Unsettled pattern keeps scattered rain around this week

 After scattered storms produced heavy rainfall for some Sunday afternoon, things were quick to quiet down over the evening. Scattered showers may remain possible at times overnight, with highest coverage South of Rockford across Central Illinois. Where heavy rain fell during the afternoon, patchy fog may be possible overnight.

Most of the area Monday afternoon will be dry, with another chance for scattered showers and storms to increase in coverage after 5-6PM. High temperatures will return into the upper 70s and near 80° if there are a few breaks in the clouds.

We will remain under this unsettled pattern with scattered showers and storms through the middle of the week. A slow-moving low pressure system will slide across the Central U.S. and into the Ohio River Valley between Tuesday and Friday, bringing scattered showers and storms with it.

The exact position of this cutoff low pressure will have big implications on coverage of rainfall locally in Northern Illinois. A further South track may allow for drier air to wrap in North of the system's center, which could limit overall rainfall locally for at least Wednesday. But if the low tracks overhead, scattered showers will be highest in coverage between Wednesday and Thursday. With the scattered showers and added clouds, afternoon highs will be relegated to the low 70s Wednesday and Thursday.

Due to the lower confidence, forecast coverage of rain between Wednesday and Thursday is only 40%, but could rise if confidence on the track of the low increases. Slowly, moisture will pull away by the end of the week drying things out Friday into Saturday. High temperatures will return back to the mid and upper 70s by the weekend.

Scattered showers and thunderstorms possible this week

Just like yesterday morning we are starting today with some precipitation in the area, although not as widespread as yesterday morning's thunderstorms. A few isolated showers will be possible through the morning today with another round possible later into the afternoon anywhere from 1-4 p.m. today, however thunderstorm chances today look to be slightly lower compared to yesterday.

Over the next few days, isolated to scattered showers/storms will continue to remain possible as a few upper-level disturbances make their way overhead towards the middle of the week. Not only that but temperatures will fall towards Wednesday as a low-pressure system from Canada brings in slightly cooler air. 

Even with slightly higher precipitation chances during the week our total accumulation of precipitation looks to remain relatively low due to the scattered nature of showers over the next few days. Slightly higher moisture values will remain to our southeast so expect rain totals near an inch a bit further south while here we may approach 0.25".

The low-pressure system previously mentioned will stall overhead here by Thursday which will keep upper level forcing around long enough for a few isolated showers to still be possible later this week. However, the farther we go into the week the less moisture will be available so expect precipitation chances to be a bit more limited towards the end of the week. 

Intermittent showers and a few storms throughout next week

 Similar to Saturday, Sunday will bring spotty showers and storms to parts of the Stateline. Most will remain dry through the early afternoon before scattered showers increase in coverage over the second half of the day. Spotty showers and storms will remain possible into the evening followed by the potential for some areas of fog Sunday night into Monday.

Much of the week will feature isolated to widely scattered showers most days. This means coverage of rain any given day will remain near or below 40%. No single day will be a washout, but intermittent showers and a few storms will remain possible many days. It is plausible even a 20-40% chance for rain could result in no rainfall for a day or two, as that means 60-80% of spots are dry at any given time. But multiple rounds of spotty showers and isolated storms will be possible nearly every day next week.

Highest potential for rain will be Monday through Wednesday, but rainfall coverage will only peak at 40-50% at the most between those three days. Most of the week will only feature 20% coverage of rain, including Sunday.

The exact coverage of showers and storms next week will be determined by the merger of two upper-level waves. This process is called "phasing". How much phasing occurs will determine the strength and placement of the resulting single wave. If this tracks overhead, it could result in continued showers each day throughout the end of next week. If it stays just South, we may end up drier after Tuesday. Either way, temperatures will drop a bit through the week, back to the low and mid-70s for highs by Wednesday.

Unsettled pattern brings scattered showers this weekend

 After several days of dry late-summer heat, we will see a new pattern take hold over the next week. Scattered showers and a few storms will be the story almost every day through the next week or so. While there is a chance for rain every day, there will be many dry hours between rounds of showers. No single day looks to be a washout in the immediate term.

Scattered shower and storm coverage begins Friday night with highest potential arriving after 10PM. We will hold onto scattered showers through Saturday before a bit of a lull in the coverage of rain Saturday night and Sunday. Widely scattered to scattered chances for rain and storms will then continue into next week.

Here is an example of what scattered showers may look like at any given time through much of the forecast period ahead. There will be dry pockets in between rounds of rain, but showers will continue on-and-off throughout much of next week.

Slowly but surely, we may begin to add rainfall amounts up through the middle of the week. No single day will bring significant and widespread rain. But in aggregate, many locations might be able to see up to an inch of rain through Tuesday evening. This will not be much to eat into the monthly rainfall deficit of more than 2", but it will start to close the gap.

Football forecast: Isolated showers and storms this evening

 A cap, or lid on the atmosphere, seems to have prevented some of the shower activity from growing in height across much of Northern Illinois. This has limited the lightning threat significantly. There is still a low-end (~10%) chance for some lightning, but the threat is lower for now. Chances for showers increase steadily over the next several hours, with low-end chances for lightning throughout the night.

Isolated showers have begun developing across the Stateline Friday evening, but our risk for any lightning and thunder through 7PM is a bit on the lower side. Highest potential for any lightning would be positioned mainly to the West of I-39 through about 7PM.

This potential will slowly spread East through 10PM but remain low in coverage. Potential for a lightning strike in the vicinity looks to be around 20-30% for most spots. Many locations will remain dry at any given time. The risk for a few steady showers and bolts of lightning remains isolated, but not zero.

If you're heading out for football tonight, keep an eye on radar and be prepared for any lightning delays! Air temperatures will drop into the low 70s by the later part of the game as we maintain the mostly cloudy sky and isolated storm potential.

Lunar occultation creates a stunning sight in the sky Friday morning

Did you catch it? If you were up early enough, you would have been able to see the waning crescent moon and the planet Venus having a friendly convo this morning. Here's a view via our skytrack camera over by the Poplar Grove Airport. The bright start to the moon's 4 o'clock is a star called Regulus, the brightest object in the constellation Leo.  

Now, if you were waking up in northeast Canada, Russia, Greenland, Western Europe or North Africa, you would have seen an even closer conjunction, possibly to the extent where the moon is hovering in front of Venus. This is called a Lunar Occultation where one object is hidden from the observer by another object that passes between them. In the morning's that follow, Venus and Regulus will pull further away from the moon!

Scattered rain chances pop in for the last weekend of summer

Yesterday was the warmest day of this summer-like stretch as the afternoon high at the Rockford Airport peaked 2° shy of the 90° mark. 

 

 

As we close out the last full week of astronomical summer, temperatures remain summer, though cool as we inch towards the fall equinox. In fact, today's high of 83° is still on par with what we typically see in late-June and late July. However, today involves a bit more cloud cover and our next opportunity for rain and possibly a few thunderstorms. 

 

This will primarily be during the afternoon for spots near the Mississippi River, then shifting towards the I-39 corridor this evening into tonight. Isolated rain chances will carry on into Saturday morning, with lows falling into the low 60s. 

 

 

With low pressure spinning nearby, we can expect showers to be a possibility again Saturday afternoon into the early stages of Sunday. In the end, I think most locales will be able to pick up .25" to as much as .50" of rain. This will not a drought-buster, but it's something! Like today, an isolated thunderstorm or two cannot be ruled out. Highs will cool as the weekend progresses, landing around the 80° mark Saturday and then in the upper 70s Sunday.

This rollback in high temperatures comes just in time for the Fall Equinox on Monday. It's at 1:19PM when the sun's light crosses the celestial equator, resulting in nearly equal amounts of daylight and darkness for all parts of the Earth. Average highs are typically in the low 70s and average lows are the low 50s. Highs will be in the upper 70s to start, then falling towards seasonable by Wednesday.