Going from spring to winter in just one weekend may cause a few headaches

A developing low pressure system caught my attention early Wednesday morning regarding the weather for this upcoming weekend....and even into next week.  We've basically got two weather systems that will impact the Midwest from Thursday through Sunday night.  The first one will bring us rain later this afternoon and evening and the second will be a cold front that will be here by Saturday night.

The first low in Texas will continue to draw moisture northward this afternoon with rain likely developing around 3pm and continuing into the overnight.  Precipitation type will be all rain for this evening because temperatures throughout the atmosphere will be warm enough to support it.  Once the low moves into Michigan by Friday it will weaken and become 'caught up' in the jetstream leaving Friday evening and Saturday afternoon fairly dry.  The second system will pull a cold front through by Saturday afternoon with colder air moving in by Saturday night.  The BIG question with the second system is just how far east the front will be by Sunday morning.  It looks like low pressure will develop on the southern end of the cold front and pull north as the front moves through northern Illinois and southern Wisconsin.  If the front stalls near Chicago snow may fall for the first half of Sunday.  If the front is far enough east then all the precipitation will stay east as well.  Last night it looked like there was the possibility of accumulating snow by Sunday but models this morning have backed off just a bit on that idea.  Of bigger concern may the transition period late Saturday night.  Temperatures a few thousand feet above the surface will have dropped below freezing by Saturday night but at the surface temperatures may be just near or slightly above freezing.  This could cause any rain that would be falling to transition to sleet or freezing rain before switching to snow.  Something to keep in mind if you'll be out late Saturday or early Sunday.

Helpful rain on the way

Moisture will be in full supply Thursday and Friday as low pressure lifts through northern Illinois by Thursday night.  Rainfall amounts could reach three quarters of an inch, or higher, for some with slightly lower totals north of the state line.  Locally higher totals near an inch could even be possible if a thunderstorm or two develops overnight Thursday.  Even though it's not snow, any type of precipitation we can get will be beneficial as most of northern Illinois and southern Wisconsin remain in severe drought.

2012: Warmest Year On Record for the U.S.

The headline of this post shouldn't come as a shock to anyone. The reason I bring this up is because NOAA published a very cool article giving the heat of 2012 a visual component that puts it in a different perspective.

Difference from Average Temp: 2012

Here's the temperature analogy map for the U.S. over the course of 2012. Every state in the contiguous 48 saw higher than average temps... some (like us) more than others.

Difference from Average Temp: March

Things really kicked off in March. The map shows nothing but dark red for the eastern two-thirds of the country. Rockford saw average temperatures a good fifteen degrees above normal. This, combined with a mild winter in 2011-2012, would be the start of our massive drought that we're still dealing with today.

Difference from Average Temp: July

July was another scorcher. While the map isn't as impressive, we saw plenty of 100° days and very little rain to help ease the pain of these soaring temperatures.

Difference from Average Temp: October

We did some small breaks in the heat, however. August through November either saw normal temps or below normal temps. October, for example, shows some blue throughout the midwest, but at this point, it really didn't mean much.

To check out the full article, which includes temperature anomaly maps for the entire year and every month of 2012, click here. -BA

Pattern change will bring colder weather back by the middle of January

A split flow pattern in the jetstream once again keeps us stuck between the extreme cold to the north and the active weather to the south.  Mild, Pacific air will be in place these next several days warming temperatures 15° to almost 20° above average!  One thing that may prevent the warmth from getting too out of control may be the lingering cloud cover and fog.  Something we'll have to watch these next few days. 

Cut-off low pressure in northern Mexico will bring heavy rain and severe weather through parts of Texas, Louisiana, Mississippi and Alabama through Wednesday night before the low lifts into northern Illinois by Thursday evening.  Rainfall, heavy at times, along with a rumble of thunder or two will occur Thursday through Thursday night before ending by Friday.  As the low moves into Canada by Friday afternoon a deep trough will begin to build in the west while warmth continues to expand across the Great Lakes and Northeast.  A strong cold front will move through Saturday afternoon with the core of the cold air brushing us to the north.  Temperatures will drop from the 40s Saturday down into the 20s by Sunday on the heels of a gusty northwest wind.  The colder pattern looks to remain in place next week as an overall hemispheric pattern shift occurs as blocking high pressure develops near Alaska and the southeastern part of the United States. 

A Case of Déjà Vu?

Today is kicking off a week's worth of unusually warm weather. The only thing more unusual than this weather is the fact that we saw the exact same thing this time last year!

Here's a look at the week ahead and how the forecast stacks up against this time last year. If the forecast holds, we won't be as warm as 2012, but we'll still talking about an impressive stretch of 40° weather.

If this year is anything like 2012, look out. Last January saw six days of highs of 50° and twelve days of highs of 40°!

5 year anniversary of January 2008 Poplar Grove tornado

A weather pattern more typical of spring than winter occured on the afternoon of January 7th, 2008. Around 3:30pm that afternoon an EF3 tornado touched down near Poplar Grove in Boone County and moved northeast to just north of Harvard in McHenry County. Click here for a complete analysis of what occurred.

Temperatures warm but it may not feel like it

We've reached that point in winter where climatologically we should be entering the coldest part of the season, but temperatures this week will be anything but cold.  Blocking high pressure to the south will keep any storms moving out of Canada the next few days to the north in Minnesota and Wisconsin.  This means temperatures will continue to warm as what remaining snow is on the ground continues to melt.  Highs the next several days will warm well into the 40's; almost 20° above average! 

Cut-off low pressure in the southwest will move northeast through the middle of the week bringing with it warmth but also the threat for rain, not snow, by Thursday and Friday.  Despite the rain falling temperatures will continue to warm with a strong southerly wind.  The mild weather continues through the beginning of the weekend until a strong cold front sweeps through Sunday.  This will drop temperatures closer to average by Sunday afternoon.

While mostly sunny skies will be found this afternoon the gusty southwest wind will have an opposite affect on the wind chill.  Temperatures today will rise into the upper 30s, but a southerly wind gusting as high as 25-30 mph will cause the wind chill to remain in the upper 20s and low 30s.  So another day to bundle up!