Current Conditions
Temp5.5 C
RH28 %
WindNE 15 mph
RoadOpen (4x4)
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Hawaiian Islands Synoptic Discussion and Guidance

FXHW60 PHFO 142019

Area Forecast Discussion
National Weather Service Honolulu HI
1019 AM HST Tue Jul 14 2020

Light to moderate trade winds will become even lighter from Thursday
into Saturday, with winds increasing again by Sunday. Fewer showers
are expected from later today into Thursday, with the potential for
another batch of showers to affect primarily windward areas Thursday
night and Friday, and maybe again on Sunday. Some afternoon clouds
and showers can be expected over leeward areas when winds are light.


Light to moderate trade winds will become even lighter from Thursday
to Saturday as a trough (remnants of what was once TS Cristina)
passes between the islands and the trade wind supporting high
centered to the distant NE. While a low aloft will linger NW of the
islands and deliver periods of high clouds the next couple of days,
a mid-level ridge will build over the area from the NE, and the
island atmosphere will become increasingly stable. Combined with
diminished upstream moisture, this is expected to lead to fewer
showers from this afternoon through Thursday. Although the ridge
will remain in place through the weekend, models are now indicating
that some of the moisture pooled S of the Cristina remnant will move
over the islands, bringing an increase in showers later Thursday
into Friday. Models also indicate a surge of moisture moving across
the islands as trades build on Sunday.

Afternoon sea breezes will drive cloud and shower formation over
leeward areas that will gradually diminish after sunset - daily on
the Big Island, and Thursday-Saturday on the smaller islands when
large scale winds are lightest.


High pressure is still centered well to the northeast of Hawaii and
continues to bring the state east to northeast tradewind flow.
With moisture and an upper level disturbance passing over the
western part of the state, showers should continue for Oahu and
Kauai while some clearing works into areas over the Big Island and
Maui County. Clearing should also begin to work into areas over Oahu
but showers may linger over Kauai through the afternoon. The shower
activity has kept ceilings low for north through east sections of
all islands. Expect gradual clearing to lift clouds as we progress
through the afternoon from the Big Island westward. Until then, low
clouds are causing mountain obscuration for all islands above

AIRMET SIERRA remains in effect for north thru east sections of all
islands above 2,000ft feet due to tempo mountain obscuration from
clouds and showers.


High pressure far northeast of the state will maintain moderate to
locally fresh trades through most of the work week. Winds will be
slightly increasing this afternoon and evening, but is expected to
remain below Small Craft Advisory levels at this time.

A weak disturbance is expected to move to the northeast of the
islands Thursday and Friday which could further disrupt the trade
wind flow. A brief period of light to moderate trades with afternoon
sea breezes will be possible during this time. Expect the trades to
ramp back up over the weekend as that disturbance dissipates and the
high pressure strengthens to the north of the state.

Overall, no significant swells are expected through the forecast
period. Small background surf will continue along south facing
shores over the next several days. A small south-southwest swell is
possible over the weekend. East facing shores will continue to
experience small short period surf produced by the trade winds
locally and upstream of the state. An increase is expected over the
weekend as the breezy trade winds return. Surf along north facing
shores will remain nearly flat through the period.






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