Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 816 AM EDT Fri Apr 06 2018 Valid 00Z Sat Apr 07 2018 - 00Z Sat Apr 14 2018 Guidance continues to point to this weekend as the most favorable period for heavy rainfall potential over the state. A cold front now making its way through the area will leave behind a southwest-northeast axis of high moisture (precipitable water values of 1.50-2.00 inches or so) through the weekend. Shortwave energy approaching from the west will provide upper level support for enhanced rainfall while a possible surface trough over the eastern islands could provide a low level focus for activity. During early next week the one notable change in the guidance is toward somewhat greater southeastward progression of the aforementioned shortwave. This will push the moisture axis a little farther southeast as well, with the Big Island remaining the most favored location for enhanced rainfall. High pressure building eastward along 30-35N latitude will provide a trend toward brisk east-northeast trades early-mid week, and while the surface gradient relaxes a bit by Thursday-Friday a trailing high will maintain trades through the end of next week. With an upper ridge building over/north of the islands as well by Tuesday onward, guidance continues to show a general westward progression/dissipation of the axis of highest moisture by Wednesday-Friday. Persistence of trades through then will continue to support showers primarily over but not confined to windward facing terrain. There will likely with some decrease in intensity corresponding to the decreasing deep moisture and higher heights aloft. Rausch