748 
FXHW60 PHFO 080624
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
824 PM HST Mon Nov 7 2022

.SYNOPSIS...
Several high pressure systems far north of the islands will drift
eastward through the week keeping moderate to locally breezy 
trade winds in the forecast. A band of low level clouds will 
drift into the islands tonight on the easterly trade winds, 
increasing shower coverage through early Tuesday morning. 
Expect typical trade wind shower activity from Tuesday afternoon 
onward with drier trends each day and wetter trends through the 
overnight to early morning hours, favoring windward and mountain 
areas.

&&

.DISCUSSION...
Looking at the satellite picture this evening, subtropical jet
cirrus is outlining a weak ridge over the state. An upper level
trough lingers northwest to north of the islands. Zooming in
upstream of the islands a weak low level cloud band is drifting
into the windward slopes of all islands. Unsettled weather along
this cloud band will raise trade wind inversion heights through 
early Tuesday morning and produce a brief period of enhanced 
shower activity. The 2PM HST upper air soundings show more stable
conditions aloft with temperature inversion heights around 6,000
to 7,000 feet. However, radar profile (VAD) winds are currently
showing reflectivity echos from 8,000 to 10,000 feet this 
evening, suggesting a deepening of the boundary layer and a 
lifting of the trade wind inversion heights as the low level cloud
band arrives.

A progressive west to east moving weather pattern far north of 
the islands will continue into the weekend, with high pressure centers
and cold fronts are passing far north of the island chain through
the weekend. The current high pressure center, far north of the 
islands, will continue to slowly drift east to southeast over the 
next two days as a cold front also drifts eastward into the 
Central Pacific basin. The ridge over the state will move closer 
to the islands and briefly strengthening the trade wind speeds 
into Tuesday. Moderate to locally breezy trade winds will continue
into the weekend as two additional high pressure systems pass 
eastward, far north of the island chain. Trade wind directions 
will shift to a more east-northeasterly direction from Wednesday 
onward.

A typical trade wind weather pattern will continue each day with
trade wind inversion heights ranging from 6,000 to 8,000 feet. An 
upper level trough, currently northwest of the state, will move 
over the islands from Tuesday to Wednesday with only slight
increases to local rainfall coverage. Overall passing showers 
will remain in the forecast into the weekend, mainly affect 
windward and mountain areas with higher rainfall amounts in the 
overnight to early morning hours. Leeward areas will see drier 
conditions with only isolated showers in the forecast. 

&&

.AVIATION...
Moderate to locally breezy trade winds will continue through
Tuesday, strongest during the late morning and afternoon hours
when gustiness can be expected. A band of low clouds and showers
will move through the islands tonight and Tuesday morning,
bringing periods of MVFR cigs/vsbys to windward areas and sending
some showers into leeward areas more frequently than normal as
well. Conditions should improve Tuesday afternoon.

AIRMET Sierra is now in effect for mountain obscuration across
windward sections of most islands. This AIRMET will likely
continue through mid to late morning Tuesday. AIRMET Tango is also
in effect for moderate low level turbulence over and downwind of
the terrain of all islands. This AIRMET will likely remain in
place for the next few days.

&&

.MARINE...
High pressure ridging will remain north of the area into the 
weekend. Under this regime, trade winds will remain fresh to 
strong, with a Small Craft Advisory (SCA) continuing in effect 
for most waters around Maui County and the Big Island through 
Wednesday afternoon. However, the SCA will likely be extended 
beyond that time frame.

The strong trade winds in the vicinity of and upstream of the 
islands will likely maintain slightly elevated, rough surf along 
east facing shores into mid-week.

A series of small to moderate north-northeast swells are expected
through Friday. These swells were mostly aimed east of the state
so there is a larger margin of error during the next several days.
We should see a small, medium-period north-northeast swell begin 
to arrive Tuesday, followed by a slightly larger pulse Thursday. 
These swells should provide a modest boost in surf heights along 
most north facing shores and select east facing shores from 
Wednesday through Friday. Looking ahead to the weekend, a large 
northwest swell arriving late Friday night will likely cause surf
to reach the High Surf Advisory criteria along most north and 
west facing shores of the smaller islands starting Saturday. 
Exposed areas could also see seas reaching the Small Craft 
Advisory threshold of 10 feet during the peak of the swell 
sometime late Saturday into Saturday night.

Surf along south facing shores will remain small through most of
this week with minimal background energy. A small, long-period 
south-southwest swell, which may arrive as early as Friday, could 
potentially provide a noticeable boost in surf heights along south
facing shores this weekend.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 PM HST Tuesday for Kaiwi Channel-
Maui County Windward Waters-Maui County Leeward Waters.

Small Craft Advisory until 6 PM HST Wednesday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big 
Island Southeast Waters.

&&

$$

DISCUSSION...Bohlin
AVIATION...Jelsema
MARINE...Kinel