BRRRY SCURRY....

Folks around the Midwest Tuesday morning are doing the brrry scurry with temperatures at thier coldest levels since Christmas. In fact, locations north of I-80 could dip to 15 below and may end up with the coldest readings of the winter so far. On the bright side, wind chills are essentially non-existant with high pressure directly overhead.

All things considered, the overall set-up overnight was perfect for the coldest temperatures this air mass could produce. The combination of light winds, clear skies, and dry air, maximized radiational cooling allowing what little heat we generated Monday to rapidly vanish in the night air. Another critical ingredient, especially in the northern half of my area is fresh snow cover. It serves to intensify the cold even more in situationa such as as this with readings 5-10 degrees colder than they would be without the snow pack..

It remains to be seen just how cold we will get but the EURO shows lows across the deeper snow cover along and north of HWY 30 pushing 15 below. Some local spots in the far northwest may push minus 20. At the time of this post around 2:00am Waterloo had already reached 20 below!

By the way, we continue to see a remarkable difference in snowfall this winter across the state of Iowa with Keokuk in the SE reporting just over an inch and places in NW Iowa like Sibley and Spirit Lake topping the 42" mark with plenty of winter still ahead of us.

Here's where the heavier snow fell in Saturday's system.

This graphic shows the seasonal snowfall accumualtion through the 30th. As lame a winter as it's been for snow in my area, just a short ways north it's been a big winter for white gold in the upper Midwest. The NWS office in Chanhassen, Minnesota (the west side of Minneapolis) has racked up 56.4 inches. 250 miles SE in Dubuque, Iowa (4.5 hrs.away), we've had 14.5 inches. Ugh...

One thing we don't have to worry about anytime soon is stormy weather. After a farily active 2 week pattern, the jet slowly evolves from NW flow to one of westerly flow by the weekend. The positive TNH (tropical northern hemispheric pattern) is breaking down. As such, following a cold week, temperatures will moderate significantly this weekend when the 500mb jet goes to this Saturday morning.

Note the difference from where we are Tuesday at noon.

Neither of the above upper air patterns is favorable for moisture or precipitation. The EURO has this for total precip. the next 7 days.

The GFS is hot on its heels.

Note the 5 day temperature departures once we get into the westerly (zonal flow) this weekend. This is over the period February 4th-9th.