Thunderstorm Update

4:00pm UPDATE:  Showers and thunderstorms have diminished in coverage locally, with severe weather affecting suburban Chicago.  It appears that the threat for any strong thunderstorms has moved out of the Stateline area.

4PM ExacTrack Radar

4PM ExacTrack Radar

(2:24 PM) nwsbot: Local Storm Report by NWS MKX: Como [Walworth Co, WI] trained spotter reports HEAVY RAIN of M1.02 INCH at 02:15 PM CDT — 1.02 inches of rain in 1/2 hour ending at 215 pm.

(1:57 PM) nwsbot: Local Storm Report by NWS LOT: N Capron [Boone Co, IL] public reports HAIL of penny size (M0.75 INCH) at 01:37 PM CDT — relayed via media.

(1:56 PM) nwsbot: Local Storm Report by NWS LOT: Harvard [Mchenry Co, IL] public reports HAIL of penny size (M0.75 INCH) at 01:35 PM CDT — relayed via media.

(1:54 PM) nwsbot: Local Storm Report by NWS LOT: N Capron [Boone Co, IL] cocorahs reports TSTM WND GST of E50 MPH at 01:40 PM CDT — winds estimated around 50 mph and heavy rain.

1:45pm UPDATE: Severe Thunderstorm Warning for Walworth County in Wisconsin until 2:30pm. Moderate-to-large hail (up to half-dollar size) is the main concern, with heavy rain and gusty wind likely as well.

ORIGINAL POST: Saturday morning’s extensive cloud cover, which limited the heating and energy from the sun—one of the components for stronger thunderstorms—has helped to lower our already small severe weather threat.

Minimal-to-Low Severe Risk

Minimal-to-Low Severe Risk

With the cold front pushing its way across the Mississippi River accompanied by light showers, the best chance for strong-to-severe weather appears to be focused east of Interstate 39.  This is great news, considering this system produced tornadoes in Iowa on Friday.  I’ve lowered our Threatrack to Level 1 west of I-39 and kept it at Level 2 east of I-39, where a few storms from central Illinois could brush our eastern coverage area.

1:30pm ExacTrack Radar

1:30pm ExacTrack Radar

Until the cold front passes, pop-up showers and thunderstorms will contain heavy downpours with potentially small hail.  An isolated stronger storm may also contain gusty wind.  By dinnertime, the front should be east of our area.  Keep it tuned to the weather blog for more updates as necessary.

 

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

This post was written by qni_it on October 5, 2013

Threatrack-3 Saturday

untitledUpdate: New RPM model has come in with similar results to our previous post. Severe thunderstorms will be possible with the frontal passage in the mid-afternoon hours. Be ready for changing weather and have a way to get the warning. Now is a great time to download Exactrack|HD to your iPhone, iPad, or Android device. Just search “WREX Weather” on the App Store or Google Play. Also, you can follow me on Twitter for updates on the forecast. http://www.twitter.com/ericsorensen Note: All warnings are displayed on our 13 Weather Authority Twitter page http://www.twitter.com/13wxauthority

1

We are forecasting an Enhanced Risk of severe weather across Northern Illinois and Southern Wisconsin Saturday. For that reason, our Threatrack has been raised to level 3. The blue arrows indicate the direction the storms will be moving.

A strong cold front will be progressing east through the day, reaching the Mississippi River by noon and the Rockford Metro by 3pm. Showers and thunderstorms will be widespread along the front with a few severe. The main threat will be damaging wind and large hail. However, a few tornadoes will be possible!

The severe threat will go down very fast after 5pm as the front passes through completely. This is a look at the simulated radar from our RPM Computer Model (right). untitled2It shows a north-south squall line from Madison through Rockford, down to Bloomington-Normal. However, the strongest storms may not be south of here. Instead, we’ll have to closely watch to see if there are any leftover low-level boundaries that could disrupt the flow of air into these storms. If there are any disrupting boundaries around, storms may begin to spin and produce a tornado before they merge into a line.

SVRnam212F036Finally, in order to accurately forecast what’s going to happen we need to look at similar systems in the past. This graphic shows all of the severe weather reports (green-hail, blue-wind, tornado-red) in the 15 most similar storm systems to this one. It gives us a good idea of the greatest potential. Of note, are a few very long-track tornadoes south of here in the top-15 analogs.

We can’t say whether we will see significant damage from severe, only to urge everyone to be ready for changing weather on Saturday. More people count on us for severe weather coverage than anyone else and the 13 Weather Authority team will be ready! -Eric

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Posted under severe weather, Threatrack

This post was written by qni_it on October 4, 2013

Another Round of Scattered Storms

Much like we witnessed on Friday, scattered showers and thunderstorms will dot the radar again on Sunday.  There are some differences in the forecast, however.  With a fast-moving cold front expected to slide through the area early in the day, there will be a limited amount of time for the sun to warm things up before cloudcover and the threat for rain arrives.  Our high temperatures will likely climb into the middle 80s—perhaps only near 80 in southwestern Wisconsin, where the effects of the front will strike first.

18zfuturetrack1sept2013

A broken line of showers and thunderstorms will develop along and ahead of the front and push southeast through the region.  FutureTrack depicts this potential line of storms entering the Rockford metro around 1pm.  It appears that some areas well west of Rockford could pick up a shower or two before the afternoon hours.  Moisture is more limited with this system, compared to Friday, so not all areas will see rainfall.  Chance of rain is 50%, so some backyards will remain dry on Sunday.

threatrack1sept2013

The threat for strong thunderstorms exists.  However, given the swift speed of the cold front, the best chance for any severe weather appears to be just south and southeast of our local area.  Central Illinois and parts of Indiana will have more time to warm up on Sunday, creating an atmosphere primed for a few stronger thunderstorms.  The main threats Sunday will once again be hail and gusty wind.  Excessive rainfall, like we saw on Friday, is less of a threat due to the fast-moving nature of the front and associated thunderstorms.  If your travels take you to Bloomington-Normal, Peoria, Champaign, or Indianapolis, keep an eye on the sky.

-Joe

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Posted under FutureTrack, rain, Threatrack, weather

This post was written by qni_it on August 31, 2013

Threatrack-2 Friday evening

THREATRACKA very hot and humid airmass will be in place across Northern Illinois and Southern Wisconsin ahead of a fairly strong cold front that will move southeast into our area by evening.

Temperatures will surge into the middle 90s with dewpoints in the lower 70s. Instability ahead of the front will promote thunderstorm development, mainly after 4pm. Storms will have the capability of producing damaging straight line wind and possible large hail. Stay with the Weather Authority as we keep you updated, especially if you have outdoor plans Friday evening. -Eric

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Posted under Threatrack

This post was written by qni_it on August 29, 2013

Scattered T’Storms on Sunday

A cool front that moved through the Stateline on Friday night has set up shop as a stationary front in northern Missouri and central Illinois. The hot & humid airmass will remain south of that front.  However, it will begin to push back north as a warm front throughout the day Sunday. As that front moves north, a few scattered showers and thunderstorms will dot the sky across northern Illinois and southern Wisconsin.  Sunday will be mostly cloudy, although a few sunny breaks are likely.  Highs will reach the lower 80s.  While we’ve got the chance to see some wet weather throughout the day, the best chances will come during the afternoon, evening, and nighttime hours on Sunday through very early Monday morning.

Monday should see a midday break with a brief return to the hot and humid air. Expect a partly cloudy sky with highs in the upper 80s. By the evening, more scattered showers and thunderstorms will develop and last into the nighttime hours.

A few heavy downpours are possible at times over the next 48 hours.  However, the rain and thunderstorms will be scattered in nature, so not everyone will receive the same amount of rain across our 13 counties.

-Joe

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Posted under rain, Threatrack, weather

This post was written by qni_it on July 20, 2013

Severe thunderstorms possible Friday

CaptureA cool front will work into the region on Friday, providing enough lift for thunderstorms in the afternoon. Because the airmass will be fully charged with instability, a few storms could be severe. The main threat will be damaging wind and this will be more of a concern immediately to our east. From Chicago through Lower Michigan, storms could produce extreme wind…possibly on the order of 80-90mph! The further west you go into Eastern Iowa, the threat will be lower due to a lack of wind shear. -Eric

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Posted under Threatrack

This post was written by qni_it on July 18, 2013

Scattered Storms Through Midweek

 
A warm and humid Sunday night is expected for Rockford and the Stateline, with low temperatures bottoming out near 70 degrees. An stray shower or thunderstorm is possible, with our chances increasing  after 2am as a line of scattered showers and thunderstorms from Duluth, Minnesota to Denver, Colorado pushes east.
 
A few rumbles of thunder are expected around dawn and during the morning hours of Monday. While we’ll hang onto the chance for a pop-up shower or storm all day, it appears we may catch a break in the action during the midday hours.  Later in the day and into Monday night, that chance will increase yet again.  High temperatures on Monday will be similar to Sunday’s upper 80s. Some backyards will flirt with 90 once again.  Our dewpoints will be in the tropical range and the humidity will be very umcomfortable.  Area heat indices will top out between 95 and 100 degrees!
 
 
Tuesday will be another hot and humid day with the best threat of scattered showers and thunderstorms.  Some of the thunderstorms may be stronger during the afternoon and evening hours as a cool front begins to approach the area. Gusty wind and sizeable hail will be a concern, as well as potential heavy and flooding rain.
 
The threat for scattered storms will linger into the first half of Wednesday as a cool front pushes through the Stateline.  Behind the front, a pleasantly warm and noticeably less humid airmass will arrive with Canadian high pressure.  Thursday through next Sunday will be calm with ample sunshine.
 
-Joe
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Posted under rain, severe weather, Threatrack, weather

This post was written by qni_it on July 7, 2013

Scattered Storms Tonight

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

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

This post was written by qni_it on June 15, 2013

Significant Risk of Severe 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

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

This post was written by qni_it on June 12, 2013

Severe Threat Overnight Through Wednesday

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

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

This post was written by qni_it on June 11, 2013