Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 326 AM EST Wed Dec 18 2019 Valid 00Z Thu Dec 19 2019 - 00Z Thu Dec 26 2019 ...Very strong trades Friday into Saturday... ...Heavy rain possible next week... A weakening upper high will continue to dissipate as troughing near 180 deepens. By Friday, another front will approach the region and perhaps stall over or just south of the islands by Sunday, enhancing windward/mauka showers with some locally modest amounts and leeward spillover. At the same time, strong surface high pressure (1033-1035mb, which is much stronger than average for late December) will bring in windy trades (20-35kts with higher gusts) Friday into Saturday or early Sunday before slackening by Monday. To the west, the models/ensembles still show developing low pressure moving off the ITCZ near 20N/180 by 00Z Sat in concert with the digging upper trough. After moving northward on Sat, then perhaps pausing on Sun as the upper trough approaches it, the system should begin to move northeastward next Monday. The GFS was still a bit quicker than the ECMWF/Canadian (by about 12-18hrs), but the core of high precipitable water values (over 2 inches) should reach into Kauai around Monday with heavier rainfall possible on Tuesday per the ECMWF. The quicker/slower timing has remained rather constant between the GFS/ECMWF, but would prefer to lean toward the slower side given the deep/anomalous nature of the system. Rainfall core should progress eastward on Wednesday, into the central islands, but with lower confidence in timing by then. Fracasso