Pleasant Tuesday, then watching midweek storm chances

Pleasantly Dry Tuesday:

Tuesday brings more of the same comfortable summer weather we enjoyed on Monday, with just a little extra warmth. High pressure remains firmly in place across the western Great Lakes, keeping conditions quiet with  mix of clouds and sun. As a result, afternoon highs will climb a few degrees higher compared to yesterday, reaching the upper 80s. All in all, it will be another pleasant July day with very little to disrupt outdoor plans.  

Midweek Storm Chances:

Wednesday looks to stay mostly dry as temperatures continue their upward trend. Most Stateline locales should reach the upper 80s. Winds will begin out of the southeast before gradually turning southwesterly later in the day as a cold front approaches from the northwest. This boundary will have enough support to spark up our next chance for showers and storms, with the highest potential residing north of the Illinois/Wisconsin border. That is where the Storm Prediction Center has placed areas under a level 1 of 5 Marginal Risk with areas further north into Wisconsin being placed under a level 2 of 5 Slight Risk.  

Current indications suggest much of this activity will weaken as it approaches northern Illinois, limiting both coverage and intensity. Even so, a few showers and thunderstorms cannot be ruled out overnight into the early stages of Thursday. Additional rain and storm chances may persist into Thursday afternoon and evening as a weak area of low pressure (M.C.V) slides into the central portions of Illinois. At this point, the better chance for heavy rainfall to the south of interstate 88, but something to monitor as we get into the second half of the week.  

Periods of heavy rain possible later in the week

 

Following what was a very active holiday weekend with several days of severe weather and heavy rainfall, high pressure over the Great Lakes has kept our skies clear Monday afternoon. It's also taken away some of the humidity with temperatures in the low 80s area wide. High pressure will remain put over the Great Lakes the next couple of days helping to keep skies clear and temperatures warming through the middle to upper 80s. By the middle of the week, though, you may notice a slight increase in humidity.

If we scan the skies further northwest across the Plains, you'll see a line of thunderstorms developing from northwest Minnesota, southwest into western Nebraska. These are along a cold front that'll eventually move in our direction later in the week. The chance for showers and thunderstorms will gradually increase by the middle to end of the week. The severe chance looks to be on the lower end thanks to overall weaker forcing in the atmosphere, but the slow-moving boundary could lead to periods of heavier rainfall beginning Wednesday night and lasting through Friday night.

Thunderstorms will be likely to our north during the afternoon Wednesday as a cold front moves through Wisconsin. Locally, our skies will remain dry through most of the day. Temperatures will warm into the mid, perhaps even upper, 80s. By Wednesday night, the front will be moving towards southern Wisconsin where it'll start to slow down a bit, stalling near the state line through Thursday. With an increase in moisture along and ahead of the front heavy rainfall will be possible during that time. While likely not as much as the rain some experienced over this past weekend totals reaching close to half an inch, up to an inch, are possible. The best chance for rain appears to be Wednesday night into Thursday, and then possibly again Friday into Friday night. But the Friday rain chance (and how much rain we see) will depend on whether or not we see an area of low pressure move through. Some of our forecast models are suggesting one will develop, while some are not. If we do not see the low, then rainfall totals may not be quite as high. 

Humidity and rain chances retreat for a few days, remains summer-like

 After a week of oppressive humidity followed by daily thunderstorm chances, the quieter pattern will be a welcome sight for many. It will not be overly cool by July standards, but the humidity will drop a bit with dew points in the low 60s or even 50s! That will result in plentiful sunshine and afternoon highs in the low to mid-80s. We will remain dry through at least Wednesday afternoon, but chances for rain and storms return late Wednesday into Thursday.

The pattern will remain warm going forward in the coming weeks, aided by a large ridge of high pressure developing over the Western plains. This will spread heat and humidity our way, but a subtle West-Northwest orientation to the upper level pattern overhead may not result in quite the oppressive heat as those West of us will see.

It does look likely we will see more mid/upper 80s or low 90s through much of next week, backed up by the Climate Prediction Center's outlook. This favors about a 50-60% chance to see above average temperatures between the 11th-15th. Average high that time of year is right around 84° for Rockford. Summer is far from over, and it looks like we don't have to wait long for our next round of true heat!

Isolated storms could accompany 4th of July firework displays

Storm Chances Again:

After several days of oppressive heat and humidity, the worst of the summer sizzle (for now) has finally begun to wither away. Temperatures will trend in the direction of early-July standards, however, the active weather stays put into the weekend. 

A frontal boundary slowly sinking south from central Wisconsin will serve as the focus for scattered storms this afternoon and evening, with chances stretching into the overnight hours. Some of which could be strong to severe. The Storm Prediction Center has left the entire region under a level 2 of 5 Slight Risk for scattered strong to severe storms. Damaging straight-line winds, along with heavy downpours, will be the primary concerns. This will be something to monitor if you have any Friday evening plans such as attending City Market. Otherwise, expect humid conditions to stick around with afternoon highs in the upper 80s.  

4th Of July Weekend:

4th of July weekend also features the opportunity for a few showers and thunderstorms. Forecast models continue to indicated a weak area of low pressure or an M.C.V (Mesoscale Convective Vortex) drifting into Wisconsin during the day. 

  

This feature could provide enough lift to spark isolated thunderstorms as holiday begin during the afternoon, with a few storms potentially lingering into the evening. Not everyone will see rain, and much of the weekend does feature a good amount of dry hours mixed in. But if you are heading to any firework displays this weekend, keep an eye on the forecast as well as the radar. Afternoon highs, upper 80s for Saturday with low 80s for Sunday.  
  

Heat subsides a little bit, still warm into holiday weekend

 Thursday marked the 4th day in a row that Rockford reached a high of 91°! During that time, peak heat indices ranged from 100-105°. The last time we saw such a streak of heat was nearly this exact time last year! Typically, average highs are around the mid-80s, so we were 7-8° above average each day!

The next few days will feature a subtle decrease in humidity and heat, but it will still feel like summer over the holiday weekend. High temperatures will likely push close to 90 again Friday, upper 80s Saturday, then low 80s Sunday. Each day will feature at least some isolated to scattered thunderstorm potential, so keep tuned to the radar if you're going to be outdoors for any of the holiday festivities!

Severe Thunderstorm Watch issued for parts of the area Thursday afternoon

5pm Update: A Severe Thunderstorm Warning has been issued for northwest Green County until 6pm. The storm is currently moving east at 40 mph and capable of producing 70 mph wind gusts and quarter sized hail. An isolated tornado is also possible.  

A Severe Thunderstorm Watch has been issued for Rock, Green, and Walworth counties until 10pm in southern Wisconsin. Severe storms have developed this afternoon along a stalled boundary to the north and west, impacting northeast Iowa and southwest Wisconsin over the last couple of hours.

The storms are generally moving in the east/northeast direction and are likely to impact southern Wisconsin over the next couple of hours. It is possible that a few of the storms could dip south of the state line into far northern Illinois by 5pm-7pm. If so, there would be a risk for an isolated severe storm or two through sunset.

We may then see additional thunderstorms later this evening, closer to Midnight, move into the area. If so, there is a low-end risk for those storms to also reach severe limits with primarily a wind and hail threat.

Extreme heat lingers as storm chances return this evening

Extreme Heat Continues:

There were a few minor adjustments made to the Extreme Heat Warning last night. The National Weather Service removed Jo-Daviess, Carroll, and Stephenson Counties from the warning as slightly lower temperatures and heat index values are expected in those areas. However, the rest of the Stateline remains under the Extreme Heat Warning until 12AM Thursday night.   

Hot Thursday Ahead:

As for today's forecast, a few isolated thunderstorms remain possible early this morning, but much of the day will feature partly cloudy skies. Despite the slight drop in humidity compared to the past few days, high temperatures remain the same, peaking in the low 90s for the 4th consecutive day. When combined with the lingering humidity, heat index values will approach the 100° mark and may briefly rise above it for an hour or two during peak heating hours. 

Storm Chances Return:

Along with keeping an eye on the heat, watch for severe potential this evening into tonight. Much of that potential will depend on whether the atmosphere can recover following a round of showers and storms that pass through Wisconsin early in the day. It also will depend on if the frontal boundary responsible for redevelopment remains intact or fizzles out as it slides closer to the Illinois/Wisconsin border. 

Highest severe threats will be strong winds, along with frequent lightning and heavy downpours. For that, the Storm Prediction Center has areas  under a level 2 of 5 Slight Risk for scattered severe storms. They also have a level 2 of 5 Slight Risk in place for the entire Stateline area tomorrow as a secondary boundary sinks south.