We will continue to string together some really nice afternoons but there are some ‘wrinkles’ have developed in the extended forecast
SUNNY STRETCH AND DRY AIR
Following a terrific weekend we start the work week with sunny skies but added some thin/high clouds during the day. They were not enough to slow temperatures rising from the 40s outlying to the lower 80s late in the day. This air is very dry, meaning there is not any real water vapor in the air. The relative humidity late day was under 30% in most locations.
Dry air cool and warms rather easily and it is not uncommon when these conditions are present that temperatures can vary as much as 30-degrees from the morning low to the afternoon highs. That was exactly the case in Bloomington Monday. They started the day at 48° and ended with a high of 80-degrees under mostly sunny skies. Though we will not be as cool Tuesday there will be a slight chill to start the day with some outlying locations opening the day perhaps just below 50-degrees. Sunshine will once again be plentiful and likely to remain that way for the rest of the week.
FIRST, is the passage of a backdoor cold front late Wednesday. Ahead of the front, potentially the warmest afternoon of the year with a forecast of 85° or nearly 10-degrees above normal. Late in the day, a cold front will spread south, southwest from Michigan bringing an abrupt change to the temperatures. This so-called ‘backdoor cold front’ will stiffen winds from the northeast and deposit much cooler air starting Thursday. We are expecting a few mornings to again dip into the 40s, Thursday and Friday with afternoon high temperatures struggling to reach 70-degrees Thursday afternoon. Afternoon temperatures will modify starting Friday and will be quite pleasant for the entire holiday weekend. That is a very large change from late last week when real summer heat looked to take hold.
The second, noticeable change in the long-range forecast is the emergence of an upper-low deposited over the Tennessee Valley. It’s weak and small but could lead to a stray/widely scattered shower Race Day. Stay tuned!
Rain is still not a real concern for the next several days. Month looks to end drier than average. We are nearly 1″ below normal entering the day. Overall, there are no real organized threats for area-wide rainfall for several more days.