If you noticed in my local forecast, scattered showers are expected today, but with a twist. With the right ingredients in place, a couple of cold air funnels may occur.
So what are cold air funnels?
They form beneath showers when the air aloft is especially cold. These funnels occur when the air near the surface is warm enough to lift, causing convection to bubble up and form showers. These conditions are even ripe enough to produce some pea-size hail, which we saw in spots early this morning. On the surface today, we see the core of this spinning low just to our west.
Temperatures around 15,000 to 20,000 feet above the ground are quite cold now, and combined with the shift in winds near the base of the cloud, a cold air funnel develops.
Cold air funnels are usually harmless, but on rare occasions they can touch down and cause EF-0 levels (winds up to 85 mph).
It is usually not necessary for the National Weather Service to issue Tornado Warnings for cold air funnels. Since they are so weak and short-lived, they are also very difficult to detect on radar.
In many cases, spotter and public reports are are the only reliable sources we have when cold air funnels do occur in the area. If you happen to see one, please don’t hesitate to let us know!