Heavy rain producing thunderstorms possible this weekend

 

Isolated showers, and even a few reports of funnel clouds, occurred the last couple of days as subtle and weak upper level disturbances moved through the Midwest. But the rain will become a little more heavy and steady through the weekend as several waves of showers and thunderstorms are expected through Sunday.

Skies will remain mostly clear Thursday night, however, a line of thunderstorms moving through

Iowa will continue to move east and southeast through the night. As this line encounters a little more dry air over the Stateline, they should continue to weaken. However, we'll likely see few showers and isolated storms hold together long enough to impact parts of northwest Illinois through sunrise. As the line of showers continue to move east through the morning, a general weakening trend can be expected.

Winds will remain from the south during the afternoon which should be enough to give temperatures a little more of a boost into the low 80s.

An upper level low quickly moving across the Midwest will slow as it nears Iowa Friday, allowing a few stronger storms to develop west of the Mississippi River Friday afternoon. Isolated thunderstorms are likely locally late afternoon, with a heavier rain falling Friday evening.

The heavier rain Friday night should be coming to an end by Saturday morning, but additional thunderstorms will occur as both the surface low and upper level low near the Stateline. While instability won't be terribly high, quickly rising air throughout the atmosphere could not only produce a few stronger thunderstorms during the afternoon, but also the chance for a few funnel clouds with any of the more vigorous shower or storm activity. Heavy rainfall will also occur with totals possibly reaching one inch, or higher, for some.

Sunday we'll also see a chance for a few showers and thunderstorms, but coverage should be less than that of Saturday. Highs through the weekend will only warm into the middle to upper 70s.

More of the Same for Thursday, Rain Still a Good Bet This Weekend

On This Date:

While the weather pattern as of late has been relatively dry, that couldn't be said for this time period back in 2015. A line of strong to severe storms tracked through the northern half of Illinois, producing torrential downpours, flash flooding, and sporadic wind damage. 

Overall, a whopping 2.87" of rain was observed at the Rockford Airport, breaking the previous daily record set in 2005. Now, rainfall of that magnitude is NOT in the forecast for our Thursday, but rain will become a decent bet by the weekend. 

More of the Same:

In a similar fashion to the past few mornings, we'll wake up to a round of patchy dense fog. Visibility at times could be as low as a mile, especially in low-lying and open/rural areas. 

If you plan to travel, make sure to give yourself extra travel time. Otherwise, skies will turn partly cloudy by the afternoon with highs peaking in the lower 80s. Along with the additional cloud cover comes a slim chance for a late-day shower. Once the heating process from the sun diminishes, any chance for a shower should end by sunset.

Weekend Rain Chances:

Overnight Thursday into Friday, forecast models our next storm system will be sliding into the Western Great Lakes. Along for the ride comes multiple rain chances that extend well into the upcoming weekend. The first coming in two rounds, one early in the day and then again as the evening commute approach. Both look to be rather weak and isolated in nature, and shouldn't pose the threat for severe weather. 

Low Severe Risk Saturday:

Models continue to place the better opportunity for rain, even the potential for a few thunderstorms, on Saturday. Earlier this morning, the Storm Prediction Center placed areas to the south and west of Rockford under a Marginal Risk (level 1 of 5) for severe weather. This is for any storm that may pose a risk for damaging straight-line winds and small-sized hail. 

The storm system then looks to track over the northern half of Illinois, sliding to our east-southeast by Sunday afternoon. This will allow scattered shower and thunderstorm chances to carry on into the end of the weekend before drying takes place into early next week. While it’d be premature to cancel any outdoor plans, it would be wise to make sure to have an umbrella on hand just to be safe.

Fair Weather Continues, Heavy Rain A Possibility This Weekend

Days Getting Shorter:

As the autumnal equinox inches closer, the amount of daylight we get to enjoy continues to slowly shrink. Over the next two months, the Stateline loses roughly 2 hours and 49 minutes of daylight. 

By the time October 17th rolls around, our sunrise time will be register near 7:15AM while our sunset will end up closer to the 6PM hour. Now, with the 13 hours and 48 minutes of daylight we have today, there will be a good amount of sunshine to enjoy. You just may have to dodge a raindrop or two during the afternoon hours. 

Fair Weather Continues:

With skies remaining mostly clear overnight, patchy dense fog will once again be a possibility for the start of our day. Especially in open and low-lying areas. Otherwise, a few morning clouds will give way to partly cloudy skies by the afternoon. 

With winds continuing to come off the lake and a little moisture being present, we could see a few isolated sprinkles during the afternoon and evening. In a similar fashion to Tuesday, high temperatures will end up in the lower 80s. Thursday also features a partly cloudy sky, highs in the lower 80s, and the possibility for a shower or two during the afternoon.

Next Storm System:

As of this morning, the storm system that we are tracking for the upcoming weekend is slowly spinning over the central Canadian prairies. As it approaches the Stateline, rain chances will increase overnight Friday into Saturday, with the highest probability for thunderstorm development arriving during the latter half of Saturday. 

 

With that being said, rain could be heavy at times. As far as the severe threat is concerned, it's a bit too early for specifics. Highs Saturday and Sunday will cool back down into the upper 70s. Once the system is to our east, the weather will slowly quiet down into the early stages of next week. 

Cool nights, warm afternoons

Temperatures the last couple of days haven't strayed too far from their typical August numbers; overnight lows in the upper 50s and low 60s with afternoon highs warming into the mid and upper 70s. While temperatures have been slightly below average the last couple of days, highs Tuesday warmed into the low 80s.

Under a clearing sky Tuesday night temperatures will dip into the middle to upper 50s. As our winds turn light, areas of fog are likely Wednesday morning. High temperatures Wednesday afternoon will warm back into the low 80s - near normal for mid-August.

The cool nights and warm afternoons will be common the next couple of days as northeast winds continue to pull down a drier air mass. This will leave dew point temperatures in the upper 50s and low 60s Wednesday and Thursday before a rise in moisture later in the week and weekend.

The drier air mass will also give us a bigger range in temperatures from the morning to afternoon, known as diurnal range. As the sun heats the atmosphere, air

molecules are able to move around more freely within the drier air, versus an air mass that is high in moisture. This, in turn, heats up the air faster - allowing temperatures to warm quickly and further from the morning starting point. It's also what allows the temperature to fall quickly at night. When the dew point temperature is high, the air molecules are less efficient in heating up keeping a small range in temperatures from morning to night. 

Pleasant Stretch Continues, Rain Holds Off Until Friday

Not So Summer-Like:

The official high at the Rockford Airport Monday just barely hit the 80-degree mark. Although this did land us closer to mid-August standards, this marked the 8th straight afternoon where high temperatures fell cooler-than-average. 

On plus side, the lack of excessive heat and humidity made for a comfortable start to the school year for some. Not only that, It also gave our A/C units another opportunity to rest. 

Pleasant Stretch Ahead:

For today, we can expect that below-average streak to continue as our surface winds remain out of the northeast. This will likely land high in the upper 70s for most, with a spot or two touching the 80-degree mark. With an area of high pressure locked in place over the Great Lakes, today will feature a bit more sunshine than Monday.

More of the same can be expected for Wednesday as the high over the Great Lakes region fails to move even by the slightest. The day looks to kick off with wall-to-wall sunshine, with a few fair weather clouds popping up for the afternoon. 

In a similar fashion to Monday and today, winds remain out of the northeast, allowing temperatures to peak near the 80-degree mark. Guidance then shows a few more clouds filling our skies on Thursday, with temperatures landing smack dab on the seasonable mark. This is all ahead of a slow-moving low pressure system that looks to end our dry streak and bring rain chances for the weekend.

Late-Week System:

Towards the late Friday/Friday night time frame, models shows slow-moving cut-off low-pressure system sliding to the west. Ahead of this feature comes a surge of moisture which will eventually lead to our next chance for rain. 

Saturday looks to be our best day for rain, as scattered showers and storms are somewhat likely. Chances look to carry on into Sunday, with conditions drying out for the beginning of next week. The potential for severe weather remains low at this point in time. But something to still monitor! Up until then, enjoy the pleasant weather folks!

Comfortable for 815 Day, Spotty Shower or Two Possible

Weekend Recap:

If you were sitting there thinking to yourself that the weather from this past weekend had a fall-like feel to it, you thought correct. With clouds hanging over the Stateline, high temperatures were limited to the low 70s both Friday and Sunday. To put how early this taste of fall is into perspective, we don't normally see our average highs fall into the low 70s until the end of September. As for the the new work week, it looks like much of it will be spent under this cooler flow regime, leaving high temperatures cooler than average. 

Remaining Cool:

Much of this year's edition of "815 Day" will be spent under a partly to mostly cloudy sky, with temps peaking in the upper 70s. 

Although this does land a few degrees warmer than the highs from Sunday, this will mark the 4th straight day in the 70s. Tuesday also features highs in the upper 70s. However, an area of high pressure over the Great Lakes will help bring a little more sunshine into the mix.

Cooling Back Down:

By week's end, thousands of kids across the Stateline will be back in the classroom. Fortunately, the weather doesn't look to become overly hot and humid for their return. 

Guidance keeps the weather dry into the second half of the week, with highs slowly climbing near seasonable-levels. Following a cut-off low late Friday into Saturday, highs will fall back into the upper 70s for the weekend.

Cooler trend to stick around this week

 

An abundance of cloud cover Sunday afternoon kept temperatures in the upper 60s and low 70s, with Rockford reaching a a high of 73 degrees. That's nine degrees below the average high of 82 degrees.

Cloudy skies are to be expected through much of Sunday night, but we should manage to see a little more sunshine for the afternoon Monday. Temperatures will still remain cool with highs reaching the upper 70s.

East to northeast winds throughout the week will help keep temperatures slightly cooler than our typical mid-August highs; temperatures this week will remain in the upper 70s, to right around 80 degrees. High pressure sinking in from the north will remain north of the Stateline through most of the week, shifting overhead and then to the south towards the latter half of the week. 

Another drop in temperatures is likely for the

upcoming weekend as a cut-off low develops over the Midwest and Great Lakes, bringing temperatures back down into the 70s, with a chance for rain, next Saturday and Sunday.