Illinois Severe Weather Preparedness Week

Monday, February 28th, through Friday, March 4th, is Illinois Severe Weather Preparedness Week.  During this times it's a good idea to freshen up on your severe weather safety plans.  If you don't have one, it's an even better time to put one together!

Severe weather can occur any time throughout the year, but is most favored during the months of April-June in northern Illinois.  But as the January, 2008, Poplar Grove tornado and November, 2010, Caledonia tornado showed us severe weather and tornadoes can occur even in the 'off-season'.  In fact today, February 28th, marks the 5 year anniversary of the tornado outbreak that occurred in northern and central Illinois.  According to Chicago National Weather Service there were ten tornadoes that occurred in northern and central Illinois.  Two of those tornadoes, rated EF-1, occurred in Ogle and Whiteside counties near Oregon and Coleta.  This is just another example highlighting severe weather during the colder seasons.  The more favored time of day for severe weather and tornadoes to occur is typically between 3pm and 10pm, but severe weather can occur at any time of the day.  Damaging winds and flash flooding often times occurs with more overnight severe weather.

During severe weather preparedness week take time with your family to review your severe weather safety plan.  If you don't have one, now is the time to put one together.  Along with making sure you have safety procedures to follow at home, make sure they are in place at work, school, while on the road, etc.  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. 

 

Rather Quiet Week Ahead, Best Chance for Rain Arrives This Weekend

Moving Right Along:

Before we get into the forecast for this week, I would like to welcome you all to the last day of meteorological winter! That's right folks. We'll be jumping into the meteorological spring season once the clock strikes midnight tonight.  

Meteorological spring consists of the three month period of March, April and May. At the beginning of March the average high temperature is right around 40 degrees. But by the time we get to the end of May the average high temperature is in the mid to upper 70s. Looking at the week ahead, much of it will be spent under dry conditions and mild temperatures. 

Mild Monday:

High clouds kicks off our Monday, with sun peeking through during the afternoon. The sunshine, along with an organized southwest wind, will help our highs climb into the mid 40s. Despite the clearing that takes place, clouds will be rather quick to gather right back up overnight as a cold front approaches from the Upper Midwest. 

Even with the cold front sliding through early in the day, highs once again are expected to top out in the mid to upper 40s. Similar to today, most of your Tuesday features a partly to mostly cloudy sky, with a sprinkle or two possible early on.

Rather Quiet Work Week:

Guidance shows another cold front sliding through Wednesday evening into Wednesday night. This one having a little more "oomph" to it, allowing a rush of cold air to filter in for Thursday. Highs will fall from the mid 40s to the upper 30s which ends up a couple of degree below-average. 

Warmth re-surges ahead of a lifting warm front towards the end of the work week, placing highs in the low 40s for Friday. As a potent and organized system slides into the Midwest, moisture will increase significantly into Saturday, bringing not only rain chances but also thunderstorm chances Saturday night. 

Above average temperatures to end February

 

Temperatures over the last weekend of February warmed into the 30s and 40s, reaching 41 degrees Sunday afternoon in Rockford. While not significantly above average - average high is 38 degrees - the abundant sunshine made it feel fairly comfortable as we near the end of Meteorological Winter. Meteorological Spring begins Wednesday, March 1st, and is the transition period between Meteorological Winter and Summer. It consists of the three month period of March, April and May. At the beginning of March the average high temperature is right around 40 degrees. But by the time we get to the end of May the average high temperature is in the mid to upper 70s.

The last two days of the month will continue to feature slightly above average temperatures with highs rising into the low to mid 40s; both 45 degrees Monday and Tuesday. The warm up is the result of several fast moving, but mostly dry, low pressure systems moving in from the northwest.

A big ridge of high pressure over the West has positioned the jet stream pretty much right over the Plains and Midwest. This sets up a fairly favorable area for these storm systems to move along. A cold front passing through Sunday will quickly be pulled north as a warm front Monday morning. This will shift surface winds back around to the southwest for much of the afternoon. Another cold front will move through Tuesday before being pulled back north as a warm front Tuesday night and Wednesday. Moisture with each passing system appears to be relatively weak, limiting any precipitation chances in the short-term.

There may be some light precipitation Wednesday into Thursday as a cold front slides through Wednesday afternoon, stalling just to the south Thursday morning. With a cooler air mass behind the front a chance for a few flurries could be possible during that time.

By Friday afternoon a strong storm system will build across the center of the country as the jet stream is forced back north over the Great Lakes.

This is due to a deep trough (dip) in the jet stream over the West Coast - a pattern flip from earlier in the week. A draw of warm air ahead of the low will be pulled into the region Friday night and Saturday, but so will a significant amount of moisture. Showers are likely to develop during that time, initially beginning Friday night. Surface temperatures may be just cool enough to support some mixed precipitation, especially north of the state line, into Friday evening. Then rain showers will last into Saturday, along with the chance for a few thunderstorms.

More warmth and sunshine this week

 Today was a very pleasant day with lots of sunshine and warmth. We made it into the 30s despite starting the day in single digits for the morning low temperature. A very large area of high pressure situated over Southern Illinois and Eastern Missouri helped to keep skies clear and winds fairly light. As that high pressure moved further East, winds picked up a little bit out of the Southwest here across the Stateline.

Those clear conditions will continue once again tonight, as we will see clear skies once again this evening. The good news with that, is that temperatures will not be nearly as cold as they were last night with all the colder conditions. Temperatures will only make it down to the low 20s and upper teens around here, with a lighter wind than last night.

Tomorrow, temperatures will rebound even further, getting up to the mid and even upper 30s. We will once again see very bright and sunny skies, and even less wind than there was today.

The next time we see much of anything as far as cloud cover is not until Monday. Most of those clouds will be upper level clouds, but we remain holding on to partly cloudy skies. Temperatures will even warm into the 40s.

The warmth and calm conditions will continue for a few more days beyond that, mainly due to the upper level pattern in the jet stream helping to support the high pressure off to the Northwest. This strong high pressure will help to keep storm systems mainly either North or South of the Midwest, dur to the split flow in the stream.

This is set to change near the end of next week, as the jet stream shifts and the high pressure erodes away. This will change the flow of the jet stream and therefore allowing any potential storm tracks to move through the Stateline. The pattern will shift to a more active one beginning next weekend.

Speaking of that active pattern, the Climate Prediction Center has identified the area as a more active one, predicting above average precipitation in the period between 6 and 10 days from now.

They are also predicting above average temperatures, so likely we will see some rainfall as opposed to snow.

But in the short term, the calm and quiet conditions continue. There is a very slight chance for precipitation on Thursday, the main pattern shift is not until next weekend.

Slippery Travel Likely Friday Morning, Tranquil Weather Arrives for the Weekend

Road Check: 4:30AM

As our snow chances wind down, roads are either mostly or completely covered with the fluffy snow that fell overnight. The Department of Transportation is reporting that the worst road conditions are being observed along and east of Interstate 39 and Interstate 90. 

If you plan to travel this morning, please allow for extra travel time and also take it VERY slow. Keep in mind also that the potential for blowing and drifting snow will be present throughout the morning hours, especially on east and west roadways. 

Road Check: 6:30AM

Over the last hour, we've seen slight improvements in road conditions across the region, especially for the counties that hug the Illinois/Wisconsin border. Most of the region however is still under the mostly covered category, with the worst conditions being felt across Ogle and Dekalb counties. 

Tranquil Moving Forward

An area of high pressure is expected to slide in behind Thursday's snow-maker, bringing a drier forecast for our Friday. Cloud cover early on is expected to break apart by this afternoon, allowing for mixed sunshine. However, because of the fresh snowpack and limited sunshine, highs remain seasonably chilly in the mid to upper 20s. 

Temperatures then cool down into the lower teens overnight, with plenty of sunshine returning for the first half of the weekend. Thanks to an organized southwesterly wind, highs are expected to climb closer to seasonable by Saturday afternoon, peaking in the low to mid 30s. 

Despite the fact a cold front slides through early Sunday, highs will end up above-average by a few degrees. The cold front will come through dry, just bringing a few more clouds to the area. But by Sunday afternoon, partial sunshine is expected with dry conditions carrying on into next week.

Winter Weather Advisory Issued, Steady Snow Moves In This Evening

Winter Weather Advisory:

Thursday kicks off with a couple of flurries. But thankfully that won't bring any impacts to those heading out for the morning commute. It's during the evening commute where you'll want to take extra caution as a more pronounced and steadier snowfall moves in, making for hazardous travel. For that, the National Weather Service has placed the entire viewing area under a Winter Weather Advisory from 3PM today until 6AM Friday. 

Timing Out the Snow:

Guidance continues to show snow beginning during the mid to late afternoon hours, with chances remaining likely into tonight. During the very early stages of Friday, the snow will depart to our east, leaving us under a mostly cloudy sky. With the nature of tonight's snow being light and fluffy, it won't take much for roads to become slick and snow-covered, especially with how cold road temperatures are at the current moment. Extra caution will be necessary for those traveling this evening and then again for those heading out the door Friday morning. 

Snowfall Comparison:

When it is all said and done, we'll be waking up to a fresh swath of 1"-3" come Friday morning, with a few 4" totals residing near Lake Michigan. This upcoming snowfall however won't nearly be enough to take a nice-sized bite out of our massive snowfall deficit. As of this morning, Rockford has only observed 14.1" of snow since December 1st, landing roughly 13" below average. It's also well below our seasonal snowfall from at this point last year as we we're sitting at 32.8" by February 24th. 

With an area of high pressure sliding to our northwest, Friday morning 's cloud cover will give way to mixed sunshine by the afternoon. Temperatures, mainly because of the limited solar radiation and fresh snowpack, are expected to peak in the mid to upper 20s.

Cold Wednesday Ahead, Snow Chances Return Late Thursday

Cold Wednesday: 

Tuesday featured a mixed bag of everything thanks to a complex storm system sliding to our south. While yesterday's headache is behind us, impacts will still be felt during the early stages of Wednesday. Not necessarily with the main roads, but parking lots, sidewalks, bridges, overpasses, side streets and back roads will be most susceptible to icy spots this morning. 

On the backside of Tuesday's storm, northwesterly winds sent temperatures and wind chills tumbling, making for a bitterly cold start to our Wednesday. In fact, temperatures are sitting 20-25° colder compared to Tuesday morning. Kids heading back to school, and those heading into work this morning will need to "dress for the weather" before they step out. Despite the potential for mixed sunshine this afternoon, highs will struggle to climb out of the low 20s. With winds remaining out of the northerly direction, wind chills remain in the teens.

Next "Hiccup":

Clouds are expected to thicken up Thursday ahead of our next chance for wintry precipitation. With a very cold air-mass firmly in place, this upcoming chance will be more than likely in the form of fluffy snow rather than a wintry mix. It won't be until the late-afternoon/early evening hours in which snow will begins to fall, meaning conditions for much of the day remain dry.

Snow is then likely going to continue for much of the night, lingering into the early stage of Friday. This will likely bring a few headaches for those traveling during Friday's morning commute. Models have remained consistent over the past few days when it comes to snowfall totals, placing a swath of 1"-3" across the Stateline. 

If Rockford picks up more than 1.2" of snow, this upcoming event would place in the top 5 for highest daily snowfall totals this season. Yes, you heard me correctly. I said top 5. The highest daily snowfall total observed at the airport this winter was 4.3" back on New Year's Day. Cloud cover is expected to linger for much of Friday, with a passing flurry or two possible during the afternoon. Highs look to remain in the 20s for the rest of the work week, climbing into the low 30s for the upcoming weekend.

Icy conditions continue Tuesday night

 

The rain, freezing rain and freezing drizzle has come to an end Tuesday evening, but the icy and slick conditions will remain as temperatures continue to fall through the low to mid 20s.  A Winter Weather Advisory was extended to include all of northern Illinois Tuesday morning, and still remains in place for Winnebago, Boone, Ogle, Lee, DeKalb and McHenry counties until 7pm due to those icy conditions.  A few flurries may be possible through the evening as temperatures continue to cool.

The icy and slick conditions will continue into Wednesday morning as temperatures are expected to drop into the low teens.  Parking lots, sidewalks, bridges, overpasses, side streets, back roads, etc will be most susceptible to the ice as any residual moisture from the morning and afternoon freezes. Main and well traveled roads may not experience as much of an impact.  Be careful when out traveling, especially now that it is dark.  Roads that appear wet may actually be iced over.  This is known as black ice.  Temperatures through Wednesday and Thursday will remain below freezing.

Dense Fog, Heavy Rainfall Set to Bring Messy Travel Tuesday Morning

Winter Weather Advisory:

Earlier this morning, the National Weather Service added a few more counties have been added to the WINTER WEATHER ADVISORY. This includes Winnebago, Boone, and McHenry Counties and this portion of the advisory will run from 8AM this morning to 4PM this afternoon. This is mainly due to the chance for freezing rain early on, which may lead to a few icy spots on the roadways.

Flash Flood Watch:

Although nothing has changed with the FLOOD WATCH that's in place this morning, Winnebago, Boone, Ogle, Lee, DeKalb, and McHenry counties remain under the FLOOD WATCH until mid-day today. Heavier rainfall rates, especially those produced by any thunderstorm that develops, could result in flooding issues in low-lying and flood-prone areas. We also have to take into account the runoff produced by this morning's rainfall. This will likely cause some of the local rivers, streams and creeks to rise.

Dense Fog Advisory:

In addition to the Winter Weather Advisory and the Flood Watch, Ogle, Lee, and Dekalb Counties are also under a DENSE FOG ADVISORY until 10AM this morning. Visibility values could be lower than a mile at times until the expiration of the advisory. And due to showers and thunderstorms passing over the area during the early morning hours, visibility may fluctuate while traveling over short distances. 

What to Expect:

A frontal boundary draped over the Stateline Tuesday morning is the main culprit behind this morning's messy weather. This potent boundary is acting as a divider between the cold air to the north and the warmer air-mass to the south. 

Areas north of the frontal boundary, those that live along and north of highway 20, will be more susceptible to the potential for mixed precipitation. Hence why areas hugging the Wisconsin/Illinois border are placed under the Winter Weather Advisory. Ice accumulations of a tenth of an inch, to at the highest two tenths of an inch. Rainfall-wise, amounts will range from a quarter of an inch, all the way to three quarters of an inch, especially those that encounter this morning's thunderstorm potential.

The chance for heavy rain continues into the late-morning/mid-day hours, with showers slowly tapering off by mid-afternoon. On the backside of this complex storm system, a light and scattered mix of rain and snow will be possible before we dry out by this evening. 

Even with the precipitation coming to an end, I still urge you to take extra caution if you plan to travel prior to the evening commute. Conditions remain dry overnight, with skies remaining mostly cloudy into the early stages of Wednesday. As an area of high pressure takes control of the Upper Midwest, tomorrow morning's clouds will give way to some afternoon sunshine. Despite that, a northerly to northwesterly wind will limit highs to the 20s, which is more than ten degrees below normal.

Freezing rain and heavy rain possible through Tuesday

 

A WINTER WEATHER ADVISORY has been issued for Walworth County in southeast Wisconsin beginning at 6pm Monday night and for Green and Rock counties in south-central Wisconsin beginning at 11pm.  the advisory will also go into effect for Stephenson and Jo Daviess counties at Midnight, lasting through Tuesday afternoon.

A FLOOD WATCH has been issued for Winnebago, Boone, Ogle, Lee, DeKalb and McHenry counties beginning at Midnight and lasting through Tuesday morning.

A complex winter storm system is moving across the middle of the country Monday evening, bringing heavy snow to the northern Plains and far Upper Midwest, while heavy rain falls further south.  Sandwiched in between is the Stateline, set to receive a combination of both freezing rain and heavier rainfall Monday night into Tuesday.  Cloud cover will continue to thicken through Monday evening as moisture streams into the region.  Areas of drizzle and fog are likely to develop over the next couple of hours before a steadier rain moves in after 9pm/10pm.

Temperatures are slowly beginning to trend down, falling through the mid 30s north of Rockford.  However, as warmer air surges northward ahead of an approaching low it'll help draw a little of the warmer air back north.  This should help bring temperatures back up above freezing through most of the overnight and into the beginning of Tuesday.  The exception may be right along the state line, north of Highway 20, and into southern Wisconsin where temperatures will be border line freezing, and slightly below.  In those areas the risk for freezing rain will be higher through Tuesday morning and afternoon. 

Ice accumulations of a tenth of an inch, to at the highest two tenths of an inch, are possible in the counties under the Winter Weather Advisory.

For areas south of Highway 20 there could be some freezing rain that mixes in Tuesday morning, but of greater concern will be the heavy rainfall.  With the Flood Watch in place for counties south of Highway 20 heavier rainfall may cause excessive runoff, leading to localized flooding in some areas,

especially low lying and flood prone locations.  The runoff will also cause some of the local rivers, streams and creeks to rise.  Ice jam flooding may also occur from the rising rivers and the ice breaking apart.  Rainfall amounts will range from a quarter of an inch, all the way to three quarters of an inch, perhaps an inch, between now and Tuesday afternoon.  Thunderstorms may also occur during the overnight and early Tuesday which would increase the risk for heavier rainfall during that time.  Some of the storms could also produce some small hail.

Temperatures will slowly begin to trend downward throughout the day Tuesday, falling into the teens Tuesday night.  For areas that are under the Winter Weather Advisory, slick conditions due to ice accumulations are possible.  Please take extra caution while out Tuesday morning and afternoon!

    

Winter Weather Advisory Issued, Icy Start to the Work Week

Winter Weather Advisory:

As of early Monday morning, Winter Storm Warnings span from W. Montana to NW Wisconsin for heavy snow accumulation through Tuesday. Locally, it'll be the threat for mixed precipitation that may cause a few headaches on the roads. 

For that reason, the National Weather Service has placed Green, Rock, and Walworth Counties in S. Wisconsin, along with Jo-Daviess and Stephenson Counties in N. Illinois under a Winter Weather Advisory. The advisory for our three S.Wisconsin counties will be in effect from 5PM this evening up until 6 Tuesday evening. For Jo-Daviess and Stephenson Counties, the advisory will be in effect from midnight tonight until 2PM Tuesday afternoon. 

Timing Out the Mess:

President's Day starts off dry, with temperatures sitting in the upper 20s and low 30s. But by the late afternoon/early evening hours, light rain will begin to move in from the southwest. 

Overnight, temperatures are expected to cool back into the low 30s, which will allow for a transition to mixed precipitation. Once the transition occurs, wintry mix chances are set to continue into the early stages of Tuesday, though there will be breaks in the action. Travel-wise, significant impacts aren't expected for the commute this morning. Though it would be a good idea to use extra caution if your schedule takes you into work tonight or Tuesday morning.

With northeast flow remaining dominant on Tuesday, temperatures are only expected to top out in the low to mid 30s. This will be cool enough for precipitation to remain in the form of freezing rain/sleet/snow into the afternoon hours. 

The brunt of this icy stretch looks to occur across southern Wisconsin where spots could pick up 1/4". For areas along highway 20, the most you could see is 1/10", with little to no accumulations occurring south of the highway. Behind this storm system, cold air filters into the Stateline for Wednesday, resulting in highs in the low 20s. However, sunshine returns thanks to a strong high pressure system over the Upper Midwest.

Wind Advisory Issued, Winds Ramp Up Again Late This Weekend

Blustery Friday:

After another missed opportunity for the Stateline to see accumulating snow yesterday, our attention now turns to the threat for gusty winds. Earlier this morning, the National Weather Service placed the counties that hug the Illinois/Wisconsin border under a Wind Advisory. 

This advisory will be in effect from 2PM this afternoon to 3AM Saturday morning, with gusts peaking around 35-45 mph. Thankfully, winds won't be an issue for the morning commute. However, that can't be said for the drive home as the strongest winds will be sliding into the Stateline during that time. You may want to take extra caution, especially if you travel in a high-profile vehicle. Another impact to look out for is the threat for blowing and drifting snow, especially if most of your travels occur in open areas.

Few Late-Day Flurries:

The same disturbance that will bring us blustery conditions later on today will also bring the chance for a few late-day flurries. Chances look to come to an end as we enter the overnight hours. However, the strongest winds look to stick around into the early stage of Saturday morning.

Once today vigorous and quick-moving system is over the northern Great Lakes, skies will begin to clear, resulting in another bitterly cold morning to kick off the weekend. The difference with tomorrow's cold is that the lingering gusty wind will allow wind chills to bottom out between -10° to 15°. Despite the cold, high pressure settles in for the first half of the weekend, resulting in plenty of sunshine throughout the day. However, highs will take a quick hit thanks to the cold front sliding through this evening, with most peaking in the low 20s.

No Break From the Wind:

Gusty winds make a return for Sunday, this time being out of the southwest. This will allow a big-time warm-up to ensue, allowing highs to climb from the low 20s Saturday to near 50-degrees by Sunday afternoon. 

Along with the warm-up, dry weather continues, with clouds slowly increasing into Monday night. This is all ahead of another storm system that looks to impact the area early next week, bringing a chance for mixed precipitation. At the same time, temperatures will enter a cooling trend, landing in the upper 20s by the middle of the week.

Slippery Travel Possible, Flurries Return Friday

Slick Spots Possible:

As we've been hinting at throughout the week, there was a big possibility that the Stateline would miss out on another winter storm. Unfortunately for the snow-lovers around the area, that possibility has become reality. Earlier this morning, the National Weather Service took Whiteside, Lee, and Dekalb counties out of the Winter Weather Advisory, while also shifting the Winter Storm Warnings south of I-80. Locally, slick and icy spots will be possible. Not only because of the mixed precipitation that passed through after midnight, but also because of the moisture left behind by yesterday's rain. With temperatures plunging behind yesterday's cold front, any moisture laying on the roads could freeze, resulting in slippery travel. 

Wind-Whipped Snow:

Our Thursday starts off cloudy and breezy. As we approach mid-day, guidance does bring the second wave of precipitation into the area. Much of what falls locally will be light. 

But because of a gusty wind out of the north and northeast, blowing and drifting snow will be likely throughout the afternoon and into the early portion of the evening commute. Snow chances look to come to an end early this evening, leaving us with a mostly cloudy sky going into the overnight hours. As high pressure settles to our west, skies will clear some, allowing skies to turn partly cloudy by tomorrow morning. Along with the clearing does come a shot of very cold air, which will bringing our overnight lows into the single-digits. 

Late-Day Flurries:

Despite the bitterly cold start to our Friday, we'll see a good amount of sunshine early on. Clouds will gather up somewhat during the afternoon as our next disturbance swings into the northern Great Lakes from the Canadian prairies. Guidance shows a chance for a few flurries arriving Friday evening, lasting into the early hours of Friday night. 

Highs remain in the 20s for the first half of the weekend, with winds picking up out of the south and southwest for Sunday. That will allow highs to reach the mid to upper 40s before dropping back into the 30s for early next week! 
 

Wintry mix follows rainfall Wednesday; Slick spots possible Thursday morning

 A WINTER WEATHER ADVISORY has been issued for Whiteside, Lee and DeKalb counties beginning at Midnight Wednesday and lasting through 6pm Thursday.  A very warm Wednesday afternoon with strong winds from the south brought temperatures into the low to mid 50s.  The high temperature in Rockford reached 55 degrees, just two degrees away from a record high of 57 degrees set back in 1921!

But temperatures are beginning to fall behind a cold front that is moving across northern Illinois and southern Wisconsin, shifting winds around to the west and northwest.  Scattered rain showers will continue for the remainder of the evening before transitioning over, and mixing with, a little freezing rain and sleet.

This transition looks to take place between 9pm and 10pm, first across the southwest and west before stretching east and northeast around Midnight.  This will occur as temperatures slowly fall to the freezing mark.  After Midnight temperatures will continue to fall as snow slowly begins to mix in on the backside.  This looks to take place between Midnight and 2am/3am.  Some minor accumulations are possible with the snowfall.

A drying north wind will move in early Thursday leaving us mostly dry during the morning.  However, residual moisture from the rain Wednesday, along with any light freezing rain or snow that may accumulate, could cause some icy spots during the morning commute.  This will need to be something you keep in mind while out traveling.

The break in the precipitation doesn't last all day as

the second wave of low pressure moves into southern Illinois during the afternoon.  This will cause snow to spread in from the south, reaching northern Illinois after Noon.  Accumulating snowfall does appear likely for some across the region, with a couple inches falling within the counties under the advisory.  Outside of that, snow totals look to remain light.  Having said that, winds will be increasing from the north during that time causing some issues with blowing snow as it falls.  As a result, visibility could be reduced during the

afternoon and early evening commute.  Skies are expected to dry out towards Thursday evening as temperatures tumble through the single digits Friday morning.