This page has daily 12Z model output discussion as it comes in. Discussion updated Monday-Friday by 12:00 NOON.
HEADLINE: MID-DAY GFS SUPPORTS DAYS 7-9 PRECIP IN ARGENTINA…
North America: The 12z run is unchanged in keeping the focus of heavy rain on days 3-4 across the Deep South and south of the Delta. This run is a little drier with the early week 2 rain in the Midwest, and otherwise similar to previous cycles.
South America: This run is halfway between the slower 06z and faster 00z runs on returning rain chances to Argentina around day 8. Overall this run seems like a reasonable midpoint in timing and coverage. Otherwise no changes.