Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
306 AM EST Fri Dec 24 2021

Valid 00Z Sat Dec 25 2021 - 00Z Sat Jan 01 2022

An anomalously strong high pressure system should remain anchored
in the North Pacific between Hawaii and Alaska through much of the
next week. An upper low breaking away from the omega block and
drifting west towards the island chain should interact with a
stationary front to the north this weekend. This will likely bring
an increased chance for showers across Hawaii, although the
guidance continues to suggest the bulk of the heavy rainfall
should stay west of Hawaii. After this weekend, the models
generally take this low across or north of the main islands, as it
weakens in favor of another low dropping southward well to the
west. But the lingering boundary should continue to keep showers
across Hawaii. By later next week, the upper high may finally
begin to drift slowly to the east, which may bring in gusty trade
winds to the region.

The models continue to show the possibility of another vortex
forming well to the east of Hawaii early next week, with potential
tropical characteristics associated. However, there are large
uncertainties remaining as to its eventual track and interactions,
if any with Hawaii. Much of the guidance shows this system should
meander and remain well to the east, although the 00z ECMWF
continues to show it drifting in a more westward direction, with
some moisture moving over the northern Hawaiian islands during the
middle of next week. The track, structure, and intensity of this
system should continue to be monitored in future model runs.

Santorelli