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

After several weeks with allergy counts sitting firmly in the “high” categories, we have finally seen them drop back into the moderate category for the time being. These cooler temperatures combined with the lack of wind as of late have helped to stifle pollen counts just a bit, giving us allergy sufferers a quick break. With wind expected to be on the increase over the next few days, its a good bet that polllen counts will once again be on the rise. -Greg

Posted under pollen count, weather, Wind

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

April 14, 2013 High Temps

An interesting scenario was observed on Sunday. A warm front traveled north during the late morning hours and set up shop along the Illinois-Wisconsin border. North of the warm front, the wind blew out of the east.  The cool water temperatures of Lake Michigan helped to moderate the air mass and kept a chill in the air. As a result, much of our southern Wisconsin counties had temperatures stall in the upper 40s and lower 50s.

South of the warm front was a different story! With a south to southeast wind, many communities along and south of Interstate 88 and west of Interstate 39 climbed into the lower 70s! Freeport, Rochelle, DeKalb & Galena all recorded their first 70-degree temperatures of the year.

Temperature vs. Wind Direction

The Rockford & Belvidere area was in somewhat of a transition zone.  The warm front lifted north of the metro area around 2pm and allowed temperatures to climb into the upper 60s. However, around 4:30pm the front sagged to the south. As a result, the wind direction shifted from the mild southerly breeze to the cool easterly breeze and temperatures fell into the upper 50s around dinnertime.  Not long after sunset, however, the front moved back north of the metro area.  Even without the help of the sun, the warm air advected from the south and temperatures climbed back into the middle 60s!

-Joe

Posted under weather, weather geek, Wind

Complex Sunday Forecast

There’s no shortage of things to talk about in regards to the weather lately! This upcoming week is already showing many similarities to the previous week: an extended unsettled period with rounds of rain showers and cool temperatures.  One of the most interesting days of the next seven is Sunday.

A warm front will continue to push north out of Missouri on Saturday night.  As a result, scattered rain showers (with perhaps a rumble of thunder) are likely after midnight and especially during the pre-dawn and early morning hours of Sunday.  With temperatures in the 30s, a few wet snowflakes may briefly mix in at the onset of the rain showers. Things should quiet down by late morning as the warm front will continue its push toward southern Wisconsin.

GFS Temperature Model

While a quick shower is possible during the afternoon & evening hours, the bulk of Sunday should remain dry. A few breaks in the overcast will allow for some peeks of sunshine. Wind gusts out of the south will approach 35mph. However, those strong winds will help propel our temperatures into the upper 60s!

NAM Temperature Model

Using a blend of our forecast models and taking into account some breaks in the cloud cover, some hometowns to the south of Rockford have a decent shot at 70 degrees!  This warmth, however, with be short-lived.

A cold front will pass through northern Illinois and southern Wisconsin on Sunday night, bringing heavier showers and thunderstorms.  With the passage of the front coming after dark, the energy and instability that will fuel the thunderstorms to our west during the daylight hours will decrease for us.  Severe weather is not anticipated locally but small hail may accompany a few of the heftier thunderstorms.

Lingering showers are likely into the pre-dawn hours of Monday as temperatures fall into the middle 40s. When it’s all said and done, our rain gauges may pick up half an inch. Higher rainfall totals are possible with any thunderstorm activity.

FutureTrack Rainfall

Beyond Sunday, we’ll have to keep our umbrellas handy as another frontal boundary will set up shop to our south and bring round after round of rain through at least Thursday. -Joe

Posted under rain, weather, Wind

If you have been itching to dust off the golf clubs and squeeze in a few rounds like I have, you only have one decent shot at making that happen this week. As of right now we only have one day that looks to remain completely dry and that luckily is tomorrow. Temperatures will be down across the board so a morning tee time would be a very chilly option as we will be in the 30s. Clouds will persist most of the day with an afternoon high temperatures of 45 degrees. Expect many courses to be cart path only tomorrow due to the excessive rain we have seen the last week. Also, be prepared to deal with some wind on the course with gusts up to 30mph. Those aren’t the most ideal conditions for golfing, but they are the best we will have all week. -Greg

Posted under event, First Look, rain, Wind

The heavy rainfall and scattered thunderstorms have moved on, for now that is. The next 24 hours will be focused around much cooler temperatures with overnight lows once again in the 30s, and tomorrow’s highs only in the low to mid 40s. Tonight a few scattered showers could flair up and there is a small shot that a few snow flakes might be seen late tonight into tomorrow morning. On the back side of this potential mixy precip, the wind will ramp up by tomorrow afternoon. Sustained wind speeds of 15-25 mph are likely with gusts above 30 mph. Hang on to your hats! -Greg

Posted under rain, snow, Wind, winter weather

Even though a few rain showers are dotting the landscape Saturday afternoon, the atmosphere is still relatively dry.  Humidity values will generally remain below 40% while wind gusts have the potential to approach and even exceed 40mph through the evening. The dry air combined with a consistent wind speed and higher gusts puts us at risk for the spread of wildfire.

There have been been a few reports of grass and brush fires across rural Winnebago & Ogle County.  The best plan of action is to stop any outdoor burning on Saturday.  Wait until Sunday, when our sustained wind speed will be below 10mph. -Joe

Posted under safety, wildfires, wildlife, Wind

High pressure will be in firm control across the Stateline on Wednesday.  As the ‘big blue H’ drifts southeast from Minnesota and eventually into Ohio, we can expect a nearly calm wind, mainly clear sky, and abundant sunshine.  With the lack of cold air advection, our high temperatures will be able to rise into the upper 40s.  By late in the day, the area of high pressure will be to our east. Since wind flows clockwise around an area of high pressure—we’ll begin to see a south-southwest breeze—transporting in the warmer temperatures from the south.  The milder air will make itself known across the region on Thursday as temperatures will climb into the upper 50s and even touch 60 degrees in a few spots!

A cool front will drop south out of Wisconsin late Thursday, shifting our wind out of the northeast for Friday.  While this will knock temperatures down, ample sunshine and the strong early-April sun angle will keep our highs in the lower 50s on Friday.

-Joe

Posted under FutureTrack, weather, Wind