Area Forecast Discussion for Hawaii

Area Forecast Discussion   Issued: 04/14/2026 04:31:00 PM UTC

                        
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FXHW60 PHFO 140631
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
831 PM HST Mon Apr 13 2026

.SYNOPSIS...
Light to moderate rain persists across the central portion of the
state along a weak line of convergence that is expected to lift
north and dissipate this evening. Light and variable winds will
favor some onshore sea breezes through midweek. By the latter
half of the weak, light east to southeast winds and quieter
weather return to the forecast. This weekend may see a boost in
showers as an upper level disturbance approaches from the
northwest.


&&

.SHORT TERM UPDATE...
Issued at 820 PM HST Mon Apr 13 2026

Light to moderate band of showers continue across the central
portions of the Hawaiian Islands, namely southwest of Oahu and
Maui County. Rainfall has been negligible so far, but not
anticipating much from any showers forthcoming. Winds remain light
and from the southeast, and may result in land and sea breeze.
Overall the latest forecast has done an excellent job tracking the
current trends and therefore no amendments were necessary for this
update.


&&

.PREV DISCUSSION...
A band of mostly light showers has shifted slightly east over the
central islands this afternoon, contrary to what most of the hi-
res model guidance was showing this morning, which showed the line
shifting westward. Most of the rainfall has been focused over
Oahu and Maui County, with a few hundredths of an inch recorded at
most locations since this morning.

For what it`s worth (and it may not be much based on what was
already mentioned), hi-res model guidance suggests that shower
activity will diminish later this afternoon as the current line
lifts north and falls apart, then additional light to moderate
showers may reorganize along another weakly convergent boundary
near Kauai overnight and persist in the vicinity through at least
Tuesday. For the latter part of the week, trades will try to
return, but may have a hard time doing so as a nearly stationary
surface trough forms and persists northwest of the state, making
it hard for the high pressure to the northeast to take over the
local winds. Overall, winds are expected to be light east to
southeasterly. With light winds prevailing, and if diurnal
heating is strong enough, land and sea breeze activity may bring
interior showers during the day and partial clearing overnight for
the rest of the island chain. Otherwise, isolated light showers
will move in on the weak southerly flow for the west half and on
the southeasterly flow for the east half that will become light
east to southeasterlies across the state for the latter part of
the week.

With lots of deep moisture sticking around through the forecast
period, a mix of low and high clouds will stick around and it
won`t take much to trigger shower development. Precipitable
water values (PWats) are expected to remain between 1.8 and 2
inches through midweek before dropping slightly to 1.5 to 1.8
inches for the latter half. For reference, the average PWats for
this time of year is around 1.2 inches.

This weekend, an upper level trough will dig down rather close to
the state from the northwest. While most of the model guidance
doesn`t do much with it at this point, it`s worth keeping an eye
on to see if it will help to enhance shower activity over portions
of the state, especially with ample moisture lingering and cooler
temperatures moving in aloft.

&&

.AVIATION...
Issued at 820 PM HST Mon Apr 13 2026

Low cigs and scattered SHRA will continue across the islands
tonight. MVFR conds possible but VFR should prevail. Winds will
generally be driven by land-sea breezes, flowing light at less
than 10 kts. The forecast generally trends back toward benign
trades by the midweek.

Moderate icing is possible so long as this ongoing system remains
over the islands.

No AIRMETs in effect.


&&

.MARINE...
Issued at 820 PM HST Mon Apr 13 2026
Light to locally moderate south to southeast flow will continue
through tonight as a weak surface trough remains draped across
the state. The trough will move very little the next several days
and allow weak easterly flow to persist. There will be passing
showers associated with the feature, but not expecting anything
heavy. High pressure begins to take over at the surface, causing
gentle to moderate easterly trades to gradually develop across the
Hawaiian coastal waters by this weekend.

A small, medium-period, northwest swell will continue to slowly
diminish through the rest of the week.

A new south swell arrives on Tuesday, providing a boost to surf
along south facing shores through mid week before gradually
subsiding into the weekend.

Surf along east facing shores will remain below seasonal average with
lighter than average trade winds near and upstream of the islands
forecast through next week.


&&

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

&&

$$

SHORT TERM UPDATE...Pierce
DISCUSSION...Farris
AVIATION...Walsh
MARINE...Thomas