Thursday, August 29, 2019

Storm Threat Quickly Decreasing Thursday Evening

Our storm chances Thursday evening continue to dwindle with every passing hour as very little storm, or even shower, activity has developed overhead. The cold front is passing through southern Wisconsin and northern Illinois currently and there have been a few more clouds associated with the front, but limited activity showing up on radar.

An isolated shower/storm will still be possible through sunset but mostly for locations east and southeast of Rockford. Winds behind the front are beginning to shift around to the West and will turn Northwest overnight and into Friday. 

Severe Threat for Later Today

By definition, we had a GORGEOUS start to our Thursday. It was a bit chilly to start off as temperatures under mostly clear skies and light winds "bottomed out" into the low 50s. However, it would be a good idea to get any plans or activities done early today. This stretch of dry and tranquil weather will come to an end as afternoon thunderstorms could sweep through the Stateline.

After having a fall-like chill in the air yesterday, highs today will warm up around seasonable into the low 80s. We will have the breezy conditions stick around during the day as well. But this time, winds will be out of the southwest. Sustained winds today are likely to peak once again in the 15 to 20 MPH range, but wind gusts could be between 30 and 40 MPH. This is why our temperatures will be warmer, and also why we will see an increased amount of humidity during the second half of our Thursday. The higher dew points that are pulled into the region could help with the development of thunderstorms later today. It isn’t until after prime heating, which is typically around between noon and 4 P.M, that thunderstorm risks increase.

The Storm Prediction Center did upgrade the viewing area to a slight risk (2 out of 5) for severe weather yesterday. They did keep the Stateline under the slight risk in this morning's outlook as well. Ahead of an approaching cold front, isolated to scattered storms will be possible, bringing the threat of damaging gusty winds and heavy rainfall. There is a threat for large hail and a brief tornado or two, but these two threats are going to be very isolated.

By 4 P.M, model guidance indicates a few spotty storms are likely to develop across far northwest Illinois and southwest Wisconsin. This broken line of storms will then track southeastward towards the Highway 20 corridor between 5 and 7 p.m. That is why it would be great to have the rain gear on hand as you head home later today and to take it slow during the evening commute.

Storm coverage should begin to decrease by 8-9 p.m. and the weather will quiet down going into the night tonight. Following the cold frontal passage, a drier and cooler air mass will settle into the region for Friday. Highs will drop back into the 70s bringing back that feeling of fall that we have gotten used to over the past few days. The cold front that moves through tonight will stall out and become a stationary boundary to our south, keeping rain chances going on Saturday. On top of the rainy start to the weekend, highs look to stay cool through the weekend before a warm up arrives for the start of the work week.

Wednesday, August 28, 2019

Strong Thunderstorms Possible Thursday Afternoon and Evening

Skies will remain clear and winds will calm Wednesday night allowing overnight lows to fall into the mid 50s for the start of Thursday. Southwest winds will increase mid-morning, gusting to 35 mph during the afternoon. The first half of the day Thursday will remain dry but the chance for thunderstorms will increase ahead of a cold front that will pass through the Stateline by sunset.

Instability (energy in the atmosphere) will rise during the day as nearly full sunshine warms the atmosphere. Dew point temperatures will warm back into the mid 60s, after falling into the 50s Wednesday. The higher the dew point temperature warms, the better chance we will have for strong to severe thunderstorms late in the day Thursday. Our window for storms will be from 2pm to 8pm. After 8pm the cold front will be to our east, ending the storm threat.

Any thunderstorms that develop and turn strong will have the potential for damaging winds and hail. Heavy rainfall will also be a concern, along with an isolated tornado.

Breezy Today, Stormy Thursday

It's been a while since we have actually felt the summer time heat here in the Stateline. In fact, here is a little statistic for you. 13 of out of the last 19 days here in Rockford have been below average. And by the way the forecast looks for the rest of our Wednesday, we look to tackle on another one as highs only climb into the low 70s.

Low temperatures this morning under mostly clear skies "bottomed out" in the 50s across the Stateline. The coolest spot throughout the morning was Galena which made it down to 51°. As the day progresses, temperatures under sunny skies will be quick to rebound into the low to mid 70s. Just to put that into perspective, average highs this late in August are in the low 80s, so today will be unseasonably cool.

The big weather headline for today isn’t the cooler temperatures, though. Westerly winds will be the primary factor in today’s forecast. Currently, winds are already gusting upwards of 30 mph in a few spots across the region. A strong low pressure system up in Canada and a high pressure system are creating a tight pressure gradient at the surface. When you have that pressure gradient, winds ramp up as of a result.  Sustained winds today are likely to peak in the 15 to 20 MPH range, but wind gusts could be between 30 and 40 MPH. This may bring a few traveling issues today, especially if you are traveling on north to south oriented roads, such as I-39 or I-90 into southern Wisconsin. You’ll definitely want to keep an extra tight grip on the steering wheel.

Winds today will be strongest between noon and 5 p.m., with the breezy conditions diminishing by this evening. Sunshine will stick with us throughout the day, but we definitely will see another round of those "fair weather" cumulus clouds build in this afternoon. Temperatures overnight tonight under mostly clear skies will once again have the opportunity to "bottom out" into the low to mid 50s, So it wouldn't be a bad idea to grab a light jacket as you head out tomorrow morning.

Thursday will definitely be a transition day. As that high pressure system slides to the southeast of the Stateline, winds overnight will turn more southwesterly. This is going to help warm our afternoon high temperatures for tomorrow back towards seasonable. Highs tomorrow will be featured in the low 80s before a cold front brings an end to the quick warm up. Increasing heat and humidity ahead of that cold front could also spark a few thunderstorms during the afternoon hours. Some of which could strong or severe. The Storm Prediction Center has placed the Stateline under a Marginal (level 1 out of 5) threat for severe weather. It will be something to keep a close eye on.

Tuesday, August 27, 2019

Cooling Winds Wednesday Followed by a Quick Warm Up Thursday

West winds will pick up again Wednesday afternoon, gusting 30-35 mph, as low pressure moves into southeast Canada. A cold front passing through the Stateline Tuesday night will bring minimal rain chances locally, but pull down a slightly cooler air mass Wednesday afternoon.

Highs on Tuesday reached 80 degrees in Rockford but will only warm into the mid 70s on Wednesday. Winds Wednesday night will be quick to shift to the southwest Thursday, gusting to 30 mph but also boosting temperatures back into the 80s for the afternoon. Another cold front will be quick to move in Thursday evening providing a slight chance for showers and thunderstorms, but another drop in temperatures Friday and Saturday.

Monday, August 26, 2019

Heaviest Rainfall Monday Morning in Nearly Two Weeks

Over an inch of rainfall came down Monday morning for many across northern Illinois, with some locations picking up nearly an inch and a half to two inches! Officially at the Rockford Airport 1.04 inches of rain fell, making it the highest rainfall total since August 11th when 1.82 inches of came down. Most of the rain has ended Monday evening with just a few sprinkles/light showers expected over the next few hours.

A cold front stretching back through the Upper Midwest will move through around Midnight. Showers and thunderstorms associated with the front have been moving into Wisconsin, but there hasn't been much rain development southward into Iowa. I'm still keeping an isolated shower/storm chance overnight, but most will end up dry heading into Tuesday morning. An isolated shower can't completely be ruled out ahead of another cold front Tuesday evening, but most will remain dry.

Monday's Morning's Rainfall

After a pleasant weekend with plenty of sunshine and low humidity, we are starting off the work week with a dousing of heavy rain across the Stateline. It's been the trend so far during the month of August in which the work week starts off with a good amount of rainfall. Including this morning's total of .98" (as of 10 A.M), rainfall on Monday's have contributed to 2.12" of Rockford's monthly total of 5.48". As the day progresses, we could tackle on a little more as rounds of heavy rain will likely stick around off-and-on through the remainder of our Monday.

Rainfall Totals (As of 10:00 A.M):

Rockford: .98"
Rochelle: .91"
Dekalb: .75"
Savanna: .69"
Sterling: .50"
Monroe: .36"

A low pressure system across central Illinois is the source for the pockets of heavy rain that pushed into the region this morning. This low will continue to push more moisture-rich air northward, rainfall totals could be quite impressive by the time the rain comes to an end. Overall, rain totals could approach 1" - 1.5", pushing 2" locally in some spots. It will make your life much easier if you keep the rain gear on hand today.

The latest update from the Storm Prediction Center has taken our viewing area out of the marginal (level 1 out of 5) risk. Instead, the region is currently in a general, non-severe thunderstorm risk for this afternoon. An embedded rumble of thunder is possible through the early hours. Higher risks for thunderstorms arrive this afternoon and evening ahead of an approaching cold front. The cloudy skies will help limit the severe potential later today as instability (or energy in the atmosphere) remains limited. This will also keep temperatures from climbing above 80°. Highs this afternoon may only climb into the mid-upper 70’s.  Dew points will be much higher than what we experienced over the weekend, meaning the mugginess is back. But not for long!
The cold front mentioned earlier is set to pass through early tonight. Not only will it bring lower humidity to the region, cooler and drier air will slowly inch southward behind the front. Expect high temperatures by midweek to drop just slightly into the low to mid 70’s with more sunshine returning to the forecast. It seems like we will stick with the below average temperatures through the end of August and into the start of September.

Sunday, August 25, 2019

Light Showers Sunday Evening, Heavy Rainfall Possible Monday Morning

Sprinkles and light rain showers have developed Sunday evening but will remain light and scattered through the rest of the night. Rain will become a little more heavy and steady by Monday morning as moisture increases into northern Illinois and low pressure approaches from the west.

Moisture in the atmosphere will increase to over one inch by Monday morning, leading to the

possibility of heavy rainfall throughout the morning commute. Instability will remain limited, so only embedded thunderstorms are possible.  Severe weather is not expected during the morning.

The rain will last through mid to late morning with a little break in some of the heavier activity for the afternoon. A warm front will quickly lift north during the late afternoon increasing the dew point temperature, as well as the humidity. A cold front will be quick to move in from the northwest Monday night leading to a second round of thunderstorms during the evening. While most of the strong to severe thunderstorms will remain positioned to our southwest throughout the day, some storms Monday evening could have a strong wind gust or two associated with them. Heavy rain will continue to remain a threat through Monday night.

Thursday, August 22, 2019

Abnormally Dry Conditions Continue in Illinois

The latest drought monitor from the National Drought Mitigation Center continues to show abnormally dry conditions across much of northern Illinois, while moderate drought conditions persist over west-central Illinois.

A little over 42 percent of the state is considered abnormally dry, down from 44 percent from last week. Seven percent of the state is now considered in moderate drought conditions, slightly up from the 6 percent from last week.

August is actually a little over an inch above average with 4.38 inches of precipitation recorded for the month. Dry conditions are expected through the weekend before a quick moving system works into the Midwest and Great Lakes early next week.

Cooler Weather Settles in Behind Cold Front

Dew point temperatures so far this week have been on the uncomfortable side, but I am happy to say that relief has arrived. Showers and storms developed Wednesday afternoon as a cold front progressed through the area. Rockford (KRFD) actually ended up with .45" of rainfall. Lows this morning from Galena to Rochelle were able to fall into the middle to upper 50s. So despite a chilly start across the region, highs today should still be able to climb into the upper 70s. High pressure sitting to the northwest will allow the winds to flow out of the northeast which will help bring low humidity to the Stateline.

Now, this northeasterly flow at the surface will also be responsible for the development of a lake breeze boundary off of Lake Michigan this afternoon. As this lake breeze pushes inland, this could provide enough forcing for a pop up shower or two. So this is why we introduce a slight chance in the forecast, especially for our eastern counties. But mostly sunny skies will likely dominate most of our day today.
Overnight, lows will fall into the lower to middle 50s. Typically on average, the middle of September is when we see low temps in the low 50s. Friday morning will feature another quiet and crisp start with plenty of sunshine and those seasonably cool temperatures. The "taste of fall" continues through the day tomorrow as tomorrows high will be the coolest of the 7 day forecast. More sunshine and wind flow out of the northeast will once again allow temperatures to climb into the upper 70s. If you plan on making it out to City Market, it looks like the fabulous evening to go out and enjoy the festivities.

The upcoming weekend looks to keep the pleasant weather going. High temperatures slowly climb closer to 80°, but the cool mornings will allow you to keep the windows open overnight. High pressure anchored over the Midwest will slowly slide to the east. This allows for highs to reach into the lower 80s by the end of the weekend ahead of an approaching cold front that looks to slide through on Monday. We will also see an uptick the humidity as well going into the start of next week. That is why I continue to put this message out there; please take advantage of the weather that mother nature is giving us the next few day. You won't regret it! 

Wednesday, August 21, 2019

Sunny, Dry Conditions To End Your Week

A high pressure system is taking shape far to the north of the Stateline.
It will begin to greatly impact our weather as early as the predawn hours of Thursday. As it brings northerly flow to the Stateline, it will bring our dewpoint temperatures down into the mid-50's calling for dry, comfortable conditions, few clouds, and little, if any, rain. The northerly winds will also advect cooler temperatures into the region likely keeping us below 80 degrees for Thursday, Friday, and Saturday.
There is a slight chance that, on Thursday, northeasterly flow will pull some moisture from the lake and throw up a few brief, light showers in the evening hours of tomorrow. Otherwise, no rain is expected.
The highest confidence for clear skies and no rain belongs to Friday. The system will propagate southward and position itself over Lake Superior. Being much closer to the Stateline, we will more easily feed off of the system's descending air which makes it very difficult for rain and clouds to form.
The system will strengthen rapidly overnight Friday into Saturday as it will move to our northeast. No rain and few clouds are expected for Saturday as well.
As the high pressure center moves to our far northeast on Sunday, the clockwise rotation of the winds as they diverge around the system will result in south-southeasterly flow which will advect a good amount of moisture into the region. As that moisture builds throughout the day, we will have a chance for showers come Sunday evening.
On Monday, an area of low pressure will sit to our northwest and drag along with it a strong cold front which will likely provide us with hefty showers as the front passes over late in the day.

Monday, August 19, 2019

Stormy Tuesday, Lower Humidity Midweek

As we head into the start of the work week, most of the region remains dry until tomorrow. Although, the only thing to keep in mind for today is a slight chance for an isolated shower or two. A mid-level system that is currently over Idaho this morning will pivot across the Great Plains and Midwest by early Tuesday. Futuretrack has a large complex of thunderstorms, or what we call a Mesoscale Convective System (M.C.S), developing overnight into early tomorrow morning across Iowa.

Typically, these systems are known for their damaging wind gusts and heavy rainfall. This storm system looks makes a run at northern Illinois, but model guidance keeps it south of I-80. We seem to be on the northern fringe of the M.C.S as it tracks southeastward into central Illinois. The Storm Prediction Center has introduced  a SLIGHT RISK (level 2 of 5) that does include a few of our southern counties and extends all the way through southern Illinois.The rest of the region remains in a MARGINAL RISK for severe weather (level 1 of 5).

Thunderstorms that blast through the area tomorrow morning will signal a return to cooler weather. The heart of the cooler air likely doesn’t make it into the region tomorrow, as highs are expected to be in the mid and upper 80’s And with wind flow at the surface still remaining out of the southwest through the day, its going to feel very humid at times. However, a break from the humidity is on the way. A cold front that is set to pass through Wednesday morning will bring a fall-like air mass to the region by mid-week. Especially by the second half of the week. Highs will be near 82 Wednesday with a mix of sun and clouds followed by highs in the upper 70’s by Thursday and Friday with much lower humidity.

Friday, August 16, 2019

Isolated Showers Shift East Friday Evening

Light showers came down Friday morning with skies turning partly cloudy during the afternoon. Low pressure passing over northern Illinois helped fire off a few more isolated thunderstorms late Friday afternoon over Wisconsin and DeKalb County in Illinois.

As the low continues to move east showers will also move east, leaving our skies partly cloudy for the remainder of the evening. It'll still feel a little muggy overnight with areas of fog, some dense, possibly by Saturday morning. Isolated thunderstorms are possible Saturday afternoon with heavy rainfall possible early Sunday morning.

Rain Chances Increase into Next Week

As heat and humidity are expected to build, the pattern over the Stateline turns a bit more active. Northern Illinois will find itself in what is known as the “ring of fire.”. Meteorologically, the "ring of fire" begins when a potent ridge of high pressure forms over a region. In this case, this ridge will take aim at the four corners region once again. This ridge will displaced the jet stream further to the north, mainly around the Upper Great Plains/Southern Canada vicinity. Any system that rides over the ridge and will likely track into the Midwest. This pattern will provide multiple opportunities for storms through the weekend and into the start of next week. This could slowly help out with the drought situation that is growing across the State of Illinois.

As the ridge begins to grown in size, models continue to show the first opportunity arriving overnight Friday into Saturday morning. However, this complex of thunderstorms will most likely impact areas closer to Peoria and across central Illinois. For the Stateline, this will only bring additional cloud cover for the start of our day tomorrow.

The outflow from these morning showers and storms could spark a few afternoon thunderstorms locally, though. That is why the Storm Prediction Center has expanded the severe threat for tomorrow. Placing a good chunk of our viewing area under a Marginal Risk (level 1 of 5) and a few spots our towards the west under a Slight Risk (level 2 of 5) for severe weather. However, most of our day tomorrow looks to remain fairly dry with highs in the low 80s.

The second round of storms we are monitoring, moves in overnight Saturday into Sunday morning. A Mesoscale Convective System (M.C.S., or a line of thunderstorms) will track into the region from the west. Typically with an M.C.S, gusty winds and heavy rainfall are the biggest concerns. But at the moment, it is hard to tell what the biggest threats will be since model guidance continues to show a weakening trend with this system comes before it comes blasting through northern Illinois. Aside from the storm chances, heat and humidity are set to return to the region. Highs by the start of next week will be in the middle and upper 80’s with dew points likely to be near 70°.

Thursday, August 15, 2019

815 Day Forecast

Today is not just another Thursday, but it's 815 Day across the Stateline. A day where we get to celebrate the city of Rockford. And if you can't go out and partake in the festivities, I only ask for you to do one thing. Please take a few minutes to step outside and just enjoy the beautiful weather that mother nature is presenting us with today. It is essential that you take a few minutes of your time to soak in the pleasant conditions. A high pressure system at the surface will be in command through our Thursday bringing nothing but sunshine to our region. That along with the combination of low humidity and comfortably warm temperatures will make for a spectacle of an afternoon. Winds out of the north and northeast should limit our highs only to the upper 70s to low 80s.

High pressure currently sitting to the west of the region will slowly slide over the Great Lakes region later today. This will allow a bit of moisture to stream in resulting in a spotty afternoon shower or two to develop primarily over our eastern counties as a lake breeze boundary comes off Lake Michigan. But rest ashore, many dry hours are in store through the day and into the overnight.

As a disturbance tracks through the jet stream, it will bring a chance for showers and thunderstorms. Before midnight, things look to remain fairly dry! If you are planning on going to the Winnebago County Fair in Pecatonica, dry weather will persist through the event. Though clouds will likely be on the increase as the system draws closer. Rain chances don’t really arrive into the forecast until around the time of the morning commute tomorrow morning. As usual, heavy rain is possible underneath any thunderstorm that develops. Between Friday and Monday of next week, several rain chances will move through. We will also experience an uptick in the humidity levels as winds switch to a more southerly and southwesterly direction.

Wednesday, August 14, 2019

Brief Funnel Clouds Wednesday Afternoon

Widely isolated showers developed Tuesday afternoon and evening and produced brief heavy downpours. Lightning was absent from most of the shower activity, so thunder was extremely limited.

The showers developed as an upper level low moved over southern Wisconsin and northern Illinois. At the surface, there was a weak boundary (wind convergence line) over northern
Illinois. Cumulus clouds started to build high in the sky as the low passed overhead. The quickly rising clouds and boundary near the surface allowed enough convergence and spin to develop in the atmosphere to produce brief funnel clouds.

The pictures above were taken shortly after 12:30pm Tuesday afternoon from Browns Mill Road in Stephenson County, looking to the east/southeast. The photos are from Patrick
Murray. You'll notice the funnel isn't very big and is not attached to a thunderstorm cloud. These types of funnel clouds rarely touch down and typically don't last too long. If they do touch down, minimal damage can occur.

Rain Chances Continue Into Our Wednesday

Before we jump into the forecast for today, a few of our viewers captured stellar weather pictures this morning. First, we would like to thank our First Warn weather watcher Sandy Bruch. She took this photo of a blanket of fog laying over the corn fields in her backyard. In fact, visibility in portions of Stephenson, Lee, and Whiteside Counties did drop below 1/4 a couple of times as the morning progressed. Clutch sunrise photo Sandy!

Our second photo comes out of Delavan, Wisconsin up in Walworth County. An isolated thunderstorm that was tracking east towards Milwaukee produced an outflow boundary, also known as a gust front, as it was weakening. Fellow storm chaser Corey Bull captured this stellar photo of a shelf cloud on the leading edge of the gust front as it was tracking through Southern Wisconsin. We tend to call pictures of individuals in front of a shelf cloud a "shelfie".  There's some weather humor for you!

As far as the weather for today, a low pressure centered over southwest Wisconsin will continue to track southeast ward through the day and could provide the spark for additional rain and storm chances this afternoon. The severe threat looks to remain low for today, but a gusty isolated thunderstorm or two is possible. Part of the reason severe weather isn’t expected relates to the shortage of instability or energy in the atmosphere. Shower chances look to linger into this evening, but shouldn't bring any hazardous driving conditions on your drive home later on.

While we have some humidity still sticking around, conditions through the day will feel a tad less muggy from what we experienced yesterday. Today's highs will only climb into the upper 70’s under mostly cloudy skies. If we get some clearing, a few spots could peek into the low 80's. But, the most recent visible satellite imagery shows just how stocked our area is with clouds as that low pressure continues to spin southeastward into northern Illinois. Now today is the first day of the Winnebago County Fair. Gates open at Noon! If you are heading out to the fair today, just have a place to go under or have the umbrella on hand just in case a few showers do pop up this afternoon and evening. Happy "Hump" Day Stateline!

Tuesday, August 13, 2019

Isolated Thunderstorms Tuesday Evening

Isolated thunderstorms have developed over parts of Wisconsin and northeast Illinois Tuesday evening. Severe weather is not expected, but a thunderstorm moving across McHenry County in northeast Illinois is capable of heavy downpours and gusty winds. This storm is moving to the southeast towards the northwest suburbs and Chicago.

A few additional thunderstorms over southwest Wisconsin will move southeast into Jo Daviess and Stephenson counties. These storms are weakening, but will still be capable of heavy downpours.

Most of the storm activity will last through sunset with isolated showers and mostly cloudy skies heading into Wednesday morning. An approaching low pressure system from the north will help aide in a few additional showers for Wednesday afternoon and evening. Severe weather is not expected with those storms.