Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 812 AM EDT Sun May 17 2015 Valid 00Z Mon May 18 2015 - 00Z Mon May 25 2015 The 17/00Z ECENS/GEFS ---for the first time in awhile---were in good 'synch' with the amplified pattern emerging across the eastern Pacific. Their deterministic runs --- to a lesser extent were in better than average agreement --- into day 4/5 before reverting back to more of a blended ECENS mean and ECMWF solution. This would not cause much difference in the current forecast sequence for Hawai'i. The good fortune being---the remnants of 'Dolphin' were carried in the westerlies with a certain degree of accuracy to 170E longitude (@ 21/12Z). The subtle differences between the deterministic ECMWF and GFS begin to emerge along the Dateline and 50N latitude---but downstream along 155W both solution could easily be utilized for 500mb trough and surface trough placement @ 22/12Z --- north of Hawai'i. After day 5---the deterministic ECMWF continues with the idea that a good portion of the remnant moisture and energy associated with 'Dolphin' remains at high latitude near 50N and becomes anchored in Aleutians. The last 3 cycles of the ECENS means have ---slowed--- in response to these trajectories and solution. The 17/00Z GEFS has made a major shift---and at best--- its extremely amplified solution in the northeast Pacific and Alaska is 'better'. But difficult to describe what's going on after day 5 --- and recommend not using its solution east of 150W after day 5. The equatorial trough contains a rather interesting mid-level wave pattern --- but not necessarily something that has impact for Hawai'i weather aside from some high cloudiness. What's interesting is the benign mid-level wave train migrating east-northeastward from 15N 170W to the Mainland (southern Arizona). Can't recall a time (over my 30 years) where I have seen this sort of 'linked' southern stream pattern in mid-May!? Vojtesak