Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 300 AM EST Wed Dec 23 2020 Valid 00Z Thu Dec 24 2020 - 00Z Thu Dec 31 2020 Today's guidance continues to show variations in the pattern as features progress along just to the north of the state. At the start of the period expect fairly light winds and land/sea breeze focus for shower activity that should be modest given an upper ridge overhead and moderate precipitable water values. By later this week and weekend a front approaching/reaching the northwestern islands may increase precipitation somewhat while trailing high pressure strengthens the trades as it builds north of the area--returning rainfall focus to windward/mountain areas. Then trades should weaken and turn more southeasterly early next week as the surface high continues eastward and another front approaches. Consensus currently indicates this latter front should not quite reach the main islands, while light to moderate trades continue into midweek. Regarding recent/ongoing guidance discrepancies, one appears to have been resolved while another persists. The previous wide disparity in moisture forecasts valid around Friday has been resolved by the latest GFS/GEFS mean trending to the drier ECMWF/ECMWF mean. Meanwhile there is still uncertainty over the details of shortwave energy that is most likely to track north and east of the state late this week and weekend. The 12Z ECMWF mean shows a slower shortwave and a surface reflection sufficiently strong to break up the surface high tracking to the north of the state. Once again the 00Z UKMET is also on the slower side aloft but dampens out the surface low to yield high pressure more like consensus. Looking at the new 00Z ECMWF mean into the start of the weekend, it has weakened the shortwave somewhat and dampens out the surface low like the UKMET. The UKMET scenario that eventually brushes the eastern islands with its upper feature is still within the minority side of the full ensemble spread. One other note is that latest guidance has generally trended a little northward with the southernmost extent of the front that reaches the area late this week. Rausch