Arctic Weather Expected This Weekend

An arctic weather outbreak is poised to strike the region this weekend. A combination of arctic air and heavy winds will lead to brutally cold wind chills, possibly exceeding -20F degrees. Read on!

Let's start off with what we already know. The current temperature is mild, and highs today will likely pass 40 degrees. Clouds are sticking around the area this morning, but should begin to leave as warm southerly winds begin to enter southern Wisconsin.

Sounds pretty nice, right?

Yes, it does, but temperatures will begin to rapidly decrease as strong cold air advection begins to take place. A deep low pressure system will pass far to our north; the cold front, however, will start pushing in bitterly cold temperatures tonight.  Pressure will also rise behind the cold front.

HPC Forecast. Notice the low pressure system to our north, and the cold front trailing it.

In addition to the cold temperatures, wind gusts are expected to exceed 40 mph. In response to this current forecast, the National Weather Service has issued a WIND ADVISORY for all of SE Wisconsin.

The coldest day of the week will likely be Monday or Tuesday. More cold air will advect into the area Sunday night or so, so highs will likely stay in single digits, and winds will be gusting around 30 mph.

Let's take a quick look at a section of GFS MOS guidance:

GFS MOS (MAV)
 KUES   GFS MOS GUIDANCE    1/19/2013  0600 UTC                      
 DT /JAN  19      /JAN  20                /JAN  21             /     
 HR   12 15 18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 00 06 
 X/N              42           7          12          -2        1    
 TMP  34 35 40 40 34 28 20 12  7  9 10 11  9  6  5  3  2 -2 -1 -2 -5 
 DPT  30 32 32 29 24 18 11  3 -2 -1  1  0 -2 -3 -3 -4 -5 -7 -7 -9-15 
 CLD  OV OV OV BK SC FW CL FW SC BK OV OV OV OV OV OV OV BK OV BK SC 
 WDR  22 22 23 25 27 28 29 29 29 30 29 29 29 29 29 29 28 29 28 29 29 
 WSP  07 07 12 15 16 23 22 19 15 14 13 13 10 09 09 10 12 13 16 15 13 
 

This MOS text is showing Saturday 18z temps at 40 degrees. Sunday 18z? 10 degrees. Monday 18z? -1 degrees. Keep in mind this is not counting wind chills. 

So here is my forecast for this weekend! As I always say, don't replace NWS forecasts with my personal forecasts. Thanks.

Today:  Mild. Winds will start to pick up this afternoon. WIND ADVISORY in effect. Highs in the lower to mid 40s. Partly to mostly cloudy. Winds gusting 30 mph or so.

Tonight: Getting colder! Lows around 10 degrees or so. Windy. Wind gusts around 40 mph or so. Wind chill low around -10 degrees.

Sunday:  Cold. Highs in the lower teens. Winds gusting 20 - 30 mph. Wind chills -5 to -10 degrees.

Monday: Highs in the single digits. Winds around 20 - 30 mph.  Wind chills around -5 to -10 degrees.

Monday Night - Tuesday Morning:  Lows in the negative single digits! Winds gusting around 15 to 25 mph. Wind chills -15 to -25 degrees.


Thanks for reading! I will be publishing a new update soon regarding snow chances over the next couple weeks.

-Chris