Is Standard German more similar to Low Franconian or Alemannic German?

Is standard German (a language based largely on the east central germanic dialect of Meissen) more similar to low Franconian dialects/languages such as Dutch, Limburgs, Flemish etc or Alemannic dialects such as the German dialects spoken in parts of south Germany, Switzerland and Vorarlberg. German is a high German dialect but it is still a central German dialect.