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Temp2.4 C
RH90 %
WindN 32 mph
RoadOpen (4x4)
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Hawaiian Islands Synoptic Discussion and Guidance

839
FXHW60 PHFO 051317
AFDHFO

Area Forecast Discussion
National Weather Service Honolulu HI
317 AM HST Wed Aug 5 2020

.SYNOPSIS...
High pressure north of the state will keep moderate to breezy
trades in place through early next week, with the trades peaking
over the weekend. Showers will favor windward and mauka areas
through the period, with a stray shower occasionally spilling
leeward. A disturbance moving through aloft is expected to
increase shower coverage and intensity Wednesday night through
early Friday.

&&

.DISCUSSION...
Currently at the surface, a 1030 mb high centered around 1050
miles north of Honolulu, is driving moderate to locally breezy
trade winds across the island chain early this morning. Infrared
satellite imagery shows partly to mostly cloudy skies across the
state, with cloud coverage the greatest in windward areas. Radar
imagery shows scattered showers moving into windward slopes and
coasts, with a stray shower or two drifting leeward from time to
time. Main short term focus revolves around rain chances during
the next few days.

High pressure will remain nearly stationary to the north of the
islands for the next few days, keeping moderate to breezy trade
winds in place. The high will strengthen to around 1035 mb this
weekend, and with inversion heights lowering to around 6 kft, the
trade wind speeds should increase to breezy levels statewide. The
high will weaken slightly and move to a position well north of
the islands early next week, and this should lead to a slight
easing of the trades, although moderate to locally breezy
conditions will likely continue.

As for weather details, fairly typical conditions will persist
through early next week, with showers favoring windward and mauka
areas and the occasional leeward spillover. There is an increase
in deep layer moisture associated with a mid-level disturbance
that will spread from east to west across the islands tonight
through Thursday night however, and this should bring an increase
in shower coverage and intensity as it moves through. The
moisture depth will climb to around 15 kft during this period, and
this will likely send more showers into leeward areas as well.
Given the persistent trades keeping showers moving along, no
flooding issues are expected, but some higher rainfall totals can
be expected.

&&

.AVIATION...
A high pressure ridge north of the islands will keep moderate to
breezy trade winds in the forecast for the next several days. Low
level turbulence will continue over and south through west of
island mountain ranges. A disturbance moving in from the east will
bring enhanced showers to the Hawaiian Islands starting tonight
and continuing through Thursday. Brief periods of MVFR conditions
are expected in showers mainly over windward and mountain areas
of each island.

AIRMET TANGO remains in effect for tempo moderate turbulence
below 8000 feet for areas over and immediately south through west
of mountains.

&&

.MARINE...
A high north of the area will remain nearly stationary and slowly
strengthen through the weekend. A Small Craft Advisory (SCA)
continues for the waters around Maui County and the Big Island
through Saturday due to strong easterly trade winds. However, the
SCA may need to be expanded over the weekend as trades intensify.

A small, and fairly short-period, southeast swell will persist
into next week but the Big Island will block some of this swell
from reaching the rest of the islands. Long-period swells from
deep in the southern hemisphere will remain small. Small surf
along east facing shores will build through the weekend as trade
winds strengthen.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 PM HST Saturday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big
Island Southeast Waters.

&&

$$

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

Bulletins, Forecasts and Observations are courtesy of Honolulu National Weather Service Forecast Office