Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 807 AM EDT Fri Apr 12 2019 Valid 00Z Sat Apr 13 2019 - 00Z Sat Apr 20 2019 ...Heavy rain possible into the weekend... An upper-level low situated southeast of Hawaii early this morning is expected to persist through the weekend and into early next week before moving eastward away from the state. Models/ensembles show broad agreement on this evolution, with relatively minor differences primarily in the depth of the feature. At the surface strong high pressure anchored well northeast of the state is expected to keep moderate trades in place into early next week, before these begin to relax by midweek as the surface high weakens and moves east. The combination of the upper low generating enhanced instability along with some degree of deeper moisture pooling will be sufficient to produce scattered showers and even a few thunderstorms, which should focus primarily across windward locations, but with some expected spill over into leeward areas as well. Convective activity focus largely across the eastern portion of the state today through Mon, before a gradual decrease in activity begins after that time. Areas of heavy rainfall and localized flooding will be possible, with higher rainfall rates promoted by at least some degree of added instability beneath the upper low. ECENS probabilities continue show the greatest potential for heavy rains across eastern portions of the Big Island. By the middle of next week, as the upper low moves east, light to moderate trades are expected to continue with more isolated windward shower activity. Any influence from a fairly active frontal zone across the north central Pacific appears likely to remain north of Hawaii through next Fri. Ryan