Understanding severe weather: frequency and preparedness tips

Severe Weather Frequency:

It's that time of the year once again - when we pause to review the key components of severe weather and discuss how to stay safe when strong to severe storms are threatening your area. 

Of course, severe weather can occur at any point in the year if the atmospheric setup is right. That being said, there are two periods on the calendar when the threat for severe weather is typically highest across northern Illinois. Our primary severe season occurs in the spring - typically April, May, and June followed by a secondary season in the fall. 

Time of Day:

Severe thunderstorms can also happen at any point in the day, but the most favored window is between 3PM-10PM. But once we move into the evening and overnight hours, things can get even more dangerous. Nighttime severe weather is harder to spot, people are settling in or already asleep, and threats like strong winds, tornadoes, and flash flooding become a lot more hazardous as visibility and awareness is much lower. It's a big reason why we emphasize staying weather aware and have multiple ways to receive watches and warnings, even when the sun goes down.

P.P.M.A - Plan, Practice, Monitor, Act:

That is why it is important to remember the four key steps: plan, practice, monitor, and act. Before any threat for severe weather arrives, make sure you've created a safety plan and practice it - whether that be at home, school, or at work. Make sure your severe weather kit is up to date as well, stocked with things like snacks, water bottles, flashlights, extra batteries, and clothes like closed-toed shoes. 

 

Once the threat for severe weather arises, keep up with the latest updates through the First Warn Weather App, through Eyewitness News broadcasts, and a NOAA weather radio. Staying informed gives you valuable time to reach. And when a warning is issued or strong to severe storms are moving in, don't wait- act immediately and get to your shelter.

Mild, but unsettled for the first week of meteorological spring

Mild, but Unsettled:  

After a weekend that brought slightly chilly highs in the upper 30s, milder weather is set to take over as we head meteorological spring. With it however will come several opportunities for rainfall. 

Today will be dry and pleasant, with highs climbing into the mid to possibly upper 40s.  

Overnight Mix:

Clouds will gather up this evening into tonight as the first of many systems pushes in. Dry conditions will hold tight until about midnight, possibly into the early stage of Tuesday morning. After about 2AM-3AM, isolated light showers are expected to filter in from the west. At first, a shallow layer of cold air may allow for a few brief patches of freezing rain, though the expectation is for any mix to quickly turn to plain rain before mid-morning Tuesday. 

Shower coverage will increase slightly late Tuesday morning into Tuesday afternoon with a few pockets of steadier rain being a possibility. With that being said, several dry periods can also be expected with high temperatures peaking in the low 40s. 

 

  

Late-Week Chances:

Several more storm systems are on the table between Wednesday and early Saturday, resulting in the higher potential for rainfall locally. Next highest chance will arrive Wednesday evening into Wednesday night as a weak surface low wobbles in from the southwest. A better chance for more widespread rainfall will accompany a slightly stronger low and it's associated warm front Friday into Friday night.  

Forecast models continue to show the axis of heavier rainfall ending up to our south. Areas from southeast Oklahoma to central Illinois/Indiana could wind up with 2"-4" of rain during this stretch. 

This of course would be where the highest chance for flash flooding would end up. 

Warmer and wetter pattern begins Monday night

 The first week of meteorological spring will start out with some sunshine, but clouds and more widespread rain potential will fill in over the course of the week. We will not see much cloud cover Sunday night into Monday morning, allowing temperatures to quickly warm from the low 20s to the mid-40s by Monday afternoon. Thicker clouds filter in by evening ahead of the first of several weather systems.

We will remain dry through about 12AM-3AM Tuesday morning, but isolated and light rain will begin to develop before daybreak Tuesday. Initially, there may still be just enough cold air in place to cause a few patches of freezing rain, but this will quickly flip over to just liquid rain by morning.

Coverage of showers will be a bit higher late Tuesday morning into the afternoon, with a few pockets of steadier rain. There will be several dry hours Tuesday afternoon and evening, but it will remain damp with some spotty drizzle mixed in. Temperatures will struggle to reach as warm as they were Monday considering the added cloud cover and spotty rain.

More widespread potential for rain arrives Wednesday and again Friday with stronger passing waves overhead. Each of these could bring some pockets of steady to heavy rain with a few embedded rumbles of thunder. Some drier windows between systems will be centered around Wednesday morning and Thursday afternoon. In total through Saturday morning, rainfall may amount to around an inch for most in Northern Illinois. There may be a sharp cutoff with under a half inch for some in Wisconsin and the most abundant rain remaining across Central Illinois. Temperatures will continue to rise, particularly with Friday's passing system bringing afternoon highs up near 60°!