JACK FROST HAS "NOT" LEFT THE BUILDING...
A strong late season shot of Arctic air is on the way to the Midwest! As you read this the leading edge of the polar front is diving rapidly southeast. Strong cold air advection has put an end to any of Thursday night's showers in my southern counties.. The front is set to whip up a good wind out of the northwest that reaches 30 mph. Temperatures will have to fight hard Friday to get out of the 40s as the cold air pours southeast.
These are the mid-afternoon readings the EURO forecasts Friday.
These are the wind gusts just above the deck at 10 meters.
That provides us with wind chills that are going to be in the 30s the bulk of the day.
Friday night an expansive high settles over the area bringing the core of the cold air directly overhead. 850 temperatures (at 5,000 feet} will dip into the range of -4 to -7 which is at this point in May occurs about once every 15 years. With winds subsiding and very dry air (dew points in the mid to upper teens} temperatures will free fall after sunset approaching or exceeding record lows in all areas. The NWS in the Quad Cities has issued a freeze watch which will likely be upgraded to the warning category later Friday.
The NWS shows a range of 27-32 for lows around my region. In general that sounds good but I would not rule out a 24 or 25 in some of the colder valley locations. Readings in spots, generally in the northeast half of my area could stay below freezing 5 or 6 hours which could seriously damage tender plants and vegetation. The records for Dubuque, the Quad Cities, Burlington, and Cedar Rapids are listed in red on the graphic below.
The typical last date of a 32 degree temperature is roughly April 18-23...2-3 weeks earlier than this.
After the frosty start Saturday morning, conditions will improve Saturday but it will remain quite cool by May standards. Highs will range from the low 60s SW to the upper 50s NE. The next clipper in the NW flow arrives with light precipitation chances Saturday night and Sunday. Highs drop to the 50s Sunday with brisk NW winds, clouds, and scattered showers. Looks like a pretty lame day.
Another sprawling high follows the showers bringing clearing skies and the chance of more frost Monday and Tuesday morning. Enough already!
Just for human interest for you back home, here in Maine a late spring snow is expected. Where I am in Portland 2-3 inches looks possible Friday night. Here's what the EURO and GFS are showing for snow around the state
That's a pretty impressive storm for any time of the year. Assuming this happens, I will have seen my first 1" of snow this season October 28th and my last May 9th...very early and late. Lucky me! Roll weather...TS