Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 710 AM EST Tue Dec 16 2014 Valid 00Z Wed Dec 17 2014 - 00Z Wed Dec 24 2014 High pressure initially to the north of the state will move east but be replaced by another high on Thu, so expect trades to weaken a little through Wed and strengthen again Thu. By the weekend the departure of this high, along with an approaching front supported by an amplifying/sharpening trough aloft, will likely lead to weaker and/or more southeasterly winds. Passage of this fairly strong front early next week should be accompanied by a period of organized rainfall of varying intensity. Models/ensembles agree well on the forecast at the surface and aloft to about early Mon and then diverge with respect to timing of the upper trough and potential for an embedded closed low to form, along with the associated surface evolution. 06z trends in both the operational and parallel GFS are slower, which would suggest leaning perhaps 2/3 toward the slower ECMWF/ECMWF mean timing. However the operational 00z ECMWF run pulls its upper low so far southwestward by next Tue-Wed that it achieves some 500mb height anomalies that are 4-6 standard deviations below normal. This along with the fact that parallel GFS runs do not close off a low aloft as quickly as the 00z ECMWF or 00z/06z GFS recommend the more open 00z ECMWF mean as the best individual piece of guidance at this time. Rausch