Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 05/01/20

Area Forecast Discussion

National Weather Service Honolulu HI

 359 PM HST Thu Apr 30 2020

.SYNOPSIS...
A mostly dry and breezy trade wind pattern is expected through
early next week. The best chance for showers will remain over
windward and mountain areas, mainly through the overnight and
early morning hours. The gusty trades may relax early next week as
a disturbance approaches from the north. This may bring an
increase of showers across the state towards the middle of next
week.

&&

.DISCUSSION...
A 1026 mb high centered about 700 miles northwest of Kauai is
producing breezy to locally windy trade winds over the state this
afternoon. During the next 24 hours, very little change in
weather is expected, with wind speeds holding at 20 to 30 mph for
most areas across the state. The Wind Advisory has been extended
through Friday afternoon for portions of Maui County and the Big
Island due to the potential wind gusts of up to 50 mph.

As we head into the weekend, the 1026 mb high is expected to
weaken, as a front passes well north of the state. This should
allow winds to drop below advisory thresholds, but breezy
conditions are expected to hold through the weekend. As far as
rainfall, we will likely continue to see lighter than normal trade
wind showers through Monday, due to a strong high pressure in the
upper levels of the atmosphere. Showers will be most favored
across windward and mauka areas during the overnight and early
morning hours.

Starting around Tuesday of next week, an upper level trough is
expected swing near the state and could bring an increase in
showers and a decrease of trade winds. The models are still having
a hard time resolving the surface features for next week. The 12Z GFS
is showing a light wind pattern with a surface trough developing
just north of the state. Meanwhile, the 12Z European model is
showing the ridge of high pressure persisting north of the state,
which would lean more towards a wet trade wind pattern. The
current forecast has been adjusted to be in line closer to the
European model.



&&

.AVIATION...
Surface high pressure north of the state will allow for moderate
to strong east northeasterly trades today and create moderate turbulence
for aircraft on the leeward side of the mountains. Isolated
showers will mainly affect windward portions of the islands this
afternoon. By tonight, expect an increase in cloud coverage and
showers along the windward slopes and coasts and accompanying
brief MVFR conditions.

AIRMET TANGO remains in effect for south thru west of mountains on
all islands below 8000 feet due to moderate turbulence.



&&

.MARINE...
A series of high pressure systems building north and northwest of
the state will keep fresh to strong trade winds in place through
Monday. The trades will ease Tuesday and Wednesday of next week,
as a trough of low pressure develops along a decaying frontal
boundary north of the island chain. A Small Craft Advisory (SCA)
remains in effect for most marine zones through 6 PM Friday. The
SCA continues through 6 PM Sunday for the windier channel waters
and all leeward waters. The SCA may need to be extended into
Monday for the typically windy waters around Maui and the Big
Island, with conditions dropping below SCA thresholds for Tuesday
and Wednesday of next week.

A series of north-northwest and northwest swells will move
through the islands during the next 7 days, keeping steady small
to moderate sized surf in place along north and west facing
shores. Surf along east facing shores will hold steady through
the weekend, then lower a bit heading into the middle of next
week as the trades diminish. Small background southerly swells
will continue along south facing shores through the middle of next
week. Surf is expected to remain below advisory thresholds along
all shores through the middle of next week.



&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 6 PM HST Friday for Lanai-Kahoolawe-Maui
Central Valley-Kohala.

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

Small Craft Advisory until 6 PM HST Friday for Kauai Windward
Waters-Oahu Windward Waters-Maui County Windward Waters.


&&

$$


DISCUSSION...Kino
AVIATION...Thomas
MARINE...Jelsema