Warm, breezy today—storm chances return Friday

Warmup Continues: 

Yesterday was another beautiful day, though it gave us a true taste of summer with highs climbing into the low to mid 80s across the region. Today, we turn up the heat a bit more as southwesterly winds become better organized, helping boost temperatures even higher for our Thursday. Expect afternoon highs to top out around 87 degrees beneath a partly cloudy sky. It'll be a bit breezy at times, with gusts reaching up to 25 mph this afternoon.  

Rain Chances Increase:

Cloud cover will begin to increase this evening as our next system organizes to the west. Even so, forecast models continue to slow down the eastward push of developing showers and thunderstorms, keeping most of the activity just out of reach through much of the night. As it stands now, the better chance for rain looks to hold off until closer to daybreak tomorrow morning, when that line of showers and storms finally works its way into the Stateline. 

Severe, Flash Flood Potential:

Another round of showers and storms is expected to fire up over Iowa by Friday afternoon, and where these storms form and track will be key for us here in the Stateline. That placement will play a big role in both our severe weather potential and the risk for flash flooding heading into Friday night and Saturday morning. Right now, the Storm Prediction Center has much of the Stateline under a Marginal Risk (isolated threat) for strong to severe storms, while the Weather Prediction Center has placed half the region under a Slight Risk (15%) for excessive rainfall and possible flash flooding. Precipitation chances should diminish or taper off Saturday morning as the main upper-level feature pushes to the east of the area.    

 

Prospects for much-needed rainfall increase into the second week of June

 While the last month plus has been rather dry across the Stateline, but we may begin to see more of a pattern change on the way before too long. We will see a few chances for at least scattered showers starting late this week and toward the weekend, particularly over Friday.

Another favorable window for some downpours or storms will arrive early next week. Abundant gulf moisture will inch Northward after Sunday, bringing increased rain chances toward Monday-Tuesday in particular. The deeper "Precipitable Water" values indicate more moisture than could be rained out given the right conditions.

Even subtle waves in the atmosphere will be able to produce scattered downpours, and that looks likely between Monday and Tuesday. That rainfall may not be widespread for everyone at any given time, but more locations than not should be able to see some of the beneficial rainfall early next week.

Rainfall coverage will be key in determining how much of the Stateline sees this soaking rain potential versus those who don't. Monday and Tuesday will probably be between 40-60% coverage, meaning only around half of the area will see rain at any given time. I'm not expecting the rain to be overly widespread, meaning there should be at least some dry time between waves of rain.

Even though the rain will not be overly widespread for everyone, the rich moisture will result in heavy downpours when rain does fall. Through the week, that will begin to add up with some rainfall for many locations around the region. Computer models may not have an easy time predicting how much widespread rainfall we will see this far out due to the scattered nature of the showers and storms. That said, there is an increasing chance for most of the area to see a half inch or more of much-needed rain through mid-next week.

Warm-up well underway, few storms possible by Friday

Warmer Wednesday:

It's been a stellar start to June, with plenty of sunshine and highs hovering around 80-degrees - about as nice as it gets without high humidity levels. That quiet, comfortable weather pattern sticks around today as high pressure remains in control, keeping skies partly to mostly sunny. With a light southerly breeze, highs will tick up a bit compared to Tuesday, pushing a bit further into the low 80s, right around 84.  

Rain Chances Increase:
 
Thursday brings a bit more heat, with temperatures peaking in the mid to upper 80s. Along with the above-average warmth, expect an increase in cloud cover by the afternoon, which may be enough for a stray sprinkle or passing shower. 

  

Rain chances look a bit more promising on Friday, especially as we get into the afternoon. Showers, and even a few thunderstorms cannot be ruled out as the day unfolds. Right now, forecast models are honing in on the higher rainfall totals staying just to our north and west, but some areas could still pick up close to a half inch of rain - or even a bit more. 

  

As always, how much we see will ultimately depend on how Friday's rain and storm chances materialize. Severe potential is low but an isolated severe storm or two will be possible given the amount of energy, moisture, and lift in the atmosphere. 

For that, the Storm Prediction Center has placed the entire Stateline area under a level 1 of 5 Marginal Risk, with a higher potential for severe storms across Iowa and southern Minnesota. 

Warm & quiet through Thursday, unsettled by the weekend

Ridging Remains:

June is off to a great start across the Stateline. Despite a bit of cloud cover at times yesterday, temperatures still made a comfortable climb into the upper 70s, giving us a really pleasant early-summer feel. And this pattern isn't going anywhere soon. 

A ridge of high pressure remains firmly in place in the upper-levels of the atmosphere, helping to steer away any meaningful rain chances away today, tomorrow, and for much of Thursday. Expect afternoon highs to peak in the low 80s this afternoon under plenty of sun. Low 80s are also on the table for Wednesday, though expect there to be a few more clouds.  

Ridge Breaks Down:

Forecast models then show a change happening as we get closer to the weekend. That ridge begins to break down a bit, opening the door for a few shortwaves or upper-level disturbances to pass through. 

 

  

This setup will help a pull a plume of richer moisture northward into the Midwest and the western Great lakes, adding a little more fuel to the atmosphere. As a result, rain chances, along with the potential for a few storms, will tick upward, especially Friday and during the day Saturday. Currently, it doesn't look like either day will be a washout. 

Even with the added clouds and chances for rain, temperatures will stay on the warmer side, peaking in the low to mid 80s. Overnight low remain on the mild side, ending up in the low 60s. 
 

Dry pattern holds as meteorological summer kicks off

Historically Dry May:

Even though we picked up a little bit of  rain overnight, it didn't add up to much - just 0.05". That brings our total rainfall for the month of May to only 0.52", officially making it the 2nd driest May on record. A stark turn around from the wet start to spring, and a clear sign of just how dry conditions have been across northern Illinois.  

Meteorological Summer: 

June 1st marks the official start of the hurricane season in the Atlantic Ocean - but closer to home, it kicks off meteorological summer. This is the time of year when our average temperatures begin to peak, with normal highs climbing into the low 80s across northern Illinois. It's the beginning of our warmest stretch of the year, where longer days and stronger sun really start to take hold.  

Remaining Dry:

High pressure remains firmly in place, which means rain chances will stay limited. The tradeoff, though, is a pleasant stretch of weather - expect plenty of dry time today, Tuesday, and Wednesday with highs holding steady in the low 80s, right in line with early summer comfort. As we get closer to the weekend, there are some early signs of that rain chances may tick slightly higher, but for now, meaningful rainfall still looks hard to come by. 

High and dry early this week, increasing humidity by weekend

 [6:20PM] While most of the area will be dry this evening, a few very isolated sprinkles may be able to work through some drier air through the night. The rainfall will not amount to much. Only a few hundredths of an inch may come down for those who do see any rain.

Pending we don't see any measurable rainfall before midnight, this May will go down as the driest on record for Rockford. Only 0.47" of rain fell this entire month at the airport, compared to the average 4.18" rainfall we typically see in May. Especially remarkable given how long ago some of the other top 5 have been!

A tiny bit of moisture may produce few sprinkles from time to time from late evening through the overnight hours, but most of the area will remain dry at any given time. Whatever rain does fall probably will not amount to much, likely less than a tenth of an inch for those who do see rain.

Another round of dry high pressure will then take hold early in the week, bringing pleasant afternoons and cooler nights. Monday and Tuesday night could feature lows nearing the upper 40s in a few locations!

But the lack of humidity will not last for long. As that area of high pressure slides away, surface winds will turn to come from the Southwest. That will bring an increase in moisture, especially at the surface. Dew points will likely climb into the 60s by Friday evening. A more unsettled pattern will develop as a result, with at least isolated chances for some showers and storms beginning Thursday night. While it may not be a soaking rainfall for everyone, prospects for much-needed rainfall look a little better through the first week and half of June.

Subtle pattern change may bring slim rain chances late next week

 While we have been stuck in the warm and dry pattern lately, subtle changes may be on the horizon. The large scale upper level ridge has been a dominant feature for our weather pattern, bringing surface high pressure systems, a dry Easterly wind, and very little rainfall over the last week or two.

That ridge will begin to break down late into the week, resulting in at least a few slim chances for rain starting Friday. Increased jet stream flow overhead will result in increased moisture and subtle waves that are able to precipitate some of that moisture out as rain.

Unfortunately, it probably won't be the widespread and soaking rain that we need, but anything helps at this point. Coverage of rainfall may not reach much higher than 30-40% at any time Thursday night through the weekend, but at least some locations in the Stateline will have a shot at some rainfall, though others may end up staying dry. It's not much, but it's a start!