Monday, March 18, 2024

Tornado Myths: Tornado cannot cross bodies of water

With tornadoes come a lot of believable myth such as they stay away from highly populated areas or mobile homes attract tornadoes...

All are false by the way. But once such myth was busted not once, not twice, but three times during the severe weather outbreak last Thursday. 

The myth, that areas around rivers, bodies of water, or mountains are spared from tornadoes. Last Thursday, a tornado formed in Indiana, crossing the Ohio River THREE TIMES during its lifespan. 

This tornado would be given an EF-2 rating by the National Weather Service in Louisville, KY. 

What should you take away from this?  Tornadoes can INDEED cross rivers, touch down in the mountains, roar through valleys, and hit highly populated areas. In other words, tornadoes can occur anywhere if atmospheric conditions are favorable. 

Say it ain't snow? Next snow chance arrives after seasonal switch

A wind shift to the northwest left temperatures on St. Patrick's Day in the upper 30s. 

Relative to average, this landed 7° below our average high for March 17th, marking Rockford's first below average day since February 24th. 

Chilly northwest flow is expected to dominate a good chunk of the new work week, leaving temperatures below average for the most part.

The only day of warmth comes Tuesday, which coincides with the spring equinox. A brief period of southwesterly flow will push highs into the low 50s under partly cloudy skies. 

A cold front then looks to come through during the late-morning and early afternoon time frame, quickly shifting winds back to the northwest. 

This will leave highs in the upper 30s and low 40s for the remainder of the work week. 

Now, Rockford's last measurable snowfall came on February 23rd where the airport picked up 1.0". Why do I bring that up? Unfortunately, this week's chilly trend will set the stage for the Stateline to see it's next chance for measurable snow. 

This comes in the form of a clipper system which is shown sliding into the western Great Lakes Thursday evening into Friday morning. Right now, it looks like the highest chance for accumulations will be along and north of I-88, up into S. Wisconsin. But that will be something to monitor as we inch closer to the event itself.

Sunday, March 17, 2024

Wintry weather returns as Spring begins

 


After several record high temperatures were reached in February and early March, our pattern turns a little more winter-like as we move into the Spring season.

For the rest of Sunday evening skies will remain mostly cloudy with a few scattered snow flurries from time to time. Gusty northwest winds will ease some through the evening as overnight lows fall into the low to mid 20s.

Temperatures Monday will also fall below average (average high is the upper 40s) reaching only the upper 30s for the afternoon. As the cooler air remains in place aloft it'll help build a little instability during the afternoon. This will likely lead to skies turning partly to mostly cloudy once again. A few flurries can't be ruled out during that time as well, but no accumulating snow can be expected.


Winds will turn back to the west and southwest Tuesday bringing temperatures back into the mid-50s for the afternoon. This will likely be our warmest day out of the next seven. Quiet conditions can be expected going into Wednesday but a cold front early in the day will help hold temperatures in the low 40s.

By late week a quick moving upper-level disturbance will race southeast, crossing the Midwest late Thursday into Friday. Colder air associated with the system is likely to bring a period of wintry weather to the Stateline. For some, this could include some accumulating snowfall through Friday morning. For others, a little more of a mix or a few rain showers. This could cause some minor impacts for the commute Friday morning.


The overall pattern through the end of the month is likely to feature below average temperatures and above average precipitation. This doesn't necessarily mean all precipitation will fall in the form of snow - remember our average high is in the upper 40s now and by the end of the month the average high is in the low 50s. But it doesn't look like we'll be seeing the 60s or 70s any time soon.

Friday, March 15, 2024

Hold on to your Shillelaghs! Gusty winds settle in for PaddyFest

Thankfully, the Stateline didn't have to deal with the potential for severe weather after such a soggy and gloomy start to our Thursday.

In even better news, yesterday's active weather isn't expected to carry on into our Friday. High pressure sliding in will allow sunshine to make a quick return to round out the work week. Even with a cool northwesterly wind in place, expect temperatures to peak in the low to mid 50s. 

Winds become the big story for Saturday. A cold front sliding in from the northwest will tighten the pressure at the surface, allowing winds to increase. 

Between 10AM-5PM, west-northwest winds could gust up to 30-35 mph at times. If you have Paddyfest on your schedule for tomorrow, make sure to hold on to any St. Patty's day decor!

Cloud cover will also increase early on, leaving skies partly to mostly cloudy for the afternoon. Despite the the additional cloud cover and wind change, highs should still peak in the upper 50s. 

Temperatures will then take a tumble for St. Patty's Day itself, leaving highs in the low 40s. A disturbance shifting through late Sunday into early Monday may have enough lift for a flurry or snow shower. An area of high pressure to the west will then dry our weather pattern out for the start of next week!

Thursday, March 14, 2024

Heavy rain likely during the morning commute, severe threat lower

Two robust areas of showers and thunderstorms are moving across Illinois this morning...

The first is positioned north of the warm front and is literally lined up with I-80. The second is in the form of what we can an M.C.S or a Mesoscale Covective System which is the line of storms that extend from Quincy to the Quad Cities. 

I'll start with the good news, most of the more robust thunderstorm activity will remain south of the region, hence the watch to our south. Any storm that manages to track north of I-88 will likely encounter cooler air, allowing it to weaken. On the flip side, we're still in for some heavy rainfall and even small-sized hail during the morning commute hours. To be prepared, make sure to have the rain gear as well as giving yourself extra time for travel.

Occasional showers and storms will continue to be a possibility into the late-morning hours, with a sizable break to follow during the afternoon.  

As we've discussed on multiple occasions this week, the position of a warm front was the big uncertainty with the afternoon and evening threat. As it stands this morning, it looks like the warm front will remain south of I-80, keeping winds off of Lake Michigan for the entirety of our Thursday.

This results in a much lower threat for general and even strong to severe storms. In their early-morning outlook, the Storm Prediction Center shifted the level 2 Slight Risk south, leaving areas along and south of highway 20 under a level 1 Marginal Risk. With that being said, keep an eye on things later today. 

From there, scattered showers and an isolated storm or two will remain a possibility into the early stages of Friday morning. As today's rain-maker pulls away, clouds should give way to a decent amount of sunshine by the afternoon, leaving highs in the low 50s. A parade of cold fronts will march through the area over St. Patrick's Day weekend, cooling highs into the 40s into next week.

Wednesday, March 13, 2024

Active pattern begins today, strong storms possible Thursday

It's quite remarkable to think that our average high doesn't hit 70° until mid-May, and yet Rockford has witnessed six 70° days in 2024.

That is now the most on record through March 12th since records began in 1905. 

Temperatures remain rather warm for Wednesday, though tagging along with today's warmth will the start of what is to become an active pattern.

Following last night's weak disturbance, a ridge of high pressure will briefly settle in. This will leave most of the daytime hours, especially to start, dry. As we jump into the afternoon, clouds will increase, turning skies mostly cloudy. Not too far behind that will be a chance for a few widely-scattered showers and an isolated thunderstorm.

Again, temperatures will end up unseasonably warm compared to mid-March standards. However, not warm enough for a third 70° day. 

A round of showers and storms will develop over the Midwest this evening. This is what we will have to keep an eye on for tomorrow morning as forecast models lift this activity into the area.

By the time they enter the Stateline, they will have likely be in a weaker state, posing a risk for heavy rainfall and small-sized hail. Now, there is still time for the forecast to change. With that being said, the stuff that passes through during the morning will play a huge role into the late-day threat. 

If the morning activity comes through with more intensity than what models are showing, this would toss the afternoon threat into the garbage. Why? Lapse rates and instability would take a hit. But also, this will help keep the warm front that we've talked about in prior updates well south of the area. 

If this activity manages to weaken and we do end up seeing a sizable break, this will allow the warm front to creep closer to I-88, increasing the potential for severe weather locally. Concerns would include large hail, following by heavy rain, strong winds, and an isolated tornado. From what I saw from forecast models this morning, it's going to be tough for the warm front to lift into north central Illinois. Plus, the northeasterly flow north of the front will also make things difficult for any organized convection. Again, something to monitor this afternoon and overnight tonight. Rain should carry on into the early stages of Friday, tapering off before mid-day. Highs will briefly hit the 50° mark.

Tuesday, March 12, 2024

Another 70° day likely ahead of our next active pattern

Plenty of sun and a rather robust southwesterly wind left much of the Stateline in the 70s Monday. 

For Rockford, this was the 5th time since the year began where highs have come in at or above the 70° mark. Guess what? That's 5 more 70° days than what we had at this point last year.

Officially, the Rockford Airport peaked at 71°, tying the record high set in 1990. While record warmth will be out of our reach today, we can expect to add another 70° day to the tally. 

A warm southwesterly breeze lingered overnight, leaving us in the upper 40s and low 50s. This warmer start is going to lead to another unseasonably warm afternoon with highs in the low 70s. 

Our forecast high of 73° is a handful of degrees away from our record high of 78° set in 1990. In a similar fashion to Monday, winds become windy, gusting up to 30 mph during the afternoon.  All remains dry ahead of a weak disturbance that may bring the area a shower or two overnight. Overall, the best chance is for any rainfall will be to the south of I-88. 

Sliding in behind tonight's disturbance is a ridge of high pressure which will keep things under control for the middle of the work week. 

Although we're not expecting a third 70° day, highs will still manage to climb into the upper 60s under a mix of clouds and sunshine. It's also during this time where a backdoor cold front to our south will turn into a warm front. The position of this warm front will determine two things, 1. how warm we get on Thursday. And 2. Thursday's storm chances. 

Earlier this morning, the Storm Prediction Center placed areas to the south and west of Rockford under a level 2 of 5 Slight Risk. The rest of the region is under a level 1 Marginal Risk. 

Again, this would be for the late afternoon and evening hours on Thursday. If everything were to come together, all severe hazards would be on the table. For now, it will be important to keep an eye on forecast as Thursday approaches.