ABOUT WHAT YOU WOULD EXPECT...
After a rather poor start, the holiday weekend weather got better and better ending with a picture perfect Labor Day. The image's below (courtesy of the Library of Congress), show a 1942 Labor Day parade that was very well attended. I'm sure the weather was not as nice as what we enjoyed around here this year.
If there is one thing I can say about our weather going forward it's that there's not much to get excited about beyond Tuesday. All signs after that point to a multi-day stretch of dry weather that could even last into early next week. Temperatures will be close to normal Tuesday through Thursday before a warming trend gets us well above average Friday and Saturday.
Examining the short term synoptic set-up I do see a front that is projected to pass Tuesday afternoon. While there's some meager moisture in place, forcing is best well to the north and a cap (warm-air aloft) could inhibit showers or storms from forming in some areas as the front passes in the afternoon. That said, there is a decent build up of instability (CAPE) across the south at mid-afternoon.
With respectable instability in place, should the cap break, there is the possibility of a broken line of showers and storms along the front, especially in the area near and southeast of the Quad Cities. Additionally, a few light morning showers are possible in my northern counties. The 3K NAM is the most aggressive in showing the cap eroding enough for scattered development in the afternoon. The GFS is the driest solution and is high and dry with a quiet frontal passage. I'm leaning towards the idea that at least a few showers and storms will initiate. How soon and how widespread is open for debate but the southeast is the most vulnerable and we'll just have to see how the set-up evolves as the morning progresses. Overall, I think most areas end up with little (light amounts) to no rainfall. Here's what I'm seeing for rainfall potential.
The dry GFS
The 3K NAM
The 12k NAM
Whatever happens, the front will be out of the area by late Tuesday evening and a much drier air mass will invade the Midwest. By dawn Wednesday dew points are down in the 40s. That will provide cool nights and pleasantly mild days through Thursday. Very nice highs in the 70s!
By late week you can see the upper air flow goes west to east (zonal) over the upper Midwest. Such a pattern will allow warmer air to return Friday and Saturday. Highs are expected to go from the low 80s Friday to the mid 80s Saturday.
The next challenge is what to do with a frontal passage Saturday evening. The big two (the EURO and GFS) go their separate ways here. The GFS drives the front through Saturday afternoon and forces it well south of the Midwest Sunday. The EURO stalls the front in northern Missouri and then brings a wave along it Sunday that sparks showers and storms. I like the less amplified look of the EURO and suspect the GFS is too far south with the boundary giving credence to the rain threat. This may take a day or two to fully resolve but no matter the outcome I do expect significantly cooler temperatures to be back with us Sunday to close out the weekend.
So that's the long and short of it for a Tuesday. Hope you all had a fantastic holiday weekend. Back to the grind! Roll weather....TS