Thursday, November 26, 2015

Soggy Turkey Day

On and off showers are continuing to cross through the Stateline this morning. More rain continues to develop to the north and west along the cold front.

If you're headed out to the Turkey Trot this morning prepare for on and off rain along with areas of drizzle. Overall it is going to be a very damp day with quite a few puddles, from the rain as well as all of the melting snow we've had. Temperatures for the Turkey Trot will be in the lower 50's and temperatures this afternoon will warm into the mid and upper 50's with the help from gusty southerly winds.

The heaviest rain will move in this evening, though our far northwestern counties could see the heavier rain a little earlier, because the cold front will be stalled just to the northwest of the Stateline. If you're planning on shopping tonight, you might want to head out a little earlier, as the showers will be more scattered through the early evening, but the heavy rain with the cold front moves through around 10pm and into the overnight hours. The rain will stick with us through the morning and into Friday afternoon before the cold front clears the area.

Wednesday, November 25, 2015

Wintry Thanksgiving Day Weather in the Plains & Rockies

Many winter weather watches, warnings and advisories have been issued ahead of what will be a messy, and potentially dangerous, Thanksgiving in the Plains.

Ice accumulations are possible in the panhandle of Texas and Oklahoma as a very strong cold front pulls cold air all the way down into northern Texas Thursday and Friday.  If you're travel takes you anywhere north, northwest or west of here Thursday, be aware for quickly changing conditions.  Roads will turn slick, especially later in the day Thursday.

Stay ahead of the changing weather with the First Warn Interactive Radar.  Go to and click on the weather tab.

Tuesday, November 24, 2015

Traveling for Thanksgiving? Find Out When the Heaviest Rain is Expected to Fall

Temperatures Tuesday warmed to the upper 30's, with even a few spots reaching 40 degrees!  The warmth will continue to spread northward Wednesday and Thursday.  But with the warmth comes the rain.

The heaviest rain looks to fall Thursday evening into early Friday morning.  That's when most of our accumulating rain will take place.  As for rain totals, many will be nearing half an inch of rain by sunset Thursday, with possibly another half an inch - up to an inch - occurring Thursday evening and overnight.

If you're traveling Wednesday, locally it will be cloudy.  There will likely be drizzle and even a few lighter showers around, but accumulations are not expected to be much.  Traveling Wednesday night, fog could be more of an issue with overnight lows only falling to the low 40's.

Thanksgiving Day
Thursday will be rain for northern Illinois and southern Wisconsin.  But further north in Wisconsin or west towards Iowa a wintry mix will greet you.  Possibly with some minor ice accumulation west of Des Moines, IA.  So travel with caution on Thanksgiving if you'll be west of Illinois.

For all you Black Friday shoppers, you will need the umbrella and rain gear.  With the heavier rain and extra traffic on the roads, be careful driving.  Skies will dry through the afternoon Friday and Saturday.  Then our next potential weather-maker moves in late Saturday night and Sunday.

Look for Rivers to Rise with Rapid Snow Melt

Get your boots ready this week - you'll need them!
It's been less than a week since a quick moving system dumped just under 9 inches of snow on Rockford, and up to 16 inches in other portions of the Stateline. While a lot of the snow has been cleaned up, it will continue to cause a few more headaches this week as it quickly melts. Expect sloppy conditions as temperatures continue to warm the next few days, and stay above freezing Wednesday and Wednesday night. This will cause the snow melt to rapidly increase heading into Thanksgiving. Along with the mild temperatures, rain is likely as we head into the Thanksgiving Holiday. An incoming cold front will bring with it a chance for light showers and drizzle Wednesday night into Thursday, but the bulk of the rain will fall Thursday night into Friday morning. This system has the potential to bring 1-2 inches of rain to the Stateline. This is quite a bit when adding it to the snow that fell Friday, which is equivalent to about an inch of water as well. When you add together the possible heavy rain and rapid snow melt, we will likely see a rise in local rivers and streams, as well as the possibility for some minor flooding headed through Friday.

Monday, November 23, 2015

How Inversions Impact High Temperatures

Forecasting high temperatures can sometimes be a little tricky, especially when a warm up is expected after a freshly fallen snow.

For most, highs Monday reached the upper 30's.  This was warmer than what I had thought we would be.  But hey, at least it didn't end up cooler.

A new coating of snow can have an effect on high temperatures during the day, but also low temperatures at night.  Even with sun, afternoon highs will be cooler than surrounding locations with little to no snow.  The reason?  It's a term called: Albedo.  Snow has a high albedo.  This means that most of the shortwave radiation that is produced by the sun and used to warm the surface of the earth is reflected back to space.  Whereas a ground that doesn't have much snow, dirty snow or is bare is able to absorb that radiation.

Temperatures Monday afternoon were cooler than surrounding locations.  Just look at the highs for today.

Strong temperature inversions can also hinder how warm afternoon highs reach.  This happens when warmer air moves in a few thousand feet above the surface of the earth.  Meanwhile, temperatures at the surface don't warm quite as fast.  A perfect example of that happening: snow on the ground and winds within the jet stream shifting around to the southwest.  Similar to what is going to happen the next couple of days.

Noon Tuesday
Look at the image to the left.  This is a model forecast sounding for Tuesday afternoon - Noon.  The red line represents the temperature in the atmosphere while the green line represents the dew point temperature.  What I want you to notice is how the red line begins to shift to the right, or represents a warming temperature with height.  That's a weak temperature inversion.  What's interesting is that this inversion strengthens just a little by 3pm Tuesday (second image to the left).  This would imply that temperatures above the surface are warming, but at the surface they might not be warming as fast.  It doesn't look overly strong, so because of that I'm going to keep my forecast of highs warming into the
3pm Tuesday
middle and upper 30's.  If, however, this inversion does develop and doesn't mix out during the afternoon high temperatures will be lower for Tuesday.

Sunday, November 22, 2015

Fog and Rain Follows Weekend Snow - Thanksgiving Travel Likely Impacted

After record breaking snow fell Friday night into Saturday, mild temperatures do return the week of Thanksgiving.  But unfortunately fog and heavy rain will follow.

With the snow pack over a foot and a half deep in some spots, temperatures will remain in the upper 20's to low 30's Monday, middle 30's on Tuesday and upper 30's on Wednesday.  Surface winds will slowly shift around to the south late Monday night.  With those south winds, more mild air will be pulled north.  Melting snow and an added increase in moisture into the atmosphere will likely cause fog to develop during the overnights this week, starting as early as Monday night.

The fog will turn a little more dense Wednesday evening and Wednesday night ahead of a warm front and low pressure system.  Gulf moisture will be pulled northward with light showers possible Wednesday evening.

Rain will fall on Thanksgiving, but temperatures should be able to reach the low 50's.  Unfortunately, that will also lead to quite a bit of fog during the day.  A cold front pulls through Friday morning with colder and drier air
following Friday afternoon.  This will push the rain east into the Ohio River Valley and temperatures will cool into this weekend.

Rainfall amounts looks to be fairly high with locations likely picking up over an inch.  With the two inches of rain that fell early last week, plus the added snow melt on top of the expected rainfall Thanksgiving, our concerns are growing for the possibility of minor flooding and slowly rising river waters.

If your holiday plans have you traveling this week, know that you will be running into rain - with the heaviest falling Thursday late afternoon into the night.

Saturday, November 21, 2015

Frigid Air to Mild Temperatures

Now that we have a snow-covered ground, clear skies, and light winds, temperatures will be allowed to drop very low tonight. Rockford will likely fall to near 3 degrees. Some areas could approach zero by daybreak Sunday morning. When a light breeze blows, wind chill values will be below zero throughout the night. Some of the wind chill readings could reach as low as -5F across the region, especially where the wind-prone areas are. There could even be wind chill readings slightly colder than that.

This will be the coldest night of the year thus far in terms of actual air temperatures and wind chills. Make sure you bring the pets inside and turn on the heat to ensure your pipes don't run the risk of freezing from the extreme cold. Temperatures on Sunday will only rise to the middle 20's despite seeing a decent amount of sunshine. We may struggle to see temperatures reach the freezing mark through Wednesday before a warm surge moves in just in time for Thanksgiving. But, with the warmer temperatures comes a chance for a moderate rainfall...right in time for the Thanksgiving and Black Friday shopping.