Update quey

I have a table (pubacc_lo) from the US government with 500,00+ rows. It has latitude and longitude in three columns
eachfor degrees, minutes and seconds. I need a Point geometry column. So I wrote this query: 

with mydata AS (SELECT (pubacc_lo.lat_degrees + pubacc_lo.lat_minutes/60 + pubacc_lo.lat_seconds/3600) as lat ,
(pubacc_lo.long_degrees+ pubacc_lo.long_minutes/60 + pubacc_lo.long_seconds/3600) as long FROM pubacc_lo) 
UPDATE pubacc_lo SET lonlat_84 = ST_SetSRID(ST_makePOINT(long,lat),4326) FROM mydata;

It appears to work, but is going to take days it seems to finish. Anybody have a faster way?