Hawaii Extended Forecast Discussion NWS Weather Prediction Center College Park MD 729 AM EST Sun Feb 10 2019 Valid 00Z Mon Feb 11 2019 - 00Z Mon Feb 18 2019 ...Unusually Deep and Southward Low Pressure brings a Threat of Strong/Damaging Winds, High Waves and Precipitation to Hawaii... Guidance remains extremely consistent in showing the dramatic amplification of central Pacific energy that has lead to closed low formation and digging to a position now near 26.5N 161W. This upper low is forecast by guidance to dig southward to near 24N by Monday and sharp digging in latest water vapor loops seems to favor a solution slightly southwest of guidance concensus. At the low's most extreme combination of depth and southward extent, recent GFS/ECMWF runs and their ensemble means still indicate that 500mb/850mb heights will reach as low as 4-6 standard deviations below normal. In response to this upper low there is good consensus an associated surface low north of the state will deepen and track as close to the islands as 22N 155W by 12 UTC Monday. The upper low may prove slow to open up over the next few days. The main surface low meanders northeast of the state before ejecting, but unsettled weather should remains over the islands as reinforcing shortwave energy/height falls dig back over the state into a lingering mean upper trough. Confidence in the specific scenario surface/aloft along with associated sensible weather effects decreases mid-later week. Accordingly, there remains a high threat for strong northerly/northwesterly winds and high waves wrapping underneath this system, with multiple periods of heavier rains embedded within the flow. There is also enough cold air aloft in this pattern to also support wintry weather at the higher summits. Please refer to watches and warnings from the Honolulu WFO for your updated local conditions and hazards. Schichtel