Drought in Hawaii, November 10 to 17, 2020

Area Forecast Discussion
National Weather Service Honolulu HI
848 PM HST Mon Nov 9 2020

.SYNOPSIS...
High pressure north of the state will keep breezy trade winds
blowing through the week, with particularly windy conditions
expected Wednesday and Thursday. Showers will favor windward and
mauka areas with a stray shower spilling leeward from time to
time. An upper level trough moving over the islands may enhance
trade showers Friday through the weekend, while also easing the
trade winds to moderate levels by Sunday.

&&

.DISCUSSION...
Currently at the surface, a 1035 mb high is centered around 1500
miles northeast of Honolulu, while a couple troughs of low
pressure are located several hundred miles west of Kauai. The
resulting pressure gradient is producing moderate to breezy trade
winds across the island chain this evening, strongest over the
eastern end of the state. Infrared satellite imagery shows mostly
cloudy skies over Kauai and some windward areas of the other
islands. Elsewhere, partly cloudy conditions prevail. Radar
imagery shows scattered showers moving into windward/mauka areas
with coverage the greatest over the Big Island. Main short term
concern revolves around trade wind trends during the next few
days.

Strong high pressure northeast of the state will keep moderate to
breezy trades in place through Tuesday. The trades should ramp up
to windy levels Tuesday night as the high builds due north of the
islands, with windy conditions holding in place through Thursday
and possibly into Thursday night. At the moment the trades appear
to peak Wednesday through Thursday, and it remains possible that a
Wind Advisory may be required for portions of the state during
this time. The trades should trend downward Friday through the
weekend as high pressure north of the islands weakens, with breezy
trades on Friday lowering to moderate levels by Sunday. The trades
appear to ramp back up to breezy levels early next week.

As for the remaining weather details, a band of low clouds and
showers will exit to the west of Kauai this evening, while
another band of low clouds and showers moves into the Big Island.
Expect mainly scattered windward showers after midnight for the
smaller islands with a stray shower spilling leeward from time to
time, while windward Big Island will likely see numerous to
widespread shower coverage as the enhanced band of clouds moves
through.

A fairly typical trade wind weather pattern is expected
overspread the state Tuesday, with this pattern holding through
early next week. Showers will favor windward and mauka areas, but
due to the strength of the trades, showers will also reach
leeward areas at times. An upper trough is forecast to move over
the state late in the week through the weekend, and this could act
to enhance showers a bit.

&&

.AVIATION...
A strong high pressure system north of the Hawaiian Islands will
spread breezy to locally strong trade winds across the state for
the next few days. Expect passing showers with cloud ceilings over
windward and mountain areas, brief periods of MVFR ceilings will
also occur in these areas, especially in the overnight to early
morning hours.

AIRMETs are in effect for mountain obscuration for Oahu and
Kauai; and low level turbulence south and west of mountains over
all islands.

&&

.MARINE...
The center of broad surface high pressure located far northeast
of the islands will be moving southwestward and closer to the
state through mid week. The movement of the high will maintain
widespread Small Craft Advisory (SCA) level moderate to strong
trades into the second half of the week. The SCA has been
expanded westward to cover Oahu's windward waters and most of the
waters surrounding Kauai County. The ongoing SCAs for all waters
except for the leeward Oahu and Kauai waters are in effect until
6 PM HST Thursday with the lone exception being for the windward
Big Island waters which goes through 6 AM HST Wednesday.

Seas will become dangerously rough and choppy under these
moderate to strong trades. A High Surf Advisory (HSA) has been
issued for the east-facing shores of most islands as the surf
continues to build under this strong trade flow. The HSA is
in effect until 6 AM HST Wednesday and this may eventually need to
be extended. Breezy trades are expected to diminish Friday and
this will scale down the areal coverage of the SCA and subside any
remaining advisory level surf.

The N to NNE swells will continue to diminish overnight as the
locally generated trade wind swell becomes the dominant swell.
There are a series of NW swells on the schedule this week. A small
short period, NW swell is slated to peak on Tuesday followed by a
slow drop through Tuesday night. On Thursday night, we are
expecting the arrival of a moderate longer period NW swell that
is forecast to peak on Saturday with a slow decline through
Sunday. South-facing shore surf will be on the small side for the
majority of the week despite a couple of new long period S to SSW
swell arrivals.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
High Surf Advisory until 6 AM HST Wednesday for Kauai Windward-
Oahu South Shore-Oahu Koolau-Olomana-Molokai Windward-Maui
Windward West-Windward Haleakala-South Big Island-Big Island
North and East.

Small Craft Advisory until 6 PM HST Thursday for Kauai Northwest
Waters-Kauai Windward Waters-Kauai Channel-Oahu Windward Waters-
Oahu Leeward Waters-Kaiwi Channel-Maui County Windward Waters-
Maalaea Bay-Pailolo Channel-Alenuihaha Channel-Big Island
Leeward Waters-Big Island Southeast Waters.

Small Craft Advisory until 6 AM HST Wednesday for Big Island
Windward Waters.

&&

DISCUSSION...Jelsema
AVIATION...Bohlin
MARINE...Blood