A Severe Thunderstorm Watch has been issued for Jo Daviess, Stephenson, Carroll & Whiteside in IL until 4:00am Sunday morning.  A Severe Thunderstorm Watch has been issued for Winnebago, Boone, Ogle, Lee, & DeKalb County in IL until 6:00am Sunday morning.  The main threat these thunderstorms are heavy downpours, frequent cloud-to-ground lightning, and very large, damaging hail.

4:10am update:  The threat for severe weather is quickly ending.  Scattered showers and thunderstorms with some embedded small hail are moving through and exiting Rock, Winnebago, Boone & DeKalb County.

2:55am update:  Thunderstorms are picking up in intensity but remain below severe limits.  Heavy rain possible in Winnebago, Machesney Park, Roscoe, and South Beloit.  Hail is possible near Lena and Pearl City.

2:50am update:  Rain and thunderstorms are now approaching the Interstate 39 corridor south of Rockford.

2:15am update:  Thunderstorms are located near Franklin Grove north to Byron.  Those are moving southeast at 40mph.  Another line of storms extends from Monroe through Davis and are moving southeast toward the Rockford metro area.  These storms have a history of producing small hail and heavy rain.

2:00am update:   Thunderstorms still capable of producing small hail were located in northern Stephenson and southern Green County.  Another cell I’m watching will move through Stockton in Jo Daviess County within the next few minutes.  Small hail is also possible along and south of US Route 30 in Lee County. 

1:50am update:  The Severe Thunderstorm Warning for Stephenson County has been cancelled.  Non-severe thunderstorms were located near Forreston and just west of Orangeville and Monroe. 

(1:34 AM) nwsbot: DVN: Freeport [Stephenson Co, IL] law enforcement reports HAIL of pea size (E0.25 INCH) at 01:30 AM CDT — hail was covering the road.

1:30am update:  The thunderstorm in Stephenson County will also affect northern Ogle County an southwest Winnebago County.

1:20am update:  A Severe Thunderstorm Warning is in effect for Stephenson County until 2:15am.  This storm may produce hail greater than quarter-size.  Locations affected include Pearl City, southern Freeport, Ridott, Baileyville, and German Valley.

1:05am update:  Thunderstorms are now moving through Warren, Stockton, and Mount Carroll.  A cell moving toward Pearl City city may contain pea-size hail. 

12:45am update:  The Severe Thunderstorm Warning has expired for northwestern Jo Daviess County.

12:30am update:  The leading edge of rain and thunder is entering Jo Daviess, Carroll, and central Whiteside County.

12:00am update:  A Severe Thunderstorm Warning has been issued for extreme northwestern Jo Daviess County until 12:45am.

11:30pm update:  Most of the rain and thunder is west of the Mississippi River.  The leading edge has entered western Whiteside County.  The general track of the storms are east/southeast.  Parts of eastern Iowa have experienced golf ball to tennis ball sized hail.

9:45pm:  Scattered showers and thunderstorms have developed in eastern Iowa and are moving east/southeast along a frontal boundary.  The main threat with any thunderstorm that develops will be very heavy downpours, frequent cloud-to-ground lightning, and very large, damaging hail.

We will keep you up to date with the latest watches and warnings as soon as we receive them.

-JA

Posted under severe weather, weather

As we witnessed today across the Stateline region, the direction of the wind makes all the difference!  For most of the day, a warm front stalled out about 150 miles south of the area, causing our wind to come from the east.  That allowed the low clouds to stick around and kept temperatures in check by cool Lake Michigan.  Rockford just barely broke 50 degrees.  Readings were in the mid 50s south of the US Route 20 corridor and mid 40s in southern Wisconsin. 

A similar scenario is possible for Sunday.  The front that kept us cool today will move north overnight and allow our temperatures to rise and some patchy fog to form.  Scattered showers and thunderstorms are possible with the passing of this front late tonight and very early Sunday morning.  By tomorrow afternoon, the sky will turn partly cloudy, helping temperatures rise above average.  However, with the frontal boundary becoming nearly stationary and stalling across the area, afternoon high temperatures will be tricky to forecast. 

Locations in southern Wisconsin such as Janesville, Milton, Delavan, Lake Geneva and parts of Illinois closer to Lake Michigan (including McHenry County) may see their wind shift from southeasterly to easterly early on, so afternoon high temperatures may only rise into the middle 60s.  Milwaukee and downtown Chicago will struggle to climb into the 50s.

On the other hand, areas south and west of Rockford like Milledgeville, Dixon, Amboy, and Mendota will climb nicely into the mid and upper 70s thanks to a persistent southeast wind. 

For the Rockford metro, Freeport, Oregon, and Rochelle, temperatures will likely reach the low 70s by afternoon.  During the evening, the wind will shift easterly and allow temperatures to tumble a few degrees.

All of this depends on where the frontal boundary sets up shop!  If it stalls out 50 miles further north or south, afternoon high temperatures will be drastically different.

-JA

Posted under weather

The Community Collaborative Rain, Hail & Snow Network (otherwise known as CoCoRaHS) is looking for more volunteers.  Anyone is eligible to help out with this not-for-profit organization.  The mission of CoCoRaHS is to provide a more comprehensive analysis of local precipitation (rain, hail, and snow).  All you need to participate is a 4-inch rain gauge, which you will use to report any precipitation that may fall.  You also need to be signed up as an official CoCoRaHS observer, which is free and simple to do.

Everyone benefits from your data collection, including the National Weather Service, climatologists, meteorologists, emergency managers, municipal government utilities (water supply, water conservation, storm water), insurance adjusters, the United States Department of Agriculture, engineers, and farmers.  The more information we have, the better we will be able to understand weather patterns and improve forecasting.

There are two upcoming training seminars that are free and open to everyone.  The first seminar is Saturday, March 31 in Saint Charles.  The second local seminar is Monday, April 23 at Northern Illinois University in DeKalb.  You must pre-register for these training classes by calling the number provided or using the email listed.  If you are unable to attend, you can still participate in an online training session at your convenience.  For more information, just visit the CoCoRaHS website at http://www.cocorahs.org/State.aspx?state=IL and register there.

-JA

Posted under weather

Thick cloud cover, fog, and an easterly marine wind off of Lake Michigan kept temperatures in the 40s and lower 50s across much of the region.

I don’t expect much change in that trend overnight so I’ll continue with mainly cloudy conditions with some break-up possible toward morning. Even though temperatures will fall into the upper 30s overnight, there won’t be a significant concern for frost with the aforementioned cloud cover. Sunday’s high temperatures will be in the middle 60s with a partly cloudy sky. As a front nears from the northwest Saturday night into Sunday morning, I do expect a few showers and thunderstorms to roam the area…but mainly during the nighttime hours. Drying conditions are expected for Sunday as high temperatures reach into the upper 70s to near 80 degrees. One thing we’ll watch is how quickly the showers move out on Sunday. If they either don’t form or move out quicker, temperatures in the low to mid 80s are certainly possible. Enjoy your weekend! -ES

Posted under weather

Showers and thunderstorms passed through the viewing area early this morning waking up many of you.  Along the leading edge of the storm, frequent bolts of cloud-to-ground lightning produced very loud rolls of thunder.  Many of us also experienced heavy downpours and small hail was reported in La Salle and Kane County. Rainfall totals varied throughout the area, with the highest around Galena,Madison, and eastern parts of Iowa.  Local amounts will likely differ from what was reported at the local observation sites, so if you have any totals send them to weather@wrex.com.  Now that everything has calmed down and most of the rain has ended, we are left with overcast skies and hazy conditions.  Visibility is around 3-5 miles and will improve throughout the day.  Temperatures will slowly climb into the mid and upper 50s this afternoon thanks to a few breaks of sunshine.

Posted under rain, weather

Showers and thunderstorms have grown to 50,000 feet across South-Central Iowa late this evening and will continue to march eastward through the night.

Because we have a very dry, stable airmass in place with dewpoints in the 30s, storms will weaken as they move across the Mississippi River into Northern Illinois and Southern Wisconsin. However with cold air aloft we could see some dime to nickel sized hail make it to the ground after midnight It’s even conceivable we could get a few storms pulse, producing some isolated quarter-sized hail.  

There will be quite a bit of lightning as rising motion continues overnight. Storms will end by 7am with general rains lingering through noon.

Our Threatrack storm risk remains at level-1.-ES 

Posted under severe weather, Threatrack

British scientists discovered what appeared to be a tornado on the surface of our sun.  NASA’s Solar Dynamic Observatory satellite was able to capture video footage of the solar tornado in September of 2011.  The extremely hot, gaseous, magnetic elements of the sun were projected out into space during this nearly 3-hour-long event!  The estimated wind speed of this ‘solar tornado’ was nearly 190 miles per hour.  Some scientists believe this to be associated with a coronal mass ejection, or a solar flare.  Solar flares are capable of disrupting Earth’s satellites, electricity, and technology.  Pretty interesting stuff!!!

-JA

More information can be found here:

http://www.astronomy.com/en/News-Observing/News/2012/03/Huge%20tornadoes%20discovered%20on%20the%20Sun.aspx

Posted under space

You might want to plan for a few extra minutes for tomorrow morning’s commute thanks to our next storm system coming in.  The latest models show a slight shift in track, placing the low a little further north.  This will place the heaviest rainfall chances over northern Illinois and southern Wisconsin.  This also means the further south you go, the less chance of rain you’ll have.  The storms with the heaviest rainfall will also cause poor visibility and watery roadways, especially if the storm drains are blocked up.  Areas in southern Wisconsin have the best chance to see rainfall totals closing in on over an inch of rain by Friday afternoon. 

Here is a timeline on what to expect as this system progresses east.  Later this afternoon and into the evening hours, our cloud cover will start to thicken up.  Light rain showers will start to form out west in Iowa and move east along with the main low-pressure system.  Rain showers with a few rumbles of thunderstorm will become more widespread overnight.  The heaviest rainfall, as of now, is planned between 5am-10am.

Posted under rain, weather

Have you ever wondered where the air we breathe is coming from? A new map allows you to see where the wind is coming from and where it’s going! Note: This didn’t work in Internet Explorer for me, but opening it in Firefox works just fine. Click here to give it a try. And don’t forget to click to zoom in and pan the map. What do you think of it? -ES

Posted under weather geek, Wind

Our next weather system is setting up over the northwestern parts of the United States and is set to pass just to the south of our area Thursday night into Friday morning.  The scenario this low-pressure system is painting out for us is showers and thunderstorms starting late Thursday night and continuing throughout the morning hours of Friday.  The main threats with these storms, as on now, would be very heavy rainfall, which some computer models are suggesting up to an inch of rainfall by early Friday morning.  We will monitor this system closely and bring you more information as it comes in.

Posted under rain, weather