Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
830 AM EDT Sat Oct 12 2019

Valid 00Z Sun Oct 13 2019 - 00Z Sun Oct 20 2019

Satellite loops show that an area of low pressure just west of the
islands is forming into a tropical cyclone. The Central Pacific
Hurricane Center will be initiating advisories on this developing
system later this morning. The system is forecast to move
northwest over the next few days , remaining well away from the
Hawaiian Islands. However, system proximity has prompted the
issuance of a flash flood watch for the western islands where
rainfall may be enhanced by deepened moisture. The system also
offers a maritime threat and small craft advisories have also been
issued for offshore the central and southern islands. Please
consult the latest advisories from your local National Weather
Service office and the CPHC.

In the wake of the system, expect much drier air and ridging aloft
moving across the state later this weekend. Beyond the weekend
expect the upper ridge to settle northwest/north of the region.
Flow around this ridge will bring in pockets of moisture from the
northeast as well as push a weakening cold front close to the main
islands by the middle of next week.  Southeasterly low level winds
will turn more easterly from the weekend into next week, and then
high pressure behind the cold front should help to strengthen the
gradient somewhat during mid-late week. Expect rainfall to be
lightest from later thise weekend when precipitable water values
should be lowest and the upper ridge moves over the area. There
should be a modest increase in windward-focused showers next week
as moisture increases somewhat and one or more impulses aloft
travel over the area from northeast to southwest.

Schichtel