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Watch vs warning › Winter storm watch vs warning

Winter storm watch vs warning

A winter storm watch means conditions are favorable for a significant winter storm. Be ready. A winter storm warning means a significant winter weather event is happening or about to happen. Travel will become difficult or impossible in some situations.

Winter alerts active where you are, right now

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Nothing has been checked yet. This is not an all clear for winter storm alerts.

This box reads public National Weather Service data when you load the page. It does not notify you, and it does not run in the background. Do not use it in place of a weather radio or your phone alerts.

The danger in a winter storm is mostly on the road and mostly from being stuck. Change your travel plans while you still have a choice.

What the National Weather Service says

Winter Storm Watch

Issued when conditions are favorable for a significant winter storm event (heavy sleet, heavy snow, ice storm, heavy snow and blowing snow or a combination of events).

Issued by
Your local National Weather Service forecast office.
How long it lasts
A Winter Storm Watch is issued when there is the potential for significant and hazardous winter weather within 48 hours.
National Weather Service: www.weather.gov/safety/winter-ww

Winter Storm Warning

A significant winter weather event including snow, ice, sleet or blowing snow or a combination of these hazards. Travel will become difficult or impossible in some situations.

Issued by
Your local National Weather Service forecast office.
How long it lasts
A Winter Storm Warning is issued when a significant combination of hazardous winter weather is occurring or imminent.
National Weather Service: www.weather.gov/safety/winter-ww

Winter Weather Advisory

Issued when snow, blowing snow, ice, sleet, or a combination of these wintry elements is expected but conditions should not be hazardous enough to meet warning criteria.

Issued by
Your local National Weather Service forecast office.
National Weather Service: www.weather.gov/safety/winter-ww

There is no single national snow total that triggers a winter storm warning. The National Weather Service does not publish one on its winter safety page. What counts as significant depends on what your area is used to, so check the page for your local National Weather Service office.

The 48 hour figure for a watch comes from the National Weather Service office in Baltimore and Washington, cited at the end of this page. The winter safety page itself does not state a lead time.

A winter storm warning can be upgraded to a Blizzard Warning or an Ice Storm Warning. Both have their own pages here.

What to do

If a winter storm watch is issued

Source: www.weather.gov/safety/winter-ww

If a winter storm warning is issued

Source: www.weather.gov/safety/winter-ww

If a winter weather advisory is issued

Source: www.weather.gov/safety/winter-ww

Common questions

How much snow triggers a winter storm warning?

There is no single national number. The National Weather Service issues a Winter Storm Warning for a significant winter weather event including snow, ice, sleet or blowing snow, or a combination of these hazards, and each local office sets the amounts that count as significant for its own area. Six inches is routine in one place and shuts down another. Check your local National Weather Service office page for the numbers where you live.

Source: www.weather.gov/safety/winter-ww

How far in advance is a winter storm watch issued?

A Winter Storm Watch is issued when there is the potential for significant and hazardous winter weather within 48 hours. A Winter Storm Warning is issued when a significant combination of hazardous winter weather is occurring or imminent, so it comes much closer to the event.

Source: www.weather.gov/lwx/warningsdefined

What is the difference between a winter storm warning and a winter weather advisory?

A warning is for a significant winter weather event where travel will become difficult or impossible in some situations. An advisory is for wintry weather that is expected but should not be hazardous enough to meet warning criteria. An advisory means give yourself more time. A warning means stay off the road.

Source: www.weather.gov/safety/winter-ww

Is a winter storm watch or warning worse?

The warning is worse. A watch means conditions are favorable for a significant winter storm and there is potential for it within 48 hours. A warning means the significant winter weather is occurring or imminent. Use the watch to change your plans, because by the time the warning is out the roads are the problem.

Source: www.weather.gov/safety/winter-ww

If you are stranded in your vehicle

Source: www.weather.gov/safety/winter-during

How a winter storm alert reaches you

Winter storm watches and warnings are not on the National Weather Service list of alerts sent to cell phones as Wireless Emergency Alerts. That list is short and does not include them. Snow Squall Warnings, a different and much shorter alert for sudden whiteout conditions, are on it.

So do not expect your phone to buzz for a winter storm warning. Check the forecast yourself before you travel.

Source: www.weather.gov/wrn/wea

How a winter storm alert reaches you when the power is out

NOAA Weather Radio All Hazards broadcasts official Weather Service warnings, watches, forecasts and other hazard information 24 hours a day, 7 days a week, directly from the nearest National Weather Service office.

A battery powered weather radio keeps working when the power and the internet do not. That is the exact situation a winter storm creates.

Source: www.weather.gov/nwr

Sources

  1. NWS: Winter Weather Warnings, Watches and Advisories
  2. NWS Baltimore/Washington: Watch, Warning and Advisory definitions
  3. NWS: Winter Weather Safety During a Storm
  4. NWS: Wireless Emergency Alerts
  5. NOAA Weather Radio All Hazards