ROCKFORD (WREX) — Severe weather occurs in the Stateline primarily during the spring and early Summer months. There are certain types of clouds to be aware of when the forecast calls for severe weather.
Puffy "balls of cotton":
The typical cloud that comes to mind when looking at a kids' drawing is likely a cumulus cloud. These puffy, cotton ball-like clouds are distinguished by their vertical growth. Cumulus clouds can be found in both tranquil weather and active weather. Cumulus clouds that are flatter tend to be found when updrafts are weak, meaning clouds are unable to grow very tall. When the tops of cumulus clouds are puffy and cauliflower-like, be on the lookout for rain showers.
When updrafts are strong, cumulus clouds can grow quickly. This vertical growth can make for violent storms, capable of producing hail, strong winds, and tornadoes. When a strong updraft is found, it can lead to what meteorologists refer to as a cumulonimbus clouds. These types of clouds can grow over 30,000-feet above the surface. Within the growing cumulonimbus cloud, updrafts can reach speeds of 50 to 100 miles per hour.
Clouds that are low to the ground are limited in their vertical growth. These types of clouds tend to have vertical growth under 7,000-feet. The clouds that generally bring light rain are called stratus clouds. They are fairly low to the ground and are gray in color, stretching across the entirety of the sky.
Stratocumulus clouds are relatively low, lumpy, and gray. When they are present at sunrise or sunset, they can make for a beautiful scene. If precipitation is falling, it's likely a light rain or drizzle.
Nimbostratus clouds are typically dark gray and have ragged bases. This type of cloud is associated with a continue rain or snow and usually cover the whole sky.
Clouds that exist in the mid-levels of the atmosphere are between 7-thousand to 23-thousand feet. Clouds are grouped by type and height, so altocumulus are mid-level, grayish-white cumulus clouds. Generally, one part of the cloud is darker than the other and form in groups a few thousand feet thick. If you hold your hand up at arm's length, altocumulus clouds are about as wide as your thumb. On a warm and humid morning, altocumulus clouds can be an indication of storms later in the day.
Stratus clouds are like a blanket that covers the sky. Altostratus clouds are clouds in the mid-level that covers the sky. They tend to be blue-gray clouds and generally do not completely block the sun or moon from view. The sky can sometimes be referred to as "milky." Occasionally, rain can fall from altostratus clouds. If that precipitation reaches the ground, the cloud becomes classified as a nimbostratus.
Higher elevation clouds are typically made up of ice and can give us some fantastic atmospheric optics, including sun dogs and halos. Clouds of this nature typically exist between 16,000- and 43,000-feet.
Cirrus clouds are made of ice crystals and look like thin, wispy white streamers high in the sky. They are typically a sign of fair weather, but they can be an indication of increasing moisture in the upper levels and precipitation.
The next type of cloud is typical of a cold winter sky: cirrocumulus. They are rounded puffs that appear in long rows high in the sky. They are the same size or smaller than the width of your smallest finger if you were to hold it at arm's length. When they cover a large section of the sky, it is sometimes called a "mackerel sky," because it resembles the scales of a fish.
Before rain or snow falls, cirrostratus typically cover the sky in a thin sheet-like blanket. The sun or moon may shine through the milky looking appearance. This type of high-level cloud cover is where halos and sun dogs generally are found. They usually proceed rain or snow by approximately 12 to 24 hours.