Isolated severe storms possible across northern Illinois Thursday

Storm Chances Return:

Apart from Wednesday's notably strong southwesterly wind, the combination of sunshine and 60° warmth made for another gorgeous afternoon.  

As we move into Thursday, this is when we enter a slightly more active and cooler weather pattern. Most of the day Thursday will be dry, though we can expect clouds to increase early on. With the current track of our next low pressure system, surface flow will be out of the northeast, resulting in cooler high temperatures. Most locales will peak in the low to mid 50s. Still mild, but not as warm as yesterday. 

In their latest round of outlooks, the Storm Prediction Center places the highest severe potential well south of the Stateline area. Areas east of St. Louis are under a level 2 Slight Risk for severe storms. 

It's in these areas where the warm front will be the focal point for strong to severe storms, allowing all hazards to be on the table. Atmospheric energy will be higher as well as moisture levels. Locally, a level 1 Marginal Risk is in place for areas like Sterling, Dixon, Rochelle, DeKalb, and Amboy. 

Precipitation Timing: 

Shower and storm chances locally will be tied to the surface low itself and should begin to increase late in the afternoon into the evening. The biggest concern with any severe storm will be large hail. 

As colder air wraps around the surface low, rain will turn to the rain/snow mix and then to all wet snow by the time we get into Friday morning. Given the warm past few days, Thursday's rain, and temperatures still only in the low 30s, accumulations will be kept to a minimum (maybe up to a half-inch). Friday's morning commute may be a bit slow with lingering snow showers and reduced visibility with winds picking up.

Cooler Moving Forward:  

After today, it's back to reality as afternoon highs return to the 30s. Mid to upper 30s into the weekend with low 30s into early next week. 

Winter-like chill returns in full force this weekend

 Each of the last 6 days has featured high temperatures well above average and even well into the 50s or 60s! Most of February has featured the milder pattern, including the last several days more than 20 degrees above average!

But all good things come to an end, as cooler air will filter back in by the weekend in a sharp reminder that it is still February. Afternoon highs will return back toward the 30s and much closer to average by the weekend, as a large pocket of colder air will settle overhead through much of next week.

As high pressure takes over Sunday, winds may be strong resulting in a wind chill factor. The coldest days in the near term will be Sunday and Monday with coldest air centered overhead. The wind direction most days will be generally out of the North, helping to keep us cooler.

We will gradually warm back up a bit toward the middle of next week as the next broad low-pressure system arrives between Tuesday and Wednesday. This could bring us a potential for more rain and storms, or snow showers depending on which side of the weather system we end up on. For now, a broader area of precipitation appears likely Tuesday night into Wednesday, with another drop in temperatures expected behind this system.

Strong winds slowly subside Wednesday evening

 The strong winds we've experienced throughout much of the afternoon will begin to subside as we approach sunset, turning much lighter later this evening. Until then, a Wind Advisory remains in effect until 6pm for all of northern Illinois as winds are still gusting around 35 mph in some locations. At the same time, the Red Flag Warning remains in effect until 8pm as relative humidity values have fallen under 20 percent in many locations.

Strong low pressure to the north near the Wisconsin/Minnesota state line has been responsible for the winds this afternoon. But as the sun sets and we lose the mixing of the afternoon (stronger winds pulled down from aloft), winds will ease as low pressure weakens and pulls further to the north.

Clouds will be on the increase through the night as the next low moves in, moving towards Missouri and northern Illinois Thursday. This will bring us our next chance for showers and even a few thunderstorms during the afternoon and evening.

Red Flag Warning in place across northern Illinois

Red Flag Warning: 

Yesterday's wildfires across Oklahoma demonstrated how easily dry, warm, and windy conditions can fuel their spread. Because today's weather conditions will be somewhat similar, the National Weather Service has placed all of northern Illinois under a RED FLAG WARNING from 10AM-8PM. 

  

Along with the Red Flag Warning, Winnebago, Ogle, Carroll, Stephenson, and Jo-Daviess Counties as well as Green County in southern Wisconsin will be under a WIND ADVISORY. This will also begin at 10AM and last until 6PM this evening.  

 

  

Timing of Strongest Winds:

Once the cold front passes through, skies clear rather quick, allowing sunshine to return. But the trade-off is wind, a gusty westerly wind that could top out around 40, possibly 45 mph at times. The strongest winds are expected to arrive late this morning and last through much of the afternoon. And typically, a westerly to southwesterly wind promotes a drier air mass, causing relative humidity values to fall below 25%. 

The combination of the very warm temperatures, dry conditions, and gusty winds will allow any fire that develops to spread quickly. 

So please, avoid outdoor burning today. You can also help prevent wildfires by clearing any brush or leaves, disposing of smoking products safely, and double-checking towing chains and tires. Winds will weaken as we head into this evening, remaining light out of the southeast overnight into Thursday.     

A few storms possible Thursday afternoon and evening

 

While it's nothing set in stone just yet, there is a risk for a few thunderstorms in northern Illinois late Thursday afternoon and evening. The higher risk remains just to our south downstate across central Illinois and Indiana. But a few isolated stronger storms could approach our southern counties by Thursday evening.

Showers moving in Tuesday evening will remain light, but a rumble of thunder or two after Midnight is possible as both low pressure and a cold front approach from the west. The low will lift to our northwest, holding temperatures close to 50 degrees overnight! This will help springboard us into the low 60s Wednesday afternoon.

A second system will approach northern Illinois and southern Wisconsin from the southwest Thursday, drawing yet another warm front north into the Stateline during the afternoon and evening. How far the front lifts north will determine just how warm our temperatures get for the afternoon, but I think it'll come close enough to at least get us back into the upper 50s, if not at 60 degrees. A few isolated showers/thunderstorms could develop as early as the afternoon along the warm front, but a cold front moving across west-central Illinois will likely fire off more scattered thunderstorm activity towards Thursday evening.

The Storm Prediction Center has most of central and east-central Illinois and Indiana highlighted under a 'Slight' risk which means scattered strong to severe storms are possible, while a 'Marginal' risk extends up near I-88 in northern Illinois as a few isolated strong to severe storms are possible. But the coverage of any storm activity this far north will depend on just how far north the warm front makes it, and if we end up within the system's narrow 'warm sector'. If that remains to our south, then the chance for thunderstorms will remain south as well. But if even a small portion of the warm sector moves into northern Illinois, then at least part of the region could be dealing with an isolated strong storm or two.

Early season storm set-ups can be a little tricky as even just a change or two in temperature or dew point can mean the difference in storms or no storms. So, as we approach Thursday just make sure you remain weather aware and updated on the forecast.

Fire Weather Watch issued for northern Illinois Wednesday

 

A FIRE WEATHER WATCH has been issued for all of northern Illinois beginning Wednesday morning and lasting through the evening. Conditions throughout the day will become favorable for quickly spreading fires.

Following a few scattered showers and isolated rumbles of thunder Tuesday night, skies will quickly clear during the morning Wednesday. As they do, west/southwest winds will increase as a drier air mass moves in, causing relative humidity values to fall below 25 percent. The combination of a warm temperatures, dry conditions, and gusty winds will allow any fire that develops to spread quickly.

Outdoor burning of any kind is not recommended Wednesday, and it is advised to be very cautious with the disposal of any burning materials. 

Warm temps persist across northern Illinois; Elevated fire risk Wednesday

Weather Throwback: 

"False spring" gave us a gorgeous and record-breaking President's Day as temperatures area-wide surged into the upper 60s. Rockford's Airport wound up with a high of 66 degrees, which crushed our previous record high of 57 degrees from 1921. Though unseasonably warm temperatures are here to stay for a few more days, it will be tough for us to see record warmth considering the 6-day stretch of record highs Rockford saw back in 2017.    

Today's Forecast:  

We'll find ourselves back in the upper 50s as the entire area will spend a majority of the day under a blanket of mid to upper-level clouds. What will be the main driver for today's temperatures climb will be the organized southeast wind that will be in place. At times, gusts could approach 25 mph. Despite the expansive cloud cover, most of the day will be dry, though expect the opportunity for rain showers to go up as we enter the evening hours.  

Next Rain Chance: 

As a warm front lifts northward, a scattered batch of showers will tag along with it. Once the front is to our north, winds will turn back to the southwest, keeping  temperatures warm. We should stay close to the 50 degree mark into Wednesday. The associated cold front will then pass through during the early stages of tomorrow morning. The chance is low but there could be an additional shower or an isolated thunderstorm as the front sweeps through. 

Elevated Fire Risk Wednesday: 

From there, the air mass will quickly dry out for Wednesday, allowing temperatures to once again warm into the low 60s. But this warmup will come with a very strong west to southwesterly wind, with gusts pushing 40 mph. This, along with the warm and dry conditions will likely to elevate the fire risk for many across the Stateline.