The Order of a Rainstorm: The Patterns that Predict Rain

halo of the sun through the clouds
halo of the sun through the clouds

You can predict a rainstorm days in advance, if you know the pattern. Storm clouds follow a pattern. The clouds form and progress across the sky in a predictable order. Some clouds bring simple rain showers. Other clouds bring thunderstorms with flashes of lightening.

The rainstorm pattern I am about to describe happens between 30° to 60° north latitude which would include North America and Europe and parts of Asia and from 30° to 60° south latitude.

 

How Clouds Change as Rain Draws Near

The clouds increase in number, size and density as rain draws near. This change in the clouds is a show that plays out in the blue sky above us.

 

cirrus clouds
high altitude cirrus clouds

Stage One: Wispy Clouds

A few wispy cirrus clouds appear in the western sky. Cirrus clouds are thin, high latitude clouds that look like thin strands of cotton candy. They whirl and curl in the sky (higher than 35,000 feet).

cirrostratus clouds
cirrostratus clouds

Stage Two: Cirrus Clouds Thicken

The cirrus clouds thicken and bunch together and become lower in the sky. The cirrus clouds become cirrostratus clouds, layers of cirrus clouds that don’t have a definite top or bottom, but spread out over a sizeable area. (20,000 feet altitude). I call these clouds, ‘a thick wet blanket’. I know when I see these clouds rain is near.

altostratus clouds
altostratus clouds – a rainstorm is coming

Stage Three: Altostratus Clouds Appear

The cirrostratus clouds are hidden or replaced by altostratus clouds which are flat, gray clouds that lie in stripes or ridges across the sky. These clouds are dark and lower in the sky. (8,000 feet altitude)

nimbostratus cloud
Nimbostratus cloud filled with rain. A rainstorm is starting. NOAA Collection. Photographer Ralph F. Kresge.

Stage Four: Nimbostratus Clouds Are Dark and Shapeless

Nimbostratus clouds move in. These clouds are low, dark, thick and shapeless. Their ragged edges produce a steady, heavy rain or snow. (about 6,000 feet)

cumulonimbus clouds
cumulonimbus clouds bring thunderstorms

Stage Five: Massive Cumulonimbus Clouds Bring Thunderstorms

Cumulonimbus clouds, massive and with broad bases may form in the spring and summer. These are the powerful “thunder clouds” which bring hail, lightning, and thunder. Heavy rain may pour down to the ground below. (base about 3,000 feet towering up to 16,000 and even up to 65,000 feet high)

As the storm passes the sky may stay overcast with gray stratocumulus clouds. Once these clouds pass through fair weather returns.

clouds in an evening sky
clouds in an evening sky

 

Now We Can Predict the Coming Rainstorm

Now we know the progression of rainstorm clouds. I have often watched as distinct types of clouds roll across the sky. The wind kicks up. The birds quiet down. The squirrels seek shelter, and a stillness fills the air. And then there is the smell of rain.

 

When is Hurricane Season?

Hurricane and Tropical Storm Names (National Hurricane Center)

The Smell of Rain

What is Fog? 

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