Atmospheric River Bringing Heavy Rain to Southern California and Heavy Snow to the Sierra Nevadas

A strong atmospheric river will continue heavy rain over southern California through Friday. The heaviest rainfall is ongoing today in the Los Angeles Basin. Flash and urban flooding is possible. A prolonged heavy snowfall has begun over the Sierra Nevada Mountains and will continue through Friday. Travel will become increasingly difficult over the passes due to snow and strong winds. Read More >

Other Domains: Acadia N.P. | Marine/Coast | Northern/Eastern Maine

High Temperature

Minimum Wind Chill

Maximum Wet Bulb Globe Temperature

Wind

Sky

Precipitation Chance

Lightning

Wet Bulb Globe Temperature (WBGT) is a measure of the heat stress in direct sunlight, which takes into account: temperature, humidity, wind speed, sun angle and cloud cover (solar radiation). This differs from the heat index, which takes into consideration temperature and humidity and is calculated for shady areas. For more background info on WBGT, click here.

101% means summit in and out of clouds
102% means summit obscured

Lightning Threat represents thunderstorm coverage at any one time in the forecast period.

Lightning Legend Lightning Safety Tips

Risk Level		Definition
	None	No lightning risk
	Limited	Thunderstorms expected to be isolated in coverage. Atmospheric conditions support cloud to ground lightning strikes in and near thunderstorms. Be aware for thunderstorms in your area.
	Elevated	Thunderstorms expected to be scattered in coverage. Atmospheric conditions support cloud to ground lightning strikes in and near thunderstorms. Be prepared to take immediate shelter from thunderstorms and lightning.
	Significant	Numerous thunderstorms are expected. Atmospheric conditions support cloud to ground lightning strikes in and near thunderstorms. Plan to take immediate shelter from thunderstorms and lightning.
	Extreme	Widespread thunderstorms are expected. Atmospheric conditions support cloud to ground lightning strikes in and near thunderstorms. Plan to take immediate shelter from thunderstorms and lightning.