Spring warmth builds, thunderstorm threat may tag along

Temperature Swings:

Even with all the sunshine we enjoyed yesterday, high temperatures just couldn't keep up. Highs only made it into the upper 40s, a whopping 33° cooler than Rockford's springlike surge on Saturday. Quite the turnaround, and a reminder than late-March can still pack some chilly surprises. 

 

Temperature Departure:

Temperatures are set to climb over the few days as our next storm system takes shape. Highs today will come in about 2 degrees above average, with a more noticeable jump settling in by midweek. Wednesday features afternoon highs roughly 13 degrees above average with highs Thursday winding up 20 degrees above average. Again, this is all ahead of a system and cold front that will knock us back down some before we get into the weekend. 

Thursday's Severe Potential:

Wednesday's warmth won't come completely trouble-free as a weak disturbance brings a small chance for rain. Most of the Stateline will stay dry, but a quick passing shower can't be ruled out. 

 

 

By the time we get into Thursday, our attention will then turn to the incoming cold front, which may trigger a few stronger storms, especially to the south and east of Rockford where atmospheric ingredients are higher. For that, the Storm Prediction Center has placed a few locales in Whiteside, Lee, Ogle, DeKalb, and McHenry County under a Level 1 Marginal Risk with a level 2 Slight Risk further south across central Illinois, Indiana, and a good portion of Ohio. Storm chances should push away with the front late in the evening into Friday morning.

Midweek warmth could also come with a few thunderstorms

 

Hard to believe that it was just one week ago that the snow was flying following our blizzard warnings that were in place for all of northern Illinois and southern Wisconsin. And what's even more impressive is that we had those conditions last Monday, and at the end of the week the sun was shining bright and temperatures warmed into the 70s, 80s, and even 90s in the Midwest Saturday! But a strong cold front early Sunday put an end to the warmth leaving temperatures in the 40s during the afternoon. The sun was able to return today but there was still a little chill in the air with temperatures staying in the mid 40s.

Clear skies will take us through the rest of the evening with a slow increase in cloud cover tonight. With such a dry air mass in place and a lighter wind from earlier this afternoon, temperatures are likely to drop into the 20s. Tuesday will feature filtered sunshine with highs warming into the low 50s. We'll continue the warmup Wednesday and Thursday with highs reaching the 60s Wednesday afternoon and possibly the low 70s Thursday. But Thursday's forecast comes with a few question marks. So, let's talk about that:

Low pressure moving across Iowa late Wednesday night and Thursday morning will pull a warm front just north of the state line by Thursday afternoon. South of the front temperatures will warm into the 70s and 80s while north of the front temperatures will remain in the 50s and 60s. A surge of moisture (higher dew point temperatures) will also follow the front, reaching northern Illinois during the afternoon. This will gradually lead to an increase in instability across central and some of northern Illinois. But at the same time the warm air aloft will act as a cap, or lid, for much of the day limiting the chance for thunderstorms. As the day goes on the cap may weaken, especially in central Illinois ahead of a cold front. And as of Monday evening, this is the area that has the highest chance for thunderstorms Thursday afternoon and evening.

Should the front slow down some we could see the chance for a few storms locally increase, but should it speed up then chance would be shifted even further to the south. It would also mean that our temperatures likely wouldn't reach the 70s. A brief return of cooler air will arrive Friday before we see temperatures warm once again heading into the weekend and next week. 

Spring strikes back: Northern Illinois warming up after a brisk start

Weekend Recap:

This past weekend delivered one of the most dramatic temperatures swings we've seen all year. On Saturday, we were basking in our warmest reading of 2026 so far - a spring-like 79°- only to watch temperatures fall all the way down to 43° Sunday. 

  

Chilly Start to the Week:

Sunday's chill lingers into the start of the work week, with afternoon highs in the upper 40s. Despite the chill, the day will feature abundant sunshine from start to finish thanks to an area of high pressure pushing in from the central plains. Wind chill values will be in the 20s to start, landing in the low 40s during the "peak heating" hours.  

Warming Trend:

Thankfully, temperatures trend more up than down over the next several days. Forecast models show our next surface low and cold front dropping in late in the afternoon Thursday. 

But before this storm system arrives, we'll enjoy a steady warm up: highs in the low 50s tomorrow, climbing into the 60s Wednesday, then low 70s Thursday. The trade-off will an increase in cloud cover and a higher chance for rain, especially Thursday as the low and front push through. Thursday could also feature the potential for an isolated thunderstorm or two. Behind Thursday's frontal passage, temperatures briefly fall back into the mid 40s for Friday afternoon before rebounding into the 50s for the weekend. 

Severe Update: 

When it comes to Thursday's severe potential, the threat currently appears low. The Storm Prediction Center highlights the highest risk south of I-80 along the advancing cold front, keeping the immediate area on the lower end for now. We'll be watching closely as any northerly shifts in the placement of that 15% (slight risk equivalent) would heighten the potential locally for strong to severe storms.   
 

Warming up this week ahead of next cold front

 It was a much cooler day Sunday than Saturday, as temperatures dropped by as many as 40 degrees from one afternoon to the next! The influence of Canadian high pressure will work to keep things chilly but dry for Monday as temperatures return to the mid and upper 40s.

The next weather system arrives mid-week in the form of an elongated area of low pressure. Ahead of this will be another warmup with drier conditions. A few spotty showers may try to develop within the area of low pressure, but most of the week will be dry.

The bigger influence from that low pressure system is the swings up and down in temperatures for the week ahead. Prior to the system's cold front coming through, we will see temperatures climb into the 60s! But the next cool-down arrives behind the front, back to the 40s and low 50s to start next weekend.

The large majority of the next week will be dry, but a few showers may develop just ahead of an along the passing cold front between Wednesday and Thursday. Widespread precipitation may be possible South and East of the Stateline toward Central Illinois/Indiana, but our chances will only be scattered.

Warmth retreats following Sunday's cold front

 

The summer-like warmth was nice while it lasted, but as the old saying goes, "All good things must come to an end". The 70s and 80s we felt Friday and Saturday will be replaced by the 40s this afternoon. In fact, as of 6am temperatures are already starting to drop as the first of two cold fronts pass through the region.

Cloud cover will continue to increase throughout the morning as temperatures slowly drop following the passage of a cold front. North winds will also increase, gusting close to 30 mph from time to time. We'll see an increase in moisture as the front passes through but limited on the overall rainfall today, with only a few hundredths to a couple tenths of an inch falling.

High pressure will move down the Plains Sunday evening, settling over the Upper Midwest Monday. This will push overnight lows down into the 20s with wind chills in the low 20s for many. There could even be a few spots that dip into the upper teens. Skies will remain mostly sunny Monday afternoon with temperatures rising back into the mid and upper 40s.

Mild night ahead, sharp cool-down Sunday

 We have a new champion atop the leaderboard of warmest days this year! Today's high temperature in Rockford topped out at 79! Unfortunately, we don't have any days that will crack the top 5 over the next few days with a cold front passing overnight.

That's because of a very sharp drop in temperatures between Saturday and Sunday. An overnight cold front will bring a change by more than 30 degrees from one afternoon to the next. Sunday's high will only top out at 49, but that may likely be reached prior to 10AM.

Ahead of the front, temperatures will remain very mild in the 50s through early morning, keeping us very mild. But behind the front, temperatures will fall through the afternoon and evening, reaching the low 40s by sunset. This also comes with a strong North-Northeast wind gusting upwards of 25 mph at times. It will come as quite a chill compared to Saturday's nearly 80-degree mark!

A few pockets of light rain or drizzle may be possible from late-morning through afternoon, but any rainfall will not amount to much. Any locations that see rain will only see a few hundredths of an inch of rain at the most. High pressure slides in for Monday, clearing us out and keeping the chill around. But another push of mild air arrives mid-week with more 50s on the way!

Spring in full force: Northern Illinois aims for its warmest day yet

Daylight Increases:

As we move past the first day of spring, the Northern Hemisphere is now gaining daylight each day on our way toward the summer solstice - which is just 92 days away. From here on out, the sun climbs a little higher and stays a little longer, giving us those steadily lengthening days! 

  

Warmest Day of 2026:

Sunrise comes at 6:57AM today, with our sunset occurring at 7:09PM. Between both times, expect a good amount of sunshine paired with warm south to southwesterly breeze. That combination will help northern Illinois achieve it's warmest day of the year thus far, with afternoon highs peaking in the mid to upper 70s. This would also go down as Rockford's third 70-degree day of 2026 - all of which have occurred during the month of March. 

Quick to Cool:

With today's warm surge into the 70s, it's a great idea to take full advantage of the springlike weather while it's here. A strong cold front is on the way, and once it moves through, temperatures will be restricted to the 40s Sunday and also for Monday. Tagging along with said cold front will also be enough moisture to spark a few scattered rain showers.  

Warm start to the weekend, sharp cool down Sunday

 Friday was a very mild day in the Stateline, especially given the 6" of snowfall that came down just in the same week! The high temperature just 3 days ago was only in the low 20s, but we reached the low 70s Friday as nearly all of the snowfall has now melted.

And the warming trend continues at least for one more day, as we will see afternoon highs climb into the mid-70s by the afternoon. While not nearly a record, it will still be very warm for mid-March standards, about 25 degrees above average!

But what goes up must also come down. An early morning cold front will lead to a sharp cool-down for Sunday afternoon, as temperatures in a few spots may struggle to reach above 50 degrees. The warmest part of the day will be centered near or just before 12PM, with falling temperatures through the afternoon into the 40s and eventually 30s. This cold front will also produce the chance for a few spotty showers, but any rainfall we do see will not amount to much.

Enjoy the warmth of Saturday while it lasts, because Sunday will be nearly 30 degrees cooler by late afternoon's time. Southwesterly wind gusts near 25 mph will aid to bring the warmth of Saturday, but Sunday's Northerly wind will aid to cool things off just as quickly. The cool-down is short-lived, as we return to the 50s and above average temperatures as early as Tuesday.

Winter ends, spring begins… and the warmth just keeps going

First Day of Spring:

Today marks the first day of spring, and the new season officially arrives at 10:46AM. As we cross the vernal equinox, daylight and nighttime become nearly identical, and from here on out, we'll see the amount of daylight continue to grow. 

  

Warmth Continues:

Spring begins where winter left off, partly sunny with afternoon highs in the low 60s. Forecast models show a cold front slipping through late in the morning in to the early afternoon. We're not expecting precipitation with today's frontal passage, but it will shift our winds around. By the afternoon, winds turn to the north, and then to the northeast overnight. This could bring the possibility for fog by Saturday morning. 
 

This warm-up fortunately will carry on into the first weekend of spring. South to southwesterly winds on Saturday will give temperatures a huge boost, landing them in the upper 60s, close to 70°. By Sunday, a cold front moves in and shakes things up a bit, knocking temperatures back into the 50s and bringing a chance for a few showers throughout the day. Temperatures trend backwards briefly for the start of next week, landing in the upper 40s Monday.  

Look back: Long stretch of record heat for Rockford in March 2012

 

Who remembers the heat wave much of the region experienced during the month of March in 2012? I know I do. The heat began early in the season during the month of March which sent many farmers into their fields to begin planting. But the jumpstart on the spring and summer warmth didn't come with much rainfall. March ended up just below the monthly average for precipitation at 2.09 inches (average 2.40 inches), and below average for snowfall. We were able to gain some moisture back during the month of April, but it was all downhill from there with several months in a row that ended up below their monthly average. This eventually led to extreme drought conditions over much of northern Illinois and southern Wisconsin that lasted well into the Fall season.

During the month of March many high temperature records were broken in a stretch of nearly 8 consecutive days of record heat: March 15th-18th, and 20th-22nd. The only day that didn't achieve a record was on the 19th when the high temperature reached 77 degrees, one degree away from the record of 78 set back in 1921.

We won't end up with any record heat this upcoming weekend, but temperatures will feel more like early to mid-May, rather than late March. Highs on Friday will warm into the low 60s but we'll likely see a little more cloud cover during the afternoon, which could limit the overall temperature - especially to the north in Wisconsin. Winds will turn back to the southwest Saturday which will push highs close to 70 degrees for the afternoon.

Melting snow provides main source of soil moisture over the next week

 The recent warmth has aided significantly in melting the snow from the ground, with snow depth at the Rockford airport dropping to 1" as of Thursday afternoon. But unfortunately, that snow melt will be the primary source of soil moisture over the next week or so, with very little in the way of precipitation chances on the horizon.

The primary chance for any rain we have will come along a cold front Sunday afternoon, but even that does not come with much abundant moisture. Any rain showers we see will be relatively spotty in nature, with a good chance that parts or most of the area see no measurable rain at all.

This is not just the case locally but also across much of the country as well. The Weather Prediction Center highlights this well, showing zero precipitation across nearly the entire Central and Southwestern parts of the country. We only have that slim chance Sunday, but otherwise remain dry into the middle of next week.

That isn't great news for the Stateline which has already seen several dry months dating back to last fall. As of Thursday afternoon, soil moisture was quite dry across a large part of the Midwest, with nearly all in the Stateline under the 10th percentile of the moisture we should have. The dry spots also correlate with the latest drought monitor released today. Some moisture will soak in from recent snowmelt, but we will not see much precipitation add to those totals in the near term.

Temperatures warm just in time for spring's first weekend

Heat Alerts Out West:

Unseasonably and dangerous heat currently has a firm grip on the southwest United States. Cities from Los Angeles to Phoenix and Las Vegas are under Extreme Heat alerts as a strong high-pressure ridge, or "heat dome" has locked itself over the western U.S. 

  

Ridge Pushes East:

How is this relevant to our forecast?  The same dome of high pressure is expected to weaken and even push eastward over the coming days. This will help drive a noticeable warm up here at home, arriving just in time for the first weekend of spring. 

  

Temperature Trend:

Friday will be warm with highs in the upper 50s. We still have a minor uncertainty with Friday's warm up as we'll have to see how things trend with the timing of the first of two cold fronts. Behind said front, we then see surface flow turn to the south and southwest ahead of an even stronger frontal boundary. 

This, along with a decent amount of sun will allow temperatures to surge into the upper 60s Saturday afternoon. Sunday's warm up also depends on the timing of the cold front as one model (the European model) was quicker with the frontal passage. This displaced the milder air to our south, leaving afternoon temperatures in the 40s. However, the American model left some room for highs to briefly reach the 50s before cooling overnight into Monday. Next week starts off cooler with afternoon highs in the low to mid 40s.    

Why does snow melt so quickly in March?

 Recent snowfall has been quick to begin melting away especially with Wednesday's sunshine and afternoon highs pushing the upper 30s. But sunshine is not the only way to decrease the snow depth on the ground! Three main ways to melt away snow is through sunshine, sublimation, or latent heat release through higher humidity.

Heat from the sun is the most commonly thought of way to melt away snow, but this is especially true for later spring months. In December and January, the angle of the afternoon sun is much lower in the sky. While March and April feature a much higher sun angle, focusing more of the sun's radiation directly to the surface, which melts the snow faster even if the temperature were the same in March compared to January.

That was certainly evident Wednesday afternoon in the Stateline, with sunshine promoting rapid snow melt in Rochelle. Another way snow can disappear even when temperatures are not above freezing is through sublimation. That is when water molecules go straight from a solid state (snow and ice) into gaseous state (water vapor). This process is most common with ice cubes that you leave in the freezer for a long time. Even though the temperature in the freezer is never above freezing, the ice cubes can get smaller as individual water molecules turn straight into vapor and dissipate into the air.

Another way to melt snow is through latent heat release. That is when moisture from the air condenses onto snow, similar to how a cup of ice water "sweats" in the summertime. That process of condensation onto the icy surface leads to a release of latent heat, which cools the air around the snow but works to heat up the snowpack itself, only further melting it away. This is the main reason why snow can melt effectively even at night! When dew point temperatures are above freezing, the moisture in the air condenses onto the snow, melting it further!

We will have both the sunshine's radiation and a moist air mass over the next few days, so expect that recent snowpack to melt away rather quickly through the course of the weekend

Temperatures continue to climb following brief period of winter cold

 

We are beginning our climb out of the brief, but potent, chill we had the last couple of days which means spring-like warmth will soon return. For the rest of Wednesday evening, we'll hold on to the mainly clear sky before cloud cover moves back in later tonight. The increase in cloud cover is the result of an incoming upper-level disturbance from the northwest. We can see those clouds across the Upper Midwest and Plains, and few radar returns moving into northern Wisconsin.

While we may see a brief period of some light precipitation late tonight, it likely won't amount to much thanks to drier air we have down near the surface. Moisture increases aloft, which is why we'll see the increase in cloud cover tonight. But that moisture will be lacking the closer you are to the surface. This dry air will likely limit just how much precipitation, if any, reaches the ground. If we do end up seeing some light rainfall, we will have to keep a close eye on temperatures at the surface because they'll be very close to the freezing mark. However, I don't anticipate many impacts to the morning commute.

Temperatures will continue their climb through the rest of the week as a strong ridge of high pressure builds out west. This will bring several days of 90- and 100-degree heat to the Southwest. Closer to home we won't experience warmth quite that significant, but temperatures warming into the 60s - possibly back near 70 degrees - by the start of the weekend appear likely. The only 'fly in the ointment' would be any lingering fog or cloud cover due to the added low-level moisture from the recent snowmelt.

 

When does spring officially begin across northern Illinois

First Day of Spring:

We are progressing through what Tom calls the "belly of the beast" as winter is in it's final days, though it has been putting up quite a tough fight. The first day of spring is Friday. It officially begins at 10:46AM and that is the moment when the Earth's tilt allows the sun to shine directly over the equator.  

Amount of Daylight:

This is also the moment when daylight and nighttime are almost perfect balanced, marking the transition towards longer, warmer days across the Northern Hemisphere. After the equinox, our next astronomical milestone is the summer-solstice, also know as the longest day of the calendar year.  

  

Temperature Trend:

Milder air spills into the Stateline for the few days of spring, leaving us with 50s Friday, then closer to the 70-degree mark Saturday afternoon. Precipitation chances over this three day stretch will be highest on Sunday as that is when forecast models show a strong cold front pushing through.   

Light snow chances across northern Illinois taper off early

Scattered Snow Early:

Snow is still falling this morning as a weak storm system moves across the western Great Lakes. While totals have been minor, the snow that has fallen so far has been enough to leave roads in some counties partially covered. Those heading out early will need to give themself extra travel time. 

 

Snow chances should taper off before mid-morning, giving way to dry but partly cloudy conditions for the afternoon hours. The sunshine will give temperatures more of a boost than Tuesday, leaving afternoon highs just short of the 40-degree mark. 

 

  

Another Weak System:

Northwest flow continues to dominate the upper-level pattern, steering another weak disturbance in the direction of northern Illinois. Forecast models remain quite scattered with how much precipitation this system will produce, leaving us with just a chance for a few showers into Thursday morning.