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

Conditions are calm and comfortable…for now. But as we head toward the weekend we increase our chance for some precipitation to creep back into the forecast. Even though temperatures have been on a steady decline as of late, we won’t be talking about snow, instead the possibility of thunderstorms comes into play. An approaching vigorous low pressure system will slowly track from the southwest up into the Central Plains by Saturday morning and could be knocking on our doorstep by late in the day Saturday. A warm front moving in from the southwest could result in an extensive area of rain and thunderstorms spanning across parts of Iowa, Minnesota, Wisconsin, and NW/Northern Illinois on Saturday morning. Then, in the late afternoon a cold front will track through and that front is what will up our chances for severe weather. We will continue to monitor the situation as we inch closer to the weekend! -Greg

Posted under event, severe weather, Threatrack, weather

The information keeps pouring in from the 2012 National Weather Association conference in Madison, Wisconsin.  The latest tidbit of ‘insider’ information, so to speak, comes from the National Weather Service (NWS).  The Storm Prediction Center (SPC), which is a based in Norman, Oklahoma, will be making some changes to their convective outlooks in 2013.  The SPC issues a convective outlook to notify the general public of the probability of severe weather, including dangerous thunderstorms and tornadoes.  These outlooks are issued for Day 1, Day 2, and Day 3.  A long term Day 4-8 outlook is also produced.

As of right now, the SPC has three categories which emphasize the expected severe potential of thunderstorms.  These categories include slight risk, moderate risk, and high risk for severe weather.  A slight risk means the threat for scattered severe weather exists (some wind damage, severe hail, and widely isolated tornadoes).  A moderate risk indicates that widespread severe weather is possible, typically across many areas.  Significant wind damage, destructive hail, and tornadoes have a greater probability of occurring.  A high risk is rarely issued.  But it can mean that all of the dynamics are in place for a major severe weather outbreak and such an event is likely (major tornado outbreak, strong straight-line winds).

Officials announced that the three categories will be retooled, and another category or two will be added in 2013.  This will be similar to 13 Weather Authority’s ThreaTrack|HD that’s already been in place and in use for many years.  The SPC looks to have at least five categories for severe weather convective outlooks in the near future.  With limited information at the moment, the new categorization structure will be along the lines of general thunderstorm, slight risk, enhanced risk, moderate risk, and high risk.  We will keep you up to date as soon as more details are released.

Speaking from experience, I prefer a few more categories.  Because every severe weather event is different, predicting its severity is a challenge.  The more options to categorize (staying within a reasonable number) an event, the better knowledge the general public will have on what to expect.  Our ThreaTrack|HD utilizes five ‘levels’ for severe weather risks.  These include minimal, low, elevated, significant, and extreme risks.  Typically, minimal and low risks are what we use most.  I believe it is best to not over-sensationalize a severe weather risk.  But I also believe that even if we have a minimal risk, mentioning it is the wise and correct thing to do.  That way, in the event of a significant or extreme risk, we will all know how serious the situation could be.

Make sure you follow @ERICSORENSEN and #NWAS2012 on Twitter and stay tuned to the Weather Blog for more tidbits and insight from this year’s National Weather Association conference.  Thanks for reading!  And feel free to share your thoughts and opinions.

-Joe

Posted under news, safety, severe weather, Threatrack, weather

A few clusters of thunderstorms will develop in the heat and instability Tuesday evening. A more complex area of thunderstorms is expected well after midnight. These are storms that formed ahead of a cool front in parts of Minnesota and Northern Iowa. A level-2 Threatrack exists for areas around Rockford and points northwest through early Wednesday morning.

As the cool front arrives in our neck of the woods on Wednesday afternoon there is an additional chance of some bigger storms. However there will be a lack of significant heating on Wednesday, compared to the middle 90s we saw on Tuesday. This should confine most of the storms below severe thresholds for much of Northern Illinois. I believe the bigger storms will likely line up from the north suburbs of Chicago, down I-55 through Bloomington-Normal during the afternoon and evening. -Eric

Posted under Threatrack

We are forecasting an elevated risk of severe weather, or Threatrack-3, for Saturday afternoon.

A strong cold front will near the Mississippi River during the afternoon after most locations in Northern Illinois and Southern Wisconsin rise into the lower to middle 90s. With dewpoints in the upper 60s to near 70, we may even have heat index values as high as 107 in the early afternoon.

Thunderstorms are expected to form in Eastern Iowa in the early afternoon, moving east-northeast into Northwest Illinois by 3pm. These storms could be severe with damaging wind and large hail. Also, within 1-3 hours of the storms forming there could be a few isolated tornadoes. With time, the storms are expected to combine into clusters and segments which will bring the threat of tornadoes down quite a bit. Still, there could be some widespread damaging wind and hail once the storms mature into the early evening hours across much of our area. The threat of severe weather will really go down after 7pm as the storms move into the Chicago Metro area.

Here’s a look at Futuretrack. It brings the strongest storms to our area around 5pm. Our advice is to not expect damaging weather. Rather, be “weather aware.” Make sure you have a way to get severe weather warnings and know where to go should you be in the threatened area.

We will have complete coverage here, on our Facebook page, and on the main weather page (up to the minute) as things change. Also, look for a live chat and live warnings and storm reports here on our blog as the front comes through. -ES

Posted under severe weather, Threatrack

6:54pm – Here’s a look at the current visible satellite view. The one cell that is trying to pop up in Northeastern Iowa is having a really tough time breaking through a cap of warm air around 25,000 feet. If the storm can’t break the cap, it won’t be very long-lived and others will likely not form. It is neat to see the shadow the cloud top is putting down on the ground to the right.

The front shows little in the way of developing cumulus so this chance of rain may just come and go. -ES

5:00pm – A cool front will progress through the region around 10pm tonight bringing at least a chance of thunderstorms to the region. A few could be severe with some 60mph wind potential, but this threat is mainly confined to Southeastern Wisconsin and Northeastern Illinois. For this reason, a Threatrack-2 is needed for the next few hours. We’ll have to see what develops out in Northeastern Iowa to determine the Rockford Metro’s risk, but the chance warrants a Level-2, 0r low risk, of severe thunderstorms after sunset tonight. -ES

Posted under Threatrack