CBM CBM Synoptic Meteorology and Weather Systems 2 — Questions and Answers
Question 1: What is a 'cutoff low' in synoptic meteorology?
- A low that intensifies rapidly over 24 hours
- An upper-level low separated from the main westerly flow (Correct answer)
- A surface low that dissipates quickly
- A low-pressure system blocked by high pressure
Correct answer: An upper-level low separated from the main westerly flow
A cutoff low is an upper-level low-pressure cell that has been 'cut off' from the main jet stream flow and can persist for days, causing erratic surface weather.
Question 2: Which front type typically produces widespread, steady precipitation over a large area for an extended period?
- Cold front
- Warm front (Correct answer)
- Dryline
- Squall line
Correct answer: Warm front
Warm fronts lift warm air gradually over retreating cold air, producing stratiform clouds and steady precipitation that can last many hours across a wide region.
Question 3: What is a 'blocking high' and its main forecasting impact?
- A high that forms over mountain ranges
- A persistent anticyclone that deflects the jet stream and stalls weather patterns (Correct answer)
- A high responsible for sea-breeze circulation
- A high that causes rapid cyclogenesis downstream
Correct answer: A persistent anticyclone that deflects the jet stream and stalls weather patterns
A blocking high is a quasi-stationary anticyclone that disrupts normal westerly flow, forcing weather systems to divert and causing prolonged dry or stormy conditions in adjacent areas.
Question 4: Positive vorticity advection (PVA) at 500 mb is associated with which surface weather outcome?
- Surface high strengthening
- Surface low development and upward motion (Correct answer)
- Subsidence and clearing skies
- Reduction in wind shear
Correct answer: Surface low development and upward motion
PVA at upper levels promotes divergence aloft, which drives surface convergence and upward motion, supporting surface low development and storm activity.
Question 5: The jet stream in the mid-latitudes is typically located at approximately what pressure level?
- 850 mb
- 700 mb
- 500 mb
- 250 mb (Correct answer)
Correct answer: 250 mb
The polar jet stream is typically strongest near the 250–300 mb level (roughly 35,000–39,000 feet), at the tropopause boundary.
Question 6: What is 'cyclogenesis' and where does it most commonly occur in the contiguous US?
- Weakening of a low-pressure system; most common in the Southeast
- Development or intensification of a cyclone; common in the lee of the Rockies and along the Gulf Coast (Correct answer)
- Formation of a high-pressure system; common in the Great Plains
- Dissipation of frontal systems; common in the Northeast
Correct answer: Development or intensification of a cyclone; common in the lee of the Rockies and along the Gulf Coast
Cyclogenesis is the development or intensification of cyclonic circulation, and it frequently occurs east of the Rockies (lee cyclogenesis) and along the Gulf and East Coasts.
CBM CBM Synoptic Meteorology and Weather Systems 2
What is a 'cutoff low' in synoptic meteorology?