487 
FXHW60 PHFO 250632
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
832 PM HST Sun Feb 24 2019

.SYNOPSIS...
A weak high northwest of the islands will move southeast and 
weaken. A surface trough east of the islands will weaken and move 
off to the east. The trailing end of a front over Kauai will move 
southeast through mid-week. Starting Wednesday night, a low will
deepen northeast of the islands while a high far northwest of the
islands builds south. The low will move rapidly away to the 
northeast on Thursday.

&&

.DISCUSSION...
Clouds and locally heavy showers over the southeast side of the
Big Island have mostly dissipated. The surface trough that has
been helping produce the showers on the Big Island is moving off
to the southeast and is not expected to affect the island after
tonight.

A weak 1023 mb surface high lies about 700 miles northwest of 
Kauai near 31N164E. Northeast winds blowing out of the high are 
pushing a band of showery low clouds over Kauai this evening. 
This cloud band, the trailing end of a front, is rather shallow
and producing only light windward showers. 

The band is expected to move slowly southeast, reaching Oahu
Monday morning and Maui County Monday night. The band will
temporarily stall over Maui County Tuesday as a wave forms along 
the band. Rainfall along the band will start off rather light, but
a trough aloft may destabilize the atmosphere starting Tuesday
evening and enhance showers. 

Starting Wednesday night, a low northeast of the area will dig
southeast as a high northwest of the islands builds south along 
165W. Strengthening north winds that will push the merging frontal
moisture southeast of of the islands. The atmosphere will stabilize
on Thursday as ridging builds over the area from the northwest.The
north winds will carry cool dry air over the islands.

&&

.AVIATION...
A surface high far north-northwest of the islands will bring 
moderate northerly winds to the area. A band of moisture over 
Kauai will spread to the rest of the islands on Monday, bringing
clouds and showers to mainly windward areas. Mainly VFR 
conditions will prevail across the sites, though brief MVFR 
ceiling may affect windward areas.

Northeast winds will slowly clear away lingering moisture near 
the Big Island. Conditions are expected to improve through the 
rest of this evening and will allow for the cancellation of 
AIRMET SIERRA for mountain obscuration on the Big Island.

&&

.MARINE...
High pressure far northwest of the state will maintain moderate 
to fresh northeast winds through Tuesday. A low to the east and a
high to the northwest produce widespread fresh to strong north
winds Wednesday through Thursday. A ridge of high pressure moving
south toward the state on Friday will briefly relax the winds 
across the state. Another front may bring fresh to strong 
northerly winds next weekend.

Small surf is expected on all shores through tonight, but a new
moderate mid-period northwest swell will be filling in through 
the day Monday. A larger long-period northwest swell will begin to
fill in on Tuesday and peak Wednesday or Wednesday night near
warning levels. The combination of this large northwest swell, 
large wind waves associated with fresh to strong north winds, 
along with a short period north swell, will lead to rough 
conditions that will require a Small Craft Advisory (SCA) for 
most waters and possibly a High Surf Advisory (HSA) for east 
facing shores as well. Winds and seas should decrease below SCA 
levels by late Friday or Friday night, with HSA level surf 
possibly holding along east facing shores exposed to the declining
north swell into early Friday.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$
DISCUSSION...Donaldson
AVIATION...Hui
MARINE...Gibbs