Tuesday afternoon weather update

 

Northwest winds were rather gusty following the passage of a cold front Tuesday morning, with gusts reaching 35 mph in some locations. As the breeze continues through the afternoon, wind speeds will gradually subside as high pressure moves in Tuesday night. This will allow winds to turn calm, or remain light around 5 mph, before shifting back around to the southwest Wednesday.

Cloud cover has been on the increase over the last few hours thanks to a stronger jet stream moving across the Plains and Midwest. These clouds won't bring us any rain but it *could help with temperatures overnight.

Overnight lows are forecast to fall into the low 40s but could be cooler if clouds thin out or clear through the night. While we won't see any sort of freeze, and the frost potential remains low for most, we're about two weeks away from when we typically experience our first Fall freeze.

For northern Illinois that occurs around the 13th of October. Freezing temperatures are not in the forecast, and we may not see the Fall chill for a little while as drier and warmer conditions are forecast through the middle of the month.

  

Cold front to bring a seasonable, windy start to October

October begins in a very early October-like way thanks to this morning's cold front.

An organized wind out of the northwest will develop around sunrise, with gusts up to 30 mph lasting into midday. Despite there being a good amount of sunshine after the frontal passage, this cooler wind will limit highs to the upper 60s which is considered seasonable for early October.

Rapid cooling takes place under partly cloudy skies overnight, leaving temperatures in the low 40s, some in the upper 30s Wednesday morning. Tuesday night will allow for rapid cooling to take place. More sunshine is on tap Wednesday. That along with a southwesterly wind will result in slightly warmer temperatures, landing most in the low 70s. At times, winds could gust up to 25 mph.

The warming trend carries on into Thursday as highs climb back towards the 80° mark. Cloud cover will increase as the day progresses as another weak cold front approaches from the northwest. In a similar fashion to this morning's front, a stray shower cannot be ruled out Thursday night into Friday. Temperatures will cool back in the low 70s to round out the work week under partly cloudy skies.

Another cold front aims to slide through the region sometime Sunday morning, bringing with it another small chance for showers. However, signs for a more widespread rainfall are slim to none not only in the near future but also in the long term. In fact, longer range outlooks provided by the Climate Prediction Center show show a higher probability for below average precipitation for not only the Stateline, but a good portion of the country.

Little change in ongoing dry conditions

 

The latest drought monitor from the National Drought Mitigation Center shows very little change for northern Illinois and southern Wisconsin with the ongoing dry/drought conditions last week.

While some improvements were noted in downstate Illinois, there wasn't much change in both the 'abnormally dry' and 'moderate drought' categories for both southern Wisconsin and northern Illinois. It looks like we'll end the month of September with almost an inch and a half deficit, despite some of the heavier rainfall that occurred early last week.

Longer range outlooks into the middle of October are a bit concerning as it is showing a higher probability for below average precipitation for not only the Stateline, but a good portion of the country. While we'll see a few cold fronts pass through this week most of them will come through the dry. The first arrives late Monday night and early Tuesday morning.

A slight increase in moisture ahead of the front may allow for a few spotty sprinkles or very light showers to occur, but nothing that would be enough to really measure by sunrise Tuesday. The second front comes through late Thursday night/early Friday morning. Again, this will have a little moisture associated with it but rain chances - at this point - will remain capped within the 20-30 percent range.

The overall pattern into the month of October is favoring a higher probability for above average temperatures, according to the latest outlooks from the Climate Predication Center. This pattern has a lot to do with the lack of colder air moving in from the north. The jet stream pattern over the next week or so is favoring more of an air mass from the Pacific, rather than from Canada or the Arctic. This means that as a series of cold fronts move through this week, we will feel a drop in temperatures but that drop will only bring us closer to where we should be for the beginning of October - middle to upper 60s. And even after those dips we will warm right back up to temperatures that are above average. This type of pattern looks to hold through at least the middle of the month.

  

Winds increase Tuesday following cold front

 

Northwest winds will increase following a cold front early Tuesday with gusts reaching 30-35 mph during the first half of the day. It'll also bring temperatures down from the low 80s they reached Monday afternoon, down into the upper 60s Tuesday afternoon.

High pressure will gradually move in from the west allowing wind speeds to calm through the afternoon and evening. This will bring temperatures down into the low 40s, perhaps upper 30s in some outlying areas, for the start of Wednesday. You may also notice a little more haze/smoke to Tuesday's sunrise as the front pulls in smoke aloft from the fires out west and northwest. Once the front passes the haze should clear Tuesday afternoon and evening.

But as winds quickly turn back around to the southwest Wednesday afternoon temperatures will warm right back into the low to mid 70s. The warming will continue into Thursday ahead of another cold front Friday morning. This, too, could bring a slight chance for some precipitation into Friday morning.  

Brief cool down to follow Tuesday's cold front

Fortunately, all the Stateline saw from the remnants of category 4 hurricane Helene was cloud cover. High temperatures warmed nicely both Saturday and Sunday landing in the low 80s. 

Skies cleared out as we approached sunset, allowing overnight lows to fall into the mid to upper 50s. The work week kicks off with plenty of sun, though a few clouds will pop up for the afternoon.

Ahead of our next cold front, winds will be out of the southeast, allowing highs to climb a degree or two higher from this past weekend. Expect highs in the low 80s. The next trough will bring previously mentioned cold front in late in the night tonight which will bring a brief shot of cooler air. Rain chances along the front are extremely limited, but a few spots may see a very isolated shower.

  

The bigger headline again with Tuesday's frontal passage is the cooler air that follows. Afternoon highs will drop from well above-average today to seasonable levels Tuesday, landing short of the 70° mark. Sunshine continues, though an organized wind out of the northwest will develop. At times, winds could gust up to 25 mph. This cool down will be brief, lingering into Tuesday night. A few locales may end up in the upper 30s Wednesday. Highs are then set to return to the 70s Wednesday, remaining in the 70s into the weekend.

 

More unseasonable warmth for most of this week

 It was an unusually warm day in the Stateline with highs once again in the low 80s for many, including a high of 81 in Rockford. This is more than 10 degrees above our average high of 70° for today's date. It was still a bit breezy as the remnants from Helene continue to pull away, but winds were weaker than they were Friday or Saturday.

Northeast winds will continue to lighten up a bit into the night and tomorrow, promoting some patchy fog overnight. A slight shift to a more Southerly direction in winds will once again allow many spots to warm into the 80s on Monday despite a bit more cloud cover.

This comes between the outgoing energy from the remnants of Helene to the Southeast and our next weather system to the Northwest. The next trough will bring a surface cold front Monday night which will bring a brief shot of cooler air. Rain chances along the front after midnight Tuesday look very limited, but a few spots may see a very isolated shower.

The bigger story will be the cooldown. Temperatures Tuesday will be more than 10 degrees cooler than the day before thanks to that front and persistent Northwest winds during the afternoon. Highs will struggle to reach 70° for many on Tuesday afternoon. Tuesday night will downright chilly as high pressure takes over. With very dry air aloft and at the surface, we will drop down into the low 40s and even upper 30s Tuesday night into Wednesday morning.

But the upper-level flow will correct itself and straighten out into a more zonal pattern. This means upper-level flow will be directly West to East with few waves in between. This will lead to a period of dry and quiet weather heading into the middle of next week.

Temperatures will only be near or below average on Tuesday and Wednesday, with the rest of the week featuring more unseasonable warmth. Highs Thursday may touch close to 80° again before another weather system may begin to slowly cool us down into next weekend. Rain chances look very limited for the next week-plus, adding onto our rainfall deficit from earlier this summer.

Mid-week cool down as dry weather continues

 Temperatures will continue to gradually fall into the night underneath the recent cloud cover that has filtered in through Saturday evening. We clear back out again overnight with mostly clear skies by early morning. Overnight lows will only drop into the upper 50s as a result. Winds will remain breezy from the North Northeast, gusting to 20-25 mph overnight.

But we warm back up again tomorrow to the upper 70s and low 80s despite the persistent NE breeze. Similar to Saturday, clouds will be thickest South and East of Rockford, slightly limiting high temperatures there. Locations Northwest of Rockford may push 80°.

Monday will bring warm but otherwise uneventful weather with partly cloudy skies and highs in the low 80s for most. Our next focus turns to an incoming cold front late Monday evening into the night, bringing a very slim chance for a shower or two along it. Most likely remain dry with limited moisture to work with.

Behind this front, drier air will filter in with incoming high pressure from Canada. Dew points will drop into the 30s and 40s, dry even for this time of year. The dry air will allow for very pleasant afternoons and chilly nights mid-week.

Both Tuesday and Wednesday will be closer to average for this time of year with highs near 70°. Plentiful sunshine amid the high pressure will be the story, but Tuesday may be a touch breezy behind the front Monday night. Tuesday night will be downright chilly with lows reaching the low 40s across the board and some spots could even dip into the upper 30s. Wednesday night will be a bit warmer as our next warm-up is on the way into the end of the week.

The chilly nights ahead may make you think of fall, and I have noticed some trees are beginning to turn colors. This map from www.explorefall.com shows some spots are beginning to see low color, with only areas well to our North seeing moderate color yet. Average peak color in the Stateline is mid to late-October.