Hottest air of the year possible Tuesday

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Updated: .
Sean Ash

Overall this shaped up to be a decent Sunday in central Indiana with highs in the upper 70s and lower 80s. You probably noticed a increase in haze and humidity, and that trend continues the next couple of days.


Areas of locally dense fog develop overnight and will impact the Monday morning commute for some. Low temperatures range from 60 to 65. Any fog should quickly depart by late morning, and hazy sun will be the rule of thumb tomorrow.


With highs in the mid to upper 80s and heat indices in the 90s, Monday will be a good pool day… something we haven’t had much of lately.


Indianapolis’ streak of sub-90 degree days is up to 313. There is a chance of snapping the streak Tuesday when temperatures make a run at that elusive number. Even if we don’t hit 90 it will certainly feel like with heat indices well into the 90s.


Our next best chance of rain and storms is late Tuesday night into Wednesday afternoon along an approaching cold front. Some of these storms will produce heavy rain and gusty wind.


If we miss 90 degrees Tuesday the streak may continue well past this weekend. Long range guidance suggesting another unseasonably cool air mass arriving July 28-30… possibly producing temperature anomalies of 10-20 degrees below normal.


Above is the upper air pattern projected by the European model for next Tuesday. This shows another pronounced trough/upper low sitting across the Great Lakes/Ohio Valley… similar to the set up that produced the chill last week.


The latest GFS ensemble 850mb (roughly 5,000ft) temperature anomaly map for the same time shows fall-ish conditions returning as well. It’s far out, but this long range signals agreeing suggest a higher than normal confidence in the day 8-10 outlook. Below is surface temperatures from the same model Indianapolis. Notice that 13 of the next 15 days produce below normal highs, and mid-70s may be too “warm” next Tuesday. It’s something we’ll monitor closely in the week ahead. (Image above and below courtesy of


In the short term, after storms on Wednesday we’re in store for a pleasant Thursday and Friday. Prior to the aforementioned cool spell next week with a period of storms that may impact the Brickyard 400 next Sunday. We’ll be fine tuning that forecast in the days ahead.


Have a great evening – Sean Ash