A number of major commentaries (mostly Trinitarian) recognize that the double use of the Divine Name in Genesis 19:24 is simply an emphatic Hebrew stylistic feature—repetition employed for emphasis—to underline that the destruction of Sodom and Gomorrah was a direct act of God, not some natural fluke.
Ellicott’s Commentary for English Readers explains that “many commentators, following the Council of Sirmium, see in this repetition of the name of Jehovah an indication of the Holy Trinity, as though God the Son rained down fire from God the Father. More correctly Calvin takes it as an emphatic reiteration of its being Jehovah’s act.”
Keil and Delitzsch’s Biblical Commentary on the Old Testament calls the phrase “from Jehovah” an emphatica repetitio (emphatic repetition), and again cites Calvin to stress that it was not according to the usual order of nature, but a manifest, extraordinary act of God, ensuring no natural causes could account for it.
The Pulpit Commentary says:
Whether this Divinely-sent rain was "burning pitch" (Keil), of lightning which ignited the bituminous soil (Clericus), or a volcanic eruption which overwhelmed all the region (Lynch, Kitto), it was clearly miraculous in its nature....the phrase is regarded as "an elegancy of speech" (Aben Ezra), "an emphatic repetition" (Calvin), a more exact characterization of the storm (Clericus, Rosenmüller) as being out of heaven.
Matthew Poole's Commentary notes the phrase "From the Lord, i.e. from himself; the noun put for the pronoun, as Genesis 1:27 2 Chronicles 7:2. But here it is emphatically so expressed," and gives one of the reasons to "signify that it proceeded not from natural causes, but from the immediate hand of God."
Some English translations, like the NET, “streamline” the repetition into an explicit statement of divine causation—again, to remove any thought that this was just an unlucky natural disaster. This also explains why, in the parallel thought of Amos 4:11, some English versions use the first-person pronoun (“I”) instead of the word “God” (e.g., NIV, NCV, TEV, CEV, NLT).
Thus, this interpretation avoids reading two Yahwehs into the text (and thus any hint of polytheism) and instead follows a well-attested Hebrew idiom (cf. Hosea 1:6–7; Zechariah 3:2; 10:12). Nor is this usage reserved for the Divine Name: the same pattern appears with Solomon in 1 Kings 8:1 and 12:21. Similarly in Genesis 4:23, 1 Samuel 20:12–13; 25:22; 2 Samuel 3:8–9. In each case, the repetition of the personal name functions to heighten emphasis. So that Genesis 19:24 has nothing to do with introducing two Yahwehs, which would clearly break with the unitary Jewish creed of the Shema in Deuteronomy 6:4.