TURNING UP THE HEAT...
Summerlike temperature are in our immediate future but you might have thought otherwise Friday morning. A beefy high pressure over the Great Lakes was feeding cool Canadian air into the Midwest sending lows into the 30s and 40s. Widespread frost and even freezing temperatures were found in parts of Iowa, Minnesota, and Wisconsin. The ASOS report from Sparta/Ft. McCoy, Wisconsin read 26. Not far away in Black River Falls the reading was 27. Elkader in northeast Iowa reached 32. Hopefully that's the last time we see numbers like that for many months!
To get temperatures that cold you must have very dry air and light winds to maximize radiational cooling. Additionally, the cold air is dense and in valley locations it pools and drains into the lowest elevations such as Sparta. All of those ingredients were in place with the amount of dry air at exceptional levels. PWAT's (available water vapor) were under 2/10ths of an inch where the coldest lows were found.
For perspective, those moisture levels are 15-25 percent of normal.
Now, if you paid attention in school, you know that dry air warms readily when strong May sunshine is applied to it. By late afternoon temperatures were back in the mid 70s around Sparta, roughly 50 degrees warmer than when the day started. Quite impressive.
Going forward some slow but important changes will take place as ridging builds further east into the Midwest. A warming trend gets underway Saturday that builds to significant proportions next week. Fortunately the bulk of the heat does not arrive until after the holiday. The end result is a beautiful Memorial Day weekend with comfortable nights and progressively warmer days. Sunshine will be abundant and humidity non-existent. This is some really good stuff. Temperatures go from 80 Saturday, to 82 Sunday, and 87 Memorial Day. Rain chances are zero and dew points never get higher than 47. Winds are in the 5-15 mph range. Wow, can you say perfect!
Tuesday through Friday of next week temperatures are further elevated. While humidity won't be a major issue there will be enough of a SW flow aloft to get some moisture back in the pattern. It will become more apparent by the end of the week and that is when it should start feeling a bit more uncomfortable. That's also when some diurnal thunderstorms could pop up on a widely scattered basis. Right now they look very spotty and coverage is likely to be limited (that's if we can even get storms to fire).
The bigger story appears to be the temperatures which on the EURO are shown reaching the 90s for multiple days, especially across the south. The EURO indicates this for readings in the Quad Cities. Normal highs go from 75-78 over the period so a prolonged stretch of above normal readings are expected. I do see notable cool-down around June 6th thanks to another one of those back door cold fronts. Maybe we can get some rain out of that.
Rainfall prospects again are far from compelling with the EURO showing 10 day totals that look like this.
If you like your weather warm and dry, this forecast is for you. It is what it is. You don't need a coat and you don't have to shovel it so I intend to enjoy it. Hope you do too. Have a tremendous holiday and here's to those who have served our nation. Roll weather...TS
