As Winter Storm Jonas begins pounding away at the northeast corridor, folks are watching weather reports with rapt attention.

For the past several days, various areas up and down the mid-Atlantic have been receiving dispatches from local and state authorities, prompted by the National Weather Service, involving winter storm "warnings" or blizzard "watches."

But, what's the difference? And, are these measurements uniform across the nation?

"Winter weather related Warnings, Watches and Advisories are issued by your local National Weather Service office," explains the NWS. "Each office knows the local area and will issue Warnings, Watches or Advisories based on local criteria. For example, the amount of snow that triggers a 'Winter Storm Warning' in the Northern Plains is typically much higher than the amount needed to trigger a 'Winter Storm Warning' in the Southeast."

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The agency adds that the difference between "watches" and "warnings" boils down to action or lack thereof.

In warnings, the NWS is advising Americans to take immediate action as a result of current or impending severe weather. In other words, warnings often indicate that folks should not travel, and they should seek shelter.

In watches, the NWS is prompting Americans to prepare to encounter dangerous weather that will make travel treacherous. 

And, in advisories, the NWS is informing Americans to stay alert and expect to travel with caution.

In other words, warnings, watches and advisories are safety measures that communicate weather's severity – and whether or not you should even leave the house.