Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 258 AM EST Wed Dec 04 2019 Valid 00Z Thu Dec 05 2019 - 00Z Thu Dec 12 2019 Moderate trades will continue through Thursday with the support of central Pacific high pressure forecast to be north of the state by Thursday night. Generally windward and mountain focused rainfall should be on the light side. Then models and ensemble means are consistent in principle for shortwave energy passing over the area Thursday night/Friday with an accompanying increase in deep moisture and rainfall, though some details have differed over the past few days. Current consensus keeps heaviest rain just south of the main islands. Over the state itself recent GFS runs and 00Z ECMWF agree on windward parts of the Big Island seeing the highest rainfall totals with some trade flow persisting as the surface high continues southeastward. Further guidance adjustments are still possible based on model behavior thus far. The weekend will feature a drier trend as the upper shortwave departs. Continued progression of the surface high into the eastern Pacific and a front approaching the main islands should lead to weak low level flow and more land/sea breeze influence. As for the approaching front, guidance has been oscillating with its ultimate southward extent by around Monday before stalling and possibly returning northward. Today's guidance average is a little north of where it was 24 hours ago and more similar to two days ago--reaching near the northwestern islands. Given the guidance behavior an intermediate solution among latest GFS/GEFS mean runs and 00Z ECMWF is likely best for a single specific forecast. The 12Z ECMWF mean was farther south than other solutions. High pressure north of the front should produce light to moderate trades and a return of windward shower focus early next week. Another front approaching from the northwest could start to weaken the trades again next Wednesday. Given the time frame the GFS/ECMWF and their means agree fairly well for this front. Rausch