Yellow area: Slight risk of severe weather between 2:30 p.m. EDT today and 8 a.m. EDT tomorrow.

There is a slight risk of severe thunderstorms in much of northeastern Indiana and northwestern Ohio this afternoon and evening, according to the Day 1 Convective Outlook that the National Weather Service Storm Prediction Center issued at 1:58 p.m. EDT. The slight risk area includes Allen County Indiana and almost all of IMO SKYWARN quadrant two. Parts of Blackford and Jay Counties are not included.

Atmospheric instability will support organized multi-cell thunderstorm clusters and line segments. Damaging winds will be the primary severe weather hazard. In quadrant two, there’s a 15 percent probability of damaging winds of 58 mph or greater within 25 miles of any point.

SKYWARN spotter activation might be needed late this afternoon through the evening hours, according to a Hazardous Weather Outlook from the northern Indiana NWS office.

Whatever agency has responsibility for activating tornado sirens in Goshen essentially sounded a false alarm yesterday.

According to a report in the Goshen News, tornado sirens sounded after Goshen Police received reports of a funnel cloud. The Goshen News report does not say who reported the funnel cloud to police, so we don’t know from that story if any of the calls came from normally credible sources or if they came only from untrained members of the general public. We can assume, however, that the people who reported a funnel cloud to police were probably looking at the cloud shown in the photo below.

Photo of “beaver tail” cloud near Goshen, from NWS website.

As well-trained SKYWARN storm spotters know, “funnel cloud” has a specific definition in meteorology: It’s a rotating cloud that often exists before or after a tornado. Not every funnel-shaped cloud is a funnel cloud and not every rotating funnel cloud becomes a tornado.

Unfortunately for those in charge of Goshen’s tornado sirens, the cloud that appeared near Goshen was not a rotating funnel cloud and the city was not in danger of a tornado.

National Weather Service (NWS) meteorologists later confirmed that the cloud was a formation known colloquially as a “beaver tail,” which is formed as air cools while being sucked into a thunderstorm, thus allowing water vapor in that air to condense into a cloud. These clouds are normally mostly horizontal. When viewed from a certain angle, however, they can appear to be reaching toward the ground. The northern Indiana NWS office posted an excellent explanation on its website. Their article includes a helpful pair of photos of the same beaver tail taken from two different locations, demonstrating the illusion that can occur.

So, how are people supposed to know the difference? A true funnel cloud rotates. A beaver tail doesn’t. “If it doesn’t spin, don’t call it in,” is a mnemonic I learned in spotter training.

Members of the general public who have never taken SKYWARN training have little way of knowing this. So what’s a public safety agency to do when it gets reports of a funnel cloud from the general public? Here’s my opinion:

1. Train public safety dispatchers to be aware that some funnel-shaped clouds that might prompt citizens to call 911 are not actual funnel clouds and therefore represent no danger to the community. This knowledge will help dispatches treat funnel cloud reports with a healthy amount of skepticism.
2. Before sounding tornado sirens, seek confirmation from trained field personnel (e.g. nearby fire fighters, law enforcement officers, EMA volunteers and/or others known to have received SKYWARN training).
3. Before sounding tornado sirens, place a quick call to the NWS. Ask if atmospheric conditions are right for the formation of tornadoes and whether NWS radar indicates any sign of rotation where the funnel cloud was reported. The NWS office can also tell the local public safety agency whether the NWS office has received any reports from trained spotters that would confirm or contradict public funnel cloud reports.

At the very least, any time a local public safety agency activates tornado sirens on its own (e.g. without an NWS warning), that agency should immediately notify the NWS that it has done so, and why. Why? Because without that notification, nobody who depends on NOAA weather radio or broadcast media for their warnings will know what’s going on!

Not everyone can hear tornado sirens where they live and work. Activating tornado sirens without contacting NWS to activate the entire warning system fails to protect those citizens who are beyond the range of sirens.

What do you think? Please add your comments below. And by the way, please understand that this post represents my personal view, not necessarily the views of any agency or organization.

Update: Severe potential less clear. Read more.

SKYWARN storm spotters in northeastern Indiana, northern Ohio and southeastern lower Michigan might need to activate late this morning and/or this afternoon, due to a slight risk of clusters of severe thunderstorms with damaging straight-line winds and large hail. Among other areas, the slight risk area includes the entire eastern half of the area served by the northern Indiana National Weather Service (NWS) office (IMO SKYWARN quadrants one and two). In addition to severe wind and hail, locally heavy rain is possible.

Within the slight risk area, there is a 15 percent probability of damaging thunderstorm winds or wind gusts of 50 knots (58 mph) or higher and hail of one inch diameter or larger within 25 miles of a point and a two percent probability of a tornado, according to the Day 1 Convective Outlook that the NWS Storm Prediction Center issued at 8:57 a.m. EDT. Read more about outlook probabilities.

In addition, SPC issued a mesoscale discussion at 8:52 a.m. EDT in which forecasters indicated that they would very likely issue a watch for northern Indiana and northwestern Ohio shortly.

Now for some meteorology: A cold front will move east-southeastward into the area today. Meanwhile, forecasters expect a corridor of moderate to strong atmospheric instability to form this afternoon across portions of Illinois, Indiana, lower Michigan and Ohio ahead of the front. These factors could combine with strong changes in wind speed with altitude to allow thunderstorms to develop near the cold front, with isolated severe wind and/or hail. The number and severity of storms depend somewhat on the amount of sunshine we get this morning. Heavy cloud cover would limit the atmospheric destabilization that severe storms require. Read more in an Area Forecast Discussion from the northern Indiana NWS office.

As always make sure you’ll be aware of any watches or warnings that NWS might issue today and remember, the Fort Wayne NOAA Weather Radio transmitter remains weak, so depending on your location, you might need another way to get watches and warnings.

Update: The 1:20 p.m. EDT update to the Day 2 Convective Outlook looks pretty much the same as this morning’s version. Our next look at tomorrow’s severe weather risk comes at about 2 a.m. tomorrow, when the first Day 1 Convective Outlook of the day comes out.

A slight risk of severe weather exists throughout much of Indiana and Ohio between 8 a.m. EDT Wednesday, August 7 and 8 a.m. EDT Thursday, August 8, according to the Day 2 Convective Outlook that the National Weather Service (NWS) Storm Prediction Center (SPC) issued at 2 a.m. EDT today. The slight risk area includes all of IMO SKYWARN quadrant two.

The outlook indicates a 15 percent probability of severe weather within 25 miles of any point in the slight risk area. The greatest risks are straight-line winds and possibly some hail. Read more about outlook probabilities.

The storms are most likely in the afternoon tomorrow, according to the Hazardous Weather Outlook that the norther Indiana NWS office issued at 5:11 a.m. EDT. That outlook also indicates that SKYWARN spotter activation might be needed tomorrow afternoon.

We get our next look at tomorrow’s weather situation when the SPC issues an updated Day 2 Convective Outlook at approximately 1:30 p.m. EDT today.