Friday, August 18, 2017

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.

Thursday, August 17, 2017

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, August 16, 2017

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.

Tuesday, August 15, 2017

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.

Everything You Need to Know About the Eclipse

We are less than a week away from the total solar eclipse and you may be wondering what some of the safe options are to view the eclipse.  It's best to view the eclipse, and safest too, with eclipse glasses.  But those may be hard to come by as many locations that sold the glasses, are now sold out.

 NASA has put together wonderful information about what exactly an eclipse is, how to safely view an eclipse, how often it occurs and what to expect during the eclipse.  You can find all the information, including a detailed map of how much the sun will be obscured in your location, clicking here.

Of course the eclipse will only be visible if the weather cooperates.  And looking out to next Monday, as of Tuesday afternoon, another storm system may be in the developing stages over the Plains late Sunday and early Monday.  This could bring a little more cloud cover into the Midwest during the afternoon and evening, along with a chance for rain/thunder by the evening.  This may be one forecast we are actually rooting for to change!  Stay tuned.

Hot and Muggy Tomorrow and What to Expect For the Eclipse

We saw some pretty dense fog this morning across the Stateline area. The reason being we had some moisture flowing through our area last night, and along with that we had clear skies.  This allowed temperatures to cool down rapidly, while dew point temperatures crept up.  This is already a recipe for dense fog development.  Along with that, winds were very slow this morning, so we had nothing to push the fog out of our area.

Luckily, we had the sun, and it evaporated that fog quickly once it came up a little more.  Sadly, that moisture inflow will continue through the afternoon, keeping it fairly muggy.  Clouds will build up as a result, but will die down later this afternoon when a high pressure influence starts to sink towards our area.  This will push some cooler air into our area as the clouds die down, keeping temperatures in the low 80°s.

That high will sink down closer to us during the overnight, clearing the skies and allowing for temperatures to be more mild in the low 60°s.  A low pressure system out west will approach tomorrow, bringing us a slight chance for storms during the afternoon, but a better storm chance during the evening.  Highs will be in the mid 80°s, with dew point temperatures in the low to mid 70°s.  This will allow for heat index values to be anywhere from the low to mid 90°s, so take precaution if you plan on going outside tomorrow and stay hydrated.  The low will bring in a warm front around 9-10pm, which will keep rain lingering during the overnight.

A cold front will move in early Thursday morning around 7-8am, so we could see a few showers and thunderstorms around that time, but the storms won't be severe.  The front will move around after 1pm, where we'll stay dry the rest of the day with temperatures in the low 80°s.  Dry weather continues through Friday, with temperatures in the upper 70°s to low 80°s.  However, low pressure influence will bring us a storm chance going into the weekend on Saturday.

High pressure influence sinks in on Sunday, keeping us dry.  However, another low moves in on Monday, increasing cloud cover and bringing rain chances late at night.  This may sound like bad news for those wanting to see the eclipse, but don't get discouraged yet.  A lot has been changing weather-wise in a short period of time, so we very well could see some big changes for the better for Monday in the next few days.

Monday, August 14, 2017

A Rainy and Gray Week Ahead

We had some rain move in from the west this morning due to a shortwave trough.  These showers have been dying down as they try to move into our central counties, the reason being the wind shear difference between our western counties and other counties.  However, a slight rain chance is still in place for everyone else for the rest of the morning while those showers linger in our western counties. 

A warm front will move in from the southwest around 1pm towards our western counties, which will bring storm chances for Jo Daviess, Carroll, and Whiteside counties around that time.  That warm front will then move in a little further into the Stateline area around 4pm, which will then give everyone else storms chances.  The storms are not expected to be severe, and will begin dying as we move through the overnight.  However, they'll die down to rain showers, which will then linger for the rest of the overnight.

There's a slight chance for rain Tuesday afternoon due to decent instability, but a bigger chance for the overnight Tuesday night as a low pressure system from the west will be moving closer to our area during that time. 
That low pressure system is the same low that's bringing us the storm chance today.  However, it's going to strengthen during the week as an upper level low over the Pacific Northwest and an upper level high in the Plains will create greater instability, further strengthening the low.  By the time that low moves in Wednesday afternoon, it'll be able to pull in lots of heat and moisture out of the south.  This will bring temperatures into the mid 80°s and dew point temperatures into the low to mid 70°s, so that heat and humidity we thought that we were done with will sadly come back.  That, combined with the incoming cold front, will give us the chance for seeing some strong thunderstorms Wednesday afternoon.

A shortwave trough will linger afterwards on Thursday, so we may see a few pop up showers during the afternoon.  Friday will be dry with a small high pressure system settling in, where temperatures will cool off a little bit into the upper 70°s.  Going into the weekend, another low pressure system moves in, bringing us a chance for thunderstorms on Saturday.

Sunday, August 13, 2017

A Few Showers To End The Weekend . . .

If we must have rain, it is nice that it decided to hold off until the end of the weekend - as a few showers have moved into the Stateline area. We had gorgeous mid-August weather all weekend with plenty of sunshine and temperatures below our normal of 83 degrees - how many summers we had to deal with 90+ degree heat and oppressive humidities!  Not this year so far! 

We will start to see further changes in our weather as we head into the core of the upcoming week.  High pressure has been in control of our weather for the latter half of the past week and has kept things dry.  Starting on Monday, that high pressure is going to move further east and we will have a number of disturbances push through giving us daily chances of rain and thunderstorms.  The rain should hold off on Monday until the afternoon or evening.  Our best chance for measurable rainfall will come late Wednesday as a storm system and associated frontal boundary will push through, and our temperatures should be close to our normal high of 83 degrees. 

Saturday, August 12, 2017

Beautiful Weekend Followed by a Stormy Week

We've had a great start to the weekend with temperatures in the mid to upper 70°s with plenty of sunshine to go along with it.  We're a little below our average of 83°, but it still felt great nonetheless.  A high pressure system is in place over our area, and will keep the skies clear as we progress through the evening, where temperatures will be in the low to mid 70°s.

The high will stay in place over our area for the overnight, which will cause temperatures to cool down pretty rapidly and this could result in some fog early tomorrow morning.  That high will track east during the day tomorrow, but we'll still get plenty of sunshine with some warmer temperatures in the upper 70°s to low 80°s. 

 You'll want to enjoy the nice weather while you can, because once we get into the work week our storm chances will go up.  A low pressure system will develop out west, and slowly progress towards our area during the work week.  It will continually pull in warm air and moisture starting on Monday, eventually warming us into the mid to upper 80°s by Wednesday.  Unfortunately, the moisture inflow will result in high humidity returning to our area by Wednesday as well, with dew point temperatures looking to be in the low to mid 70°s.

Storms are expected Monday evening, Tuesday afternoon, and Wednesday afternoon.  A cold front will move through on Wednesday, and with this being the day where we hit our peak temperatures with relatively high humidity, we could see some pretty strong thunderstorms.  The storms will linger during the late-night hours, but by that point the severity of them will go down.  The front will slowly move through our area, and will still be in our area by the time Thursday afternoon rolls around.  It'll be in Dekalb county by around 1pm Thursday, but the storms that form in Dekalb during that time aren't expected to be severe.  Those storms will die down around 4pm, when the front moves out.

The rest of the Stateline area may see some light rain showers during the afternoon, but those will clear up by the evening.  Drier air settles in afterwards, with sunshine and temperatures in the low 80° expected as we head into the weekend.

Friday, August 11, 2017

A Gorgeous Weekend Ahead

We had a warm start with overnight clouds keeping temperatures in the low to mid 60°s.  A lingering low pressure system, and a shortwave trough, have allowed for clouds to thicken up, and they'll stay that way going through the day.  A couple of showers have formed up north because of the trough, tracking south, but at the most they'll last until the afternoon, but more than likely will die down beforehand.  Skies stay cloudy going through the day, until the evening as the sun will be strong enough to evaporate the clouds.  This will give us a clearing around 7pm, which could warm our temperatures into the upper 70°s.

High pressure will move in for the overnight tonight, keeping the skies clear and cooling us down into the low to mid 50°s.  The high stays with us for the next several days, keeping the weather sunny and warm throughout the weekend, where temperatures will be in the low 80°s.  We'll gradually warm up with the increase in sunlight as we head into the work week, with a chance for seeing the mid 80°s on Wednesday.  A low pressure system will move in next Thursday, bringing us a chance for a few light showers.

Thursday, August 10, 2017

Severe Storm Threat Increasing Over Northern Illinois and Southern Wisconsin

10:30pm Update: Cold front is now moving through northern Illinois.  An isolated shower or two can't be ruled out over the next couple of hours, but skies are expected to remain mostly cloudy.  A little more calm for the overnight and into Friday.

6:38pm Update: Severe Thunderstorm Watch cancelled for Green and Rock counties.  The watch is also cancelled for Jo Daviess, Stephenson and Carroll counties in NW Illinois, and for Boone, Ogle and Winnebago counties in north-central Illinois.  It remains in effect for DeKalb, Whiteside, Lee and Walworth counties.

(5:40:52 PM) nwsbot: Local Storm Report by NWS DVN: ESE Erie [Whiteside Co, IL] trained spotter reports HAIL of quarter size (E1.00 INCH) at 05:37 PM CDT -- also wind gusts to 45 mph.

5:32pm Update: Severe Thunderstorm Warning continues for southwestern Whiteside County until 6:15pm.  Wind gusts to 60 mph and quarter sized hail are possible with this storm, currently moving east/southeast.

Outside of this warning, the weather is fairly quiet over northern Illinois and southern Wisconsin.  Right now, it appears as if the highest severe threat may be now located a bit further where a little more instability is located - over west-central Illinois.

(3:54:09 PM) nwsbot: Local Storm Report by NWS MKX: Clinton [Rock Co, WI] public reports HAIL of half inch size (E0.50 INCH) at 03:45 PM CDT --

3:50pm Update: Stronger thunderstorm located near Rockton may be capable of producing nickel sized hail.  Storm is moving east at 20 mph. 

Severe Thunderstorm Warning issued for southern Rock and Walworth counties until 4pm.  Quarter sized hail had been reported with this storm in Beloit, WI.  Storm is moving to the east at 25 mph.  Large hail will be the biggest threat with this storm.  Heads up Sharon and Walworth.

(3:37:23 PM) nwsbot: Local Storm Report by NWS MKX: Beloit [Rock Co, WI] law enforcement reports HAIL of quarter size (E1.00 INCH) at 03:29 PM CDT --

3:00pm Update: New Severe Thunderstorm Warning for Jo Daviess and Stephenson counties until 3:45pm.  Storm located near Stockton is moving east at 35 mph and capable of producing winds in excess of 60 mph and large hail.  Strongest part of the storm located just north of Elizabeth.  Please seek shelter if in the path of this storm.

(2:50:44 PM) nwsbot: Local Storm Report by NWS MKX: Argyle [Lafayette Co, WI] law enforcement reports TSTM WND DMG at 02:18 PM CDT -- power lines down.

2:48pm Update: Severe Thunderstorm Watch issued for all of N. IL and S. WI until 9pm this evening.  Storms will likely be increasing in coverage over the next couple of hours, posing a wind and large hail risk.  It's important to remain 'Weather Ready' this afternoon.  If you're out, make sure you know where the safest place for you to take shelter should severe weather move through.  Especially if you're out at the Boone County Fair.

Storm coverage will be increasing over southern Wisconsin and northern Illinois through 5pm as a cold front moves out of Iowa.  Clearing skies following moderate rainfall Thursday morning have allowed instability to grow through the afternoon.  An upper level and surface low are moving into Wisconsin, pulling the cold front east.  As the front moves into the unstable air mass, thunderstorms will continue to grow.  Large hail will be the greatest threat, followed by wind gusts to 60 mph.  Please remain alert this afternoon, especially if you're outside.  Thunderstorms will move through between 3pm and 9pm.  It's possible that a severe thunderstorm watch will may be issued for parts of the area.

A Severe Thunderstorm Warning has been issued for central Green County until 2:45pm for the possibility of ping pong sized hail and 60 mph wind gusts.  Those in the path of the storm need to take shelter immediately.  The storm is moving east at 35 mph.

Storm Threat Today with Clear Weather This Weekend

We had a rainy start this morning as heavy showers moved across the Stateline.  Wind shear was fairly high early this morning, and allowed for those light showers from the overnight to build up more during the early hours of the morning.  Behind the rain, sunny skies have been seen, with temperatures in the upper 60°s to low 70°s.  The sun was able to evaporate the cloud cover, and we'll continue to see this break until about 1pm, when a cold front moves in.

The cold front will allow for more showers and some thunderstorms during the afternoon.  We're under a Marginal Risk for severe weather, but the overall severe threat stays low as wind shear will be weak, and the atmosphere will be fairly dry.  The front will move out around 8pm, and we'll clear up for the overnight with temperatures around 60°.

With regards to storm coverage, a few more storms will be seen in our southern counties as the cold front will be more defined the further south you go.  We'll still see thunderstorms along the state line in the northern portion of our viewing area, but more will be seen down south. 

Cloud cover will thicken going into tomorrow as some moisture will linger behind the front.  This will keep temperatures a little cooler for Friday afternoon in the upper 70°s.  High pressure will begin settling in during the weekend, giving us a good amount of sunshine with some cooler temperatures.  It's possible we could see temperatures as cool as the mid 70°s by the time Sunday rolls around.  The high pressure system will fully settle in to start the work week, clearing the skies and giving us lots of sunshine, which will warm us back up into the low 80°s.

Wednesday, August 9, 2017

Total Solar Eclipse Less than Two Weeks Away

On Monday, August 21st a very spectacular astronomical event will take place over the United States that hasn't happened in nearly 99 years!  A total solar eclipse will occur from coast to coast, starting in Oregon and ending in South Carolina. 

A solar eclipse happens roughly once every 18 months, but in different parts of the world.  The last solar eclipse to occur in the United States was back in 1979.  According to NASA there are three types of solar eclipses: total solar eclipse, partial solar eclipse and an annular solar eclipse.

A total solar eclipse is when the sun, moon and Earth are in a direct line and is visible only from a small area on Earth.  For those who experience a total solar eclipse, day will turn to night.

A partial solar eclipse is when the sun, moon and Earth are not in a direct line with each other, causing only a portion of the sun's light to be blocked by the moon.

An annular solar eclipse is when the moon is farthest from the Earth and doesn't block the entire view of the sun.  When the moon travels in front of the sun it appears as a dark disk on top of a larger sun-colored disk, creating what looks like a ring around the moon.

Everyone in the continental United States will be able to view the eclipse, but only a small portion within 14 states will be in the path of totality. 

The image on the left is a map from NASA showing who will be in the path of totality.  Those who are outside the path of totality will still be able to view the eclipse, but only a portion of the sun will be covered by the moon.

It's very important to remember to protect your eyes during an eclipse.  NASA has put together a complete list of safety reminders for those who are wanting to view the eclipse.

It's estimated that millions of people will try and travel to where the path of totality will occur, with some suggesting travel on US highways turning horrendous.  Since the solar eclipse is still over a week and a half away, it's hard to give an accurate forecast for that afternoon.  But as we get closer, we will definitely be keeping an eye on the forecast for any potential storm systems or cloud cover that may limit viewing of the eclipse.  For a 'state by state' look at the cities and towns in the path of totality, click here.

Dry Stretch Comes to an End - Storms Likely Thursday Afternoon

The past several days have been pretty dry with only a few sprinkles or very light showers being recorded this past week.  That dry stretch of weather, though, will be coming to an end as early as Thursday morning for some.

Rainfall is not expected to be widespread Thursday afternoon.  And that's because despite a rise in dew point temperatures, our atmosphere will still remain fairly dry.  A line of decaying showers have been moving into Wisconsin and far northern Iowa Wednesday afternoon and evening.  This is ahead of the main cold front that is expected to move through southern Wisconsin and northern Illinois by Thursday afternoon. 

Very light showers are possible over southern Wisconsin and far northern Illinois around sunrise Thursday, but most will likely remain dry.  As the cold front approaches, we will see an uptick in a few thunderstorms for the afternoon - likely after 2pm - and early evening.  Instability in the atmosphere will increase ahead of the front, mostly because we will be pulling in a little more moisture than what's in place now, and we could see some sunshine poke through during the first half of the day.  However, the cold front itself
and low pressure system associated with the front aren't very strong.  Winds the jet stream, however, will be strong and this may be just enough to help grow thunderstorms to low end severe limits with strong winds gusts and possibly quarter sized hail.  The overall threat for strong thunderstorms is low, but it's there.  Not everyone will experience rain on Thursday and there will be some towns that may even go completely dry during the afternoon. 

Thursday Outlook
Storm Prediction Center
Once the front passes skies will remain mostly cloudy into Friday and this will hold temperatures down in the 70's for the afternoon.  Winds will be a little breezy, too.  Weekend doesn't look too bad with only an isolated shower chance late Saturday and into Sunday.

A Cool Start To The Weekend

It was another cool start with temperatures in the mid 50°s, with a few locations that dipped to the low 50°s down south.  The reason for this was a high pressure influence, which kept the skies clear during the overnight last night, allowing for temperatures to cool rapidly.  This allowed for some fog to develop early on, but the clear skies allowed the sun to heat us up pretty quickly, and it didn't take long for the fog to evaporate.

That high pressure influence is pushing southeastward, and we'll start to see low pressure influence slowly begin influencing us this afternoon when the cloud cover increases.  However, we'll still see a good amount of sunshine, and this will help warm temperatures to around 83°.  That low pressure system will get closer during the overnight, causing the clouds to increase more, and allow for warmer overnight temperatures around 63°.

The low will move in Thursday afternoon, bringing a cold front near our area around 1pm.  This will trigger shower and thunderstorm development.  The cold front will progress through the Stateline during the afternoon and evening, before clearing out around 10pm.  However, even though the storms will be with us most of the day, they're not expected to be severe.

After the front moves out, another high pressure system will move in.  The high will form due to an upper-level pattern that will allow strong sinking motion to occur over southern Minnesota.  An upper-level low northeast of Michigan, and an upper-level high in the plains, will cause the sinking motion to occur.  The high will pull in cooler air as it tracks towards us, possibly cooling us down to the mid 70°s to start the weekend.  However, once it settles in more during Sunday, we'll see more sunshine that'll allow temperatures to warm back up into the low 80°s.

Tuesday, August 8, 2017

Dry Start to the Month of August

June and July were both very rainy months with each receiving nearly 7.5 inches of rainfall.  So far the first week of August has been pretty dry with under a tenth of an inch falling.  By this time in the month we should have received just a little over an inch of rainfall.  This puts us nearly an inch under where we need to be for the month.  While we've had a surplus of rainfall and a lot of moisture in the ground from the past two months, it's beginning to get a little dry.  Especially in areas that didn't receive quite as much rainfall as some did towards the end of July.

Looking ahead to the expected amount of rain this week, Thursday is really our only best day for any rain.  And even that doesn't look like it will amount to a great deal.  Totals will most likely remain under half an inch.  A few lingering showers may persist into Friday, and then again pop up Saturday and Sunday.  But those, too, are expected to remain very light.  While I'm not concerned about drought conditions developing, we are getting to a point where we do need a little bit of rainfall.  On average, the month of August receives 4.59 inches of rain.  This comes out to roughly an inch of rainfall per week. 

Cooler Weekend

We had a bit of a cold start with some locations seeing temperatures in the upper 40°s earlier this morning.  The reason for this was a high pressure influence during the overnight which kept the skies clear, but this high pressure influence will also warm us up to the mid 80°s for this afternoon!  We hang on to the high pressure influence through the overnight tonight, where we'll cool to the mid 50°s.  The clear skies overnight will allow temperatures to cool off pretty rapidly, so we could see some light fog early tomorrow morning.

A low pressure system will begin its approach from the west during the day tomorrow and will thicken up our cloud cover.  However, we'll still manage to get into the low 80°s.  The low will move in Thursday, and bring a cold front in during the evening around 7pm.  This will allow for some thunderstorm development, but these storms won't be strong as the low pressure system will be fairly weak overall.  That front will move out Friday morning, where clouds will linger afterwards and keep temperatures a little cooler in the upper 70°s.

We'll see some cooler temperatures heading into the weekend, the reason being that we'll have an upper-level low pressure system track southeast into Michigan, with an upper-level high tracking into the northern plains.  This will cause the jet stream to have strong Meridional flow, and this will end up creating an area of strong sinking motion over Minnesota.  This will develop a strong high pressure system behind the cold front after that front moves out Friday morning.  The resulting high will then pull in cool air from the north, and depending on how strong that inflow gets, we could possibly see temperatures in the mid 70°s heading into the weekend.

That high will move in over our area Sunday, which will completely clear the skies and allow for lots of sunshine.  This will allow temperatures to warm back up into the upper 70°s for Sunday afternoon, and then into the low 80°s for Monday.

Monday, August 7, 2017

Cool This Week With a Little Rain

It was a bit of a muggy start, with the air being fairly saturated due to the temperatures and dew point temperatures being fairly close together this morning.  Luckily, temperatures have warmed up a little more, and the patchy fog has now cleared out.  Along with that, we had a little bit of rain along the stateline due to a low pressure system lingering south of our area.  Luckily, most of the day will be dry, but because that low pressure system will be lingering south of us until mid-day, we can't rule out the chance for a pop-up shower or two until a little after noon.

By the afternoon, a high pressure system will move in from the northwest, clearing our skies and giving us lots of sunshine.  Because it's moving in from the northwest, we'll see cooler temperatures in the mid 70°s during the afternoon, although a few locations in Whiteside, Lee, and the southern portion of Dekalb counties may see the upper 70°s.

That high pressure keep the skies clear for the overnight, where temperatures will cool to the mid 50°s.  The high will bring us more sunshine for tomorrow, bringing temperatures into the low 80°s.  Most of Wednesday will be sunny and dry, but during the overnight another low pressure system will move in and bring us some light rain showers.  We'll hang on to the cloud cover during Thursday, with another rain chance in the evening.  The low will move out Friday morning, giving us dry weather from then on out.

Cooler temperatures are in store this week, the reason being that an upper level low will track southeastward into the northeast corner of the United States.  This will push the jet stream a little south of our area, cooling us off.  Strong sinking motion will then result in the northwest over southern Minnesota, strengthening that high pressure system, resulting in that cool inflow from the north sustaining itself and bringing us cooler temperatures.  Temperatures will stay in the mid 70°s this week as a result, only hitting the low 80°s on Tuesday due to more sunlight.

Saturday, August 5, 2017

Nice and Cool Next Week

Temperatures were able to get a little warmer today in the upper 70°s to low 80°s, the reason being that we have a low pressure system out to our west, which has been pulling in warmth and moisture to our area.  This allowed for some cloudier conditions today, but we still got to see plenty of sunshine.  That low pressure influence is closing in on our area while the low center tracks southeast, which is why clouds will continue increasing through the evening and overnight.

The resulting moisture inflow will keep the clouds in our area through tomorrow, and also bring us a slight chance for some light rain showers.  The warm front will stay well to our south, but with how much moisture is moving in, we could see a couple of pop up showers tomorrow morning down in Whiteside, Lee, and the southern portion of Dekalb county; and then everywhere else going into the afternoon due to daytime heating.  The overall rain chance is low, as couple pop up light rain showers are possible.

Luckily, the rain chance decreases as we head through the afternoon as that low pressure system will move southeastward with the flow of the jet stream.  However, we'll still hang on to the cloud cover through Sunday night.  The clouds will clear out Monday mid-day when a strong high pressure system moves in from Canada.  This will push the jet stream south, thus keeping that low pressure system south, and bring us dry and cool weather for most of the work week.  We'll see temperatures in the low to mid 70°s during the week, but the dry influence will keep the skies clear, so we'll have plenty of sunshine to go along with the 70°s.

That high pressure system moves out late Friday night, allowing a weak low to move in Saturday morning and bring us a chance for some light rain.

Friday, August 4, 2017

Cooling Down

It was a pretty cool and windy end to the work week, as temperatures stayed in the low to mid 60°s during the afternoon.  The only reason we saw 70° temperatures at the start of the evening was because the clouds cleared just in time to give us some warm sunlight. 

The reason we saw the colder air today was because we have a low pressure system to the north, and a high pressure system to the west.  This allows for a strong channeling of cooler air from the north, but this would only bring us into the low to mid 70°s.  However, this was also occurring in the mid and upper-levels of the atmosphere.  This allowed for a 'wall' of cold air to move in from the north, cooling down our atmosphere quite a bit, and combined with the fact that the low pressure system kept our cloud cover pretty thick through most of the day, temperatures were able to settle in the low to mid 60°s.

Luckily, that high pressure system out west has been moving closer to us, which is why the clouds cleared up during the start of the evening.  That high pressure system will move over our area for the overnight and keep the skies clear, which will cool us down into the mid 50°s.  That high will track southeast tomorrow afternoon, where it'll be able to pull in some warmer air out of the south, bringing us into the upper 70°s. 

Another low will move in from the west on Sunday and pull in some warm air and moisture into our area.  This will thicken up our cloud cover Sunday morning, which will keep temperatures from getting warm.  Along with that, the moisture inflow from the south will form some light rain showers during the afternoon, which will cool off the already lowered temperatures from the cloud cover even more.  This will result in temperatures only reaching the upper 60°s on Sunday.

Once we get into the work week, a high pressure system will move in from the north and keep our temperatures fairly cool for most of the work week in the low to mid 70°s, but it'll also keep the weather dry.  The high will settle over our area towards the end of the week, which will bring us more sunshine and allow temperatures to warm up into the upper 70°s.

Fall-like Friday

You'll forget we're starting August, and not October this afternoon with a bit of a chill in the air. High temperatures this afternoon will climb into the upper 60's to near 70°. Our average high for the beginning of August is 83° but today's high will be more typical of the 30th of September.

Northwest will increase in response to a tight pressure gradient as the strong departing low pressure currently sits over northern Lake Michigan, and high pressure moves over the Plains. In response stronger winds are generated which help to draw in the cooler air from the north.

Today will be the coolest out of the next seven days, but most of the next week ahead will be below average.

 But it won't just be the Stateline that will notice the cooler start to August, most of the country will. The Climate Prediction Center outlook shows most of the country with below average temperatures through the 13th of August. The highest probability for below average temperatures will be centered in the Plains, but the Midwest is also in a high probability shade for below normal temperatures.

Only part of the country feeling the heat will be the Pacific Northwest, with high probabilities for above average temperatures through the middle of the month. The past week for them has been record setting with high heat, and even wildfires for some in that area.

Thursday, August 3, 2017

This Evening's Storms and Cooler Weather On the Way

We've had a bit of a gray Thursday with scattered storms earlier in the afternoon, storms ahead of the front earlier in the evening, and now a line of storms moving east through the Stateline.  Luckily, these storms have shown a weakening trend, the reason being that our atmosphere is fairly dry, which isn't good for thunderstorm development.  However, these storms are still producing some heavy rain, and gusty winds are still possible while these storms weaken.  We've had radar-indicated reports of 50-60mph wind gusts in a couple of instances, but other than that wind gusts haven't been high enough to cause serious damage.  Hail was reported earlier as well, but only nickel-sized.  Since then, hail development has been hindered as instability has gotten lower.

The cold front will move out around 9pm, where we'll stay dry for the overnight with temperatures cooling to the mid 50°s.  However, there will be a strong inflow of cold air behind that front as we head through the overnight, which will cause winds to pick up a little bit between 10-15 mph.  This effect will also be occurring in the mid and upper-levels of the atmosphere.  This leads to a large 'wall' of cooler air moving into one area, so the force is greater.  Thus, strong winds come about, and this is also why we'll be cooler for tomorrow as well, and even the next few days.

We'll have another low pressure system sit west of us on Sunday, but it'll only bring some light rain showers to our area during the afternoon.  The light rain could pick up again early Monday morning, but other than that we'll stay dry next week as another high will move in Monday afternoon. 

Thursday Storm Potential

Thursday will be another day to stay weather aware with strong storms possible across the Stateline in the late afternoon and evening.

We're watching a low pressure system that is currently over southern Minnesota that will quickly strengthen and deepen as it moves into Wisconsin this afternoon. In response to that a warm front will lift across northern Illinois and is forecast to make it to Wisconsin. We need to pay close attention to where this warm front stalls because it will be the focal point for potential super cell development. The highest wind shear (winds changing direction with high) with be found closest to the low pressure and warm front intersection, this is where a few isolated tornadoes will be possible.

For northern Illinois strong to severe storms are still possible, but the main threats will be potentially strong damaging winds, large hail, and heavy downpours.

While we will have showers and storms this morning, the strong to severe threat goes up later this afternoon when upper level winds strengthen from the west. At the surface winds will be out of the south as the warm front passes to the north, and upper level winds will be from the west.  This wind shear will fuel storms this afternoon and evening. The time frame we want to stay weather aware will be between about 4-9pm this evening.

We'll make sure to keep you posted with storm potential through the day.