Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Honolulu HI
1000 am HST Monday Sep 22 2014
increasing trade winds will bring some relief from the humidity
today. Trade winds will build to moderate strength by Tuesday...and
modest rainfall will be focused over windward slopes as well as the
Kona slopes each afternoon. A wet trade wind pattern will develop on
late Wednesday and Thursday and will persist through the weekend.
some relief from recent humid conditions is in store today. Morning
island observations show gentle trade winds already established...
and a further increase is due as the day GOES on. Day time high
temperatures will be running around seasonal normal...upper 80/S to
around 90...but dew point temperatures will be down a few degrees
from yesterday. The combination of some trade winds with the slight
drop in dew points will bring at least some relief from the humid
conditions we have been experiencing.
Trade winds will be building today. An old frontal boundary about
350 miles north of the islands will continue to fall apart...
allowing a surface high 1100 miles northwest of the state to exert a
greater influence. As a result...trades will build to low end
moderate levels...and clouds and modest showers will be focused
across windward slopes. Expect afternoon clouds and spotty showers
on leeward Big Island slopes with a brief heavy shower possible. On
the smaller islands...some afternoon clouds will develop over
leeward terrain...but rainfall chances will be low. Moderate trade
winds and a stable rainfall pattern will be established by Tuesday.
An increase in shower activity in the trade wind flow is due during
the second half of the week. A band of moisture associated with
remnants of a front will drift southward and stall over the islands
late Wednesday and Thursday as the surface high passes by to the
north. Moisture from the band will linger over portions of the state
through Sunday...providing enhanced windward rainfall and likely
spreading some showers to leeward areas. A middle to upper level trough
is expected to move near the state from southeast Friday and
Saturday...and this could trigger some heavy showers on the band.
For now...the forecast remains broad brushed with higher probability of precipitation and no
mention of heavy rainfall. The details will become clearer over the
next couple of days.
trade winds will predominate today...and are expected to strengthen
further on Tuesday. Clouds and showers will be focused primarily
across windward and Mauka areas...with brief MVFR conditions
occurring in showers. Sheltered leeward areas may still see sea
breezes this afternoon...which will contribute to interior clouds
and a few showers. There may be isolated MVFR conditions within
these showers as well.
no issues in the short term. Increasing trade winds will bring
border line Small Craft Advisory winds to the typically windy waters
around The Big Island and Maui County starting later today or
tonight. Surf will remain around background levels through much of
the week. A slightly higher swell...possibly up to 4 feet...is
expected from the north-northeast Thursday through Saturday. A moderate south-southwest is
due this weekend.