Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 302 AM EST Wed Feb 26 2020 Valid 00Z Thu Feb 27 2020 - 00Z Thu Mar 05 2020 ...Heavy rain quite possible this coming weekend into next week... Upper ridging around 170W will surge northward later this week ahead of a system off Asia lifting toward the Aleutians. This will allow troughing and eventually a closed low to move westward across the islands Sun-Mon. The 00Z models were in good agreement with this evolution which also shows an upper high cresting atop the upper low Sunday in a short-lived Rex block configuration. At the surface, models show a 1040+mb high settling near 38N/150W Sat/Sun then drifting slowly to the east Mon-Wed. The pressure gradient of ~20mb over ~1000mi will yield breezy trades especially Friday through Monday or Tuesday. By next Tuesday into Wednesday, the upper low should lift northward and weaken into an open wave as heights rise back above average over the state. Prefer a blended solution between the 00Z GFS/ECMWF given their similar evolution but different QPF solutions. Upper low will bring cold/unstable airmass through the region with 500mb temps potentially down to around -17C per the 00Z GFS/ECMWF and freezing levels near 9500ft/700mb. This would support some convection in addition to potentially heavy snow on Mauna Kea and Mauna Loa. Several inches of rain are possible as the upper low passes through as deep tropical moisture may get pulled to the north and northwest on the east side of the upper low. Highest probabilities lie over the Big Island, then decreasing to the northwest amid increased uncertainty. Models vary quite considerably on amounts but the overall pattern and evolution support the threat for heavy rain. By next Wednesday, with the upper low likely disintegrated and heights on the rise, rainfall amounts and coverage should decrease. Fracasso