Wildfire in Hawaii, June 11 to 12, 2019

Area Forecast Discussion
National Weather Service Honolulu HI
328 PM HST Tue Jun 11 2019

.SYNOPSIS...
A front will remain northwest of Kauai through Friday. Over the
weekend, the front will move away to the northwest as a strong new
high builds far northeast of the area. An area of tropical
moisture may move over the islands from the southeast during the
weekend.

&&

.DISCUSSION...
The 2 PM surface analysis shows a 1026 mb surface high far
northeast of the area near 47N133W and a 1024 mb high 900 miles
northwest of Kauai near 32N168W. A northeast to southwest front is
nearly stationary about 250 miles northwest of Kauai. The highs
and front will remain nearly stationary through Friday. The high
pressure north of the main Hawaiian Island will maintain easterly
trade winds over the islands but the front will keep the pressure
gradient slack enough to keep the winds moderate in strength over
the smaller islands. A ridge aloft over the area will keep the
atmosphere over the islands dry and stable. The trade winds will
push some showers ashore, mainly during the nights and mornings,
and afternoon sea breezes will produce some clouds and showers
over the lee slopes, mainly on the Big Island and Maui. Little
change in this pattern is expected through Friday morning.

The global models show a trough in the lower troposphere, most
evident between 5000 and 10000 feet above the surface, moving over
the islands from the southeast on Friday. An area of increased
atmospheric moisture will accompany this trough. Some of the
moisture is likely to move over the Big Island starting Friday
and produce an increase in rainfall there, especially on
Saturday. Some of the moisture could spread over the smaller
islands, but the Big Island will be most affected.

A strong new high is forecast to build far northeast of the
islands next week. This high is likely to produce breezy trade
winds through at least the first half of next week.

&&

.AVIATION...
Surface high pressure continues to dominate to the far northeast
of the State, while a stationary front remains planted northwest
of Kauai. This pattern will once again help generate weak to
moderate trades this afternoon and evening, generally 10-15 KT.
Isolated showers will stick to mainly mountain areas, then
transition to windward coasts and slopes by tonight. Otherwise,
partly cloudy and VFR conditions expected for the smaller island
leeward locations.

No AIRMETS are currently in effect.

&&

.MARINE...
A stalled front around 230 nautical miles northwest of Kauai
continues to keep the surface ridge suppressed southward with
weaker than normal trade winds for this time of year. This will
result in gentle to moderate breezes over Kauai and Oahu waters.
However, the pressure gradient remains sufficient to produce
moderate to locally fresh winds over the typical Maui County and
Big Island waters, where a Small Craft Advisory remains in effect.
Little change in these conditions is expected for most of this
week. As the front dissipates late in the week, the ridge will
strengthen and move northward, likely allowing trades to increase.

Surf is expected to remain below advisory levels along all shores
for most of this week. Small northwest swells will support small
surf through Thursday, with a slight bump up Friday through the
weekend. A small south-southwest swell will linger for the next
couple of days, keeping some waves around for south and west shores.
A significant long-period south swell is expected to arrive toward
the end of the week and linger through the weekend, likely producing
advisory level surf as it peaks Friday and Saturday.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory until 6 PM HST Thursday for Maalaea Bay, the
Pailolo and Alenuihaha Channels and waters south of the Big
Island.

&&

DISCUSSION...Donaldson
Aviation...Thomas
Marine...TS