Unseasonable warmth with thunderstorm chances to start the week

 

Starting today, our temperatures will begin to slowly creep back average as high temperatures will be in the 60's and 70's over the next few days! That's in thanks to a consistent southwesterly breeze that will help to steadily improve temperatures along with an arriving low-pressure system by Tuesday morning that will also bring the possibility of a few thunderstorms.

The first of those chances will come late Monday night and into Tuesday morning as a weak disturbance moves overhead. With warm and humid conditions setting up for Monday, instability will gradually develop throughout the day however an atmospheric cap or "lid" will be in place keeping storm potential limited. If we can lift the cap later into the evening, the instability available would support a few isolated thunderstorms which would also carry the potential of producing hail, strong wind gusts, and heavy downpours.

As for Tuesday, if a few thunderstorms fire overnight, another round may still be possible with the disturbance aloft until the morning. However, the higher chances will come later into the afternoon as the arriving cold front may also spark off a few showers and thunderstorms.

Plenty of atmospheric instability is expected to setup both on Monday and Tuesday which will be the main fuel for thunderstorms if they do occur each day. Along with that, some dry air from our west will allow any thunderstorm to develop to carry the potential of large hail and will be capable of producing a damaging wind gust or two. As of now the Storm Prediction Center has the state line outlined in both a Day 2 and 3 Marginal Risk for the possibility of isolated severe thunderstorms. Expect chances to the forecast in the coming days, so make sure to keep an eye on the forecast!

Continued warmth fuels thunderstorm risk Monday night

 It's been a cooler stretch in the Stateline lately, but that's about to change in a big way next week! Starting Sunday, temperatures will rise back above average for the early part of the week. Highs push the mid-60s Sunday, then 70s Monday and Tuesday. Overnight lows will be very mild starting Sunday night, remaining in the 40s and 50s. That is, until our next cold front arrives.

Ahead of this front, we will see substantial instability, or storm energy, develop in the atmosphere Monday. The afternoon will be capped, preventing much if not all storm development. But overnight that cap will erode, allowing storms to form in Northern Illinois and Southern Wisconsin. Timing looks to be primarily after 10PM Monday.

A few of these storms may be capable of producing large hail and gusty winds. Any storms that produce 1" diameter hail or 60 mph wind gusts will reach severe limits. The Storm Prediction Center has placed Northern Illinois into Central Wisconsin under a Level 1/5 Marginal Risk for severe weather, indicating a few severe storms may be possible. Our primary threat will be with the large hail, but an isolated severe wind gust cannot be ruled out either.

Additional showers and storms will be possible along a passing cold front Tuesday as well, with a similar risk for some isolated severe storms. The best coverage will pass South and East of the area by Tuesday evening as cooler and drier air arrives through the course of the day. High temperatures Wednesday and Thursday will likely be back in the 40s.

Warming up this weekend with an elevated fire risk

 After a chilly and breezy Friday, this weekend will bring a steady rise in temperatures back above average. From the low 20s Saturday morning, the afternoon will see highs push back toward 50. The surface high pressure responsible for the chill will slide overhead and past us to the East by then, turning the winds back around to the South and Southwest. Sunday's high temperature will climb even higher, reaching into the low 60s.

That Southwest wind could gust toward 20-30 mph Saturday afternoon, and even higher across Iowa and Minnesota. But moisture will lag well behind the increase in winds. There is still some uncertainty about where dew point temperatures will be in the afternoon, but relative humidity percentages will be close to or below 30% much of the afternoon.

That combination of stronger winds and low humidity will develop a risk for brush fires. Dry vegetation will burn easily, and the stronger winds could allow for fires to spread rapidly. Avoid burning outdoors Saturday! Sunday could also bring some fire danger, but conditions will be slightly better to prevent widespread risk for brush fires.

The fire risk is only elevated locally but will reach critical levels to the West. Even drier air with stronger winds will result in extreme fire danger across much of the Plains including Minnesota and Iowa. A Red Flag Warning stretches from Minnesota to the Texas Panhandle, signifying the higher risk for brush fires. That's not to say our risk isn't significant, but the more extreme risk will stay just outside of our area.

Bundle up Friday—Milder days return this weekend

Temperature Tumble:

If you think it feels like a completely different season this morning, you're not imagining things. A strong cold front swept through the Stateline yesterday and flipped our weather pattern quickly. After starting the day in the upper 60s and low 70s, temperatures fell into the 50s by the afternoon, and now we are waking up to the 20s and 30s this morning.  

Chilly, Breezy Friday:

Cold air remains locked in place today and into the start of the weekend, though we remain dry. This will give us plenty of sun, however, an organized wind out of the north and northwest will cap afternoon highs in the mid 40s. Bright skies, but a definite bit in the air as we head into the weekend. High pressure will track over the region tonight, leaving us dry but also chilly with overnight lows in the low 20s. 

Weekend Outlook:

Changes are scheduled to spill in over the weekend, allowing this cool-down to be brief. High pressure will shift to our east by Saturday afternoon, allowing winds to turn to the southwest. That will help highs climb back around the 50-degree mark. The trend continues into Sunday, when even warmer air spills in and places highs in the low 60s. Expect this warm up to carry on into next week as forecast models place a warm front to the Stateline's north. 

Warmer, more active pattern begins next week into April

 A few isolated storms developed along a passing cold front Thursday afternoon and evening. Behind that cold front, temperatures drop as a pocket of cooler and drier air works through the area this weekend. But looking ahead to next week, another pattern change is right on its heels.

Stronger Southwesterly flow aloft will develop, which will work to rebound temperatures quickly back above average. This will also work to feed abundant moisture our direction, developing higher chances for rain and potentially some storms.

First with temperatures: The cooler air does not last long as we quickly flip the surface wind back to the Southwest, aiding to bring in the milder air mass into early and mid-next week. A Northerly wind will keep us in the mid-40s Friday, but 60s are back by Sunday with 70s to follow Monday and Tuesday.

While we should be dry through at least Monday afternoon, rain chances will begin to ramp up after Monday evening into Tuesday. Each wave that moves through will determine timing of the next, but we will be entering a more favorable pattern for widespread, soaking rainfalls beginning early next week. First chance for widespread rain begins Monday night into Tuesday.

Thursday afternoon thunderstorm update: Severe risk shifting further south

 8:50PM UPDATE: Our storm threat has pretty much ended across northern Illinois as storms continue to shift to the south. Colder air remains in place with temperatures now in the 30s to our north and northeast. Skies will remain mostly cloudy through the night as temperatures gradually drop back into the upper 20s.

5:35PM UPDATE: Scattered showers with a few embedded thunderstorms continue to move across northern Illinois Thursday evening, with severe storms further downstate. The storm over DeKalb County will be capable of pea sized hail as it quickly moves into Kane County. We may see a small increase in shower coverage through 8pm, but the severe threat is quickly shifting south of the viewing area.

Scattered showers with a few embedded thunderstorms have developed over northern Illinois the last few hours, but the storms have remained below severe limits. In fact, our overall thunderstorms risk has decreased and shifted south as the cold front continues to press south late this afternoon.

The threat for showers and embedded thunderstorms will continue across the Stateline as an upper-level disturbance moves in from the west with a little more coverage developing most likely after 6pm or 7pm. The strongest of the cores may still be able to produce some small hail, along with heavier downpours, but the threat for larger hail remains south of I-88.

The latest severe outlook from the Storm Prediction Center has shifted their outlook for scattered severe storms further south. This lines up better with where the cold front sits, higher instability and incoming upper-level disturbance.

Scattered showers and embedded thunderstorms will continue locally through about 9pm or 10pm, with a gradual clearing in skies through the night. Northerly winds will push temperatures into the 20s Friday morning. 

Strong cold front to bring isolated strong storms, brief cool-down

Warmth Continues: 

Spring has wasted no time making itself know in the Rockford area this year. Since March 1st, Rockford has logged four days with afternoon highs reaching the 70° mark, including yesterday. 

 

 

This taste of spring-like weather will try to make another appearance this afternoon as temperatures climb towards the 70° mark. However, we will likely come up just short as a strong cold front is scheduled to push through during peak-heating. 

 

  

Severe Potential:

Staying on the topic of today's cold front, the severe weather threat has also diminished due to the timing of the frontal passage. With the front pushing south earlier in the day, the best values of instability and wind shear will be displaced south. 

This shifts the higher potential for strong to severe storms well to the south and southeast of the area, leaving most of the viewing area under an isolated threat. There is a sliver of Lee and DeKalb County under a level 2 Slight Risk for severe weather. 

A few sprinkles and showers will be possible during the afternoon and into the evening. If a thunderstorm were to briefly form, it would likely pop along or just south of highway 20 and track south and southeast as we enter the evening hours. IF we do end up seeing a strong or severe storm, large hail and damaging winds will likely be the main concerns. Storm chances will diminish as we get into the overnight hours, allowing some clearing to take place into Friday. Remain alert and have ways to receive severe alerts.  

Trending Upward:

Similar to Sunday's cold front, the one schedule to pass on through today will bring a significant but brief drop in temperatures Both Friday and Saturday feature highs in the 40s with Friday's chill featuring a gusty wind out of the northwest. Again, this chill won't last long as warmer flow slides back in by Sunday, landing afternoon highs in the low 60s, then low 70s Monday and Tuesday.