Area Forecast Discussion
Issued by NWS Honolulu, HI

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FXHW60 PHFO 242018

Area Forecast Discussion
National Weather Service Honolulu HI
1018 AM HST Sat Mar 24 2018

Low pressure moving through the region continues to bring
inclement across the state today. Periods of heavy rainfall and
some thunderstorms are expected...mainly over the eastern half of
the state. Conditions will slowly improve across the area from
west to east this afternoon into Sunday. A light wind regime will
allow for daytime sea breezes and overnight land breezes next week.


A wide band of thick layered clouds is moving across the islands
from west to east today, bringing cloudy skies and wet conditions
to the islands. As of 10 AM this morning, moderate rains with
isolated embedded heavy showers stretch from Oahu to the Kona
coast of the Big Island. This band will move steadily east through
the day bringing improving condition to Kauai and Oahu with
increasing low clouds and showers to the Big Island. Models have
been persistent over the past few days with a surface low forming
west of the Big Island today and focusing the potential for
thunderstorms near Maui and the Big Island this afternoon. This
morning`s model runs have backed off a bit on the veracity of this
low. However, there still remains the potential of isolated
severe thunderstorms with plenty of low level wind shear to drive
those thunderstorms.

Tonight, the majority of heavy showers will have moved east of the
the smaller islands while the potential for heavy rain remains
over the Big Island. Lingering showers will remain across the
smaller islands as a second trough moves toward Kauai from the
west. This trough will increase showers again for mainly Kauai and
Oahu on Sunday with some instability provided by a transient
upper level trough.

Atop the Big Island Summits, strong winds reaching over 70 MPH
will continue with near zero visibility. Snow and freezing rain
will produce treacherous conditions above the 12,000 foot level. A
Blizzard Warning remains in effect through Sunday morning. High
winds may linger into Sunday afternoon.

Monday through Wednesday...low pressure will develop north of the
islands bringing light southerly winds to the islands Monday with
afternoon convective showers expected over the higher terrain.
Light and variable winds Tuesday and Wednesday will allow
afternoon sea breezes to develop with clouds and showers
developing over interior areas. Nighttime land breezes will push
most of those clouds over the coastal waters by late evening
bringing clear skies at night. Overall drier weather conditions
are expected compared to recent activity. A weak surface trough
may linger near the Big Island for some enhanced shower activity
along the eastern slopes.


AIRMET SIERRA is posted for mountain obscuration on all islands.
AIRMET TANGO is posted for moderate turbulence between 10000 feet
and 30000 feet. AIRMET ZULU is posted for light icing between
13000 feet and 23000 feet. Expect these conditions to continue
through the day today.

Occasional MVFR conditions have been occurring at the TAF sites
in low clouds and shra with brief IFR conditions occurring at
times. Expect these conditions to continue through the day today.
Conditions are expected to improve from west to east tonight and


An area of low pressure is still expected to make its way across
the central and eastern islands today, brining widespread moderate
to heavy rain to most of the coastal waters today and tonight. A
chance for thunderstorms, mainly over the more eastern waters,
will increase this afternoon as the upper trough swings over the
state. Mariners should be aware of the threat of inclement
weather, with locally strong winds and high seas due to possible
thunderstorms. Improving conditions are expected Sunday and the
beginning of next week as the bulk of the moisture moves away from
the islands.

Winds will be highly dependent on the exact location of the low,
but eastern waters should expect to see winds from a more south
direction, while western waters should expect north to variable
winds through tonight. Light southwest to south winds are then
forecast from Sunday through Tuesday as the low remains north of
the area. Light trades are expected Thursday before turning
southeast Friday. Winds should remain below the Small Craft
Advisory at least through midweek.

The current northeast swell will continue to subside through the
weekend. No other significant swells are expected through at
least the middle of next week. Long term forecast guidance shows
a gale force low developing off Japan and tracking east through
the week. This would translate to possible advisory level surf for
north and west facing shores next weekend. Small south- southwest
and southwest swells are also expected through the next several


Flash Flood Watch until 6 PM HST this evening for Niihau-Kauai-

Flash Flood Watch through late tonight for Kona-South Big Island-
Big Island North and East-Kohala-Big Island Interior.

High Wind Warning until 6 AM HST Sunday for Big Island Summits.

Blizzard Warning until 6 AM HST Sunday for Big Island Summits.



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