidly improving weather
- Hurricane conditions approaching
Correct answer: Continuation of current weather conditions
A steady barometric pressure generally indicates that current weather conditions will persist.
A steady barometer (pressure change of less than 0.01 inches per hour) indicates the current weather pattern is likely to continue. Rising pressure generally indicates improving conditions, while falling pressure suggests deteriorating weather.
Question 3: What is a NOAA Weather Radio and why is it important for OUPV operations?
- A commercial music station
- A continuous broadcast of weather information, forecasts, and warnings for marine areas (Correct answer)
- A satellite phone service
- An emergency-only channel that is normally silent
Correct answer: A continuous broadcast of weather information, forecasts, and warnings for marine areas
NOAA Weather Radio provides continuous broadcasts of marine weather observations, forecasts, and hazard warnings.
NOAA Weather Radio broadcasts on seven VHF frequencies with continuous weather information including marine forecasts, Small Craft Advisories, Gale Warnings, Storm Warnings, and Hurricane Warnings. Most VHF marine radios can receive these frequencies.
Question 4: What weather phenomenon is indicated by a halo around the sun or moon?
- Cold air arriving
- High cirrus or cirrostratus clouds, often indicating an approaching warm front and rain within 24-48 hours (Correct answer)
- Clear weather for the next week
- Volcanic ash in the atmosphere
Correct answer: High cirrus or cirrostratus clouds, often indicating an approaching warm front and rain within 24-48 hours
A halo is caused by ice crystals in high cirrus or cirrostratus clouds, which often precede an approaching warm front.
Halos form when light refracts through hexagonal ice crystals in cirrus or cirrostratus clouds. These clouds are often the first visible sign of an approaching warm front, which may bring rain within 24-48 hours. The folk saying ring around the moon, rain coming soon has meteorological validity.
Question 5: What is the significance of wind backing and lowering clouds?
- Improving weather conditions
- Deteriorating weather with a low-pressure system approaching (Correct answer)
- Normal daily weather pattern
- The storm has passed
Correct answer: Deteriorating weather with a low-pressure system approaching
A backing wind combined with lowering cloud ceilings indicates a low-pressure system is approaching with deteriorating weather.
In the Northern Hemisphere, a backing wind (counterclockwise shift) indicates the approach of a low-pressure systems warm sector. Combined with lowering cloud bases, it confirms a frontal system is approaching. Monitoring wind direction and cloud trends allows anticipating weather changes hours before arrival.
Question 6: What weather condition does a Small Craft Advisory indicate?
- Pleasant sailing weather
- Sustained winds of 20-33 knots and/or sea conditions dangerous to small vessels (Correct answer)
- Only rain is expected
- Water temperature is below 60 degrees F
Correct answer: Sustained winds of 20-33 knots and/or sea conditions dangerous to small vessels
A Small Craft Advisory is issued when sustained winds of 20-33 knots and/or hazardous sea conditions are expected.
A Small Craft Advisory is issued when sustained winds of 20-33 knots, frequent gusts of 25-33 knots, or hazardous sea conditions are expected. The flag signal is a single red pennant. OUPV operators must take SCAs seriously as these conditions can be life-threatening for six-pack vessels.
OUPV Weather Interpretation and Forecasting 2
What type of cloud formation indicates potential thunderstorm development?