DOG DAY PERFECTION...
Make no mistake about it, the past few days have been weather perfection throughout the Midwest. After a sizzling start to last week a fall-like air mass completely overhauled conditions over the weekend right on into Monday. You can see the stark change in the temperatures below. Highs in the low 80s and lows in the low 50s (even some 40s in spots).
What you can't see but could easily feel is the drop in humidity. Remember those heat index values which were around 110 last Tuesday?...(that's how it felt). With lows down around 50 the past few mornings its felt 60 degrees cooler. I personally appreciated that! Notice on the Davenport meteogram the past 72 hours how the dry air warmed to around 80 during the day and cooled about 30 degrees overnight to the low 50s. Winds were light but consistently out of the E/NE. Also, the smoke was largely gone from out skies and visibility was excellent at 10 miles with turquois skies.
Even Monday morning we were enjoying the fruits of high pressure with Monticello at 48 and Steve Gottschalk in Lowden reporting a 47 degree low.
Temperatures such as these are roughly 8-10 degrees below normal and more typical of mid-September.
Slowly but surely the pattern this week will turn to one more typical of mid-August. See the big Canadian high that's kept us refreshed all weekend.
It retreats to SE Canada the next 24 hours and by Friday a strong southerly flow is established with low pressure off just off to the west.
That will substantially increase water vapor and humidity levels. Here's where we are Monday morning. Very much on the dry side.
This is Friday evening and water vapor has soared to over 2 inches through the Mississippi River Valley.
That will eventually bring much higher humidity and rain chances back to the Midwest. The dew points Friday are back in the low to mid 70s which is going to make for some sultry late week conditions.
Before the deep moisture returns, chances for widespread beneficial rain remains low. However, I do expect scattered showers and storms later Friday or Friday night. I also have doubts regarding coverage and how heavy any rains will be with the current pattern so dry, I think the best approach is to account for the dryness and play it conservative in terms of how much rain may fall. I do feel a few spots could knock off 1/4 to 1/2 inch late week but many others could see little if any rain. In the end it all boils down to mesoscale details which at this distance are unforeseen.
With all that in mind, I would plan for another fine day Tuesday with all the attributes that comprise a fine August afternoon. Down the road, we are reaching the point where we need to appreciate the fact that the days have been growing shorter for a couple months. Colder temperatures are soon to follow. I already notice the sun setting earlier as the corn fields fade from green to yellow. The lengthening shadows are a sign of passage well known to our ancestors. At my age, late summer is a period of reflection where inevitably the clock seems to tick a little faster. With each passing day it becomes more apparent that time waits for no one, especially me. Make every day count. Roll weather...TS