Storms On the Way and if They Affect the Eclipse

It's been a gorgeous start to the weekend with sunshine and mild temperatures in the upper 70°s to low 80°s.  We get to hang on to these nice conditions going through the overnight, where we'll cool to the low 60°s.  However, it'll be a little muggy during the overnight, so we could see some patchy fog early tomorrow morning.  The high pressure system over our area will track east during the day tomorrow, which will allow for more warm air and moisture to move into our area.  This will give us a slight storm chance out west mid-day tomorrow, but for the most part we should stay dry through the afternoon.

A low pressure system will bring a warm front in during tomorrow evening, bringing us a chance for storms around 7pm.  The warm front will move through during the overnight, but storm chances will drop as we progress through the overnight.  However, we will see rain during the overnight, and even a couple heavy showers.  That low pressure system and that high pressure system will channel the warm, humid air into our area going into the work week.

This will increase our storm chances heading into Monday.  However, the storms are expected to be isolated, so most of the Stateline will be dry.  Along with that, partly cloudy skies are expected, but we'll be seeing upper level clouds, which usually aren't thick.  Thus, we should still have a decent view for the eclipse Monday afternoon. 


Storm chances increase going into Monday evening, where a few strong thunderstorms may be possible.  A weak cool front will move during the overnight, allowing for some thunderstorms to linger, but the severity of the storms will decrease going through the overnight.  After the cool front moves out early Tuesday morning, we stay dry for the rest of the week with sunshine and cooler temperatures in the mid to upper 70°s.

Temperature Climb and What It Means For the Eclipse

It's turned out to be a beautiful Friday as we've seen lots of sunshine and more mild temperatures in the upper 70°s to low 80°s.  However, we've got a weak low pressure system on the approach from the northwest, and this will be increasing our rain chances as we go through the evening.  Our best rain chances will start between 9-10pm, but we could see a couple light showers until then.  The weak low will clear out around 1am, and by then most of the rain will be gone.

After the low clears out, clouds will be decreasing for the rest of the overnight and into Saturday morning.  High pressure will settle in Saturday morning, bringing lots of sunshine for the weekend, but it'll also cause our temperatures to climb quite a bit.  We'll see temperatures in the mid 80°s on Saturday, and then the upper 80°s to possibly low 90°s Sunday afternoon.  It'll be fairly humid by Sunday, which could bring heat index values into the mid 90°s, so take precaution if you have outdoor plans.

Humidity will increase much more on Monday, and that high heat and moisture will allow for some thunderstorms to develop.  However, these storms will be isolated, meaning that while these storms are occurring, most of the Stateline area will still be dry.  It'll be a little cloudy early afternoon, but there will still be plenty of breaks in the clouds to allow for a good viewing of the eclipse.

A cold front moves in Tuesday, bringing storms for the early afternoon, but afterwards we stay sunny and dry for the rest of the week, with temperatures in the low 80°s.

Two Tornadoes Near Freeport Wednesday Evening

The atmospheric setup Wednesday evening was not in favor for widespread severe weather, let alone tornadic storms.  But that's what occurred just a little before 7:30pm Wednesday evening west of Freeport.


It's important to keep in mind that the Quad Cities National Weather Service radar beam, when looking at storms this far east, is not able to view the lowest part of a thunderstorm.  The radar is actually looking at the storm roughly 7,000ft above the surface.  Tornadoes that go 'undetected' on radar don't happen very often, but if they do, the tornadoes are usually fairly weak.  That's because strong tornadic thunderstorms have noticeable rotation not only at the lowest part of the storm, but also at the mid-levels.


The storm that moved near Freeport Wednesday evening had very little, if any, lightning detected with it.  What little rotation that was showing up was extremely weak and did not indicate that a tornado was going to, or in the process of, forming.  What likely happened Wednesday evening was the rain interacted with an approaching warm front in such a way that it allowed rotation to occur in the atmosphere, causing two brief spin up tornadoes.  Any stronger rotation may have very well formed below where the radar was viewing the storm.  This is why having trained weather spotters and 'ground truth' are so important to meteorologists.  It allows us know and verify what is occurring down near the surface.


Below are the findings from the damage survey from the National Weather Service:

First survey tornado path:
Rating: EF-1
Peak wind: 90 mph
Path length: 2.84 miles
Path width: 75 yards


This tornado started at 7:21pm 5 miles west/southwest of Freeport and ended around 7:28pm 4 miles west/northwest of Freeport

Second survey tornado path:

Rating: EF-0

Peak wind: 80 mph

Path length: 3.31 miles

Path width: 20 yards

This tornado started at 7:28pm 5 miles west/northwest of Freeport and ended around 3 miles west/southwest of Cedarville.

Storms Today and Whether or Not We Stay Clear For the Eclipse

We've got some storms moving east through the Stateline due to a cold front.  Showers and storms are expected the rest of the morning while that front slowly pushes through, eventually moving out of our area around 1pm.  Some light rain is possible behind the front as there will be a decent amount of energy in the atmosphere, enough to generate some light rain showers for the start of the afternoon.  However, we should stay dry the closer we get to the evening.  Highs this afternoon will be around 83°.

Cool, dry inflow will bring us down to around 63° for the overnight, and this inflow will also lower our humidity as we through the overnight.  The dry inflow will keep us mostly sunny tomorrow with temperatures in the low 80°s for Friday afternoon, but a little bit of instability will allow for a slight rain chance during the evening.  Other than that, we stay dry going through the weekend as high pressure builds, keeping the skies clear with temperatures expected to be in the mid 80°s.

Another low pressure system will move in to start the work week, and will pull in a substantial amount of heat and moisture out of the south.  This will bring temperatures into the upper 80°s to low 90°s for Monday and Tuesday, and will also increase our storm chance.

At this point, isolated storms are likely Monday afternoon, with skies looking to be partly cloudy.  However, the storms look isolated, so most places will be fairly dry, and the partly cloudy skies should allow enough room to see the eclipse.

Tuesday will be in the upper 80°s, with isolated storms possible in the afternoon, but afterwards we're looking to stay dry heading into the middle of the week.

Wednesday Evening Weather Update

Non-severe showers and thunderstorms moved through northern Illinois and southern Wisconsin late Wednesday afternoon.  A few of the stronger rain showers did produce gusty winds, but no severe weather was reported.


That line has now moved north into central Wisconsin, with additional showers and thunderstorms developing over northwest Illinois.  A warm front is draped from near Dubuque, IA to Sterling and then south of Kankakee in east-central Illinois.  The rain and isolated thunderstorms moving into Green and Stephenson counties are forming along and ahead of a warm front that will continue to lift north through the evening.  Severe weather isn't expected but with stronger winds in the atmosphere moving into the Stateline this evening, some of the storms could produce gusty winds.  Brief heavy downpours will likely be our greatest concern.


Isolated to widely scattered storms will continue to fester through roughly Midnight, with skies likely remain mostly cloudy during the overnight. 

Storm Threat Today and Eclipse Update

We had a small line of storms that pushed north through our western counties, but other than that it's been a great start to this Wednesday!  We had mostly clear skies this morning, but clouds will increase a little more going into the afternoon with the approaching warm front.  That warm, humid inflow will bring temperatures into the mid 80°s this afternoon, with dew point temperatures in the low 70°s.  This will allow for heat index values to be in the low 90°s, so be sure to stay hydrated if you have outdoor plans this afternoon, because it will feel pretty hot.

That approaching warm front will bring us a slight storm chance out west around 1pm, but a better storm chance for our western counties around 4pm.  Everyone else will see scattered cloud cover during the afternoon, but we'll still see some sunshine.  The front moves in around 7pm, where that storm coverage will increase a little more across the Stateline area.  We are under a Marginal Risk for severe weather, but the stronger storms should stay well to our southwest where a cold front will line up. 

That front will progress through the Stateline during the evening, allowing for some heavy rain showers for the overnight, but a couple storms could linger.  The front will move out around 1am, after which we'll stay cloudy for the rest of the overnight.  A cold front will move in mid-day tomorrow around 1pm, which will bring more storms.  However, the front will move out around 4pm, and then we'll stay dry going into the weekend.

A low pressure system moves in Monday.  However, there's only a slight chance for an isolated storm during the afternoon, but other than that we'll have clear skies and dry conditions for viewing the Eclipse.

Humidity on the Rise Wednesday and Thursday

Typically during the 'dog days of summer' we're talking high heat and humidity.  That has been lacking lately from the forecast, but looks to return by the middle of the week.  You may have felt an increase in humidity Tuesday afternoon, but it was tolerable. 


An approaching warm front during the afternoon Wednesday will pull quite a bit of moisture northward by Wednesday evening and Thursday.  This will push dew point temperatures close to 70 degrees by Wednesday night.  Temperatures are expected to warm into the low to mid 80's on Wednesday, and possibly mid 80's on Thursday.  With the increase in moisture, heat index readings will be nearing 90 degrees both days.  Not oppressively hot, but hot enough.  The quick increase in moisture will also lead to heavy rain producing thunderstorms Wednesday night.  Area wide anywhere from half an inch, up to three quarters of an inch of rain will be possible.  However there could be a few isolated locations, especially those that are under a heavier thunderstorm, that may end up with closer to an inch of rain.


A cold front moves through Thursday afternoon and this should bring dew point temperatures back down, making it a little more comfortable by Thursday evening and Friday afternoon.