After a few isolated showers & sprinkles this morning with a mostly cloudy to cloudy sky, scattered showers & a few potential storms will increase after noon & last off & on into tonight.
The risk of isolated severe storms looks to stay to our south & southeast.
Highs today will run in the 70s to a few lower 80s with lows tonight in the 60s to around 70. It will be rather sticky/muggy.
Scattering of showers & storms are likely tomorrow as some sun appears & the clouds bubble up. Highs will run near 80 to the lower 80s with high humidity.
Some scattered showers/storms are possible Friday as clouds bubble back up. After 60s in the morning, highs in the lower to middle 80s are likely with muggy conditions.
Rainfall today-Friday looks variable in our viewing area with some places seeing less than 0.60" & others seeing 2".
I kept with the wording of "an average of 0.60-1.50 over the viewing area".
As for Saturday & Sunday, looks very warm & humid with highs up in the 80s & lows in the 60s. Patchy dense fog is possible Saturday & Sunday mornings with cumulus clouds in the sky during the afternoons.
Showers & storms are likely Monday, especially in the afternoon & evening. Some lingering rainfall may last into Tuesday morning. It is a marginally sheared environment for severe. If we see enough sun & highs well into the 80s are fully-realized, then isolated severe risk may be introduced to the forecast.
Here is the Supercell Composite for Monday PM. Notice the core of the best conditions for severe are southeastern Missouri to Arkansas & western Tennessee. Here, the gray in Illinois & our viewing area imply perhaps an isolated severe storm.
The Energy Helicity Index (EHI) shows some higher parameters in Illinois down to Arkansas. This index of spin, shear & instability show where conditions are present to increase severe weather risk if there is a trigger for storms (without other limiting factors like a cap, for example).
Wednesday-Friday of next week look dry with partly cloudy to mostly sunny skies & highs in the upper 70s to the 80s with lows in the 50s & 60s. Should have the humidity drop. Patchy fog is possible at night.
It looks rather breezy, hot & humid for the last week of August with highs near 90 to the 90s & lows in the muggy 70 to 70s range. Heat indices may reach 100 (even exceed some) at times. The hotter than normal weather may continue to around Labor Day before it cools.
Some storms are possible, but exact timing is in question.
Notice the hotter trend for the last week of August in the EKDMOSv2 model ensembles (running model blend over & over & over to see the results).
On the right are the temperatures & each day is at the bottom. First graphic is daily highs, second is daily lows. Notice the trend upward on the back dotted line.
Notice the CMCE model ensemble temperature anomalies. The orange/red shows above normal temperatures over a large area in late August. This image was pulled from the afternoon of August 31. 7-9 degrees above normal here would signal a high in the lower 90s.
The overall above normal temperature trend may last through the first half of September before will cool below normal.
We have been straddling a Phase 7 in the MJO, models project going back to 6, 5, then 8 late August to late September.
We really never got into a Phase 3 or 5, which promotes burst of heat in our area in JJA & JAS analogs. It did get to 90 to the 90s early in the second week of August, but not mid-August like I was thinking. This MJO correlation forecasting gets a hair tricky because a Phase 3 in July to early August has a different outcome than the same phase in latter August. It is a hot phase initially, then becomes less of a hot phase feature.
Of course, other factors go into the forecast. The MJO is not a good measure of intense Plains heat waves per sey. It had no bearing on the major, historic heat wave recently in Canada, through the central & northern U.S. Plains which say 110 reached in North Dakota & +106 in Montana (100s even in southern Manitoba).
I a still going with 90 to the 90s late August, however. I do not have evidence to refute that yet.
This matches up with the thinking of a bit cooler mid to late next week, then hot, then overall warmer than normal (overall) the first half of September, then cooler than normal after the September mid point.
On a side note, low solar activity & corresponding developing El Nino Modoki (traditional El Nino's brother with warming of the equatorial Pacific west of the traditional zone) are still focal points of the late fall to winter to early spring 2018-19 outlook. We already see the strong indicators with the tropical storm/hurricane weakening to destroying shear in the tropical Atlantic & Caribbean. Meanwhile, the Atlantic overall is in a very cold phase. There just isn't a big window for substantial tropical storms or hurricanes to from in the Atlantic this season & we are approaching the peak of the season.
Low solar & Modoki promotes an overall colder & snowier than normal winter here. Another installment of the fall-winter-spring outlook will be out in the coming weeks.