Timing Thursday's Rain

As the old saying goes, "All good things must come to an end".  And that will hold true for highs later this week.  A cold front will move in from the west late Thursday, bringing with it rain and even a few thunderstorms.

The first half of Thursday will remain dry, but cloudy.  Southwest winds will increase during the day giving temperatures a boost into the upper 60's.  Most of the rain Thursday will fall west of the Mississippi River, but an isolated shower or two remains possible Thursday afternoon.

As the cold front moves further east Thursday night, rain will spread from west to east into Friday morning, with most of the accumulating rain falling overnight.  While the timing of the front isn't the best for thunderstorms, a narrow band of instability, along with a strong upper level low, will combine together to give us a chance for a few thunderstorms Thursday night.

By Friday morning the cold front will be moving east of Chicago, taking the rain with it.  Skies will remain cloudy and the winds will increase from the Northwest.  There isn't a lot of cold air initially behind the front Friday.  That arrives

Saturday. 

Locally Dense Fog Possible Tuesday Night

Update:  Dense Fog Advisory now issued for all of Northern Illinois through 10am Wednesday morning.  Take it slow on the morning commute.

Just In: A Dense Fog Advisory has been issued for Winnebago, Boone, Ogle, Lee, DeKalb and McHenry counties beginning 9pm Tuesday night and lasting through Wednesday morning.

Parts of Northern Illinois experienced dense fog Tuesday morning, with some areas south of Rockford not completely clearing until the afternoon.

While most did see sun during the afternoon, it did have an impact on high temperatures.  In Janesville, where there was very little fog, highs reached the low 70's.  In Rochelle, the high was only 64 degrees!  A result of the fog and low, stratus clouds.

Dew points today have risen to the low 50's, increasing the amount of moisture in the atmosphere.  You may have even noticed a little haze when the sun was setting tonight.  With light winds and clear skies this evening, temperatures will fall near the dew point reading.  This will allow fog to develop for the Wednesday morning commute.

Depending on how long the fog lasts into the morning, and possibly into the afternoon, it will have an impact on high temperatures Wednesday.  As it looks right now, most of the fog should be gone by mid to late morning.  Temperatures will still warm above average, but we may only reach the middle to upper 60's rather than the 70's.  If, however, the fog clears faster highs will warm into the low 70's.

Foggy Tuesday Morning

Increasing moisture from the south and light winds in place is allowing for dense fog mainly south of the Rockford area.






The National Weather Service issuing Dense Fog Advisories for Ogle, Lee, DeKalb, Carroll, and Whiteside counties until 10am. At times visibilities can be reduced to below a quarter of a mile.

Once the fog burns away temperatures will be able to warm quickly. Highs today will warm into the upper 60's, slightly cooler than yesterday. This is because there is more incoming cloud cover from the south and our southerly winds won't be as strong today. Though it will still be a very pleasant afternoon with temperatures warming into the upper 60's.

On Average First Snowfall Over An Inch Occurs During November

The month of November brings big changes to the Stateline.  Average temperatures fall from the middle 50's at the beginning of the month, to the upper 30's at the end.  Total precipitation adds up to over 2.50", but average snowfall begins to add up as well.

On average, November is the month where snow totals push over an inch.  The monthly snowfall average is 1.7", and it's - on average - during the month of November when the first trace and first measurable snow (0.10" or higher) falls.
 

Indian Summer

Through most of Autumn we've seen above normal temperatures, with many saying it was an "Indian Summer", but was it?

First we have to look at the definition of an Indian Summer; this happens when we see a period of above normal warm weather, after we see the first killing freeze of autumn.
A killing freeze is defined when temperatures reach 28° or less for the first time in the growing season. We didn't see the killing freeze until October 17th, this is when our minimum temperature reached 28°. So any warmth before that time in autumn, wasn't considered an 'Indian Summer.' Temperatures were very warm October 19th-21st, with highs in the mid 70's. This period could also be thought of as an Indian Summer. Overall the month of October was very warm, the month ended up being 2.4° above normal. This week is also the definition of an Indian Summer, as temperatures will be about 10-15° above normal. There can be more than one 'Indian Summer' in one season. Monday, Tuesday, and Wednesday all look to stay in the low 70's, however cloud cover could impact temperatures a bit. Overall, temperatures will be very mild going forward through midweek, but we return to more seasonable temperatures by the end of the week.

Northern Lights Viewing this Week

If cloud cover can hold off at night this week, Northern Illinois and Southern Wisconsin would have a decent chance of viewing the Aurora Borealis (Northern Lights) beginning Tuesday.

The Aurora Forecast from the University of Alaska Fairbanks Geophysical Institute is forecast the auroral activity to be high Tuesday, Wednesday and Thursday night.  Pending any cloud cover, those nights will be very comfortable to try and catch a glimpse of the lights.

Click here for more on the expected activity this week.

Near Record Warmth for the First of November

It's possible, but not a guarantee.  Record high temperatures for Monday, Tuesday and Wednesday are in the middle to upper 70's.  High temperatures all three of those days have a very good chance of reaching the middle 70's as strong southwest winds usher in an unseasonably warm air mass.

While we've got a chance of getting close to the records, we may fall short for a couple reasons.  The first, cloud cover.  I'm not anticipating many clouds for Monday, so highs in many locations should reach the upper 60's to low 70's.  Likely, however, not reaching our record high of 76 degrees set back in 1961.

As winds shift around to the south Tuesday and Wednesday, an increase in cloud cover could become our 'fly in the ointment' and hold temperatures in the 60's both days.  If, however, cloud cover does not develop highs on Wednesday have a very good chance of reaching the record high of 74 degrees set back in 1978. 

The other factor we have to take into consideration is that it's the beginning of November, and we just set our clocks back with the sun now setting before supper-time.  Our days are getting shorter and the nights are getting longer.  At the same time, the sun angle is getting lower and lower.  Either way, the beginning of the week will be above average.  And if cloud cover remains at bay the following days the warmth will be sticking around.