About the 5-and 7-Day QPFs

The 5-Day Quantitative Precipitation Forecast (QPF) products are created by adding WPC's 6-hour QPFs for Days 1-5 (a total of 20 6-hour periods). The Day 1-3 forecasts are prepared by our short-range QPF meteorologist, while the Day 4-5 periods are prepared by our medium-range forecasters. For the 7-Day QPF, we add to the 5-day product 6-hour QPFs for the Day 6-7 period; these 6-hour QPFs are also prepared by our medium-range forecasters. Both forecasts are created twice per day, once at 10Z and again at 22Z.

Forecasts are valid from the beginning of Day 1 through the end of Day 5 (or 7), with the 22Z issuance offset by 12 hours. For example, a forecast created at 10Z September 2, 2022, would be valid for the 120-hour period from 12Z September 2, 2022, through 12Z September 7, 2022. The Day 1-5 forecast prepared at 22Z September 2, 2022, would be valid from 00Z September 3, 2022, through 00Z September 8, 2022.

For the Day 1-7 QPF, a forecast created at 10Z September 2, 2022, would be valid for the 168-hour period from 12Z September 2, 2022, through 12Z September 9, 2022. The forecast created at 22Z would be valid from 00Z September 3, 2022 through 00Z September 10, 2022.