Before swiftly breaking the awareness and 'melt[ing] indistinguishably into it again'
The personification using 'melted' links nick / the west to the snow and being caught up in the drama of the east as the destruction for the purity of his dreams
Fitzgerald uses this moment of nostalgia at the end of the novel to show nicks realisation of his entanglement of the drama of the east, to show the inauthenticity of eastern America.
Fitzgerald creates a light. This therefore builds this critique of the American dream and its hollowness, reducing life to a singulardreamlike imagery through dynamic verb of the snow ‘twinkl[ing] against the windows’, the brief description of light in the Midwest standing as Nicks version of the ‘green light’ that was Gatsby's raisin d'etre, again contradicting the east and Midwest, showing Nicks to be soft, pure and vast rather than one singular green goal.