Tuesday, July 5, 2022

Heat Advisory Issued, Another Chance for T-Storms Arrives Late

Hot, Oppressive Tuesday:

Mother nature brought her own fireworks for the 4th of July as multiple rounds of thunderstorms tracked through the Stateline. 

All of which brought an elongated threat for severe weather and the potential for flash flooding. Now, with us still under this "ring of fire" weather pattern, the threat for severe weather returns later today. However, it'll be today's excessive heat and humidity that becomes the bigger headline.

A HEAT ADVISORY will be in effect for the entire region from mid-day till 8PM. 

During this time, highs temperatures will be peaking in the low to mid 90s. That, along with dew point temperatures in the low to mid 70s will allow heat indices to either touch or eclipse the triple-digit mark. 

If you can, limit time outdoors today. If that option is off the table, please be sure to have plenty of water on hand and take frequent breaks in the shade. Today's heat and humidity will be one of the big reasons why a few storms will be possible later in the day. And yes, severe weather is also on the table.

Late-Day Threat:

Similar to Independence Day, the entire Stateline has been placed under a Slight Risk (level 2 of 5) for severe weather. This is for the round of thunderstorms that look to form along a westward-moving lake breeze boundary late Tuesday. 

For any storm that showcases severe characteristics, damaging winds and hail will be the biggest concerns.

And of course, with the vast amount of moisture in our atmosphere, heavy rainfall and flash flooding will also be a big concern. Guidance continues to keep a chance for scattered showers and thunderstorms overnight, with a frontal boundary sinking to our south by early Wednesday morning. The northeast flow behind the front will help cool our high temperatures back down into the 80s for the remainder of the work week.

Monday, July 4, 2022

Daily T-Storm Chances, Heat Advisory Issued for Tuesday

Stuck in the "Ring of Fire":

You couldn't ask for better weather for the start of the Independence Day weekend. Both Saturday and Sunday featured sunshine from start to finish, with highs landing in the upper 80s. 

However, as we were hinting at late last week, the best rain and thunderstorm potential was unfortunately slated for Independence Day itself and the days that follow. 

This is because we are entering a more active weather pattern that we typically see during the summer month, a pattern we call the "ring of fire". Long story short, a ridge of high pressure sets up over the southern and central plains, placing the jet closer to the U.S/Canadian border. 

The northward adjustment of the jet places the Stateline in the perfect position to receive any cluster of storms that develop at the top of the ridge. In this week's case, this will bring us daily rain opportunities. The tricky part about a forecast like this is the timing as it all depends on what happens earlier in the day, or even what happens in the days prior.

Mother Nature's Fireworks:

The 4th actually starts off on a quiet note, with some sunshine possible early on. By mid to late morning, clouds are expected to increase, with the first round of showers and thunderstorms quick to follow. Guidance places the first round of showers and storms into our region around midday, with storms likely to continue in a scattered fashion, through mid to late afternoon. 

While it looks like the initial round doesn't pose much of a severe threat, that can't be said for the second round. Earlier this morning, the Storm Prediction Center placed the entire region under a Slight Risk (level 1 of 5) for severe weather. Now, the timing of the first round is KEY. 

If the thunderstorms slide in earlier, the 2nd round will track in around the time firework shows are to commence. However, if this afternoon's chances are slow to move out, this would likely delay the development of the 2nd round by an hour or two. As mentioned, this round does carry with it a higher chance for strong to severe storms, with gusty winds and heavy rainfall being the biggest concerns. If you have any plans this evening, stay up-to-date with the forecast and keep an eye on that radar! Once this cluster is to our east, conditions simmer down into Tuesday.

Daily T-Storm Chances:  

But just as quick as we are to quiet down, another chance for thunderstorms arrives late-Tuesday. For that, the Storm Prediction Center has placed the region under a Slight Risk (level 2 of 5) for severe weather. Similar to today's threat, damaging straight-line winds, heavy rainfall, and a tornado or two will be the biggest concerns. 

Heat Advisory Issued:

Along with the severe potential does come dangerous heat as a southwesterly wind will place Tuesday's highs in the low to mid 90s. With dew points in the upper 60s and low 70s, allowing the afternoon hours to feel quite oppressive. 

As of this morning, the National Weather Service has placed our western areas, Jo-Daviess, Stephenson, Carroll, and Whiteside Counties, under a HEAT ADVISORY. This will be in effect from 12PM to 8PM Tuesday as heat indices will more than likely exceed the triple-digit mark. If you can, avoid being outdoors for a prolonged period of time. If you can't drink plenty of water and take frequent breaks in the shade. Temperatures cool back down to the 80s, with another chance for thunderstorms arriving Wednesday and Thursday.

Sunday, July 3, 2022

Quiet Sunday night; Storms possible for the 4th


The weekend was hot, but not overly humid as temperatures warmed into the mid and upper 80s both days. Following a cold front Friday afternoon there was a nice drop in the dew point temperature, with numbers falling through the 50s. This helped keep the humidity at bay through the weekend. For anyone who may be enjoying any Fourth of July festivities Sunday evening, the weather looks perfect. It'll be a warm evening with a breeze from the south. Temperatures will remain in the 80s through sundown, slowly falling back once the sun sets. Skies remain clear making for perfect viewing of any fireworks displays that may be taking place.

All eyes, however, will be paying close attention to the forecast for the actual holiday - Monday - as showers and thunderstorms are likely to impact parts of the region not only during the afternoon, but possibly at night. As we enter into the first full week of July, we are also entering into a very typical summer-like pattern, known as the 'ring of fire' pattern. Under this pattern, thunderstorms and storm clusters form on the outer edge of a strong, and usually rain free, heat dome. These storms follow the winds within the jet stream, feeding off of the heat and instability. It's an often difficult type of pattern to forecast for as the exact path and timing of those storms depends on quite a few factors; a couple of those being any overnight or early morning storm activity, storm activity upstream and impacts that may have on further development downstream. For Monday, it does look like we have an opportunity for a couple storm systems to move through the region; the first during the afternoon and the second later in the evening/night.

Skies should begin relatively quiet Monday morning ahead of increasing cloud cover from the west. Temperatures will fall into the mid 60s during the early morning, rising into the mid 80s by the afternoon. An upper level disturbance currently over the Rockies is forecast to move through the Plains and right across northern Illinois and southern Wisconsin either late morning or early afternoon. It looks like our window for this first wave is roughly Noon to 5-7pm. There will likely be a dry period following the first round of rain during the evening, perhaps a couple hour window, before the second round moves through.

That second round of thunderstorms is expected to develop to our north/northwest sometime during the evening, shifting to the southeast towards southern Wisconsin and northern Illinois. These thunderstorms will be developing on the nose of an increasing low level jet (strong winds in the lowest levels of the atmosphere), as well as with increasing moisture and instability. The big question mark at this point is when do the storms develop and what is the exact track. As it stands Sunday evening, the storms could move right over southern Wisconsin and northern/northeast Illinois as early as 9pm/10pm, or hold off until after 11pm. It's also possible that the storms form more to the northeast, passing through southeast Wisconsin and northeast Illinois, bypassing most of the area. Again, this second round depends on what happens earlier in the day. Wherever these storms develop, there is a risk for a few strong/severe storms late Monday evening. Strong winds and heavy rainfall would be the biggest concerns.

If you are planning on heading out for any of the fireworks displays, please make sure you keep a watchful eye on the forecast for the evening. We'll continue to provide updates on our storm chances throughout the day.  

Friday, July 1, 2022

Early Morning Storms, Isolated Chances Over 4th of July Weekend

Drought Worsens:

Rain opportunities during the 2nd half of June were few and far between, resulting in the expansion of our regional drought. Thursday's edition of the drought monitor indicates that much of the region is now experiencing abnormally dry conditions. While our rain chances remain isolated over the 4th of July weekend, better opportunities may present themselves early next week.

Early Morning Storms:

Our first shot at some rain comes in the form of a weak cold front early Friday. Models this morning kept chances into the late-morning hours, with skies slowly clearing during the afternoon. 

If you plan to step out the door early, it wouldn't hurt to have your umbrella with you. There may be a chance for a lingering shower or two at the start of City Market. However, much of the event will be dry. Once the front is through, winds will turn to the northwest, resulting in a somewhat cooler afternoon with highs in the lower 80s. Skies remain mostly clear overnight, with lows falling into the lower 60s by sunrise Saturday. 

4th of July Weekend:

Saturday and Sunday feature dry conditions for the most part. However, energy moving in aloft may result in more cloud cover and a small shower chance Saturday afternoon. High temperatures will range from the mid to upper 80s, landing a few degrees above early-July standards. As we've been hinting at the past few days, Independence Day does also feature a chance for rain, especially during the evening and overnight hours. 

While it's too early to cancel any plans for the day, you'll definitely want to pay close attention to the forecast for the 4th of July. Forecast models then showed a few more systems sliding down a upper-level ridge over the central plains, allowing rain chances to carry on into the middle of next week. However, the confidence level on these rain chances is still low considering we are several days out. Something we'll have to keep an eye on! 

Thursday, June 30, 2022

Isolated shower/storm chance for the holiday weekend


The chance for rain and thunderstorms will return to northern Illinois and southern Wisconsin as we look towards the holiday weekend, but it won't be a complete washout and there should still be plenty of dry hours to get out and enjoy.

For the remainder of Thursday evening, skies will continue to fill with cloud cover as a cold front sinks south across the Midwest. Temperatures Thursday afternoon warmed into the upper 80s and low 90s, reaching 92 degrees in Rockford. Under the partly to mostly cloudy sky Thursday night, low temperatures will dip into the upper 60s - rising into the low to mid 80s Friday afternoon.

Friday morning will be our first chance for rain heading into the extended weekend as showers and a few thunderstorms are expected to develop along and ahead of the cold front. No severe weather is expected with the front coming through during the morning, but a few pockets of heavier rainfall are possible. As the cold front passes through early afternoon, an isolated shower or storm may still occur during as some moisture lingers around behind the front. It does appear that most areas remain dry, however, heading into Friday evening.

High pressure is quick to build in Saturday, but with the position of our jet stream overhead Saturday and Sunday, several loosely organized upper level disturbances are expected to move through the Midwest. This is known as a 'ring of fire' pattern. Heat and instability build under a strong ridge of high pressure where sinking air dominates and doesn't allow for the development of rain or thunderstorms. On the outer edge of the ridge and right along the heat dome, however, thunderstorms develop and follow the flow of the jet stream, feeding off of the heat and instability to the south. This type of pattern is very typical for July and August and often leads to more nighttime thunderstorm activity which produces very heavy rainfall and strong winds. With the heating of the day, a couple isolated showers and thunderstorms may develop this weekend. However, there looks to be many more dry hours than rainy/stormy ones through the weekend. High temperatures will warm into the middle and upper 80s.

The 4th of July itself may actually hold our best chance for rain through the weekend, which could come towards Monday evening and overnight. A little more of an active storm pattern looks to develop heading into next week with a ridge of high pressure building across the Plains, placing much of Wisconsin and Illinois under the favorable storm track for low pressure systems to move along. Timing these types of systems can often be difficult, especially several days in advance. But the latter half of Monday appears to have a slightly higher chance for rain/storm activity that could carry over into Monday night. While it's too early to cancel any plans for the day, you'll definitely want to pay close attention to the forecast for Monday. The rain and storm chance will remain with us into early next week.  

Windy & Hot Thursday Ahead, Few Storms Possible Early Friday

Windy Thursday:

Thursday calls for more suns. However, a tightened pressure gradient in between a high pressure system to the east and a cold front to the northwest will increase our winds by the mid-day hours. 

Winds will generally be out of the south or southwest, with gusts pushing 30-35 mph. That, along with the fact our ground is very dry, will elevate the fire risk across the region. 

To be safe, make sure to limit or even postpone any burning that you have planned as any fire can spread easily in these conditions. Ahead of the approaching cold front, high temperatures for a few will peak in the lower 90s. Thankfully, today's 90-degree weather is a one-day event.

Rain Potential Friday:

Clouds are expected to thicken up some overnight, with a round of scattered showers and t-storms arriving shortly before sunrise. 

Unfortunately, this doesn’t look like it will be a beneficial rain as the potential for a washout or even severe weather is highly unlikely. With that being said, it wouldn't hurt to have the umbrella on hand for Friday morning’s commute. 

Guidance shows tomorrow's rain making a quick exit before mid-day, allowing some sunshine to appear during the afternoon. Because the cold front occurs during the morning hours, highs will take a tumble from the lower 90s today to the lower 80s Friday.

4th of July Weekend:

Behind Friday's cold front, an area of high pressure takes over, allowing sunshine to return for a good chunk of the holiday weekend. Along with the dry weather does come a quick warm up as highs both Saturday and Sunday peak in the upper 80s. 

Forecast models continue to show a "backdoor" cold front sinking down from the north late in the day on the 4th. We'll likely need to keep an eye on this frontal boundary for the potential for scattered showers and thunderstorms. As I said yesterday, we're still a few days so of course the forecast will change as we inch closer. But if you have any big plans to celebrate the 4th, be sure to stay up-to-date with the forecast by downloading the First Warn Weather App!

Wednesday, June 29, 2022

Hot and windy Thursday; Rain returns Friday


Temperatures Thursday afternoon will be hot, but it won't be too humid as dew point temperatures are expected to drop into the low 60s, perhaps even mid to upper 50s, during the afternoon. Southwest winds will increase as a cold front sits to our northwest and high pressure sits to our southeast. Winds will gust as high as 35 mph throughout the afternoon and evening. This will help push temperatures into the upper 80s and low 90s throughout much of the area.

As a cold front approaches from the north and northwest Thursday night, cloud cover will gradually begin to increase. The front will cross southern Wisconsin and northern Illinois early Friday, bringing with it a chance for showers and thunderstorms during the first half of the day.

As the front sinks south by early afternoon, skies are likely to remain mostly cloudy during the day which may hold temperatures down into the upper 70s and low 80s. Right now the forecast high for Friday is 82 degrees. Heavy downpours are possible as the front moves through Friday morning, but rainfall totals don't appear to be more than half an inch. A slower moving cold front could increase the risk of thunderstorm coverage, as well as heavier rainfall into the afternoon. Right now, the threat for any severe weather appears to remain on the lower end. Skies will dry out by Friday night.