Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 204 AM EDT Sat May 09 2020 Valid 00Z Sun May 10 2020 - 00Z Sun May 17 2020 Surface high pressure is expected to persist north of Hawaii through the middle of next week, before perhaps spreading southward closer to the state late next week. This setup will allow light to moderate trades to persist, with relatively sparse moisture supporting scattered windward and mauka showers. As high pressure weakens and spreads more across Hawaii later next week, trades should weaken a bit. There remains some disagreement among ensemble guidance as to the large scale flow across the north central Pacific by later next week. The ECENS keeps a stronger ridge in place northwest of Hawaii relative to the GEFS/NAEFS means. The GEFS/NAEFS do seem to have trended toward the ECENS solution over the past 24-hours, however. The Rex Block from the North Pacific to the Arctic Ocean is forecast to persist, with the arctic ridge perhaps becoming the dominant anomaly center. This would favor somewhat more progressive flow farther south, perhaps limiting the degree of height falls toward Hawaii (more like the ECENS scenario). Given the trend toward a continued stronger ridge axis across the north central Pacific late next week, any surface frontal boundaries associated with the westerlies farther north should remain north of Hawaii through late next week. Ryan