Thanks to John Blair, Dayton Powered Paragliding.
It’s now super easy to get the local weather forecast using the web, 800-WX-BRIEF, TV, radio or even your VHF radio. Even so, at certain times of the year weather can change rapidly and you should continually keep a “weather eye” out, especially to the west, in order to foresee changes which might be impending.
Clouds are a tool you can use to predict or forecast weather. The type of cloud and direction of movement can warn you of weather changes that are imminent. Clouds are categorized by the altitude at which they appear and the shape that they take.
|High Clouds = Cirrus||Above 18,000 feet||
|Middle Clouds = Alto||6,500 feet to 18,000 feet||Altostratus
|Low Clouds = Stratus||Up to 6,500 feet||Stratus
|Clouds with vertical growth||Cumulus
Note: This is not an in-depth study of clouds so much as highlights of the basics for ultralight pilots.
Definitions to categorize general cloud shapes:
Variations of cloud types are created by combining the cloud’s shape/description with the altitudinal names as a prefix or suffix.
Cirros (high) or Cirro can be used with cumulus (heap) to indicate a cirrocumulus or high, lumpy cloud. Cirrocumulus clouds, sometime called “mackerel skies”, can indicate the approach of a hurricane in the tropics. It can also be used with stratus (flat, layered) as in cirrostratus to indicate a high, flat or layered cloud.
Alto can also be used with cumulus and stratus to indicate altocumulus and altostratus which are middle altitude lumpy clouds and middle altitude layered clouds respectively.
Nimbo or nimbus might be used with cumulus or stratus to indicate a cloud formation that is producing precipitation. These clouds could be either cumulonimbus which would be a lumpy, vertically-rising rain cloud or nimbostratus which would be a sheet or flat-looking rain cloud.
“High” clouds are above 18,000 feet
“Medium high” clouds are 6,500 feet to 18,000 feet.
These are called alto clouds. They’re used to predict weather changes in 6 to 12 hours.
“Low flat” clouds go up to 6,500 feet.
These Stratus clouds form a solid sheet or layer of cloud mass.
Clouds with vertical growth
If you still can’t remember all of the cloud names and formations, you can always watch the clouds for two specific weather situations that indicate a high probability of a storm:
1. A “lowering ceiling”: This means that the height of cloud formations continues to get lower and lower, usually caused by a warm front. As the ceiling lowers you will see clouds in the following order:
- Nimbostratus – storm clouds!
2. On the other hand, watch for cumulus (puffy) clouds that start to rapidly develop vertically to become cumulonimbus thunderstorm clouds. On hot and humid days, these storms occur over water as the radiant heat from the land absorbs moisture from nearby water and rises to produce thunderheads. These storms can also indicate a cold front and may be preceded by squall lines, a row of black storm clouds. Wind shifts unpredictably and accelerates dramatically. Lightning can occur for miles in front of a storm and after the storm appears to have passed.
Other things to look for that indicate an approaching weather change:
- Weather changes generally come from the west so scan the sky with your weather eye, especially to the west.
- A sudden drop in temperature and change in the wind (increasing winds and/or seas) often means that a storm is near.
- If you have a barometer check it every two to three hours. A rapid drop in pressure means a storm is approaching.
About John: “I have been flying ultralights for some time, but I did not have a great understanding of weather. I was always in search of something related to weather that was easy to understand. I went on the Internet looking for weather related material. With lots of research and no luck I called a meteorologist that pointed me in the right direction. What I came up with is weather 101. Flying powered paragliders and knowing what type of weather you should fly in will not only insure a enjoyable flight but a safe flight as well.”