Severe weather season is around the corner. Here you will learn what it takes for severe storms to develop and how you can prepare for them before they arrive.

The Power of VIPIR

In January WMBD and WYZZ launched a new weather system from Baron, a system we call VIPIR. This new system integrates Baron state of the art radar technology with a clean graphics package.

In addition to some of the winter weather products we’ve highlighted his winter such as road temperature forecasts and radar estimated snowfall accumulations, VIPIR will be able to analyze storms like never before. Here are some of the EXCLUSIVE tools we’ll have at our disposal this severe weather season…

Shear Rate – This exclusive product is something we call Rotation Tracker and monitors storm rotation. Using this technology we can display the rate of rotation in a storm and highlight the risk of tornadoes and wind damage based on a weak to strong to extreme scale.

SCIT (Storm Cell Identification Track) – SCITs are similar to the storm tracks provided by the National Weather Service, except these are calculated from the source of the rotation instead of the center of the storm. There are two type of SCITs, the BARON Severe Storm (Red) and BARON Shear Storm (Orange). The Severe Storm SCITs identify storms that are most likley to produce severe hail while the Shear Storm SCITs identify storms with a greater tornado or damaging wind threat. When the SCIT arrow is clicked, a storm cone will be displayed with an estimated time of arrival for areas impacted.

When used properly, SCITs can be an early warning to a rapidly intensifying storm giving you a little extra warning. You an see an example of the severe and shear storm SCITs in the image below.

VIPIR Tornado Index (VTI) – Also referred to as the Baron Tornado Index (BTI), VTI rates the likelihood a tornado is on the ground based on a 0 to 10 scale and is something you’ll only find on WMBD and WYZZ. The higher the VTI values the greater the probability a tornado is on the ground with a particular storm. Sudden jumps in VTI values indicate that the risk of a tornado are increasing. In the image below, you can see the BTI value is at a 4.4 with an active tornado warning.

Baron Button – This is a product we call Threat Tracker. There can often be a lot of noise on the radar but the Baron Button highlights the main threats in an easy to read way. This product highlights which areas are dealing with a hail threat, wind/tornado threat or a heavy rain threat. By using this product we can see estimated hail size, wind speed and rainfall rates without having to switch between multiple radar products to see them.

Hail Swath – Also known as our Hail Tracker, the VIPIR Hail Swath uses Dual Pol Technology to display the likelihood of hail based on a possible to probable to likely scale. By looking at the swath over the last 90 minutes, we can quickly tell you whether or not a storm has a history of producing hail.

Tornado Debris Signature (TDS) Swath – This is a product I hope I don’t have to use frequently. Thanks to Dual Pol Radar Technology we can no spot debris being lofted into the air by tornadoes confirming that a tornado is on the ground. If a TDS is identified on radar, VIPIR will map out a swath from when the TDS was first identified on radar until it is no longer detected. This is as close to real-time radar confirmation as it gets. Using this product we will have even more confidence on whether or not a tornado is on the ground instead of having to rely on ground reports.

Storm Preparedness

It’s important to plan ahead in the event of a severe weather outbreak. Even though severe weather may not be on the mind when the weather is cold, it’s the perfect time to have a plan in place for when the time comes. here are some tips to keep you and your family safe. 

Know Your Risk

Make sure you understand what types of severe weather could potentially impact your area. 

  • Lightning – When thunder roars, go indoors. If you hear thunder you are close enough to be struck by lightning
  • Hail
  • Damaging Winds
  • Tornadoes
  • Flash Flooding – Turn around don’t, drown. Most deaths that occur during flash flooding events can be avoided by simply avoiding flooded roadways. While the water may appear shallow, the condition of the road below the water may be poor and could lead to your vehicle being washed away.

Know the Difference Between a Watch and a Warning

  • A watch simply means that conditions are right for severe weather to occur. These watches are typically issued hours before storms have even developed and typically are very large and cover numerous counties and even states. When a watch is issued, make sure you have emergency plans in place and emergency kits ready to go.
  • A warning will be issued if an event is occurring, imminent or likely. This is the time to act!!! Seek shelter immediately in a sturdy building and avoid exterior walls and windows. It’s also good practice to stay on the lowest floor of the building until the warning has ended. 

Build An Emergency Kit

  • 3 day supply of water, one gallon of water per person per day (Family of 4 = 12 Gallons of Water)
  • At least 3 day supply of non-perishable food
  • Can opener for canned food
  • NOAA all hazards weather radio with extra batteries (Weather Radio Programming Link)
  • Flashlight with extra batteries
  • First aid kit
  • Whistle to signal for help
  • Infant  formula and diapers, if you have an infant
  • Moist towelettes, garbage bags and plastic ties for personal sanitation
  • Wrench or pliers to turn off utilities
  • Have a map and compass to help guide you to predetermined safe places and shelters that should be circled on the map. It’s important to note that streets may become unrecognizable after a significant tornado so make sure you are able to navigate without the aide of street signs and landmarks.

How Do Severe Storms Develop?

Have you ever wondered what it takes for severe thunderstorms to develop? Well look no more. Here are the primary ingredients required for severe storms.

Instability – An unstable airmass is one where there are warm temperatures at the surface and colder temperatures aloft. The warmer the air at the surface and the colder the air aloft, typically the greater the instability. 

Wind Shear – While instability is required for thunderstorms, they may not become severe unless there is enough wind shear. Wind shear is wind changing direction and/or speed with height. This allows storms to tilt and rotate allowing them to last much longer than ordinary thunderstorms do. 

Lift – You typically need something to force air to rise. While instability will force air to rise, you will often need something to get the parcel of warm & moist air to start rising. This can come in the form of mountains, fronts, and boundaries. However, seeing as Central Illinois is void of mountains, cold fronts, warm fronts and outflow boundaries can act as our lifting mechanisms.

Moisture – If an approaching area of low pressure is the engine, then low-level moisture is the fuel for these storms. For storms to become severe, we need moisture. This moisture often comes from the Gulf of Mexico. The more moisture we have, the greater the instability will be giving us a greater possibility of severe storms.

How Do Tornadoes Develop?

While pinpointing exactly when and where a tornado will touch down, we can (with reasonable accuracy) forecast days in advance when conditions are right for them to develop. Once we find that the atmosphere will be unstable enough for thunderstorms, we’ll look at the amount of wind shear that’s in place to see if any of these storms can become severe. 

In order for tornadoes to form, you need to have a significant amount of wind shear. This is wind changing direction and or speed with height. In the typical tornado set up, you’ll have southeasterly winds at the surface, a fast-moving low-level jet a few thousand feet off of the ground moving in from the south with the jet stream moving from the west at 25-35 thousand feet. 

Due to the change in wind direction and wind speed with height, air will begin to rotate horizontally. As storms begin to develop, these horizontal rolling tubes of air will be absorbed by a thunderstorm’s updraft allowing that storm to take on rotation. As the storm’s rotation tightens, the base of the storm will lower eventually leading to the development of a tornado.

Illinois Tornado Stats

While tornadoes are possible any time of year, they are more common in late Spring and early summer across Illinois. On average, Illinois sees 12 tornadoes in April, 15 tornadoes in May and 10 tornadoes in June. The reason tornadoes are more likely this time of year is due to the Jet Stream retreating north for the Summer months. This allows warm moist air from the Gulf of Mexico to interact with cool dry air coming from the north. With the Jet Stream positioned over Illinois from April through June, it allows severe storms to develop. 

Once summer arrives, the Jet Stream is typically positioned across the northern U.S. and southern Canada. This will keep the bulk of the wind shear north of Illinois lowering the overall risk for tornadoes. You will notice that there is a slight increase in tornadic activity in November. This is often seen as Illinois’ “Second Severe Weather Season” as the jet stream begins to drop south for the winter. While November is typically seen as a colder month and a time of year we start to talk about snow, tornadoes are still very possible…such as the Washington tornado on November 17th, 2013.

How Does Hail Form?

Hail forms when powerful updrafts send water droplets to the top of a thunderstorm where temperatures are below freezing. When these water droplets move into an environment where they become super-cooled or freeze into ice pellets. As these supercooled water droplets and ice pellets run into one another they will grow into larger and larger hailstones. The hail will remain in the storm until it becomes too heavy and falls to the ground. 

Hail Size Comparison Chart

0.50″ – Marble/Mothball

0.75″ – Penny

0.88″ – Nickel

1.00″ – Quarter

1.25″ – Half Dollar

1.50″ – Walnut, Ping Pong Ball

1.75″ – Golf Ball

2.00″ – Hen Egg

2.50″ – Tennis Ball

2.75″ – Baseball

3.00″ – Tea Cup

4.00″ – Softball

4.50″ – Grapefruit

For additional weather safety tips visit the following links…


Red Cross

National Weather Service

Weather-Ready Nation

WMBD and WYZZ are Weather-Ready Nation Ambassadors and will be partnering with Midland Radio Corporation, Walgreens and Hy-Vee to sell weather radios across Central Illinois. Stay tuned for upcoming events where Your Local Weather Authority and members from the NWS along with Emergency Managers will team up to program Midland Weather Radios.