Clouds increase Wednesday as rain moves in Thursday

 

Tuesday was an absolutely beautiful Fall afternoon with temperatures warming into the mid and upper 50s, officially reaching 59 degrees in Rockford; a typical Fall afternoon.  Following a few clouds early in the day, skies have remained clear for much of Tuesday night which will allow temperatures to fall back into the 30s overnight.  Patchy frost will be possible early Wednesday.

As high pressure slides further east Wednesday, cloud cover will quickly advance in from the west.  These clouds are associated with an area of low pressure, currently moving into the southern Plains and bringing a line of severe thunderstorms extending from Texas into south-central Nebraska.  Severe weather remains over the Plains Tuesday evening and then will shift across the southern states Wednesday.  As moisture slowly begins to work in from the west, cloud cover will continue to increase locally as winds remain from the south and southeast bringing temperatures into the upper 50s, to near 60 degrees, during the afternoon.

Low pressure will travel from eastern Colorado Tuesday night to far southern Illinois Thursday night.  Moisture wrapping up and around the low into northern Illinois and southern Wisconsin will allow an expansion of showers to develop, increasing in coverage Thursday afternoon and evening.  While a few lighter showers may be possible Thursday morning, it does look like that time should be dry.

Rainfall amounts won't be quite as much as what we received Sunday and Monday, adding up to between a quarter of an inch to half an inch.  There may be a few locations that receive slightly higher amounts but those look to be for areas closer to Lake Michigan, and caused more by lake effect.

Northeast winds will increase as well, gusting 30-35mph Thursday night into Friday morning.  The stronger wind gusts will continue for the first half of the day.  Rain showers may also linger through Friday afternoon but it looks like we should be drying out, but remaining cloudy, Friday night.  High pressure and a cold front arrive for the weekend which will help keep us dry, but we may see a few more clouds from time to time.

High Pressure Brings Short-Lived Break From This Rainy Weather Pattern

Month vs. Month:

Remember when Rockford posted it's 9th driest September on record? Well, that is now a thing of the past, considering the fact that our total monthly rainfall for October sits at a staggering 4.86". This currently ranks 7th for wettest Octobers on record. While it's safe to say that your rain gear can take a break and remain at home today, it'll be wise to dress warmly before you head out.

Quiet, Less Windy Tuesday:

Radiational cooling was in full-effect Monday night, thanks to an area of high pressure approaching from the west. This has resulted in a much cooler start to our day, with most of us landing in the mid to upper 30s. For those that end up closer to the freezing mark of 32°, you may walk out to the sight of patchy frost. Thankfully, this brisk and fall-like start doesn't spell the forecast for the rest of our Tuesday. 

Under plenty of sunshine, temperatures are expected to climb to seasonable levels, in the mid to upper 50s. With high pressure continuing to settle in, rain chances stay away for not only today but for much of Wednesday. Guidance does show we glide into the overnight hours tonight under a mostly clear sky, with a few more clouds moving in by tomorrow morning. This is all in response to our next storm system that will likely bring rain chances come Thursday. 

Rainy Thursday:

While clouds will continue to thicken up on Wednesday, any chance for showers does remain west of the region. It's not until late Wednesday night into Thursday morning that models do show an increase in moisture, resulting in a chance for scattered showers at first. Showers look to become more widespread as we prepare to jump into Thursday afternoon, with chances continuing into the early stages of Friday. As this area of low pressure begins to drift away from the Stateline, drier conditions are likely to ensue just in time for Friday night’s high school football match-ups.

Steady rain continues Sunday evening; Rain and wind for Monday morning

 

A strengthening low pressure system moving across the Iowa/Missouri border will continue to move towards the region Sunday evening.  A steady rain has been falling, with a few heavier downpours, for much of the afternoon and evening.  There have been, and will continue to be, a few thunderstorms across southern portions of the region - especially for southern Lee and DeKalb counties. 

Blustery northeast winds have held temperatures in

the 40s for much of the afternoon, with little in the way of a drop expected Sunday night, or rise for Monday afternoon.  The rain will continue throughout the evening before turning light, most likely around Midnight, as the center of the low crosses south of the area.  Wrap around showers are then expected into Monday morning before drying out a bit for Monday afternoon and evening.

Winds have been gusty at times throughout much

of the day, but are expected to increase as the low moves closer.  Already there have been a few gusts reaching close to 40 mph, with a few isolated locations possibly coming close to 45 mph before Midnight.  Northeast winds will remain strong into Monday morning, gusting at times to 35 mph.  The combination of the strong wind and heavy rain will not only cause ponding water on the roadways through the night and into Monday, but also cause leaves to fall off the trees and on to the roads, sidewalks, gutters and storm drains.  

This will cause some slicks spots on the roads, as well as potentially cause some minor flooding issues along the sides of the roads and ditches where the storm drains are clogged.  Be careful if out Sunday night and early Monday morning as the lack of light will make it hard to see, especially if under a heavier downpour.  And remember to give yourself extra distance when driving between you and the car in front of you as it takes a longer distance to stop on wet or leaf covered roads. 

High chance for significant rainfall early next week

 Over the next few days, we will see much more cool, fall-like conditions. This is a drastic change from last week, when our temperatures were nearly 20 degrees above normal for this time of year. With that comes wetter conditions as well, and that will be in evident Sunday going into Monday. With a low pressure system passing to our South and bringing a lot of moisture with it, it is very possible we could see upwards to an inch of rain or more.

The Weather Prediction Center put out this QPF (Quantitative Precipitation Forecast) map to show where the likely areas of high rainfall will be. It looks that most of the rain will stay to our south, but I think it is likely we will see close to an inch of rain, if not more. Let's time out this rainfall.

By late Sunday morning we should see the beginning of the rain showers moving into Northern Illinois from the South.

Heavier showers will be present in the afternoon as well, and coverage will remain high throughout the entire day.

Through the night Sunday and into early morning, persistent showers will still be present. I think the majority of these rain showers will be further North than this model shows, so there will be few breaks in the rain.

 

Sometime in the early afternoon on Monday is when the rain showers are expected to stop, but not before dumping an inch or more of rain on us.

Don't forget the umbrella through the day on Sunday and Monday!

Showers and isolated thunderstorms possible Wednesday afternoon and evening

It was another sun-filled afternoon Tuesday as temperatures once again reached the low 70s, officially warming to 73 degrees in Rockford, twelve degrees above average.  Skies remain clear for most of Tuesday evening, but we should begin to see a few more clouds filter in through the night.  This will help keep temperatures on either side of 50 degrees by Wednesday morning. 

A strengthening low pressure system developing over eastern Colorado Tuesday evening will begin moving east, pulling into northwest Iowa by Wednesday morning.  Southerly winds ahead of the low will bring temperatures into the low 70s for the afternoon.  A slight increase in moisture ahead of the low, and ahead of the cold front, will allow a few showers and isolated thunderstorms to developing during the afternoon and evening.  However, with southwest winds for much of the day it's likely we develop a cap, or lid, on our atmosphere by the afternoon and early evening.  This could help prevent thunderstorm development as the cold front nears.  A rather strong upper level jet streak is forecast to round the southern edge of the low/trough, moving over northwest Illinois and southern Wisconsin.  This will help increase the shear throughout the atmosphere (increasing winds with height), but instability remains somewhat limited.  

If, however, there is enough energy to break through the cap during the late afternoon and evening it's possible that a strong thunderstorm or two could form, with the greatest risk being wind and hail.  By Wednesday evening the cold front will have passed and this should help us remain mostly dry through Wednesday night.  Moisture wrapping back in around the low Thursday morning could bring us an isolated shower or two, with skies remaining mostly cloudy through Thursday afternoon and evening.

Chill settles in late week following a few warmer days

 

After a somewhat frosty start Monday morning, full sunshine warmed temperatures into the low 70s during the afternoon.  The clear sky will continue once again Monday evening with temperatures dipping into the mid 40s, climbing back into the low 70s Tuesday afternoon.  Average high this time of year should be in the low 60s.  Following a few warmer than normal days temperatures will drop quite a bit by the end of the week, possibly lasting through the weekend and early next week.  In between, the chance for a few showers and isolated thunderstorms. 

High pressure from Monday will continue sliding to the east Tuesday, shifting winds around to the southwest.  Winds will get a bit breezy during the afternoon, gusting close to 25 mph at times throughout the day.  While we'll see plenty of sunshine for the day Tuesday, you'll notice a few more cirrus clouds moving through the sky during the afternoon and evening.  Those clouds are forming out ahead of an area of low pressure that will strengthen as it moves across the middle of the country.

Surface high pressure anchored over the Southeast will work to block a lot of the Gulf moisture from returning to the north.  As a result, this will limit our overall rain chance Wednesday and Thursday to more scattered shower/thunderstorm activity, versus anything too widespread.  The low will move across the Plains Tuesday before entering into the Midwest Wednesday, crossing over southern Wisconsin by Thursday morning.  Southerly winds ahead of the low will keep temperatures in the upper 60s to low 70s for the afternoon, but a line of showers/isolated thunderstorms will move through for the afternoon and early evening with the arrival of a cold front.  Severe weather isn't expected. 

Temperatures won't drop right away following the passage of the front, but will cool Thursday morning as colder air slides in from the north.  Highs will drop from the low 70s on Wednesday, down into the 50s Thursday and then low to mid 50s by Friday.  Overnight lows will also take a bit of a dip, dropping back into the 30s Thursday night. 

Officially the low temperature for Rockford hasn't reached 32 degrees yet this season, but we could come close again Friday night/Saturday morning.  Outlying areas could end up experiencing low temperatures in the low 30s, with a little more widespread frost possibly by Saturday morning.

Temperatures fall into the 30s Sunday morning; More cool weather on the way late in the week

 

For the first time since the start of Fall the overnight low temperature fell into the 30s for Rockford, officially dropping to 35 degrees Sunday morning.  Even though it was closer to our normal low temperature for mid-October (low 40s) it felt a lot cooler than what we've been used to these last several weeks. 

As our average high and low temperatures typically begin cooling during the months of September and October, our actual highs and lows have been doing the opposite.  September was a warm month, averaging almost five degrees above the monthly average, and the first two weeks of October were the warmest first two weeks of October - ever - for Rockford!  Low temperatures for the first half of October have been exceptionally warm, averaging the mid 50s to mid 60s.  It's only been within the last few days that we've felt the overnight low temperature drop to where it should be this time of the month. 

The warmer nights/mornings have also helped with the high temperatures during the afternoon, keeping them above average.  Now while the warmer days and nights are a cause for celebration for some, it's important to look at the potential impacts that these warmer days have on the things around us.  The drier and warmer than normal conditions have caused the Fall colors to be delayed across the region, kept humidity levels higher impacting those who may be suffering from asthma or allergies, summer bugs/pests have been around a little longer, etc.  

Our warming climate has also had an impact on when our first Fall freeze occurs.  Since 1970, Rockford's first Fall is now occurring, on average, 15 days later than when it did 50 years ago!  The average first 32 degree temperature for northern Illinois typically occurs within the first week, to week and a half, of the month of October.  As of October 17th, our overnight low temperature has failed to reach 32 degrees; and it looks like the warmer temperatures will continue through at least the upcoming week, if not beyond.  Locally, it is the low temperature that is warming more than the high temperature - overnight lows not cooling as fast, or as low, as what they were over the last 30-40 years.  The Winter season is the faster warming season, impacting areas in the Arctic where sea ice loss has been within record territory, if not passing it, within the last few years.  

Our overnight low temperatures will warm again this week, but then are forecast to drop back into the 30s by the end of the week and start of the weekend following a cold front.  It's possible that some spots could dip near 32 degrees across Iowa, Wisconsin and northern Illinois, but widespread freezing temperatures don't look too promising.