Hottest air of the year followed by another stretch of cool air

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Sean Ash

For a change it feels like summer in central Indiana. This includes hazy sunshine, humid heat in the 80s and a light southwest wind. In what’s been the coldest July on record for the first 20 days of the month, this is welcomed news by Hoosiers longing for good “pool” weather.


The Muggy Meter continues to creep into the humid to uncomfortable range with dew points in the 60s. If you’re heading to Victory Field this evening for the Indianapolis Indians it’s a good idea to dress in comfortable clothes. But it will be a great evening for baseball and anything else outdoors.

Dewpoints INDIANS

Much like the past couple of mornings, areas of locally dense fog will accompany the Tuesday morning commute. Though it’s difficult to pinpoint exact locations… low-lying areas, riverbeds and valleys are usual suspects for low visibility.

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Any fog will quickly dissipate to allow for a hazy sky. Temperatures will quickly warm into the lower 80s by 11am and upper 80s between 2-4pm. For the first time this year Indianapolis may officially hit 90 degrees… snapping the 314 day sub-90 degree day streak. This is the 8th longest streak in the past 30 years for the city and we’re now a month past the climatological norm for the first 90 degree temperature.

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Regardless of the city technically hits 90 degrees it will certainly feel like with heat indices in the mid to upper 90s. Storms will continue to bypass the central Indiana to the north-northwest tomorrow. But we’ll monitor a storm initiation along a cold front late tomorrow evening in the Michiana area for local impact.

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Our next best chance of rain and storms will be Wednesday. Though it’s not an ideal set up for severe weather, locally strong storms are possible and heavy rain is likely in any storms that develop.

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By Wednesday evening much of the are will be north side of a cold front and feeling the impacts to the return of northwesterly wind. This will bring the first of two much cooler than normal spells to the region… but will be tame compared to what’s brewing for the July 28-30 time frame.

rpm4 JET

As noted in the blog yesterday, another sharp atmospheric trough will establish itself over the Great Lakes and Ohio Valley early next week. The end result will below normal temperatures and daily chances of showers and storms underneath an upper low.


Analog data (above) give this forecaster higher than normal confidence on this pattern delivering fall-ish conditions for days 7-10 in the forecast period… with 95% of 105 analogs (similar historical atmospheric conditions) delivering below normal air. (Map provided by


Both the European (above) and GFS (below) models show another air mass capable of producing temperature anomalies of 10-20 degrees below normal. This would result in near record low maximums next Tuesday and Wednesday. Stay tuned as we update this trend.


Tomorrow is hands down our hottest day of the next couple of weeks. The graph above is highs/lows from the GFS Ensemble output displays how we’ll most likely be on the cooler side of normal after Tuesday. (Three images above are courtesy of

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The transition to the cool pattern next week may deliver scattered showers and storms this weekend. Confidence is low at the moment on coverage and timing… but there is potential impact to Brickyard 400 festivities this weekend. Check back for updates and have a great evening – Sean Ash