Cooler Thursday, Storm Chances Arrive Late Saturday

Spring-Like Stretch: 

Weather-wise, it couldn't get any better than what the Stateline witnessed over the last 3 days. Warmer starts have led to unseasonably mild afternoons, with highs feeling more like early-spring than late-winter. But as the saying goes, all good things must come to an end as a cold front Wednesday evening has brought a big shift in our weather pattern for Thursday. 

Cooler Thursday:

Behind yesterday's frontal passage, our surface winds shifted to the north, allowing a colder air-mass to filter into the Stateline. Temperatures early Thursday are sitting in the mid to upper 20s, landing a few degrees lower than previous mornings. This cooler start will spell a MUCH cooler day overall as highs peak in the upper 30s under a mostly cloudy sky. 

Guidance continued to show a little moisture streaming in above the surface, which may lead to a passing flurry or two. But with plenty of low-level dry air and dew points in the single-digits to lower teens, it may be hard for any chance of precipitation to reach the surface. Similar to last night, skies remain mostly cloudy tonight, with temperatures falling to seasonable levels by Friday morning. 

Saturday's Storm Potential:

Our weather pattern then turns a bit more active as we head into the weekend. Following a relatively quiet and warmer Friday, a potent storm system over the Midsection of the U.S is expected to bring rain and storm chances late-Saturday. Most of Saturday looks to remain dry, with our best chance for precipitation arriving by Saturday evening and Saturday night. Showers are extremely likely during that time, and the chances for a few rumbles of thunder and heavy downpours are still very much in the conversation..

Earlier this morning, the Storm Prediction Center has placed the eastern half of Iowa under a Slight Risk (level 2 of 5) for severe weather. This is where the best forcing will be as the surface low as the surface low itself will be tracking into the southwestern and western Iowa. 

On the outskirts of the Slight Risk, a Marginal Risk (level 1 of 5) is in place which does cover a good chunk of the Stateline. This is for areas along and west of I-39, with gusty winds and even small hail in some of the stronger storms. Similar to how we conduct a forecast for winter weather, the forecast is subject to change as we're still roughly 48 hours away from the event. But this is a good time to catch up on your severe weather safety plan. Or better yet, introduce one if one isn't in place.

Illinois Severe Weather Preparedness: Weather Hazards

 

As Illinois Severe Weather Preparedness week continues it's important to understand the types of weather hazards that occur with thunderstorms: tornadoes, hail, lightning, wind and flooding.  All of these hazards can not only be very destructive, but they can also be very deadly.  Even when a storm is not considered 'severe' the lightning with the storm can be very dangerous.

In order for a thunderstorm to be considered severe,

certain criteria must first be met.  Hail stones reaching a quarter size in diameter (one inch) and wind speeds over 58 mph help to classify a storm as severe.  The larger the hail stone and/or stronger the wind, the stronger the thunderstorm.  There is no criteria for a storm that has heavy rainfall or frequent lightning to be considered severe, but still those storms can be very dangerous.  Heavy rain can lead to flash flooding which is the second leading cause of weather related fatalities, following heat.

Whenever you hear thunder or storms are close by, it's important to seek shelter until the storm has passed.  If you can hear the thunder, you are close enough to get struck by lightning.  Remember the saying, 'When thunder roars, go indoors'. 

Temperatures near 60 degrees Wednesday afternoon

For the third day in a row the high temperature reached 50 degrees or higher, with Wednesday's high topping 58 degrees.  This was roughly twenty degrees above average; upper 30s is average for the beginning of March.  But those warm numbers will drop back through the evening as a cold front moves in from the north.  Already temperatures across southern Wisconsin have fallen through the low 40s.

As the cold front pushes south a few scattered light showers are possible through 8pm/9pm.  After that, temperatures will continue their fall down into the low 20s for the start of Thursday.  Highs Thursday afternoon are only expected to reach the mid 30s, but will rise into the low 40s Friday.  We'll see the temperatures rise once again heading into the weekend, reaching the low 60s for Saturday afternoon.  Long range outlooks, however, are favoring a higher probability for below average temperatures that would take us through mid-March.  As for precipitation, outlooks are also favoring a slightly higher probability for above average precipitation.  This could mean more snow potential, but that will depend on overall temperatures during that time.

Severe Weather Safety: Knowing Where and Where Not to Take Shelter

Taking Shelter At Home:

Severe weather can occur at any point in the year, but is mostly favored during the months of April, May, and June in northern Illinois and southern Wisconsin. Again, the key to tornado survival is having a safety plan practiced and in place so that you're ready when severe weather threatens.

Your safety plan should be known by everyone in the house and practiced at least twice to three times each year.  Remember, when orchestrating a severe weather safety plan, the location of your safe place should be either on the lowest floor of the home, preferably a basement, or the innermost room. 

Such as a bathroom, an interior closet, or the space underneath a staircase.You want to have as many walls in between you and the outside as possible for maximum safety. Avoid taking shelter next to doors, windows, and exterior rooms. It's these areas in a home that are more susceptible to the fast-moving debris in the wind generated by the tornado. 

Caught on the Roads:

Now, being in a vehicle is a terrible place to be when the threat for severe weather or a tornado is present. If faced with a severe threat while on the road, your best course of action will depend on your exact location, the timing of impact, road options available, and nearby structures. 

If the severe thunderstorm activity or tornado is far enough away from your location and road options are allow, you should try to find a sturdy and firmly built structure for shelter. One thing you shouldn't do is take shelter underneath an overpass. A lot of the time people think that this is a way to minimize the damage to their vehicle and lower the risk of injury or death. This is definitely NOT the case. In fact, taking shelter underneath a bridge or an overpass exposes you to higher wind speeds. Any debris that is picked up by the wind produced by a storm or a tornado will become channeled underneath, increasing the risk for injury. 

More importantly, your parked car could block traffic or block the path of emergency vehicles trying to get to the injured. The First Warn Weather Team will continue to provide information throughout the week, highlighting severe weather terminology, safety, and ways to receive watches and warnings.  For more on severe weather preparedness, you can always visit Chicago National Weather Service.

Spring-Like Stretch Continues, Cooling Down into Thursday

Spring-Like Stretch:

Fortunately, our weather pattern has felt more spring-like as we made the jump from meteorological winter to meteorological spring. The Rockford International Airport has come in with an average high of 52.5° the past two days, landing 10°-15° above average. This little taste of spring is expected to last one more day before a "stronger" cold front cools us back down into the second half of the week. 

Mild Wednesday:

The day kicks off under a mostly cloudy sky as a weak disturbance slides to our west. Guidance does pull in enough moisture for a few widely-scattered sprinkles and drizzle during the morning hours. With our regional temperatures sitting in the low 30s, I wouldn't be surprised if this morning's precipitation chances fell as freezing drizzle. 

Thankfully for those heading out, road temps will be way too warm for any slick spots to form. Despite the fact that today features a bit more cloud cover than the past two days, the sun will make an appearance from time to time. High temperatures Wednesday will likely reach 50 degrees, but then are expected to fall back even further behind yet another cold front Wednesday night and Thursday.

Colder Thursday:

Behind Wednesday's system, northeast surface flow will be in place, bringing a much colder day for Thursday. Highs will take a 15° to 20° drop, with most landing in the mid to upper 30s. Cloud cover is expected to stick around for much of the day, with a few flurries possible. This upcoming cool-down is brief as temperatures will climb back into the low 40s for the end of the work week. 

Rain and thunderstorm chances return by the weekend

As we close out the books on Meteorological Winter and begin Meteorological Spring, the weather around the Stateline definitely felt more spring-like Tuesday afternoon.  Back to back 50 degree days Monday and Tuesday could be met with another 50 degree day Wednesday before temperatures drop back by the end of the week.

There has been a gradual increase in cloud cover Tuesday evening, and those clouds are expected to

further increase through the night.  A cold front passing through the Midwest earlier in the day will begin to be pulled back north as a warm front Wednesday morning.  High temperatures Wednesday will likely reach 50 degrees, but then are expected to fall back even further behind yet another cold front Wednesday night and Thursday.  A few sprinkles or a quick passing shower are possible Wednesday afternoon, with a few flurries into Thursday.

A stronger storm system will move in towards the end of the week, pulling the cold front back north as a warm front Friday night.  Behind the warm front lies quite a bit of warmth as temperatures Saturday *could* come closer to 60 degrees during the afternoon.  But with that warmth also comes an increase in moisture.  Very high levels of moisture for the beginning of March are forecast to be in place Friday night and Saturday afternoon.  As low pressure nears the Stateline from the west, scattered rain showers will develop late Friday night, continuing into Saturday afternoon and evening.  Heavier rainfall, with even the risk of thunderstorms, will also be possible as both a vigorous upper level and surface low move across the Midwest.  By Saturday night/early Sunday a cold front will have moved through, but temperatures for Sunday won't fall immediately behind the front.  Scattered showers will also be possible for Sunday afternoon, followed by another low that looks to move in late Sunday night and Monday.  Depending on the track of this low, a little more wintry weather may occur.

The increase in moisture, warmth and overall instability Saturday could lead to the potential for strong/severe storms over parts of Iowa during the afternoon and evening, with an elevated risk for damaging winds.  Right now areas west of the Mississippi River need to monitor the potential for severe weather for the weekend.  Locally, our risk remains low but the timing of the cold front will determine if we could see a few stronger storms Saturday night.  Localized flooding may become a concern if the heavier rain showers do occur Saturday night.

 

Unseasonably Mild into Wednesday, Briefly Cooling Down for Thursday

Meteorological Spring:

Not only was yesterday the end of February, but it also marked the end of Meteorological Winter. And what a way for meteorological winter to go out huh? The combination of yesterday's beautiful sunshine and organized southwest wind allowed high temps to peak on either side of the 50-degree mark. Despite a frontal boundary sliding trough this morning, this seasonably mild and comfortable weather pattern is here to stay into the middle of the week. 

More of the Same:

Along with a shift in our surface winds, this morning's cold front will bring a small chance for patchy drizzle or a few sprinkles. 

Guidance continued to keep a chance into the mid-morning hours, with dry and cloudy conditions lingering into the lunch hour. Behind the departing front, clouds will somewhat clear, allowing for another partly sunny and mild afternoon. Highs for most will end up in the upper 40s, landing 10° to 15° above the average high for the beginning of March. Clouds thicken up overnight, with temperatures landing in the upper 20s and low 30s by Wednesday morning.

Wednesday's Cold Front:

Ahead of a secondary cold front, Wednesday features another mild afternoon with highs on either side of the 50-degree mark. Forecast models this morning did show enough moisture for a few sprinkles to pop-up from time to time. 

The difference with Wednesday's frontal passage is that it will actually have a cold air-supply to go along with it. This will help briefly drop our high temps from the low 50s Wednesday to the mid to upper 30s on Thursday. Lingering moisture will warrant the chance for a few passing flurries. Otherwise, conditions remain relatively quiet ahead of a potent system that formulated over the Midwest, bringing the Stateline rain and thunderstorm chance by this weekend.