Severe storm potential returns late Saturday, stretches into Sunday

Portions of the Central U.S saw a bona fide tornado outbreak Friday afternoon as tornadoes were reported from Texas to Nebraska and Iowa.

All in all, a total of 78 tornado reports were obtained by the Storm Prediction Center. 

The National Weather Service in Omaha, NE and Des Moines, IA will be quite busy over the next couple of days rounding up information that will help determine the strength of yesterday's tornadoes. 

As the powerful storm system that was responsible for Friday's outbreak drifts away, another will follow in its footsteps allowing the threat for significant tornadoes to carry on into Saturday.   

Earlier this morning, the Storm Prediction Center upgraded areas from northern Texas to southeast Kansas to a level 4 of 5 moderate risk. Locally, we remain under a level 2 of 5 slight risk for severe weather this afternoon into tonight. 

Ingredients-wise, there will be a good amount of instability and moisture in place. However, the other two ingredients for strong to severe storms are shear and lift which is what we're severely lacking. That, along with having a capping inversion in place will leave storm potential very low during the daylight hours. Again, the "cap" acts as a lid, severely limiting thunderstorm development. 

Temperatures, thanks to a good amount of sunshine and a rather robust southwesterly wind will end up more summer-like, in the upper 70s. From there, the "cap" is shown breaking apart late in the afternoon, bringing the coverage for storms to increase into Saturday evening and Saturday night. These storms would also pose a risk for severe weather, mainly large hail and damaging winds, along with heavy rainfall and flash flooding in the areas that see repeated rounds of storms.

As we've mentioned in previous discussions, Sunday's severe threat will all be dependent on what occurs Saturday night into Sunday. The Storm Prediction Center has left the N. Illinois and S. Wisconsin under a level 1 of 5 Marginal Risk, mainly for hail and winds. Heavy rain will also be a concern. 

This active pattern is shown stretching into the early stages of Monday before a somewhat less active pattern settles in starting Tuesday. As always, continue to monitor the forecast as well as have multiple ways to get watches and warnings!

Multiple storm chances likely this weekend, some being severe

A look at water vapor imagery this morning shows the two storm systems that will help drive this weekend's active weather. The first being the low that is spinning over the central plains and the second which is making landfall along the west coast.  

For the most part, the severe threat this afternoon will reside further to the west closer to the low. Locally, heavy rain and small hail will be possible as a few showers and thunderstorms track through during the midday/late afternoon hours. 

A secondary round of showers and thunderstorms is then expected to track in shortly after sunset, with chances lasting into early Saturday. These will be a little more intense, having a better chance for heavy downpours as well as hail.

Despite having a gusty southeasterly wind in place, highs will be limited to the upper 50s, close to 60-degrees. Temperatures from there will remain steady in the upper 50s into Saturday morning.

Saturday has been trending drier and drier by the day as what is known as a "cap" or atmospheric lid keeps storm chances low during the daylight hours. 

With that being said, I would keep an eye on the radar if you have plans Saturday afternoon. If any storm were to break said cap, it would quickly strengthen and become severe. At this moment in time, the chance of that happening is very low. 

What will be present however is a decent amount of sunshine, a stronger southwesterly wind, and highs in the upper 70s, close to 80-degrees.

Gusts Saturday, especially during the late morning and early afternoon hours, look to peak around 45mph. Chances for showers and thunderstorms are then set to increase into Saturday night. 

Sunday's severe threat will be dependent on two things, the first being what occurs with thunderstorm activity to our west Saturday night. The second, the arrival of the secondary upper-level system. Taking these uncertainties into account, the Storm Prediction Center has placed the entire region under a level 1 of 5 Marginal Risk for severe weather. Remember to stay weather aware this weekend, especially if you have any outside plans! 

Freeze Warning Issued Wednesday night

 

A Freeze Warning is now in effect for all of northern Illinois and southern Wisconsin as overnight temperatures will fall into the upper 20s and low 30s.

Skies will remain mostly clear overnight as just a few high-level clouds move in from the northwest. The combination of lighter winds, clear skies, and low dew point temperatures will allow evening temperatures to drop quickly after sunset, falling as low as 28 or 29 degrees in some locations by Thursday morning. The current forecast low for Rockford is 31 degrees.

Frost and freeze conditions are expected which will harm, or kill, sensitive vegetation if left unprotected outside. If you do have any sensitive plants or vegetation, you'll want to either cover them or bring them inside tonight. 

Northern Illinois placed under Freeze Watch

Tuesday was the 4th day in a row where the Stateline saw highs end up warmer than the previous day. 

After ending up in the low 40s Saturday, upper 50s Sunday, and upper 60s on Monday, temperatures peaked in the low 70s Tuesday.

Now, I wish I could say that yesterday's 70s were here to stay for more than one day. Unfortunately, that isn't the case as cooler air continues to spill into the region behind Tuesday's potent cold front.

Wednesday starts off with lingering clouds, but also temperatures in the low to mid 30s. As we inch closer towards mid-morning, the expectation is for clouds to decrease, leaving us with plenty of sun. 

What's going to limit our potential to warm efficiently will be today's breeze off of Lake Michigan. Though not as strong as Monday and Tuesday, gusts up to 20 mph will be possible. This will leave our highs in the mid to possibly upper 50s.

From there, the perfect formula will be in place for the likelihood for frost into Thursday. It's for that reason that the National Weather Service has place our entire region under a FREEZE WATCH. This will run from 12AM to 8AM Thursday.

If you have done any early-season planting, make sure those plants are covered. Any potted plants must be brought indoors to avoid being damage.

Few storms possible this afternoon, low severe threat

Temperatures have been on the up and up, peaking in the upper 60s Monday afternoon. With Monday's 60° weather however came a rather robust southwesterly wind, gusting up to 35 mph at times. 

It's because of this warm wind that temperatures are starting out much more comfortable this morning, with most sitting in the low to mid 50s.

Winds remain gusty out of the southwest as our next cold front approaches from the west. This will allow highs to creep closer to the 70° mark. Unlike Monday however, this potent cold front will also generate enough lift in our atmosphere for a few showers and thunderstorms to develop. 
   

This would be during the mid to late afternoon hours, with severe potential remaining low. With that being said, one or two of these storms could become strong enough to become severe warned. 

If that were to be the case, strong winds and large hail would be the biggest concerns. The Storm Prediction Center does have areas east of Janesville, Freeport, Mount Morris, and Amboy under a level 1 Marginal Risk for severe weather. 

Post-cold front, our weather pattern briefly cools down for the middle of the work week. Temperatures overnight will fall into the low 30s, only peaking in the low 50s Wednesday afternoon. 

Despite the cooler trend in temperatures, Wednesday remains dry under partly cloudy skies! This dry stretch will carry on into Thursday, with highs ending up back in the low 60s! 

Clouds thicken Monday ahead of a light rain showers Monday evening

 

Cloud cover will continue to thicken up Monday evening ahead of a cold front that'll pass through the region Tuesday morning. A few showers have been developing on radar but the dry air mass at the surface has prevented a lot of the rain from actually reaching the ground. Nonetheless, a shower or two can't be ruled out around 8pm/9pm.

Increasing winds in the jet stream Tuesday morning will allow a few showers to occur, but mostly for those south of I-88. A quick push of dry air Tuesday afternoon will allow skies to clear and temperatures to warm into the upper 60s. This warmth combined with colder temperatures aloft will cause the air to rapidly rise from the surface. This quick rising air will help increase some of the instability in the atmosphere, despite dew point temperatures only in the upper 40s, to right around 50 degrees.

A few isolated thunderstorms will be possible during the afternoon and early evening, with the greatest chance lining up from around McHenry County, down through DeKalb, Ogle, and Lee counties. Within the stronger thunderstorms hail up to quarter size (one inch in diameter) will be possible. There is also a small chance that we may see some funnel clouds develop, especially for any storm that forms right along the surface boundary. The chance for that is low, but it's there.

Once the storm threat passes skies will turn partly cloudy as high pressure moves across the eastern Great Lakes. Temperatures Tuesday night will fall into the low to mid 30s. Winds will remain slightly elevated which should prevent frost from developing, but patchy frost may be possible for some early Wednesday. A better chance for frost will occur Wednesday night and Thursday morning.

  

Frost Advisory in place early, windy and warm Earth Day ahead

It's another chilly late-April morning for many as frost advisories stretch from the Oklahoma/Arkansas border to Cape Cod, Massachusetts.

The portion that includes all of our northern Illinois counties runs until 8AM. 

With Monday's forecast comes a mixed bag of news, including an increasing southwest wind, increasing clouds, and a quick warm up. 

The best chance for sunshine will be during the morning hours as clouds are expected to gather up after the mid-day hours. This, along with a rather robust southwesterly wind will help temperatures warm nicely into the upper 60s. 

Forecast models then show the first of two early-week opportunities for rain moving in tonight, primarily between sunset and midnight. 

This will be in the form of a few light showers, with most of the precipitation staying north of the Illinois/ Wisconsin border. The second comes with a cold front which looks to slide through the region late in the afternoon Tuesday. 

Tuesday's chance will have a bit more "ummph" to it, allowing a few non-severe storms to be possible. All in all, the heaviest rain looks to occur well south of the region in central Illinois. 

We then cool off for the middle of the week as highs go from the upper 60s to the low 50s. This cool down is brief as highs look to climb back into the 60s starting Thursday, then 70s starting Saturday. With this massive warm up comes an active stretch of weather that will bring the chance for storms Friday, Saturday, and Sunday. 

In the Storm Prediction Center's latest long-range severe outlook, they have taken the entire Stateline out of the 15% risk. Areas west of the Mississippi River remain under what is equivalent to a level 2 slight risk for severe weather.

Changes are expected in the coming days, so make sure to check the forecast frequently!