Duane1966,
I don’t see where your link provides examples which show that it was common to forecast that a daytime or a night time would be involved with an event when no part of the daytime or no part of the night time could have occurred.
Two possible answers were raised in the article.
1.) “‘Three days and three nights’ is a special phrase used in the ancient world with the meaning ‘long enough to be definitely dead.’ It derives originally from the ancient pagan notion that the soul’s trip to the after-world took three days and three nights. Jesus’ use of the same phrase for the duration of his death before his resurrection (Mt 12:40) carries a similar force: it is a way of saying that he would really die, NOT that he would be literally dead for exactly seventy-two hours. ‘Three days and three nights’ was a Jewish idiom for a period covering PARTS of three 24-hour ‘days-and-nights’ (cf. 1 Sam 30:12-13; Est 4:16-5:1).” (New Bible Commentary, p 819,920 under Jonah 1:17/Matt 12:40)
“In ancient literature [three days and three nights] indicated a period so long that if someone appeared to be in the realm of death for that length of time, only divine intervention could bring him back to life. …Three days may also simply mean a fairly long time (cf. 1 Sam 30: 12; Esther 4:16). In Jonah it heightens the picture of the great power of God who can save his disobedient messenger even after ‘three days and three nights.’ Much later Jesus’ disciples on the way to Emmaus had given up hope because ‘this is THE THIRD DAY since it happened’ (Luke 24:21).” (The Books of Joel, Obadiah, Jonah, Nahum, Habakkuk and Zephaniah commentary by John D.W. Watts [Cambridge Univ Press, 1975], p 82f)
2.) Whenever Jesus refers to His suffering of three days, it begins when he is handed over to the authorities. This occurred on the Thursday night when Judas betrayed Him.
In light of the above, the assumption of referring the “depths of the earth” to the tomb may be wrong. There are scriptures that liken “earth” to the heart of man, which is also described as exceedingly wicked (Gen 6:5-7, Jas 4:4). Thus, when Jesus shares in our sin, He is in the “depths of the earth”.
So, three nights = Thursday night, Friday night, and Saturday night.
Three days = Friday, Saturday, and Sunday.