NOAA's Storm Prediction Center (SPC) is responsible for issuing severe thunderstorm and tornado watches across the United States. A watch means that conditions are favorable for the development of severe thunderstorms or tornadoes over the next several hours.

Between 2015 and 2024, the SPC issued an average of 588 watches per year—about 70 percent of those were severe thunderstorm watches, with tornado watches making up the remaining 30 percent.

The phrase "particularly dangerous situation" (PDS) is enhanced wording added to severe weather watches in the United States when significant severe weather is expected.

Forecasters with the SPC issue several PDS watches each year for predicted severe thunderstorm or tornado outbreaks. The SPC issued about 5 PDS watches per year between 2015 and 2024.

The SPC issues a PDS Severe Thunderstorm Watch ahead of derechos—squall lines producing widespread wind damage—or when severe thunderstorms are expected to produce widespread destructive hail (usually baseball size or larger).

The SPC issues a PDS Tornado Watch when forecasters are confident that the environment is capable of supporting multiple intense tornadoes, producing damage equivalent to an EF-2 or stronger on the Enhanced Fujita Scale.

Local National Weather Service offices also have the leeway to append "particularly dangerous situation" to localized alerts, such as flash flood watches or red flag warnings during instances of extreme fire danger.

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 146
NWS Storm Prediction Center Norman OK
1240 PM CDT Sat Apr 27 2024

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of
Western Oklahoma
Northwest Texas

* Effective this Saturday afternoon and evening from 1240 PM until 800 PM CDT.

...THIS IS A PARTICULARLY DANGEROUS SITUATION...

* Primary threats include...
–Several tornadoes and a few intense tornadoes likely
–Widespread large hail and scattered very large hail events to 3 inches in diameter likely
–Widespread damaging winds and isolated significant gusts to 75 mph likely

SUMMARY...Intense thunderstorms are expected to develop this afternoon along and east of a dryline over western Oklahoma and northwest Texas. Supercells are expected, capable of very large hail and damaging winds. The most intense cells may also produce strong or potentially long-tracked tornadoes.

The tornado watch area is approximately along and 70 statute miles east and west of a line from 35 miles east northeast of Alva OK to 45 miles southwest of Wichita Falls TX. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU6).