Funnel, Scud, ??

June 10th, 2013 at 11:47 am by under Bill's Blog, Weather

hudsonvile - looking SE festival day - jenni westra  Click on the picture to enlarge.  Jenni Vorenkamp Westra put this picture on my facebook page.  This is Sunday evening in Hudsonville, by the RR crossing looking southeast.  This was a shower (not a thunderstorm), pretty much a single cell by itself.  It did produce brief heavy rain.  I was tracking this cell on my phone while I was down at Festival and giving the Festival committee updates on where this shower and others were headed.  From a still shot, you can’t tell if the lower cloud in the middle is rotating.  This is a relatively small shower in size, not a big Oklahoma thunderstorm, so we are fairly sure that if this shower would have produced a tornado (and you don’t need lightning and thunder to get a small tornado), it would have been small and weak.  This may very well be what we call a “scud cloud“.  These are low and often scary looking clouds that hang down underneath showers or thunderstorms and can move fairly fast, but they by themselves do not produce tornadoes.  The rule to remember…if it’s not rotating, it’s not dangerous.  Tornadoes have to rotate.  They also have to be strong enough to produce damage.  A “tornado”  with winds spinning around at 40 mph may not do any damage at all and in fact, the EF scale starts at 40 mph, so technically, a circulation with 39 mph winds isn’t yet a tornado.

Now, what if you’re the meteorologist on duty.  You got a picture like this.  The first thing you would do is look closely at Hudsonville on the radar.  You wouldn’t rush to issue a tornado warning.  You’d look for other clues.  You might also call law enforcement to get more eyes on this.  Next, if you did see or hear something that might lead you to issue a warning…you might think about the area and type of impact.  If, by chance,  you were to get enough confirmation to issue a tornado warning, you could issue it for a very small area.  The shower was small and moving north.  Do you really need to issue the warning for western Kent County and have the sirens sound throughout much of Kent County?   Probably not.  A warning could be issued for a relatively small portion of Ottawa Co.  This is no danger from this shower in Holland or Zeeland, no need to sound sirens in Tulip City and disrupt activity there.  One of the questions we are looking at now when we issue warnings is impact.  Every time a tornado warning is issued, there’s an impact.  People take action.  If we issue too many tornado warnings when there is no tornado, people become complacent and not take action when there is a tornado that is a significant threat.  That’s why trained spotters (and reports from the public like this picture from Jenni)  are still a very important part of the severe weather warning process.   A very small area of SE Ottawa County did see a quick half-inch of rain from this shower, which weakened some as it got past M-45.

14 Responses to “Funnel, Scud, ??”

  1. Eric Ring says:

    This cloud was rotating, I watched it from different locations, and every time I saw it it was rotating. Some times faster then others. A buddy of mine said he thought it was a tornado, but there was no thunder or lightening, which I thought you had to have for one.

    1. Doug says:

      No, a tornado need not be accompanied by thunder and lightning, although that is frequently the case. I live in SE GR, saw the color the sky to the west was turning, and was waiting to hear a siren, but it didn’t quite get it together.

  2. Brian says:

    We were under this cell as it developed just east of Hudsonville and north of Jamestown. Lots of heavy ran and minimally gusty but nothing too spooky. We watched the radar image from 8-3 and looked for any characteristics like bow echoes but given the conditions and the shape we weren’t worried by what we saw. Didn’t witness the rotation Eric saw, but that’s not to say it didn’t have some.

  3. Harry (Battle Creek) says:

    Bill, thanks for clearing the air (so to speak) on this!

    Great write up.

    Unfortunately, people are too concerned with getting the “first call” or pat on the back for diagnosing to the public a tornado/danger when in reality it’s nothing more than a cloud formation.

    This will likely get worse with years to come, and it’s going to take people like you to set it straight.

  4. Pam(Jamestown) says:

    I saw this “thing” rotating as well. Pretty freaky looking and our trees were doing a swirling dance too. Not saying it was a tornado but I definately seen some rotation in it.

  5. DF (SE Mich) says:

    Let’s face it, the NWS needs to figure out how to issue a Tornado Watch first =)

  6. DF (SE Mich) says:

    Looks like a scud to me but saying the picture is not very good quality is an understatement.

  7. Evie says:

    Bill,
    I wanted to say thank you for the kindness you always show people when you are out in the community. You always take the time to greet people and talk with them. I was sitting high in the bleachers at the Calder Stage as Festival was beginning its closing ceremonies. I happened to see you down below talking with people. One little boy came up and you shook his hand. I don’t think you saw his face when he walked away from you but I did. He was just beaming!!! He had just shook hands with a television celebrity!!! You made his day. Your kindness made mine! Thank you

  8. mr. negative says:

    Scud…that’ what we do

  9. TomKap (Michigan St. & Fuller) Grand Rapids says:

    I’d bet that if it didn’t have that little ‘hook’ at the bottom, no one would have given this formation even a second look.

  10. P says:

    When people see things like this, they need to make a video and not take a snapshot.

  11. That is a super massive wedge tornado. In fact it’s two wedge tornadoes, swirling around each other. It’s an EF-7 I believe. I know because I am part of the Super Duper Weather Squad. It’s a good thing that didn’t touch down, it would have drilled holes in the ground that would have struck Michigan’s oil reserves that we should be drilling to stimulate our economy ;)

    1. Realistically, it was a shelf cloud. Nothing more, nothing less.

      1. BeckyinGR says:

        Yup… my daughter and I chased it for awhile for kicks and NEVER saw the alleged rotation… shelf cloud for sure. :)

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