The clouds above - שחקים shechakim, "the ethereal regions," taking in the whole of the atmosphere, with all its meteors, clouds, vapours, etc.

When he established the clouds above,.... In which the waters are bound, and yet are not rent under them; and where, in the thin air, they hang heavy with them; where they are weighed by measure, and a decree made for them when they shall fall; and when they do, the Lord makes small the drops of water, which the clouds do drop and distil on men abundantly; the spreadings of which are beyond understanding, and are unaccountable, and must be referred to the power of God; who has settled and established them in the heavens, and the laws of them, Job 26:8;
when he strengthened the fountains of the deep; gave them strength, and still continues it, to cast out their waters, which run into the main sea, and feed and fill it, and return to their place again; which strength of flowing and reflowing can be attributed to nothing else but to the great power of God, Genesis 7:11.

established . . . deep--that is, so as to sustain the waters above and repress those below the firmament (Genesis 1:7-11; Job 26:8).

In Proverbs 8:28, Proverbs 8:29, these two features of the figure of the creation of the world return (the beginning of the firmament, and the embankment of the under waters); hence we see that the discourse here makes a fresh start with a new theme:
28 "When He made firm the ether above,
When He restrained the fountains of the waters;
29 When He set to the sea its bounds,
That the waters should not pass their limits
When He settled the pillars of the earth;
30 Then was I with Him as director of the work,
And was delighted day by day,
Rejoicing always before Him,
31 Rejoicing in His earth,
And having my delight in the children of men."
We have, with Symmachus, translated שׁחקים (from שׁחק, Arab. shaḳ, to grind, to make thin) by αἰθέρα, for so the fine transparent strata of air above the hanging clouds are called - a poetic name of the firmament רקיע. The making firm עמּץ is not to be understood locally, but internally of the spreading out of the firmament over the earth settled for continuance (an expression such as Psalm 78:23). In 28b the Masora notices the plur. עינות instead of עינות with לית as unicum (cf. Michlol 191a); the transition of the sound is as in גּלית from galajta. The inf. עזוז appears on the first look to require a transitive signification, as the lxx and the Targ., the Graec. Venet. and Luther (da er festiget die Brnnen der tieffen = when He makes firm the fountains of the deep) have rendered it. Elster accordingly believes that this signification must be maintained, because בּ here introduces creative activity, and in itself is probably the transitive use of עזז, as the Arab. 'azz shows: when He set His עז against the מים עזּים (Isaiah 43:16). But the absence of the subject is in favour of the opinion that here, as everywhere else, it is intransitive; only we may not, with Hitzig, translate: when the fountains of the flood raged wildly; but, since 28b, if not a creative efficiency, must yet express a creative work, either as Ewald, with reference to מעוז, fortress: when they became firm, or better as Fleischer, with reference to מים עזים: when they broke forth with power, with strong fulness. Whether the suff. of חקּו, 29a, refers back to the sea or to Jahve, is decided after the parallel פּיו. If this word is equivalent to its coast (cf. Psalm 104:9), then both suffixes refer to the sea; but the coast of the sea, or of a river, is called שׂפה, not פּה, which only means ostium (mouth), not ora. Also Isaiah 19:7 will require to be translated: by the mouth of the Nile, and that פי, Psalm 133:2, may denote the under edge, arises from this, that a coat has a mouth above as well as below, i.e., is open. Thus both suff. are to be referred to God, and פיו d is to be determined after Job 23:12. The clause beginning with ומים corresponds in periodizing discourse to a clause with ut, Ewald, 338. בּחוּקו is the same form, only written plene, as Proverbs 8:27, בּחקו = בּחקּו = בּחקקו.
(Note: One might regard it as modified from בחקקו; but that שׁוּרי, Psalm 102:12, is modified from שׁררי, or הורי, Genesis 49:26, from הררי, is by no means certain.)

Strengthened - When he shut up the fountains in the cavities of the earth, and kept them there as it were by a strong band. The deep - Which have their original from the deep, either from the sea, or from the abyss of waters in the bowels of the earth.