It’s All About the Weather!

It’s All About the Weather! Presented by: Shawn Gindhart Kelli Hornberger

Clouds • 4 major cloud groups • High clouds • Middle clouds • Low clouds • Clouds with vertical development • Some Unusual clouds

Cirrus • Thin, feathery clouds • Cold and made of ice crystals • Fair weather clouds

Cirrostratus • Thin, sheet like, high clouds that cover entire sky • Halo around the sun • Made of ice crystals • Used to predict rain or snow within 12-24 hours

Cirrocumulus • Small, rounded, white puffs • Made of ice crystals • Produce red sunsets

Altostratus • Gray or blue-gray clouds • Made of ice crystals and water droplets • Cover entire sky • “Watery sun” • Form ahead of rain shower

Altocumulus • Gray, puffy bands of clouds • Made mostly of water droplets • On warm, humid summer mornings could lead to late afternoon thunderstorms

Stratus • Uniform, grayish cloud that often covers entire sky • Usually no precipitation, but sometimes mist or light drizzle falls

Stratocumulus • Low, lumpy rows of clouds • Blue sky can be seen between single clouds • Often appear near sunset

Nimbostratus • Dark gray, “wet”-looking, sheet like clouds • Steady rain or snow falls from clouds

Fog • Stratus cloud that touches the ground • Formed 2 ways • By cooling the air until it reaches saturation • By evaporating water into air until it reaches saturation

Cumulus • Small, puffy clouds that look like cotton balls • Dome- or tower-shaped tops • Also fair weather clouds • Made of water droplets

Cumulonimbus • Thunderstorm cloud • Dark base with anvil shaped top • All forms of precipitation • Lightning, thunder, and even tornadoes can be present

Cap Cloud • Resembles a scarf capping the top of sprouting cumulus cloud • Form when moist winds are deflected up and over top of a building cumulus cloud

Kelvin-Helmholtz Waves • Form when there are 2 parallel layers of air that are usually moving at different speeds and in opposite directions • Upper layer of air usually moves faster than the lower layer because there is less friction

Lenticular Clouds • Clouds having the shape of a lens or almond • Form on one another like a stack of pancakes • Develop downwind of a mountain

Contrails • Cirrus-like trail of condensed vapor • Form from the mixing of hot exhaust gases from jet aircraft with cold air • Made of ice crystals

Severe Weather • Blizzards • Flash Flood • Hurricanes • Thunderstorms • Tornadoes

Blizzard • Characteristics • Low temperatures • Strong winds (greater than 30 knots) • Large amounts of fine, dry, powdery snow • Reduce visibility to only a few meters

Flash Flood • Flood that rises and falls quite rapidly with little or no advance warning • Usually result of intense rainfall over relatively small area

Hurricanes • Tropical storm system • Swirling band of rotating clouds • Surface winds in excess of 64 knots (74 mph) • Heavy rain

Thunderstorms • Clusters of towering cumulus clouds that have grown • Accompanied by lightning, thunder, strong gusty winds, and heavy rain

Tornadoes • Intense rotating column of air that extends downward from the base of a thunderstorm • Winds may exceed 200 knots • Some never reach the ground

Precipitation • Types • Rain • Hail • Freezing Rain • Sleet • Snow

Rain • Any falling drop of liquid water • Diameter ≥ 0.5mm • Drizzle • Fine uniform drops of water • Diameter < 0.5mm

Hail • Pieces of ice either transparent or partially opaque • Ranging in size from that of small peas to that of golf balls or larger • Some are round while others take on irregular shapes

Freezing Rain • Supercooled raindrops that fall through a relatively shallow subfreezing layer • Freeze upon contact with cold objects at the ground

Sleet • Frozen raindrops that form as cold raindrops (or partially melted snowflakes) • Refreeze while falling through a relatively deep subfreezing layer

Snow • White ice crystals in complex hexagonal (6-sided) shapes • Often join together to form snowflakes

THE END Millersville Meteorology www.MillersvilleMeteorology.org

It’s All About the Weather!