We dropped to 50.0 right on the nose this morning at the Purdue Airport & our WLFI Ob Site where I take daily temperature, wind, dew point & precipitation observations.
This make this morning the coolest since May 30.
Lows ranged from 46-57 over the viewing area.
So when do we typically start to see chilly Fall mornings?
Highs today reached 78-83 with low humidity & smoky skies with fair weather cumulus humilis clouds.
Skies will turn partly to mostly cloudy after 2 a.m., but clear with time tomorrow morning.
After lows tonight 55-64, highs tomorrow should reach 84-89 with southwest winds increasing to 21-34 mph. It does not look humid, however.
Thick wildfire smoke will turn sky pale & hazy. It will also shave a couple degrees off our high temperatures.
After skies turning partly to mostly cloudy for a time later tomorrow night to early Sunday (lows 66-70), we should see mostly sunny skies with wildfire smoke & pale, hazy sky Sunday. Highs of 89-95 are likely with southwest winds at 21-35 mph.
It will turn more humid with heat indices rising to 92-99 as dew points rise to 66-70.
Monday looks hot & breezy with 90-95 & heat indices 93-100, followed by largely dry Tuesday with 90-94 with heat indices of 94-100 (after morning lows of 65-70).
Any storms will stay northwest & north of our area this weekend & through much of Tuesday, it still appears.
A few storms are possible Tuesday late evening-night to Wednesday as surface cold front sinks southward in response to strong surface low & upper trough in Manitoba punching into the ridge.
There is the risk of an isolated severe storm or two, so potential of MARGINAL RISK for severe (Level 1 of 5) is possible.
However, front will move back north Thursday, which could pop another storm or two.
Rainfall will be very hit-or-miss.
Wednesday's highs should run 77-84 (with wind going northeast to east) , followed by 81-88 Thursday (wind going east to southeast to south, then southwest).
Temperatures will run above normal overall for the next week.
Upper ridge should pull developing tropical system toward northeastern Mexico & Texas next week. With time, it should move east-northeastward through the Southeast U.S. as ridge moves eastward & centers over eastern Canada & New England (with near/record warmth).
So, this should keep it dry here with all of the heavy rainfall tied up in the southern U.S.
Note the expanse of that heat with the ridge shifting its center northeastward.
Next weekend to early that following week (September 20-21) look hot & windy with temperatures approaching record hot levels.
Note the big difference in temperature projected at 8 a.m. on Monday, September 20. 30s in the Dakotas will give way to record-warm mid to upper 70s (for so early in the morning during the time of year).
Some of the low temperatures that morning will break daily record warm low temperatures by 4-6 degrees in Illinois & Indiana.
This strong surface cold front should pass on September 21.
Dynamics suggests a highly-broken line of storms with SLIGHT RISK parameters for severe. Coverage only looks to run 40%, however.
All of the deep tropical moisture will be tied up in the Southeast U.S. & along the East Coast.
Lows on the morning of September 22 & 23 should drop to 41-48.
We should warm up significantly after this cool-down in late September with September 25-26 look quite warm. Some places will approach or reach 90 again.
Brief shot of cool weather will follow before temperatures go well above normal in early October.
High/Morning Low...Date, Conditions
SEPTEMBER 17-OCTOBER 4:
91/66....Sept. 17, Fri. Pt. Cloudy to Mostly Sunny, NOT Humid, (Dew Points 55-61), S Wind 5-15 mph....Records: 93-1891
94/68....Sept. 18, Sat. Mostly Sunny, Humid (Dew Points 65-70), Heat Index to 100, SW Wind 15-30 mph.....Records: 93-1891
94/73...Sept. 19, Sun. Mostly Sunny, Humid, Heat Index to 100, SW Wind 20-30 mph...Records: 94-1891
94/76...Sept. 20, Mon. Partly Cloudy, SSW Wind 15-30 mph, Heat Index to 102, Isolated Shower/Storm (20%)...Records: 95-1940
88/75...Sept. 21, Tue. Some Sct'd Showers/Storms with SLIGHT RISK Parameters for Severe...Records: 95-1940
71/55...Sept. 22, Wed. Partly Cloudy, NW Wind 15-25 mph.
72/43...Sept. 23, Thu. Partly Cloudy, NNE Wind 10-15 mph.
76/44...Sept. 24, Fri. Mostly Sunny, E to SSE to S Wind 10-15 mph.
84/58...Sept. 25, Sat. Partly Cloudy, SW Wind 15-30 mph...Records: 94-1891
88/66...Sept. 26, Sun. Partly Cloudy, Few Showers/Storms, SW Wind 20-35 mph....Records: 96-1891
72/57...Sept. 27, Mon. Partly Cloudy, NE Wind 5-10 mph.
71/45...Sept. 28, Tue. Sunny, E Wind 2-5 mph.
77/46...Sept. 29, Wed. Mostly Sunny, S Wind 10-15 mph.
82/54...Sept 30, Thu. Mostly Sunny, SW Wind 10-20 mph.
83/60...Oct. 1, Fri. Partly Cloudy, SW Wind 10-20 mph...Records: 92-1897
86/65...Oct. 2, Sat. Partly Cloudy, SW 15-25 mph...Records: 92-1983
82/66...Oct. 3, Sun. Mostly Cloudy, Some Sct'd Showers/Storms Possible, SSW 10-20 mph.
74/57...Oct. 4, Mon. Becoming Partly Cloudy, W Wind 10-15 mph.
73/52...Oct. 5, Tue. Partly Cloudy, WNW 10 mph.
72/45...Oct. 6, Wed. Mostly Sunny, W 10 mph.
71/45...Oct. 7, Thu. Mostly Sunny, NW Wind 5-10 mph.
72/42...Oct. 8, Fri. Mostly Sunny, E Wind 5 mph
77/45...Oct. 9, Sat. Mostly Sunny, S Wind 10 mph
83/52...Oct. 10, Sun. Mostly Sunny, S Wind 15-30 mph...Records: 88-1938
85/63...Oct. 11, Mon. Partly Cloudy, SW Wind 20-40 mph......Records: 86-2010
83/65...Oct. 12, Tue. Mostly Cloudy, Sct'd Showers/Storms, SW Wind 20-30 mph...Records: 87-1930
65/53...Oct. 13, Wed. Mostly Cloudy with a Few Showers, Then Partly Cloudy, Northwest Winds 15-25 mph.
64/37...Oct. 14, Thu. Mostly Sunny, N Wind 5-10 mph.
68/35...Oct. 15, Fri. Mostly Sunny, SE Wind 5 mph.