An awesome weekend is ahead weatherwise with mid-March level mid to upper 40-deg high temps.

Sunshine will be plentiful—and even more abundant than last weekend.  

It’s Pacific air which tends to be mild by day and cool at night—that means nights will see widespread 20-deg lows with the potential for upper teens colder inland locations.  But days are to average 5-deg warmer than last weekend with highs of 45 Saturday and within striking distance of 50-deg Sunday.

Two storms come on the scene next week and bring the Chicago area’s next prospects for precipitation.  The first is bring clouds in the area Tuesday (Valentine’s day) and its rains appear likely to reach Chicago later Tuesday and/or Tuesday night.  Unseasonable “warmth” by February standards appear likely to surge into the area with this system with temps reaching the low 50s—late March level temps.

A second, more powerful system comes on scene in the late Wed night/Thursday time frame. This is the one we mentioned yesterday as one related to a jet stream wind max which left the Japanese coast this past Tuesday evening heading out onto the North Pacific. A near 200 mph jet stream wind max is moving toward Alaska’s Aleutian Islands and will make its way across the Gulf of Alaska in coming days—ultimately diving into the Lower 48 and carving out a deep mid-U.S. upper trough—the type which spuns up potent surface storm systems with plenty of available Gulf moisture. That takes place the middle of next week.

Clearly at that distance in time, specifics/details have yet to be perfected. Overnight model and Friday morning model runs have shifted the track of this system over the Chicago area.  That would favor a rain-snow line west of Chicago.  The European, NWS, German and Canadian ensemble models are all on board with that line of reasoning at the moment. The Japanese model tracks the system farther south.  But while its clear a significant storm system is likely to sweep into the Midwest—there are ALL KINDS OF DETAILS to work out on it.  Strictly interpreted at this early hour—a proposition wrought with uncertainty and the potential for shifts in reasoning in the many days before it comes into this area—it would look like such a system might produce it most significant snow northwest of Chicago.  But to suggest that’s the final word on a system still 6 days and over 1,000 miles away would be folly. It’s always fascinating to watch the evolution of forecasts on this type of system and we’ll be doing just that between now and its arrival later next week.

In the interim, an ABOVE NORMAL temp regime holds with temps this week ending up nearly 10-deg above normal and 20-deg milder than last week when we were dealing with arctic air. Next week is likely to see temps running 8-deg above normal and a more modest 2-deg temp surplus appears a good bet in the week which follows—a week likely to see a series of weather system sweeping the area with rain/snow lines close enough to suggest it will be interesting to watch them.  Remember—snow can occur even in above normal temp regimes. Yesterday’s snow to Chicago west and north proves that. 

Full forecast details at the WGN Weather Center

TONIGHT: Clear and chilly with light winds near calm at times.  Low 22 O’Hare—but mid to upper teens colder inland locations.

SATURDAY: Sunny, milder by afternoon. Mid-March level highs of 45.

SATURDAY NIGHT: Clear, temps drop off and turn fairly chilly past dark.  Low 27—but upper teens to around 20 inland.

SUNDAY: Sunshine mixes with some scattered clouds as the day proceed—but remaining unseasonably mild for the time of year. Highs 48—even 50 in spots.

MONDAY: Some early clouds give way to sunny skies, breezy and continued mild. High 48.

TUESDAY: Clouding over. Growing prospects for rain later in the day—and rain likely at night. High 51.

WEDNESDAY: Some mixed sun emerges. Mild and breezy. High 51.

THURSDAY: Windy. Rain appears a good bet—but the system’s future path will have to be monitored. A shift in the storm track farther south would bring its snow closer to the Chicago area. And a shift to snow or snow showers appears a good bet at night. High Thursday 43.

FRIDAY: Possible left over flurries in the morning. But at least some clearing is likely later in the day. Windy and colder. High 28.