Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
152 AM EST Sat Nov 16 2019

Valid 00Z Sun Nov 17 2019 - 00Z Sun Nov 24 2019

As an upper-level trough passes north of Hawaii, a cold front is
forecast to stall in the vicinity of O'ahu or Maui. Models show
good consensus on this scenario, with only minor differences in
the timing of the front and the location for potential stalling.
Deeper moisture drawn northward along and ahead of the front
should increase PWs to near or just shy of 2 inches, which should
be sufficient to produce at least locally heavy rainfall through
the weekend. By Sun, models show agreement that energy should
separate from the westerlies farther north and close off an upper
low near Hawaii, which may persist at least into midweek. Despite
a gradual weakening of the surface front, instability associated
with the upper low should keep showers and locally heavy rainfall
in the picture through much of next week. Resumption of moderate
trades as the surface front dissipates early next week will also
allow for locally heavy rainfall to focus across windward and
mauka areas. By late next week, models and ensemble show consensus
that the upper low should lift out, allowing weak upper-level
ridging to build across Hawaii, with gradually decreasing moisture
across the state, and continued moderate trades supporting more
sparse windward/mauka showers.

Ryan