National Weather Service United States Department of Commerce

Unsettled Weather in Portions of the Northwest and Southwest

Widely scattered showers and thunderstorms may produce heavy rain and localized areas of flash flooding over parts of the Southwest through Tuesday. Locally heavy rainfall and gusty winds is expected to impact the Pacific Northwest and northern Great Basin. Read More >

Overview Types of Winter Weather Stay Informed Be Prepared When caught in a storm

Stay Informed!

Keep ahead of the storm by listening to NOAA Weather Radio, commercial radio, and television for the latest winter storm warnings, watches and advisories.

NOAA Weather Radio is the best means to receive warnings from the National Weather Service. The National Weather Service continuously broadcasts warnings and forecasts that can be received by NOAA Weather Radios, which are sold in many stores. The average range is 40 miles, depending on topography. Purchase a radio that has a battery back-up and a Specific Area Message Encoder feature, which automatically alerts you when a watch or warning is issued for your county or parish.

What to Listen For

The National Weather Service issues outlooks, watches, warnings and advisories for all winter weather hazards. Here’s what they mean and what to do. Use the information below to make an informed decision on your risk and what actions should be taken. Remember to listen to your local officials’ recommendations and to NOAA Weather Radio for the latest winter storm information.

Winter storm conditions are possible in the next 3-5 days. An outlook does not guarantee the event will occur, but should be a "heads-up" to monitor later forecasts and information.

Winter storm conditions are possible within the next 36-48 hours. Prepare now! Again, a watch does not mean it’s a sure thing, but is designed to alert you to the fact that hazardous winter weather could occur. Watches are issued for winter storms, heavy snow, or blizzards.

Life-threatening severe winter conditions have begun or will begin within 24 hours. A warning is the most serious of the winter weather messages and indicates that action should be taken immediately to get ready for the storm. Warnings are issued for winter storms, ice storms, heavy snow, blizzards and heavy sleet.

Winter weather conditions are expected to cause significant inconveniences and may be hazardous. If you are cautious, these situations should not be life threatening. Advisories are issued for a variety of winter weather conditions.

Winter Weather Definitions

Winter storm:
This term may refer to a combination of winter precipitation, including snow, sleet, freezing rain, etc.

Heavy snow:
In Oklahoma, heavy snow is defined as four or more inches of snow accumulating in a 12-hour period, or six or more inches accumulating in a 24-hour period.

Rain drops that freeze into pellets of ice before reaching the ground. Sleet usually bounces when hitting a surface and does not stick to objects. However, it can accumulate and cause dangerous driving conditions.

Freezing rain:
Rain that falls onto a surface where the temperature is below freezing. This causes the rain to freeze on contact with trees, power lines, cars and roads. This coating or glaze of ice causes serious travel problems, even with very small accumulations.

Ice storm:
A high impact event caused by excessive accumulations of freezing rain on trees and power lines. Generally, a quarter of an inch or more of ice is considered dangerous. However, this can vary depending on other factors.

This life-threatening event is produced by a combination of falling or blowing snow, and high winds, typically 35 mph or more for a prolonged period of time. This combination can create potentially deadly travel conditions with impassable roads and zero visibilities.

Wind chill:
The combination of wind and temperature that serves as an estimate of how cold it actually feels to exposed human skin. Wind chill values below -19 degrees are considered dangerous.