The forecast on my iPhone is for LOWER temperatures than today (its currently 95-97). The range is mid 70s to mid 80s. However, there is a chance of rain each day.
The 105 heat index is for TODAY. From the site the author linked:
DAY ONE...This Afternoon and Tonight
A Heat Advisory is in effect until 8 PM today. Heat index values
will be around 105 degrees.
A Severe Thunderstorms Watch is in effect for most of the area
until 9 PM this evening. Severe thunderstorms with damaging winds
are the primary threat.
.DAYS TWO THROUGH SEVEN...Saturday through Thursday
The chance of thunderstorms is increasing for Sunday afternoon
and evening. Some of these storms may also be severe.
.SPOTTER INFORMATION STATEMENT...
Spotters have been activated this afternoon and evening. Spotters
may need to be activated Sunday.
DAY ONE...This Afternoon and Tonight
A Heat Advisory is in effect until 8 PM today. Heat index values
will be around 105 degrees.
A Severe Thunderstorms Watch is in effect for most of the area
until 9 PM this evening. Severe thunderstorms with damaging winds
are the primary threat.
.DAYS TWO THROUGH SEVEN...Saturday through Thursday
The chance of thunderstorms is increasing for Sunday afternoon
and evening. Some of these storms may also be severe.
.SPOTTER INFORMATION STATEMENT...
Spotters have been activated this afternoon and evening. Spotters
may need to be activated Sunday.
From what I can see, the fights are scheduled for Sunday only, so not sure why the author is talking about next weeks forecast.
Its supposed to be 89-91 Saturday and Sunday, with chances of rain.