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Hawaiian Islands Synoptic Discussion and Guidance |
FXHW60 PHFO 040136
Area Forecast Discussion
National Weather Service Honolulu HI
336 PM HST Fri Jul 3 2020
Light to moderate trade winds will prevail through the holiday
weekend, then strengthen early next week. An area of increased
moisture is expected to impact the islands through Saturday.
Expect warm and muggy conditions, and an uptick in showers. The
boost in the trades early next week, will bring with it a drier
and more stable air mass.
Have made some tweaks to the first 36 hours of the forecast. Have
modified dewpoints, nudging more to the higher resolution ARW
model which was better capturing the upper 60s/lower 70s dewpoints
that we have seen in observations today. Also made some tweaks to
the PoP and associated fields. The biggest change was to lower
values over the leeward sides of the smaller islands. At the same
time, some areas across the state saw a boost in the their
The general forecast philosophy remains the same this afternoon.
The weak trough to the east of the islands has washed out and was
not analyzed with the morning analysis. The showery cloud area to
the east of the islands has started to fall apart, but satellite
derived precipitable water (PW) continues to show a sizable area
of 1.4+ inches over the central islands and upstream of the Big
Island. Anticipate another uptick in showers overnight and
As mentioned above, dewpoints have reached into the low 70s in a
few locations. Elevated dewpoints are expected to continue through
tomorrow before dropping back gradually with the new week. With
the lighter winds and elevated dewpoints, expect muggy conditions
While light to moderate trades continue, some areas have seen
winds weaken enough to allow for localized land and sea breezes.
Expect winds to strengthen as we head into Sunday. As the trades
build back in, we can expect a return to more typical trade wind
No AIRMETs are currently in effect.
A high far north of the area will maintain gentle to moderate
low-level easterly flow through the weekend. The low-level
easterly flow will be light enough to allow local afternoon sea
breezes and nighttime land breezes. VFR conditions will prevail,
but sea breezes will produce isolated MVFR conditions over west
and interior sections of the islands, mainly during the afternoon
and evening hours. The low-level flow will carry some clouds over
east sections of the islands and produce isolated MVFR ceilings
and visibilities. These conditions will be most prevalent during
the night and early morning hours.
The remains of a weak surface trough passing through the area
will bring light to moderate trades through Sunday. High pressure
will strengthen early next week, and accelerate trade winds into
the moderate to breezy range. Small Craft Advisory conditions for
the typically windy areas around Maui County and the Big Island
are expected to return by Tuesday.
A current small SSW swell will gradually decline into Saturday.
Otherwise, a mix of small background swells from the SSE and SSW
are expected through next week. Surf is expected to stay below
Surf along east facing shores will decrease through the weekend
as the trades weaken. Surf along north facing shores will remain
nearly flat with mainly background trade wind swell.
Bulletins, Forecasts and Observations are courtesy of Honolulu National Weather Service Forecast Office
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It was last modified on: Wed, Dec 17 2014 - 1841 UTC
Send comments to: Ryan Lyman