Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Honolulu HI
832 PM HST Wednesday Oct 22 2014
light southeasterly flow will bring showers into windward areas
tonight with some rainfall spilling over leeward locations. Winds
will increase Thursday and turn from the east as high pressure
builds in from the north. Light trade winds are expected next week
with showers focused over windward and Mauka areas. Muggy conditions
will remain through the period.
Tropical Storm Ana continues to churn far northwest of the state.
Ana/S low pressure and position has reduced the pressure gradient
over Hawaii and has turned winds out of the southeast. Lingering
moisture from an old frontal boundary is being pushed into
windward areas by the light southeast winds and moderate rainfall
will continue tonight with off and on rainfall over smaller
island leeward locations. The rains associated with this boundary
will clear the eastern islands tonight with lingering showers
expected over Kauai and Oahu into Thursday morning. Showers will
increase again Thursday night as a batch of moisture currently
near 24n 150w... or 500 miles east of Oahu... pushes through the
Ana will continue on a northward track tonight allowing high
pressure to build over the state from the north...and turn our
winds to a more easterly direction. Light trade winds are expected
Thursday with winds increasing to moderate levels Thursday night
and Friday. However...the energy from Ana will merge with a
passing North Pacific low Saturday and this combination will push
our trade-wind producing high eastward... and place the islands
on the outskirts of the trade wind belt. With the ridge sitting
just 300 miles north of Kauai... east-southeast trade winds will be light to
moderate over the weekend with some leeward sea breezes forming in
the afternoon. Afternoon and evening showers will be more active
than normal as two old frontal boundaries bring enhanced moisture
over the islands.
For the first half of next week...light east to southeast trade
winds remain as a cold front lingers northwest of Kauai keeping
the aforementioned high pressure shunted to the east. Global
models are highly confused with the weather scenario from
Wednesday and beyond with some bringing stronger trades and others
placing a cold front near Kauai. The current forecast calls for
moderate trades and this forecast will remain until model
solutions become more consistent.
Muggy conditions will prevail through the forecast period with dew
points remaining in the low 70/S.
clouds and numerous light showers associated with an old front will
continue across Hawaii this evening...then slowly diminish Thursday
morning. Broken MVFR ceilings...reduced visibility and mountain obscure will
be the impacts tonight...and airmet Sierra for mountain obscure is posted
for much of the state. Trade winds along with a drier airmass will
return to the state on Thursday...with VFR conditions prevailing.
a small north swell will decrease tonight. A small north-northwest swell will
arrive Thursday and fade into the weekend. A small/moderate north
swell is expected to arrive Friday night and continue through
Sunday. Surf from these swells will remain below advisory levels.
Only small surf is expected at south and east facing shores.
Winds and seas will remain below Small Craft Advisory levels through
the forecast period.
Morrison...discussion and marine