Month reaches its midpoint with waves of windy rain; temps make it the 5th warmest December of past 142 years

The Chicago area’s on the front end of a more active weather pattern. It started here with last weekend’s rainy system—a storm which produced more than a foot of snow across the upper Midwest—with Minneapolis at its snowy epicenter.

This weekend’s storm system is also unleashing its precipitation in liquid form in Chicago. What snows are to fall with this latest disturbance will take place well to the north.

A third in this developing series of storms, is to ride across the region late next Wednesday and Thursday on a track oriented farther south than either of the first two. It’s possible this could place the Windy City much closer to the demarcation between rain and snow—and early indications of wrap-around snows reaching Chicago appear stronger than with the first two systems. It’s potentially a pattern shift which will warrant careful scrutiny over the coming week.

The tendency toward liquid-form precipitation to date has been an outgrowth of the significantly milder than normal weather pattern which has dominated December. The month reaches its mid-point Saturday and boasts a remarkable 11+-degree temperature surplus—mild enough to place it 5th warmest among the 142 Decembers on the weather record books here.



Storm behind Saturday’s Midwest rain has history of Texas panhandle tornadoes/severe t-storms and big mountain snows/high winds across the Southwest


Saturday’s spells of wind-driven rain are accompanying a storm with a history of impressive wind, rain and snow production in the Southwest and a late season outbreak of tornadoes and severe weather in the Texas Panhandle Friday.
Snowfall totaled 19 inches at Forest Lakes and 16 inches at Alpine—both in Texas—with 13 and 10 inch tallies reported at Mt. Charleston and Rainbow Canyon, Nevada and 9, 8 and 6.3 inch accumulations at Luna, Red River and Taos in New Mexico.  Durango Colorado got into on the storm’s snowfall with a 7 inch total.
The storm’s winds were equally impressive. Tolar, New Mexico clocked 75 mph gusts while White Sands, NM recorded 69 mph velocities and Buffalo Lake and El Paso—both in Texas—were hit with 68 and 66 mph gusts.



Saturday warmest temps may come after sunset


Vigorous southeast winds, slicing off Lake Michigan’s low and mid 40-degree waters, are blowing as Saturday opens. It’s a set-up which limits warming as the day gets underway.  But during Saturday afternoon and night, more southerly winds are to develop sending temperatures to within striking distance of 50-degrees over the vast majority of the Chicago area. An influx of “warmth-retaining” Gulf moisture will not only fuel Saturday afternoon and night’s showery spells but will also buoy temperatures which may hover well into the 40s to the low 50s well into Saturday night.



Bear/Packers game looks sporadically drizzly, fairly windy and, by December standards, mild


The weekend storm’s backwash flow (the winds which blow from the northwest on the system’s west side), is to hold cloud cover and patches of passing drizzle or light rain over the Chicago area Sunday for the Bears/Packers game.  Though game-time temps will pullback a few degrees from the highs likely to be established Sunday morning, the 40s predicted at kick-off time represent “mild” readings by December standards.



Continuing lack of measurable snow puts record at risk Sunday; only one other season over past 128 years without measurable snow by this date


Measurable snow (0.1 inch or more) is highly unlikely through Sunday.  This appears to all but assure the old record of Dec. 16 for the latest measurable snow here is likely to be tied.  Failure of measurable snow to fall through the following night (Monday night at midnight) would break the record.

It’s possible a streak of light snow could develop Monday night.  Were it to generate 0.1 inch of snow or more, that could derail the move toward establishing a new record.



Active storm track setting up across the country next week and the week after, tugging lobes of colder air into the Midwest


The regular series of precipitation-bearing systems we’ve discussed here is part of an “active” pattern expected to dominate over the next two weeks. Were one or more of these systems to put snow down on the ground, they would establish the “track” over which the Arctic Express could run leading to colder temperatures in December’s back half than in its opening weeks.

Model solutions appear to be tracking in the colder direction—though the level of chill is far from extreme. Still, there could be periods in which the chilliest temperatures yet may occur as part of this forecast scenario.


Next Friday could see season’s first freezing temperature


One such cold plunge could arrive next Friday on gusty northwest winds and produce Chicago’s first sub-freezing day of the season.


Finally some snow? European ensemble model suggests snow for Christmas while Weather Service models persist with forecasts of snow later that week


Christmas week—the period which follows next week here in Chicago—is predicted by both the European Center’s model and the National Weather Service “GFS” model—as likely to produce sticking snow.  These forecasts admittedly reach into the “fantasy” time range and are subject to potential updates. But the arrival of snow wouldn’t be at all inconsistent with climatology (historic patterns)!

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