Watch vs. Warning #
Watch = conditions are favorable, be prepared. Warning = it's happening now or imminent, take action. Watches are large and last hours; warnings are small polygons lasting 30–60 minutes.
Tornado & Severe Thunderstorm Alerts
A Tornado Warning is not a Tornado Emergency, and a PDS watch is a very different animal from a regular one. This page explains every tier of tornado and severe thunderstorm alert the NWS issues, including the damage-threat tags you see on modern warnings. These are the alerts Xtreme Weather Discord (XWD) pushes in real time during coverage; the codes for every other hazard live on the NWS Alert & Product Codes page.
What is a Tornado Watch? #
A Tornado Watch means conditions are favorable for tornadoes to develop. Issued by the SPC, watches typically cover large multi-county/state areas for several hours. Stay weather-aware — be ready to act if a warning is issued.
What is a PDS Tornado Watch? #
A PDS Tornado Watch is issued when the SPC puts the probability of significant (EF2+) tornadoes at 80%+, with an expectation of multiple long-track tornadoes and potential for violent (EF4–EF5) touchdowns. There are no hard automated criteria — it's a forecaster call, and they're rare (less than 3% of all watches). Treat the day as an outbreak day from the moment it's issued.
What is a Tornado Warning? #
A Tornado Warning means a tornado is occurring, imminent, or indicated by radar within the highlighted polygon. Take shelter immediately — get to the lowest interior room, away from windows. Warnings typically last 30–45 minutes and apply only inside the polygon, not the entire county.
What is TOR-C? #
TOR-C is the Confirmed detection tag on a Tornado Warning — meaning a tornado has been visually confirmed by a spotter, law enforcement, or emergency management. The C stands for Confirmed, not Considerable. It is a detection method tag (like TOR-R and TOR-O), not a damage-threat tag.
What is TOR-O? #
TOR-O indicates a Tornado Warning with Observed detection — meaning a spotter, law enforcement, or NWS personnel has visually confirmed the tornado. Stronger evidence than Radar Indicated.
What is TOR-R? #
TOR-R means Radar Confirmed — the tornado is confirmed by radar evidence, such as a debris signature, rather than by a visual report. Still take it seriously.
What is TOR-P? #
TOR-P indicates a PDS Tornado Warning — a Tornado Warning using Particularly Dangerous Situation wording for an especially dangerous confirmed tornado threat. It sits below a Tornado Emergency in severity and should be treated as an immediate life-threatening situation.
What is a PDS Tornado Warning (TOR-PDS)? #
A PDS Tornado Warning uses Particularly Dangerous Situation wording — reserved for situations involving a confirmed violent tornado posing an extreme threat to life. PDS is a wording designation, not an IBW damage tag. It sits a step below a Tornado Emergency in severity. Take shelter immediately.
What is a Tornado Emergency (TOR-E)? #
A Tornado Emergency (TOR-E) is the highest tier of NWS tornado wording — a Catastrophic damage-threat tag attached to a Tornado Warning. It indicates a confirmed, violent tornado moving into a populated area with a severe threat to life. It is not a separate product — it's the most extreme phrasing inside an active Tornado Warning.
What Triggers a Tornado Emergency? #
NWS guidance suggests considering a Tornado Emergency when: (1) a tornado is confirmed on the ground, (2) VROT is ≥ 70 kt on radar, and (3) STP is ≥ 6 in the near-storm environment, AND the storm is moving toward a populated area. It requires shift supervisor approval. It is the rarest, highest-tier warning in NWS's product suite.
What is a Severe Thunderstorm Watch? #
A Severe Thunderstorm Watch indicates conditions are favorable for severe storms producing damaging wind and large hail. Issued by the SPC over a broad area for several hours.
What is a PDS Severe Thunderstorm Watch? #
A PDS Severe Thunderstorm Watch is a rare, high-end watch issued by the SPC when an exceptional severe thunderstorm outbreak is expected — typically significant wind events (70+ mph), very large hail (2"+ widespread), or both. Far less common than a PDS Tornado Watch but signals an extremely dangerous non-tornadic threat.
What is a Severe Thunderstorm Warning? #
A Severe Thunderstorm Warning (SVR) means a storm is producing — or imminently capable of producing — 1"+ hail and/or 58 mph+ winds. These storms can still spawn tornadoes without notice. Move indoors and away from windows.
What is SVR-C? #
SVR-C is a Severe Thunderstorm Warning with the Considerable damage-threat tag — typically 70 mph+ winds and/or 1.75" (golf ball) hail. No WEA alert is sent at this tier, but damage is likely.
What is SVR-D? #
SVR-D is the Destructive damage-threat tag — the highest severe thunderstorm tier. Requires 80 mph+ winds and/or 2.75" (baseball) hail. Triggers a Wireless Emergency Alert (WEA) to phones — the same as a Tornado Warning.
What is an SVS? #
A Severe Weather Statement (SVS) is the follow-up product issued to update or cancel an active warning. SVSs contain the latest storm position, intensity changes, and additional impact info.
What is an Extreme Wind Warning (EWW)? #
An Extreme Wind Warning (EWW) is a short-fuse product issued when hurricane-force surface winds (74+ mph) from a tropical cyclone are expected to begin within 1 hour. It's a take-action-now product — if you haven't evacuated by the time an EWW is issued, shelter in place immediately.