Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 816 AM EDT Sat Apr 18 2015 Valid 00Z Sun Apr 19 2015 - 00Z Sun Apr 26 2015 From this weekend into early next week expect trades to be on the moderate to strong side as eastern Pacific high pressure is replaced by another surface high tracking eastward across the mid-latitude Pacific. By the middle of next week winds should become more southeasterly. Generally windward focused showers should be fairly light given precipitable water values around or below an inch into Mon and presence of a ridge aloft over or just north of the islands. Over the past couple days guidance has become increasingly divergent and inconsistent with respect to the handling of a central Pacific upper low and the corresponding surface front. One note of interest is that even with the varied eastward extent, multiple solutions suggest the upper low will extend far enough south to yield 500mb height anomalies reaching as low as 4-5 standard deviations below normal. Latest trends of the ECMWF/ECMWF mean to the western side of the guidance spread occupied by GEFS means from 24 hours ago, plus the tendency for closed lows to have timing in the slower half of the envelope, seem to favor moderately slow timing. The 00z GEFS/ECMWF means best represent this idea as the 00z ECMWF is farthest west at some forecast hours. This preferred scenario would keep the surface front well west of the islands through the forecast period with southeasterly trades persisting over the state though with a gradual weakening trend. Farther eastward progression of this system would lead to a more enhanced band of rainfall reaching the area, a scenario that still requires monitoring even if given somewhat less probability than the preferred one. Rausch