Expect More Supercells Over Wyoming This Week

According to Don Day, regional weatherman from Day Weather, we can expect more supercells in the next few days.

Conditions are lining up for - pardon me - the perfect storm.

High pressure brings up wind and moisture from the gulf.

A low-pressure system brings down cool moisture from the north.

Wyoming is in the middle.

Expect most of these storms to build east of the divide, over the planes.

That covers the same areas that experienced these storms last weekend.

The complete forecast from Don Day can be seen in the video below.

In the past week Wyoming, and nearby states, have suffered through some "supercell" thunderstorm activity.

Beautiful to watch, from a distance.

Horrible to be caught underneath one.

Let's take a look at when a thunderstorm actually reaches the size that we can call a supercell and what causes it.

Supercells are the least common type of thunderstorm.

But when they do happen, we know it.

They will produce the most severe weather, including damaging winds, very large hail, and sometimes weak to violent tornadoes.

These massive storms contain a deep and persistent rotating updraft called a mesocyclone.

Below is a timelapse of supercells forming.

Supercell thunderstorms can last for several hours.

Wind shear not only creates the mesocyclone, but it also allows the storm to be tilted, which is important for maintaining a separate updraft and downdraft region.

A separate updraft and downdraft allows the supercell to be long-lived because it reduces the likelihood that too much rain-cooled, stable air from the downdraft region will be ingested into the updraft, causing the storm to weaken. (National Weather Service).

These storms are not always as wet as you might think

They often pop up in the dryer regions of Texas and Oklahoma Panhandles.

Miniature supercells are smaller versions of classic supercells, they typically form in the cool season.

The figure below shows the vertical wind field associated with a typical supercell thunderstorm.

The storm is rotating counter-clockwise (red arrows), which is typical for most long-lived supercells in the Northern Hemisphere.

The striations of the low-level clouds reflect, in part, converging low-level winds (green and yellow arrows) curving into the rotating updraft of the storm.

This rotating updraft is known as a mesocyclone.

The anvil-shaped formation at the top of the storm marks the level at which the updrafts reach the stratosphere, lose buoyancy (ie., stop rising) and begin to move downstream (blue arrow). (NOAA).

Local and regional meteorologist Don Day of Day Weather told us that he expects to see more of these storms as we go through this wetter, cooler, summer.

The conditions are lining up just right.