Thanks to Saturday morning’s showers and considerable cloudiness, a stable atmosphere was in place over northern Illinois and southern Wisconsin for much of the afternoon.  As a cool front pushes toward the area, though, thunderstorms will develop ahead of this boundary for the evening and nighttime hours.  The thunderstorms will be scattered in nature.

Looking at the latest trends, the best threat for any severe weather appears to stay just south of our area.  However, we may see a stronger thunderstorm or two across some of our thirteen counties.  The stronger storms will contain heavy rain, small hail, frequent lightning, and brief gusty wind.

The scattered thunderstorm activity will wind down after midnight, allowing for some breaks in the cloud cover.  Patchy fog may develop toward dawn.  It looks like we’ll sneak out a dry day on Sunday, with much of the stormy activity confined to central Illinois and points south.  We can’t rule out a widely-isolated thunderstorm, especially south of Interstate 88.

-Joe

Posted under Exactrack|HD, rain, severe weather, Threatrack, weather

If you haven’t read through Chief Meteorologist Eric Sorensen’s Tuesday blog post regarding our severe weather threat for Wednesday afternoon, I’d recommend it. You can find his blog post HERE. 

A somewhat stable airmass is in place across the Stateline for Wednesday morning.  Overnight showers and thunderstorms in western Iowa fizzled out before they crossed the Mississippi River into Illinois.  The result is a mostly cloudy morning with a few breaks of sunshine.  Humidity and temperatures will be on the rise throughout the day, with highs expected to reach the middle 80s.

The meteorological ‘ingredients,’ so to speak, are coming together for severe weather later today.  With a surface wind still expected out of the southeast and an upper-atmospheric wind out of the south-southwest, directional wind shear and storm rotation will be a concern this afternoon and evening.  A warm front is still expected to lift into northern Illinois this afternoon, at least as far north as the Interstate 88 corridor.  It is along this front that supercell thunderstorms may develop.  Supercell thunderstorms have the potential to produce strong wind gusts, large damaging hail, and possibly a tornado.  These threats will all be of local concern this afternoon, including torrential rain.

Don’t panic.  However, today is a good day to be ‘weather aware’ and keep an ‘eye on the sky.’  Make sure you have a severe weather safety plan in place.  We haven’t seen a threat like this across the Stateline for a few years.  Let’s plan for the worst and hope for the best.

As far as timing goes, our array of forecasting products are not on the exact same page. However, the best timeframe for severe thunderstorms to develop is this afternoon and evening.  Storms may begin to form in eastern Iowa around 2pm through 4pm and move east-southeast into our area after that.  Some model solutions begin a bit earlier, some begin later around dinner time.  We do know that this afternoon and evening will be active. 

Don’t forget, you can track the storms on your smart phone with our 13 Weather Authority App or sign up for severe weather text alerts.

-Joe

Posted under rain, safety, severe weather, Threatrack, tornado, weather, Wind

Severe thunderstorms are a good bet across parts of South Dakota, southern Minnesota and northwestern Iowa late Tuesday. In fact, the Storm Prediction Center has placed that region in a Moderate Risk (a category that is not issued very often).  Should these storms hold together, there is the potential for a derecho to develop. “Derecho” is a meteorological term derived from the Spanish language word for “straight.”  It refers to a widespread and rapidly-moving wind-storm associated with a bow-echo line of thunderstorms that can last hours and overnight. Straight line winds over 80mph can produce damage across areas hundreds of miles long and more than 100 miles wide.  Typical derecho events see a southeasterly turn in the progression of the line of storms.  However—and I cannot stress this enough—derecho events are extremely difficult to forecast until they have formed.  This will need to be monitored locally as we head into the overnight hours (pre-dawn hours of Wednesday).

Severe thunderstorms are a possibility again on Wednesday. A round of showers and thunderstorms in the early morning may yield a break during the middle part of the day.  By the afternoon and evening a warm front will lift north toward the Stateline. If we get enough daytime heating, our atmosphere will destabilize and showers and thunderstorms will form.  Some of these storms may take on supercell form, which could produce large hail, heavy rain, strong wind gusts, and an isolated tornado.  Perhaps the highest threat will be just southeast of us from Chicago south to Champaign and east through Indiana and western Ohio. 

This blog post is not meant to scare; it’s meant to inform you of the possibility of severe weather.  Not all of us will be affected; however, the threat exists across our entire region.  It’s a great time to be weather aware!  Join 13 Weather Authority Chief Meteorologist Eric Sorensen at 5, 6, and 10pm tonight for further forecast updates and analysis.

-Joe

Posted under safety, severe weather, Threatrack, weather, Wind

Brace yourselves. Clouds and rain are in the forecast….again!  If you thought it’s been cloudy and rainy lately, you are correct.  Looking at the past 30 days, there have been 21 days with at least a trace of rain reported at Chicago Rockford International Airport! 

Sunday will start off mostly cloudy and mainly dry, with just a few isolated showers dotting the radar.  Scattered showers and thunderstorms will become more numerous as we head into the afternoon and evening hours.  A breezy south wind, 10-20mph, will help temperatures rise to near 75 despite the clouds.

This system that is headed our way for Sunday brought severe weather to the Great Plains on Saturday.  While the chance for severe weather is low locally, there is a minimal threat for a few stronger thunderstorms Sunday afternoon. I anticipate the best threat of severe weather to stay just south of our local area, affecting Bloomington, Peoria, Springfield, and St. Louis. 

The showery, thundery weather will continue Sunday night as well.  As the system pushes off to our east, a few lingering scattered showers will remain in the forecast through Monday afternoon. 

-Joe

Posted under FutureTrack, rain, severe weather, Threatrack, weather

The chance for showers and even a few thunderstorms will increase after midnight and into the pre-dawn hours of Sunday.  A nearly-stationary warm front will help to act as trigger for these showers to form. The general direction of the precipitation will be east-southeast along and just north of the warm front.  We will see the scattered showers and thunderstorms continue for the morning hours on Sunday. It looks like we will see a break in the action midday, with just a few isolated showers and an otherwise mostly cloudy sky. Temperatures will reach the lower 60s by afternoon.

More scattered showers and a few thunderstorms will redevelop and dampen our Sunday evening and overnight.  The warm front will remain to our south even into Memorial Day (Monday), so scattered showers and thunderstorms are a possibility yet again.  While severe weather is expected to stay in the Great Plains, some of our thunderstorms may put down heavier rain and small hail.

Don’t forget! You can track the rain on your smartphone with the 13 Weather Authority ExacTrack App.  -Joe

Posted under FutureTrack, rain, Threatrack, weather

Severe thunderstorms and even a few tornadoes were observed across the Great Plains States on Saturday afternoon and evening.  That threat will shift a little further east on Sunday.  The National Weather Service’s Storm Prediction Center  has issued a moderate risk for severe storms in places such as Kansas City and Joplin in Missouri as well as Oklahoma City and Tulsa in Oklahoma.  These areas will deal with the threat for damaging wind, large hail, frequent lightning, torrential downpours, and possibly a tornado.

There is also a risk for severe weather further north into Minnesota and Iowa for the day Sunday.  By Sunday evening, that threat for a few stronger storms will exist here in northern Illinois and southern Wisconsin.  Hot and humid conditions are expected across the Stateline during the day with temperatures warming into the upper 80s.  Much of the first half of the day will be dry, with just a slight chance for a shower or two.  By late afternoon and early evening, a few thunderstorms will push into the area from the west.  Thunderstorms are not expected to develop in an organized pattern locally, so not all backyards will see the rain.  However, any strong storm we may see late Sunday will carry the primary threats of strong wind and large hail.  Thanks to the setting sun, solar heating (which helps to destabilize the atmosphere and ‘fuel’ thunderstorm development) will come to an end and the threat for stronger storms will decrease quickly after dark.  General showers and weakening thunderstorms will be scattered about the area overnight Sunday and fizzle out by dawn Monday.

Monday continues to have the best chance for severe thunderstorms.  Should we see enough breaks in the cloudcover leftover from Sunday night’s storms, our high temperatures may be similar to Sunday’s.  Otherwise, humid conditions and low 80s are in the forecast.  A vigorous center of low pressure will continue to slide east and shower and thunderstorm development is likely out ahead of it in our area Monday afternoon.  Some thunderstorms have the potential to take on supercell form, which includes the very slight chance for an isolated tornado.  The main concerns for Monday will be damaging straight line wind, large hail, frequent lightning and heavy rainfall.

Stay tuned to the Weather Blog and WREX.com, or you can follow the 13 Weather Authority on Facebook and Twitter for all of the latest updates regarding the chance for severe weather in northern Illinois and southern Wisconsin.  -Joe

Posted under FutureTrack, rain, safety, severe weather, Threatrack, weather, Wind

Clusters of showers and thunderstorms fired up along a frontal boundary in northwestern Wisconsin, southern Minnesota and northern Iowa on Sunday night. While this activity will likely lose energy and weaken before having an effect on the Stateline, the boundary will continue to push east for Monday.  A few showers are possibly near Dubuque, Iowa and southwestern Wisconsin Monday morning as this activity fizzles out.

While temperatures are expected to warm into the low 70s locally with some sunny breaks, a few showers and thunderstorms may redevelop along and ahead of the boundary on Monday afternoon in northwestern Illinois.  There is some concern that a thunderstorm or two may contain sizeable hail and gusty wind.  While our risk for a severe thunderstorm is low, it is not out of the question…..especially along and west of Interstate 39.

It is important to keep in mind that showers and isolated thunderstorms will be scattered in coverage, so not everyone will get wet. The chance of rain is only 50 percent. Be sure to tune into 13 News Today and 13 News at 5 and 6pm on Monday for the latest details. -Joe

Posted under FutureTrack, Threatrack, weather

Two modes of severe weather are possible within the next 24 hours. First, a threat of more flash flooding tonight with an additional 1-3 inches of rainfall likely. With enhanced thunderstorm activity after midnight, local spots could receive that much in just a short amount of time. Please be advised that most flooding deaths occur due to drivers crossing flooded roadways, especially at night. “Turn Around, Don’t Drown.”

In addition to flash flooding, river levels will continue to rise into “Major Flood” categories. Be ready for levels to rise another 1-2 feet! Since crests are not anticipated until the weekend, we will detail the particulars in the coming days.

Severe thunderstorms will be possible as a warm front lifts into our region by midnight. Through the early morning hours of Thursday, severe weather will be possible with damaging wind and potentially large hail. However, as low pressure tracks from Southeastern Iowa into Southern Wisconsin, we will be in a “sweet spot” for potential tornadic activity. Unfortunately, this will occur during peak-heating of Thursday afternoon. Because of this, we have elevated the Threatrack to Level 3. If the threat increases and there is a significant threat of widespread severe weather, we would achieve a Level 4. Level 5 is reserved for a tornado outbreak. While that is not anticipated, your tornado procedures should be in place. Please think NOW where your safe place is and make sure you have a way to receive Severe Thunderstorm and Tornado Warnings.

The threat for severe weather will exist after midnight until the frontal passage around 6pm Thursday. This includes large hail and damaging wind. The threat for tornadoes will exist 2-6pm Thursday afternoon. -Eric

Posted under severe weather, Threatrack, tornado

It remains to be seen whether the instability needed for severe thunderstorms will be this far north, but much of the Central U.S. has the potential to see damaging, dangerous weather on Tuesday.

Threatrack|HD is an index of potential thunderstorm severity. We utilize CIPS data which finds parallels to the current set-up to thousands of systems in the past. In addition, we utilize model data and forecasts from the National Weather Service Storm Prediction Center. The numbered system roughly corresponds to the percent-chance of severe weather with a level-5 being a 50% chance of severe thunderstorms. In this case, a 20% chance of severe thunderstorms exists for Northern Illinois and Southeastern Wisconsin.

Using that data, areas most prone to widespread damage include much of Arkansas, Southeastern Missouri, and far Southern Illinois. These areas are in a “significant risk” for a possible outbreak outbreak of severe thunderstorms and isolated tornadoes.

An “elevated risk” exists for areas shaded in yellow. This is where severe weather is likely, but on a more isolated scale. This set-up will support isolated tornadoes in these areas…possibly into the southern suburbs of Chicago.

Right now, we are forecasting a “low risk” of severe thunderstorms for Northern Illinois and Southeastern Wisconsin. This means, be ready for large hail and damaging wind, with an outside chance of a tornado. Please note: As new data comes in, this map will be refined Monday night and again Tuesday morning. -Eric

Posted under severe weather, Threatrack

The Gulf of Mexico is open for business (with plenty of moisture and mild air flowing into northern Illinois and southern Wisconsin along a low-level jet stream).  Not to mention, a strengthening center of low pressure and cold front continues to head our way.  Heavy rain with some embedded thunderstorms (producing even heavier downpours) will affect us overnight through Sunday afternoon.  Severe weather will stay well south of the area overnight, with possible strong storms as close as northern Indiana Sunday afternoon.  The main headline for this weather system is rainfall.  Every model I looked at had at least 1.35 inches of rain falling in Rockford.  A majority of the models put well over 2 inches of rain down, with one projecting nearly 3.50 inches!  Playing it conservatively, I believe that our area will have rainfall totals under 2 inches.  That’s still impressive!  Don’t expect much, if any, flooding.  With a nearly 12 inch deficit in rainfall since January 1st, the ground should be able to soak up the rain.

It’s likely that our overnight temperatures will be as warm if not warmer than during the day Saturday.  Temperatures will be nearly steady in the lower 60s until late Sunday morning.  By then, the cold front will be knocking on our door.  Temperatures will fall into the lower 50s behind the front for Sunday afternoon with wind gusts increasing to over 30mph at times.  By Sunday evening, most of the rain will have moved east and out of the picture.

-Joe

Posted under flooding, rain, severe weather, Threatrack, weather