I'LL TAKE A MULLIGAN...
Sometimes I observe a coming weather pattern and it looks so dreadful I wish I could just take a pass, or maybe a mulligan as golfers do when they just pick up the ball and try again. That pretty much sums up my thoughts on what's to come over the weekend and early next week in our weather pattern.
Take a look at the upper air pattern that takes shape over the period April 27th to May 6th. A classic blocking pattern is established that forces a closed 500mb low to develop over the Great Lakes. It gets captured in such a way that allows a strong cyclonic flow to rotate around the center for nearly a week. It's like somebody threw a rock in the middle of the proverbial atmospheric stream. The normal west to east flow is disrupted until the rock is removed (or in this case the pattern breaks down).
What this does is drain cold air from the polar regions directing it into the deep trough over the central U.S. In the next animation you can watch the cold air pulse as it circulates southward around the vortex centered over the Great Lakes. The end result is a prolonged period of below normal temperatures throughout the Midwest.
As chilly as it will be at ground level, temperatures at 5,000 feet (850mb) will fluctuate between -3 and -5C...way below freezing. With the late April sun being so direct and strong, that causes significant instability that results in plenty of clouds, gusty winds, and crisp temperatures.
This goes on for several days and just the mere instability will drive spotty showers. These are not heavy and tend to be hit and miss. Beyond that, from time to time vorticity will spin in around the parent low and add some extra forcing. That could create a couple periods where somewhat more organized pockets of precipitation develop. These are very hard to foresee and time at this distance but remain a possibility. Overall, precipitation will be light but its a very unsettled pattern where spotty brief light showers could randomly pop up on multiple days, especially Saturday-Tuesday.
I dare say with the very cold air aloft, some wet snowflakes could find their way into the showers, especially Sunday or Monday. It's not a sure thing but the mere thought of snowflakes as May approaches is not easy on the psyche if you get my drift.
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THE LITTLE WHITE CHURCH AWAITS YOU
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IT COULD BE WORSE...
As I mentioned earlier, this set-up is not conducive for heavy rain amounts. Most areas Saturday-Tuesday should see rain totals of a 1/4 inch or less. The EURO suggests amounts like this Saturday through Monday.
The GFS is in reasonable agreement.
Temperatures are a sore subject for me as one who is ready for summer. Here are the daily temperature departures the GFS shows for the 7 day period April 30-May 7th....roughly 7-9 degrees below normal per day. Really!!
Monday May 1st looks particularly fresh with the GFS indicating highs in the mid 40s north to the low 50s south. Norms are in the mid to upper 60s.
Morning wind chills Monday are in the 20s across much of the Midwest. Boo to that.
By the way, things are starting off a bit cold Wednesday morning with Freeze and Frost Warnings covering the area. Temperatures in the range of 27-34 will blanket the region as the day begins. More frost or freeze warnings are anticipated in the coming week with the next round of cold.
Meantime, some decent weather is on the table the rest of this week. Dry conditions are expected and highs go from the 50s Wednesday to the low to mid 60s Thursday and Friday. Then the slide begins. Dang I could sure use that mulligan!
One thing that I am heightened by is the EURO's depiction of the MJO heading into phases 4, 5, and 6 during early May. Those are mild phases whose analogs correlate to above normal temperatures. That should put this chilly three week stretch of sub-par weather behind us.
Well, that's all I have for now. Seize the day, it promises to be a respectable one, just a tad cool. Roll weather...TS
