Originally, the day 1-3 used "See Text" (not outlined in the categorical versions), Slight (1), Moderate (2) & High (3); Day 4-8 Outlooks outlined a 30% area if confidence was high enough. Now, they use (1) Marginal (replaces See Text and is outlined in the categorical versions), (2) Slight, (3) Enhanced (replacing the upper-end of slight), (4) Moderate and (5) High. Also, a 15% risk is available to use in the Day 4-8 Outlooks.
The SPC then issues Mesoscale Discussions followed by either Severe T'storm or Tornado Watches, if conditions are favorable for severe weather in and around the watch area. After that, it is handed off to the WFOs for warnings & statements:
- Hazardous Weather Outlook (HWO): issued when forecast calls for severe weather
- Special Weather Statements (SWS): strong storms approaching
- River Flood Watch: river flooding probable
- River Flood Warning: river flooding imminent
- River Flood products are usually issued by the River Forecast Centers
- Flood Advisory: very localized flooding, primarily near creeks and streams
- Flood Watch: widespread flooding from heavy rain probable
- Flood Warning: widespread flooding... occurring or imminent
- Flash Flood Watch: quick flooding probable
- Flash Flood Warning: quick flooding likely
- These are not issued if the flooding is only expected to affect the usual poor drainage & low-lying spots
- Severe TS Warning: severe storm or severe storm conditions imminent
- Wind gusts of 57.5 mph or greater
- Hail at least 1" thick occurring
- Tornado Warning: tornado occurring (spotter report) or imminent (radar indicated rotation)
- Tornado Emergency: strong tornado (potentially w/ at least 100 mph winds) occurring & moving toward major population center
So, my questions are:
- Would you take action or increase level of concern if you were in a marginal risk of severe storms? How about slight? Enhanced? Moderate risk? High risk? Or should we change those categorical names?
- What do you do if you hear that a watch is issued? What about when a warning is issued? Does knowing the outlook category matter in each of those situations?
- There's confusion as to the difference between a watch and warning, primarily because they both begin with "W." How would you fix the NWS alerts suite? We have Outlook, Statement, Watch, Advisory, Warning, Emergency.
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