This dataset depends on the following independent variable (i.e, grid):
grid: /S (days since 1960-01-01) ordered [ (0000 1 Jan 2019) (0000 1 Feb 2019) (0000 1 Mar 2019) (0000 1 Apr 2019) (0000 1 May 2019) (0000 1 Jun 2019) (0000 1 Jul 2019) (0000 1 Aug 2019) (0000 1 Sep 2019) (0000 1 Oct 2019) (0000 1 Nov 2019) (0000 1 Dec 2019) (0000 1 Jan 2020) (0000 1 Feb 2020) (0000 1 Mar 2020) (0000 1 Apr 2020) (0000 1 May 2020) (0000 1 Jun 2020) (0000 1 Jul 2020) (0000 1 Aug 2020) (0000 1 Sep 2020) (0000 1 Oct 2020) (0000 1 Nov 2020) (0000 1 Dec 2020) (0000 1 Jan 2021)] :grid
so there will be 25 links below for the different files.
You may want to get a utility like wget which can download sets of files. For example (all one line)
wget -r -l2 -nd --no-parent -e robots=off -v --relative 'http://45.183.221.150/SOURCES/.NextGen/.CPT/.1p0/.Guatemala/.GFDL-CM2p5-FLOR-A06/.Forecast/PredErrorVars/S/%28days%20since%201960-01-01%29streamgridunitconvert/downloadsarcinfo.html'
single quotes are necessary in unix to protect the url from expansion; probably necessary in other cases as well