הַמַּ֔יִם אֲשֶׁ֖ר מֵעַ֣ל
The waters which are above
Proponents of a local firmament, that is the atmosphere, hold to one of two interpretations. The ambiguity allows either one.
The most natural and expected is that the waters above are the clouds. Faced with evidence from the text of different conditions on the early texts and clues to a milder overall climate, others have proposed some kind of vaporous or ice layer in the upper atmosphere.
However these waters above ( מֵעַ֣ל ) the firmament were possibly much further away. The format with both below and above appears to have the positions at extremes. The prefixes "m" and "l" are used in format "from here to there". Compare "מֵעַ֣ל לָרָקִ֑יעַ" with "מִתַּ֣חַת לָרָקִ֔יעַ".
This leads some scientists to merge the text with observations of nature. The result works well both in nature and supernatural metaphor. The waters that once were together are now separated by insurmountable distances. The earthly waters are often feared, while the lofty stars and galaxies are misunderstood.