When a weather alert interrupts your afternoon, the single most important thing is knowing which kind it is — because a watch and a warning call for completely different responses, and mixing them up leads people to either panic early or ignore the one that matters.
Watch: conditions are favorable
A watch (severe thunderstorm watch, tornado watch, winter storm watch) means the ingredients for dangerous weather exist over a broad area in the coming hours. Nothing has happened yet. The classic analogy: a tornado watch means the ingredients for a tornado are on the counter; a warning means one is in the oven. What a watch asks of you: stay reachable, keep an eye on the sky and the radar, and mentally walk through where you'd go — but your barbecue doesn't need to end. Most watches expire without the hazard ever touching your neighborhood.
Warning: it's happening
A warning means the hazard is occurring or imminent for your specific area — radar has detected it or spotters have confirmed it. This is the act-now tier: a severe thunderstorm warning means damaging wind or hail is inbound within minutes; a tornado warning means take shelter immediately, not after one more look outside. For outdoor plans, a warning during your window isn't a judgment call — the event pauses, people move inside or into vehicles, and you wait it out. Warnings are typically short (30–60 minutes) because they track actual storms.
Advisory: nuisance tier
An advisory (wind advisory, winter weather advisory, heat advisory) covers weather that's disruptive but not immediately dangerous with sensible precautions — the tier where you swap the umbrella for a rain jacket, secure the canopy, or move the toddler's party indoors while the adults carry on. Advisories are the most commonly ignored alerts, and mostly that's fine; the exception is heat advisories, which quietly send more Americans to the hospital than any dramatic storm category.
How alerts appear on Weather or Not
Every check on this site automatically pulls active NWS alerts for the exact location you enter and shows them above the forecast — and any warning overrides the verdict entirely, no matter how mild the rain percentages look. That hierarchy is deliberate: percentages are probabilities, but a warning is an observation. When the two disagree, believe the warning.