National Weather Service United States Department of Commerce

Much cooler temperatures and heavy rain forecast in the Northeast

The recent summer-like temperatures in the eastern U.S. will come to an abrupt end on Friday as a strong cold front sweeps across the region. Heavy rain and gusty winds will accompany the front. Some of the rain could be heavy, leading to flash flooding from the Ohio Valley to northern New England. Read More >

Air Quality

The National Oceanic and Atmospheric Administration (NOAA), in partnership with the Environmental Protection Agency (EPA), issues daily air quality forecast guidance as part of a national Air Quality Forecasting Capability. NOAA's National Weather Service (NWS) currently provides forecast guidance for ozone and smoke based on numerical atmospheric predictions updated twice daily. read more ...

Air Quality Forecast Guidance
Air Quality Alerts (AQA)
Air Quality Indexes (AQI)
About the Air Quality Index

The EPA developed the Air Quality Index (AQI) which reports levels of ozone, particle pollution, and other common air pollutants on the same scale. An AQI reading of 101 corresponds to a level that is above the national air quality standard - the higher the AQI rating, the greater the health impact. The AQI is divided into color-coded categories, and each category is identified by a simple informative descriptor. The descriptors are intended to convey to the public information about how air quality within each category relates to public health. 

The table below defines the AQI categories.

AQI AQI Category AQI Color Formulas
Numbers (Descriptor) Color (RGB) (CMYK)
0 - 50 Good Green 0,228,0 224,0,224,30
51 - 100 Moderate Yellow 255,255,0 0,0,255,0
101 - 150 Unhealthy for Sensitive Groups Orange 255,126,0 0,132,255,0
151 - 200 Unhealthy Red 255,0,0 0,255,255,0
201 - 300 Very Unhealthy Purple 153,0,76 0,153,80,102
301 - 500 Hazardous Maroon 76,0,38 0,76,38,179
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