BRIGHT AND SHINY WITH A HINT OF FROST...

terryswails1
May 12, 2021
2 min read

Tuesday was a pleasant but cool May day around the central Midwest. Highs barely touched 60 but that was a big improvement from where the day started. Many areas from HWY 30 north reported scattered light frost with lows in the 30s. Freeport in NW Illinois dipped to 30 with a number of other locations at 34.

In NW Iowa Estherville plummeted to 26 with Mason City down to 28. Silver Bay, Minnesota was one of the coldest at 19 degrees with widespread 20s in Minnesota and Wisconsin.

Wednesday morning promises even colder readings around my area with low to mid 30s expected to be common. Frost advisories will be in effect until 7:00 AM as far south as HWY 34.

Wednesday and Thursday promises more of the same with abundant sunshine, cold nights, and cool days with highs right around the 60 degree mark. That cutting north wind will be substantially lighter easing the wind chill and making for tolerable afternoons, even though highs will remain 8-10 degrees cooler than normal.

Friday we should hold onto sunshine much of the day but as high pressure slowly heads east, return flow around it will begin to gradually usher moisture back into the Midwest.

You can see how that increases available water vapor. We go from this Tuesday with values around .25 inch.

To this Sunday evening with amounts up to 1 to 1.25 inches.

That's going to eventually bring some clouds and precipitation in for the weekend. The EURO holds most of the rain off until later Saturday afternoon or evening. Once again dry air is playing a roll in the northward progression of the rain.

The EURO

The GFS is of the same mind set but a little slower with the showers reaching HWY 20 late Saturday evening. Here's what the two models show for rainfall through Sunday night. There's a bit of tweaking but all things considered pretty good agreement in amounts and placement more than 96 hours out.

The GFS

Now, a summer note to end on. The GFS MJO (Madden Julien Oscillation), as shown by the dotted green line is going into phase 6 by May 25th. The phase analog for phase 6 temperatures (center right panel) is very warm implying a toasty end to May. The GFS MJO modeling has been doing very well lately adding a little extra confidence to this idea. We'll know soon enough.

Meanwhile, the severe weather season continues to be shut down with minimal prospects for strong storms into next week. The NWS in Des Moines has issued only 3 severe thunderstorm warnings the entire year (no tornado). That warning count of 3 is the all time low at that office through May 11th. The previous record was 7 in in 1987.

In 2008 the total number was low at 63 May 11th, but severe weather went wild from late May through July culminating in a record 639 severe thunderstorm and tornado warnings being issued. We are not out of the woods by a long way.