Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 801 AM EDT Tue Jul 31 2018 Valid 00Z Wed Aug 01 2018 - 00Z Wed Aug 08 2018 A deep layer/warm core high to the north of Hawai'i will strengthen this week along 170W just south of the Aleutians (about +2 sigma 500mb heights). A pair of TUTT cells/upper lows will retrograde about 20 degrees to the south of the positive height anomaly between the 25-30th parallels over the next week in the vicinity of the island chain. Models/ensembles remain stable in this evolution, so a blend of the available guidance should suffice for the forecast expectations during the next 7.5 days. Above average moisture persists through Wednesday due to the movement of an easterly wave by the archipelago and the retrogression of TUTT cell #1 into the Papahanaumokuakea Marine National Monument, returning back towards climatological values on Thursday/Friday in its wake, albeit briefly. Another increase is forecast Friday night into Sunday with another surface easterly wave connected to TUTT cell #2. Both periods of enhanced moisture should bring above average chances/coverage of rain to the 50th state. As TUTT cell #2 departs next Monday into Tuesday, precipitable water values should return back towards climatological norms for early August. Roth/Fracasso