Weather Alert in Illinois
Air Quality Alert issued July 4 at 4:19AM CDT by NWS Chicago IL
AREAS AFFECTED: McHenry; Lake; Kane; DuPage; Kendall; Grundy; Northern Cook; Central Cook; Southern Cook; Northern Will; Southern Will; Eastern Will
DESCRIPTION: The Illinois Environmental Protection Agency has determined that an Air Pollution Action Day will be declared for the greater Chicago Metropolitan Area and is IN EFFECT UNTIL MIDNIGHT CDT TONIGHT. An Air Pollution Action Day is declared when weather conditions are such that widespread ozone and or particulate levels are expected to be at or above the Unhealthy for Sensitive Groups category of the Air Quality Index for multiple days. Ozone is expected to be the primary pollutant of concern, but fireworks emissions may also contribute to higher AQI readings for both PM2.5 and Ozone at times. Active children and adults, especially people with pulmonary or respiratory disease such as asthma, should limit prolonged outdoor activity. Area residents are urged to reduce pollution levels. Air quality forecasts, current air quality, and tips on how you can reduce your emissions can be found at www.airnow.gov. Media contact...Illinois EPA.
INSTRUCTION: N/A
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Weather Topic: What is Evaporation?
Home - Education - Precipitation - Evaporation
Next Topic: Fog
Evaporation is the process which returns water from the earth
back to the atmosphere, and is another crucial process in the water cycle.
Evaporation is the transformation of liquid into gas, and it happens because
molecules are excited by the application of energy and turn into vapor.
In order for water to evaporate it has to be on the surface of a body of water.
Next Topic: Fog
Weather Topic: What are Fractus Clouds?
Home - Education - Cloud Types - Fractus Clouds
Next Topic: Freezing Rain
A fractus cloud (scud) is a fragmented, tattered cloud which has
likely been sheared off of another cloud. They are accessory clouds, meaning they
develop from parent clouds, and are named in a way which describes the original
cloud which contained them.
Fractus clouds which have originated from cumulus clouds are referred to as
cumulus fractus, while fractus clouds which have originated from stratus clouds
are referred to as stratus fractus. Under certain conditions a fractus cloud might
merge with another cloud, or develop into a cumulus cloud, but usually a
fractus cloud seen by itself will dissipate rapidly.
They are often observed on the leading and trailing edges of storm clouds,
and are a display of wind activity.
Next Topic: Freezing Rain
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