| Is usually most evident in the circulation and temperature fields of the middle troposphere and may show little or no sign on a surface chart |
| Occurs frequently in winter to the south of the Alps when this region is under the influence of cold north-westerly airstream |
| Normally disappears at night and occurs almost exclusively in summer |
| Develops usually in winter when very unstable maritime polar or maritime arctic air currents stream southwards along the eastern side of an extensive ridge of high pressure, in association with occluded systems |
New: Boost Your Preparation!
On our site, you'll now find our new PRO Simulation Panel! Here are some of the exclusive benefits you get by unlocking it:
Prefer to practice on your smartphone? 📱 Discover the Mobile APPs.
You can still continue with the free version, which gives you access to 75% of the questions with a limit of 3 simulations per hour.
You have reached the free limit
Upgrade to the PRO version to practice without limits and unlock all features for a complete preparation.
Upgrading to PRO gives you access to:
...and much more!
📱 Or discover the Apps to study offline too
Your next free test will be available in: 1 ora
QuizVds.it - Facebook - Contact Us - Donation - Cookie Policy - Privacy Policy - Terms and Conditions - Partner