Hazy skies possible as high pressure shifts east

 

You may notice a little more of a hazy look to the sky the next couple of days as smoke from numerous, and large burning, wildfires out west shifts east under a shifting ridge of high pressure.

Visible satellite imagery Tuesday evening shows quite a bit of smoke over the Rockies and Plains from the wildfires, and stuck under the strong heat dome over the West. As our winds aloft turn more to the northwest, and then southwest, Thursday and Friday

the smoke will move a little further east over the Midwest and Great Lakes. The concentration of smoke likely won't be as high as it currently is out west, but a more hazy look to the sky is possible, causing a more vibrant and colorful sunrise and sunset, especially if we see cloud cover during that time.

Rain showers and tumbling temperatures for the weekend

 

High pressure remains in control over the next several days helping to keep skies rain free through the end of the week. Temperatures Tuesday afternoon warmed into the middle and upper 70s/low 80s, with Rockford's high temperature reaching 81 degrees. Mostly clear skies and light winds will allow temperatures to fall into the middle to upper 50s Tuesday night/Wednesday morning.

The chance for rain will return for the weekend,

however, as a cold front moves towards the Midwest from the northwest and low pressure moves in from the south. The strong ridge of high pressure that has brought record heat across the West will begin to break down by Thursday and Friday. This break down is in response to a strong jet stream wind moving overtop the ridge, carving out a trough (or dip) in the jet stream across the Plains and Midwest.

At the surface this will produce an area of low pressure that'll remain well north of the Stateline, but its cold front will move through sometime during the afternoon Saturday. Ahead of the front temperatures will continue to warm into the 80s, but behind the front temperatures will fall quickly.

There isn't a great deal of moisture that forms ahead of the front. In fact, most of the rain will likely end up falling behind the cold front Saturday evening. But the combination of both the low to the south and cold front from the west will increase our chance for rain through the end of the weekend. Rainfall totals look to range anywhere from a quarter of an inch, to three quarters of an inch.

A rather chilly air mass is set to follow the front Sunday and Monday which could push temperatures down through the 70s, with highs even in the 60s possible! This would up being well below average for this time of year. Temperatures beyond next Monday look to moderate some, rising back into the middle 70s. 

What's Behind the Heat Wave on the West Coast?

Multiple Records Broken:

While the weather was quiet and cool here in the Stateline, it was a dangerously hot Labor Day holiday for those on the west coast.

High temperatures for many ended up well-above the triple-digit mark, shattering both daily and monthly records. And with no budge in the weather pattern, it looks like this excessive heat is set to stick around for at least a few more days.

Why So Hot?:

The meteorological reason behind the extreme heat as of late, a strong high pressure system that has set up over the western United States. Otherwise known as a heat dome or an atmospheric lid, this ridge has trapped all the hottest air over the western states, triggering the intense heat. Forecast models this morning kept this "heat dome" healthy and strong until late Thursday before collapsing into Friday morning. With the ridge breaking down, this will allow some of this extreme heat to filter eastward into the Midwest. Hence why we'll see temperatures climb over the next few days. Nothing too extremely hot however.

Excessive Heat Alerts:

As of this morning, much of California sits under an excessive heat WARNING as temperatures look to peak between 100°-115°. Portions of Montana, Oregon, Idaho, and Nevada will be under a heat ADVISORY. It's in these areas that highs could range from 95° to 105°. 

All of said heat alerts last into the end of the work week. Officials urge folks under these heat alerts to reduce electricity use, practice heat safety, and resist the urge to burn. Those who work outside for a prolonged period of time will be quickly susceptible to heat-related illnesses if proper care is taken. 

Morning Fog, Isolated Shower Possible This Afternoon

Morning Fog Potential:

Clearing skies, extremely light surface winds, and a pinch of low-level moisture will set the stage for a round of patchy fog this morning. 

If you are someone who is getting back into that daily morning routine, make sure to give yourself a few extra travel minutes just to be on the safe side. Remember, it's important to travel at slower speeds, to have your low beam headlights on, and to increase your following distance if you encounter fog. Once the sun rises above the horizon, the warming ground will help the fog lift. 

Isolated Shower Tuesday:

With high pressure over the Great Lakes region, another mainly dry day lies ahead. Under a mix of clouds and sunshine, highs will peak in the upper 70s, close to 80-degrees. Now, one or two of those clouds will have the capability of growing into an isolated late-day shower. This very low threat should come to an end by sunset. A few clouds look to stick around overnight, with temperatures falling back in the upper 50s by sunrise. 

Tranquil Moving Forward:

Over the last few days, a ridge of high pressure has been stranded over the western U.S. This has kept most of the dangerously high heat over the west coast, resulting in multiple record highs. 

Towards Wednesday morning, guidance showed this ridge expanding a bit eastward, allowing some of that west coast heat to also spread eastward. This will not only keep the weather dry into the second half of the work week, but it will also bring out highs back into the low 80s. Overnight lows however look to remain in the upper 50s and low 60s range. This gradually increase in temperatures is all ahead of our next storm system which looks to make it's presence known over the upcoming weekend. 

Weekend Storm System:

Forecast models over the past 24-48 hours have trended later with this weekend's cold front, bringing it late Saturday evening. 

With it does come our next best opportunity for a few scattered showers and thunderstorms. At this time, the threat for severe weather is low. 

But make sure to stay up-to-date with the forecast over the next few days as more details become apparent. The cooler round of air that settles in behind Saturday's front will bring temperatures back into the 70s for the end of the weekend and the start of next week.

Isolated shower possible Tuesday

 

The cloud cover stuck around for some Labor Day, but for others the sun was able to shine bright late morning and early afternoon. This helped warm temperatures in a few locations into the upper 70s, while locations under the cloud cover remained in the low 70s.

We are beginning to see the skies clear from east to west Monday evening, with skies expected to remain clear for most of the night. Cloud cover does fill back

in, however, early Tuesday starting the day off under a mostly cloudy sky. There may also be some areas of ground fog.

From the clouds, a few very isolated showers are possible during the morning and early afternoon Tuesday as temperatures warm back into the middle to upper 80s. The rain is not expected to be widespread and will remain very, very isolated if it does occur at all. These light showers are in response to moisture lingering around in the atmosphere and

weak low pressure passing to our southeast. High pressure is set to settle back in and will turn our skies partly cloudy to mostly sunny, warming temperatures back up slight above average in the low to mid 80s through the end of the week.  

70s for Labor Day, Temperatures Warm Towards the Weekend

Fall-Like Sunday:

Sunday's cloud cover and cool northeasterly breeze brought a big taste of fall to the Stateline. Officially, the Rockford International Airport registered a high of 71-degrees, marking the coolest day in nearly three months. 

This comes a bit ahead of schedule as it's not until late-September that Rockford sees its average highs drop into the lower 70s. In a similar fashion to Sunday, Labor Day looks to be spent under a decent amount of cloud cover and in the 70s.

Labor Day Forecast:

A slow-moving area of low-pressure passing through the southern Illinois will continue to supply the Stateline with low-level moisture, resulting in a mostly cloudy start. 

But, as dry air works it's way into our atmosphere, we should see clouds break apart sometime during the afternoon. Temperatures remain below-average, with most of our local airports topping out in the mid to upper 70s. In other words, any outdoor plans you have to celebrate the Labor Day holiday will be good to go. Skies from there look to remain partly cloudy overnight, with temperatures falling into the low 60s Tuesday morning. 

Warming Up Late:

Guidance continues to keep a light northeasterly wind in place for Tuesday, resulting in another day with highs in the upper 70s. While much of Tuesday remains dry, a slim chance for a late-day shower or thunderstorm will be present. 

Our next cold front isn't schedule to arrive until late-Friday night and early Saturday morning. Until then, the weather remains dry. But, a warming trend in our temperatures is expected as winds turn more to the south and southwest for the late-week days. Expect low 80s to return by Wednesday, with low to mid 80s for Thursday and Friday. Beyond the cold front, it looks like northeasterly flow returns, placing highs over the weekend back into the 70s.

Fall-like feel Sunday afternoon

 

Temperatures for many Sunday afternoon have struggled to make it much above 70 degrees thanks to an abundance of cloud cover. The high officially in Rockford only reached 71 degrees late Sunday morning, falling short of the average high of 79 degrees. For many, Sunday afternoon felt more like an early October day, rather than early September.

While the clouds may thin for some during the evening, expect skies to remain mostly cloudy Sunday night with temperatures holding in the low 60s. Highs for Labor Day will also remain below average, in the mid to upper 70s.

The clouds Sunday have been the result of an area low pressure spinning downstate bringing widespread showers and thunderstorms to central and southern Illinois. We have had some drizzle from time to time, but any accumulating rainfall is expected to remain to our south. The chance for drizzle/sprinkles will continue into the evening Sunday, as the cloud cover remains during the afternoon Labor Day.

Wind around low pressure flows counter-clockwise, which has given us a breezy northeast wind for much of the afternoon. The combination of the wind and cloud cover is what helped keep temperatures below average Sunday. But, why the thick cloud cover? The counter-clockwise flow around the low has helped to pull moisture into the lower levels of the atmosphere to its north, limiting the amount of dry air from above being able to work down towards the surface. Just above the surface, the temperature and dew point temperature are nearly identical - meaning full saturation. With little dry air being able to work through the highly saturated environment, the clouds have no where to go.

This set-up also looks to carry over into Monday, although by Monday evening we should be able to see the cloud cover break a little further as high pressure moves closer to the southern Great Lakes Monday night and Tuesday. Temperatures are expected to remain below average Monday, with highs in the mid 70s, before reaching close to 80 degrees Tuesday.