Are the 5-day QPF and day 1, 2, and 3 QPFs based on the same guidance?
No. The 5-day QPF issued by our medium-range forecasters is based primarily on the 0000 UTC and 0600 UTC numerical model runs, with a quick glance at the 1200 UTC runs. The forecaster prepares a forecast for days 4-5, then adds the days 1-3 QPF issued at about 1000 UTC to get a 5-day forecast. All of this is based on 0000 and 0600 UTC model guidance. The forecaster then adjusts the 5-day total based on quick looka the 1200 UTC model output.
