WPC proposes to improve the performance and utility of the Excessive Rainfall Outlooks through several changes. The sliding valid periods could be fixed by binding the end points to 12z. Thus, all initial issuances and most product updates would cover a 12z to 12z period. The valid period for updates to the Day 1 Outlook would decrease in length but would always keep the same end point of 12z the following morning. Issuance times could also be simplified, with initial Outlooks for Days 1-3 sent simultaneously at 08z and afternoon updates synced at 20z. The evening update to the Day 1 Outlook could be moved to 01z. In addition to improving internal consistency, these changes would increase consistency between National Centers, following the 12z to 12z convective day concept and Day 1 update times employed at the Storm Prediction Center (SPC). The proposed product schedule would likely be easier for users to remember.
While Slight, Moderate, and High risk categories would remain, the See Text function could be replaced by a low-probability contour separating areas of near zero risk from areas in which convective rain rates capable of contributing to flash floods are possible - even if organized on small scales. WPC also plans to design new web graphics, with potential enhancements including color fill and addition of optional map layers. In the longer term WPC is working with the hydrometeorological community to design an Outlook product whose definition would circumvent the weaknesses of Flash Flood Guidance and emphasize prediction of the observed impacts of flash flooding.