SEVERE WX : Excessive Heat Warning View Alerts

July 12, 11:15 AM Weather Forecast Update

Some storms intense heat & Barry remnants skimming by......

Posted: Jul 12, 2019 10:35 AM
Updated: Jul 12, 2019 9:40 PM

What a comfortable morning!  It was the coolest in three weeks!  Lows ran 54-59 viewing area-wide.

Today looks great with lots of sunshine & highs 82-87.  It will be warm enough for the pool & water slides, but comfortable enough (in terms of the humidity) to be outside in general.  The UV Index will be especially high, however, so wear a hat & smother on sunscreen to avoid sunburn.  Today will be one of the easiest days of the summer to burn due to the lack of clouds, still high sun angle & also lack of thick haze. 

The stream of some wildfire smoke from Canada that we had yesterday evening has exited.

Saturday looks hot & mostly sunny with highs 88-92.  The humidity will not be an issue initially, but it will get more & more humid in the afternoon & especially by evening.  Dew points will rise from 55-60 early in the day to 68-72 by late in the day with some increasing clouds, mainly in the northwest.

This will lead to heat indices rising to 91-99.

On the periphery of the expanding heat (near the warm front), some storms are possible Saturday evening-night, mainly northeast of a Fowler to Lafayette to Frankfort line.

An isolated severe storm is possible (wind).

Sunday looks capped, but a couple random isolated storms are possible on the outflow boundary left from any storms from Saturday evening-night.

Monday looks hot & humid, but currently dry with highs 91-96 with heat indices 96-105.  This heat up will occur with the sinking air ahead of the tropical system with any isolated storms staying just south of our area on a far outer band of the tropical depression at the time.

Tuesday looks hot & humid with a few isolated storms & highs & just a bit cooler (with more clouds & much less sinking air) with highs 89-94.  Heat indices will run 97-107.

Remnants of Tropical Storm, or eventually Category 1 Hurricane Barry, will be pulled up into Arkansas & southeastern Missouri before being pushed away by a weak cold front & upper trough.

So, greater rainfall amounts & coverage will be south & southeast of our area.

Here, we are looking at some scattered storms from the far north side of the remnants.

The slightly-better storm coverage will likely occur with the weak cold front & upper trough coming through, however.

I went with 35% coverage of storms Wednesday & 40% Thursday.  The coverage amount does not ensure everyone will get rainfall, but a few amounts under the heaviest storms could exceed 2", given the amount of water available to squeeze out (high dew points).

An isolated severe storm or two is also possible on both days.

Both days look hot & muggy with highs of 90-95 with heat indices of 99-111.

After Thursday, a period of dry weather will dominate.

It looks cooler & less humid Friday-Saturday (July 19-20) with lots of sunshine.

Highs should run 79-84 with lows 55-59.

Watch the intense heat build, however!

An intense hot upper ridge will develop in the central U.S. & expand eastward.  This will happen rapidly.

By Sunday, 100s may reach central Manitoba with 90s to the western fringes of Hudson Bay!

It is possible that 100 could be reached from Manitoba & far western Ontario to Texas Sunday, making it the most-intense heat wave of the summer so far.

There are millions of unplanted acres of crops in the Plains due to the floods & persistent rains.

Now, it has been drying out & there are millions of bare, brown acres covered in silt & sand or that have been sprayed with herbicide to burn the weeds down.  Also, crops are well behind schedule, resulted in a lack of good transpiration & more soil exposed than leaf surface area.

This will result in a positive feedback mechanism to enhance the heat.  More green, lush vegetation would drive humidity, but retard heat.  Brown surfaces & bare soil will warm up much more quickly.  We have seen that in the eastern part of our viewing area & through northeasern & eastern Indiana recently with a lack of planting resulting in elevated temperature levels overall compared to the rest of the state.

However, the upper levels also support the ridging as the pattern shifts & the warming from the top down occurs, the albedo of the ground & drying soil will just enhance it.

So, a shot of intense heat with highs 93-98 are possible with +100 heat indices for a time after July 20 & before July 28.

Cooler, wetter weather should arrive as we exit July & move through early August as the pattern shifts.

In this shift, a round of storms is possible with severe weather.

Even in the cooler pattern of mid-August, at times upper troughs with stronger mid & upper levels winds will be over the area.  Even with temperatures of 80-85, with say a 70-72 dew point, you can get severe storms.  We will monitor.

More intense heat may return in late August, but it currently does not look as strong as it looks in July.

Article Comments

West Lafayette
Scattered Clouds
84° wxIcon
Hi: 91° Lo: 76°
Feels Like: 93°
Scattered Clouds
84° wxIcon
Hi: 93° Lo: 77°
Feels Like: 93°
81° wxIcon
Hi: 85° Lo: 76°
Feels Like: 86°
81° wxIcon
Hi: 90° Lo: 76°
Feels Like: 86°
83° wxIcon
Hi: 92° Lo: 76°
Feels Like: 93°
80° wxIcon
Hi: 92° Lo: 76°
Feels Like: 84°
82° wxIcon
Hi: 92° Lo: 75°
Feels Like: 91°
Broken Clouds
83° wxIcon
Hi: 91° Lo: 77°
Feels Like: 90°
Broken Clouds
83° wxIcon
Hi: 90° Lo: 77°
Feels Like: 90°
Broken Clouds
81° wxIcon
Hi: 92° Lo: 76°
Feels Like: 85°
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