Watches v. Warnings

[GalvestonDuck]

I could have sworn I asked this last year, but I don't remember the answer.

When I was younger, I'm almost certain a watch meant "conditions were favorable" and a warning meant "activity is present." So a tornado warning meant there was one spotted and/or on the ground. A tornado watch pretty much meant that we needed to keep alert, listen to the weather radio, and be ready to take cover.

But almost all of these issued warnings say "NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO (and then gives the location and movement)." "Capable of producing" but there isn't one yet.

Weird....

Did that change some time in the past when I wasn't looking? I'm sure NWS doesn't consider KY tornadoes different from TX tornadoes.

[ColdFront77]

I've heard "capable of producing" in Tornado Warnings right along.
It isn't possible to know whether or not a tornado will occur in a particular thunderstorm.

[stu]

Many tornado warnings are issued on the biases that the storm is showing rotation on radar. It is properly better to get the warning out then – even trough no eye witness reports have yet come into the local NWS office.

Best to err on the side of safety…

[GalvestonDuck]

True.

Thanks, Tom and Stu!

[ColdFront77]

Good point as well, Stu. You're welcome, Shawn.

[Stormsfury]

Many tornado warnings are issued on the bases that the storm is showing rotation on radar. It is properly better to get the warning out then – even trough no eye witness reports have yet come into the local NWS office.

Best to err on the side of safety…

Bingo ... Doppler radar scans inside of the storm giving a 3-D image of a storm structure, so to speak ... and when a storm exhibits rotation significant enough to be "capable of producing a tornado" (or commonly known as a TVS, which stands for Tornadic Vortex Signature, a warning will automatically be issued) ...

[GalvestonDuck]

So, that answers my other question also -- with the advent of all this great technology, they did change the way they issued those warnings, right? I mean, at one time, they did only issue a "warning" when there was an actual tornado because they couldn't see on radar then what they can see now?

[ColdFront77]

I have seen "Tornadic Vortex Signature" ("TVS") on Intellicast's radar summary images without Tornado Warnings being issued for those cells.

[Stormsfury]

I have seen "Tornadic Vortex Signature" ("TVS") on Intellicast's radar summary images without Tornado Warnings being issued for those cells.

I remember those days on Intellicast when they had the symbols for hail, MESO, and TVS ... I'd like to see that come back even though that was only used in the regional maps.

Speaking of Radial Velocities ... here's Houston's (From Intellicast)

Houston, TX Radial Velocity

[ColdFront77]

The "HAIL," "MESO" and "TVS" still exist on the Intellicast maps and they have had it on the United States image, as well as the regional images.

These "Radar Summary" images are the blue outlined boxes for "Severe Thunderstorm Watch boxes" and the red outlines boxes for "Tornado Watch boxes"

[GalvestonDuck]

Okay, so on the Radial Velocity site, what am I seeing? What does the dark red, almost black, to the west of Galveston tell me?

Sorry, but I'm clueless. Could you define radial velocity?