Hot and humid weather continues, strong thunderstorms possible

For the fourth time this week and for the eight time this year, temperatures at the Rockford Airport peaked in the low 90s. 

It's been so hot as of recent that the last 5 days have come in 10° above our normal highs for the June 17th-22nd time frame. Signs all point to one more hot and steamy day before much needed changes arrive following our next cold front. 

Saturday kicks off with mostly cloudy skies as a wave of torrential showers and storms slides across the southern half of Wisconsin. 

By the afternoon, partial sunshine returns, which will allow temperatures to warm rather quickly. This will likely result in Rockford's 9th 90-degree day of the year. Of course, humidity levels may be a bit more oppressive, especially since there was a few heavier downpours prior to sunrise. 

Compared to Friday, storm chances will be higher this evening as a cold front surges in from the west. The Storm Prediction Center has the region under a level 2 of 5 Slight Risk, mainly for damaging winds as well as a tornado or two. As always, have multiple ways to get watches and warnings! 

 

 

Moisture levels ahead of the cold front will be extremely high, bringing the potential for heavy rainfall and flash flooding. 

Some areas, especially those who live north of the Illinois/Wisconsin border, may pick up 2"-3" of rain over the next 24 hours. These areas are also under a Flood Watch until 10PM this evening.

Rain and storm chances come to a close before the midnight hours, leaving us with some cloud cover for the early portions of Sunday. Clouds should give way to some sunshine by Sunday afternoon, though winds will be more out of the northwest. This will make for high temperatures in the low 80s as well as lower humidity levels. The forecast calls for another day in the low 90s on Tuesday before highs cool significant into Wednesday and Thursday.

Tracking storms through tonight

 With heat and humidity sticking around another day, severe thunderstorm chances are elevated as well as a cold front moves through the region bringing strong to severe thunderstorm chances.

Currently the Storm Prediction Center has all of Northern Illinois and Southern Wisconsin under a slight risk for severe thunderstorms later this evening. The main hazards for this evening's round of thunderstorms will be damaging winds as most of the storms along the cold front will be in a line. However, lower risk hazards do include hail and a brief isolated tornado cannot be ruled out.

Tracking this risk out, storms begin in Northern Iowa along the cold front in the afternoon and begin to move east throughout the late afternoon and early evening. These storms will interact with an unstable airmass ahead of them helping create more storms and the damaging wind potential. As well some isolated showers will impact the region during the late afternoon before the main round arrives.

Moving into the 6 o'clock hour the cold front storms begin to move into Northwest Illinois as well as more storms ahead of the main line. Both isolated thunderstorms ahead of the line and storms along the line may be strong too severe with the previously mentioned hazards being the main threat. During the early evening hours, it will be most important to stay alert for watches and warnings as severe weather may approach quickly.

Near the 8 o'clock hour most of the region will be receiving precipitation and thunderstorms as the cold front continues to move east. Severe thunderstorm chances will be highest at this time and depending on storm evolution, this will determine main hazard type however with a line segment most likely damaging winds will be the main threat.

As the night continues the cold front will move through around midnight. At this time and times prior, instability will run out as the sun goes down. This will cause thunderstorms to weaken the farther east they push. By the midnight hour thunderstorms will move out of the region and with the cold front passage temperatures will begin to fall.

With the cold frontal passage tonight, this will bring cooler and more comfortable temperatures tomorrow after a night of active weather.

  
 

Storm chances tag along with this weekend's heat and humidity

Thursday's rainfall has left behind some moisture near the surface, hence the fog that is developing ahead of the morning commute.If you plan to travel, take it slow as visibility will fluctuate. 

Once the fog lets up, we're in for another quick warm up as a warm front lifts through during the mid-day hours.This will likely place temperatures in the low 90s for the seventh time this year, 3 more than the average between May and June. 

As we've seen on countless occasions this week, this heat will come with high humidity, leaving heat indices in the mid to possibly upper 90s.  

It's during this time in which forecast models do show a round of thunderstorms developing along said warm front north of the IL/WI border. With time, these will sink east-southeast, possibly bringing those in extreme N. Illinois an isolated thunderstorm chance during the evening. Temperatures remain warm overnight, landing in the low 70s. In their latest severe outlook, the Storm Prediction Center does have the marginal risk extending down to highway 20. If any storm were to remain severe, gusty winds and hail would be the primary concerns. 

Severe chances go up Saturday afternoon and evening as an area of low pressure helps bring a cold front in from the west and northwest. Areas west of Genoa, Rochelle, and Amboy have been placed under a level 2 of 5 Slight Risk for severe weather. 

Included is the risk for damaging winds, large hail, and a tornado or two cannot be ruled out. I believe the tornado threat is higher to the west where storms may have a better shot at staying isolated. Though this cold front won't have much cool air behind it, it will be enough to give us a brief break from the high heat and humidity. Highs will fall from the low 90s Saturday afternoon to the mid 80s Sunday afternoon.

Severe thunderstorm potential returns this weekend

 Along with the upcoming heat this weekend, severe weather potential begins to rise as well. Through Friday and Saturday chances for severe thunderstorms become more likely as both a warm front and a cold front move through the region this weekend.

Starting with Friday a warm front lift north through the region bringing severe thunderstorm potential with it. As this warm front moves north higher moisture and instability will be brought northward along this front. Currently the Storm Prediction Center has outlined a marginal risk for area in Southern Wisconsin. The main hazards within this risk will be damaging wind gusts and hail as any storm near the warm front matures.

This warm front moves through the region during the late afternoon and early evening hours of tomorrow night with any strong to severe thunderstorm expected to be isolated in coverage.

Moving onto Saturday now severe thunderstorm chances rise for most of the region. On Saturday an area between the warm front and cold front known as the "warm sector" is placed over the state line. Within this warm sector isolated strong to severe thunderstorms will form mainly along the cold front as it moves east through the late afternoon and early evening. Areas outlined in the yellow slight risk will have higher chances of seeing strong to severe thunderstorms while areas in the dark green will have more isolated chances of strong to severe storms.

As Saturday progresses the main threat will be damaging winds and hail through late afternoon and early evening. As the night progresses and storms begin to wain down cooler and more comfortable temperatures make their way to the state line for early next week.

Heat and humidity stick around

 After a quick break from the 90-degree heat, we've had the past couple of days high heat and high indices return. Moving on from today where humidity and thunderstorms were the main story the humidity will stick around with the forecasted heat.

With temperatures reaching back into the low 90's next week, near 100-degree heat indices will also return. With the combined higher temperatures mixed with dew points in the upper 60's to low 70's the uncomfortable pattern will stick around. Heat indices are determined by both temperatures and dew point temperatures so combining these conditions this pushes our forecasted heat indices into the upper 90's.

This weekend will be another time to practice heat safety with these conditions when outside, as well thunderstorm chances return with this heat mainly Saturday when a cold front comes through. This front will initiate thunderstorms as well as cool temperatures off into early next week bringing us some relief.

Some relief from heat coming next week

 After hitting our 4th day in a row of 90 degree plus heat we can begin to take a look beyond on the current heat. After the current forecasted heat the next couple of days, a cold front makes its way through the region on Saturday bringing some relief to the region.

With this cold front coming combined with the flattening of the previous ridge pattern, temperatures will drop into a more average pattern for Sunday and Monday. However, with this cold front coming some scattered showers and thunderstorms move through the area when this front passes through Saturday evening.

 After the front passes through Saturday night temperatures will shift into a more common summer like pattern for Sunday and Monday. Along with cooler temperatures during the day the nights will get some relief as well with temperatures dropping into the upper 60's allowing for cooler and more comfortable nights.

With temperatures dropping into the mid 80's early next week this will be a great time to get outside and enjoy the return of comfortable weather. However, don't expect these comfortable temperatures to stick around as Tuesday will jump above 90 degrees once again. 

Wednesday afternoon weather update

 

Radar update: As the cold front continues to move across northern Illinois and southern Wisconsin, widely isolated storms continue to form. Some of the showers grew tall enough to produce lightning, yielding isolated thunderstorms. The storms remained below severe limits, but some did produce quite a bit of heavy rain before weakening. We'll maintain a mostly dry sky through the night, but a weak disturbance lifting up through Missouri and Iowa will continue to keep showers and isolated thunderstorms along and west of the Mississippi River overnight. Some of those showers and isolated storms may work into parts of northwest and northern Illinois early Thursday.

Temperatures Wednesday afternoon have once again warmed into the upper 80s and low 90s, with the heat index value reaching the low to mid 90s in a couple locations.

A cold front entering into northwest Illinois early Wednesday afternoon has caused a few widely isolated showers and thunderstorms to develop. As the front spreads east, we'll likely see a few more widely scattered storms develop through sunset. While the severe threat isn't overly high, a few of the stronger storms may be capable of producing stronger wind gusts, along with heavy rain. Unfortunately, not everyone will see thunderstorms - or even rain for that matter - this afternoon.

Widely scattered storms will continue into Wednesday night with the 'highest' coverage likely over northwest Illinois and southern Wisconsin. Temperatures tonight will fall to around 70, rising back into the upper 80s Thursday. As the front stalls out Thursday afternoon it'll keep the scattered storm chance lasting into the afternoon.