Line of storms lastnight produced isolated wind damage in east-central Illinois, but no reports here. A wind gust of 36 mph was measured at the Purdue University Airport as the line passed between 3 & 6 a.m. in the viewing area. The very last of any rainfall proceeding it exited the far southeast just around 9.
With the sun appearing west to east, the re-development of scattered new showers & storms should take place near & after noon as cumulus clouds develop & build.
The rainfall should peak in coverage at 55% by late afternoon-early evening, but should rapidly drop to 30% after 8 p.m.
The mid & upper jet streak is departing, which helped storms organize last night, especially southwest & south of our area. It will keep moving & produce a severe weather event in New England this afternoon-evening.
However, given the unstable, tropical airmass with pretty low cloud bases, the relatively cool mid-level temperatures & the vorticity (spin of the air parcels) increasing with the upper low settling over the area, a landspout funnel or a landspout cannot be ruled out.
Landspouts would be the very weak equivalent of a tornado or typical funnel clouds. They look like a rope & occasionally touch down, usually doing superficial EF0 damage. Should one develop & it is reported, a very random, isolated Tornado Warning could be issued. Just keep that in mind this afternoon-early evening. Any such occurrence of funnel would be isolated, but parameters show a reasonable set up for them.
There goes the departing jet streak to our south:
It will be a humid to very humid day with highs near 80 to the mid 80s with heat indices in the upper 80s to lower 90s with a light breeze.
Areas of dense fog with very low clouds should develop overnight as any lingering showers depart. Lows will run in the mid to upper 60s.
Fog & very low clouds will gradually break up & lift Saturday morning, revealing sunshine. Clouds should then bubble up into cumulus towers by afternoon. An isolated shower/t'shower is possible from these clouds. It will be a very warm, humid day with highs well into the 80s with heat indices near 90 to the lower 90s.
After dense fog & some patchy very low clouds Sunday morning with lows in the 60s, temperatures will rebound again to well in the 80s Sunday. Fog/any low clouds will lift, break & turn into a sky of cumulus clouds with sunshine. It will continue to be humid with heat indices around 90 to the mid 90s.
With highs in the 80s Monday with humid conditions (after patchy fog & 60s in the morning), showers & storms should arrive in the afternoon & peak Monday night. There is the potential of an isolated severe storm, but the main severe corridor is setting up to our south (see text & image below this image).
The corridor of better severe weather risk Monday-Monday night continues to set up from Arkansas & northwest Mississippi to southeastern Missouri, western Kentucky & far southern Illinois. It could extend as far back as northeastern Texas.
EHI is an indicator of severe risk:
Tuesday looks showery & rather breezy from the north with mostly cloudy to cloudy skies & highs only in the 70s.
Wednesday-Thursday's weather looks good with sunshine, some clouds Wednesday & sunny to mostly sunny skies Thursdsay. Cooler temperatures, lower humidity & morning lows in the 50s to 60 (The kids will need a light jacket or sweater in the mornings at the bus stop!) will make for a nice couple of days.
Highs will run the 70s to lower 80s. Some patchy fog may also occur in the mornings.
Notice how we cool off with below normal temperatures, but the heat builds from the western U.S. to southern Canada with temperatures in Canada up to 25 degrees above normal. This is a key factor in our temperatures & overall weather down the road.
It will begin to warm up Friday to the 80s area-wide again.
Notice the surface high (oval set of lines over our area) slipping to the east & a nice southwest flow ensuing (lines tightening & oriented sideways on map).
Notice the showers/storms to our northwest on the heels of this rapid warm-up.
We may pick up high/mid clouds from this Friday afternoon-evening.
The mean temperatures for the viewing area in August have been trending upward after a cool start to the month & multiple cooler than normal days in the latter half of July (after the excessive heat wave in early July). A couple bursts of heat with some 90s & recent consistent warmth day & night have put temperatures 1-2.5 degrees above normal.
We will add to this above normal temperature anomaly, as you will see........
This map & data is courtey of the Oregon State University Climate Prism Group & Dr. Ryan Maue.
The heat will work east & south. Temperatures will run above normal day & night as we move through the last week of August to near/at Labor Day.
Here's another view of the heat working south & east:
Although the temperatures will oscillate some back & forth last week of August through early September, there is an overall trend for the mean temperatures to add up above normal.
Below normal temperature trend continue to show up past the mid point of September. This is early evening on September 17. This suggests a real, cool taste of fall from Minnesota to our area!
In terms of rainfall, data suggests 1.5-3" of total rainfall for the viewing area now to the mid point of September. This includes what we will receive today & Monday-Tuesday. So, this is below normal.
Now, one big MCS or stationary band of storms can change this & know that model resolution that far out is not great. However, this gives you an idea that there is a trend to keep the heaviest rainfall west, northwest & south of our area to mid September.
Notice how dryness turns to wetness between the early half of September & around mid-month in the CFSv2 model. This fits what I am still thinking.
With the dryness overall in the early half of September & the wetness in the latter half, as well as the heat in the early half & cooler weather in the second half, the month will probably end up with normal rainfall & normal temperatures.
You can see the trend with model run after model run with the CFSv2 that the trend is for this half & half September to even out to normal in our area after a bias toward a bit above normal, initially.
As for the start to October, it looks quite warm with above normal temperatures dominating a large area for at least the first few days.