Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Honolulu HI
954 am HST Wednesday Jul 30 2014
moderate trade winds and relatively quiet weather will continue
through Thursday. The Big Island will see increasing winds and showers
on Friday and Saturday as Tropical Depression Genevieve passes
south of the state. Drier air will push in on Sunday and Monday.
visible satellite shows partly cloudy skies with isolated showers over
windward and Mauka areas...sunny skies leeward. The current weather
will continue through the rest of the morning...with a little bit
more clouds and showers expected across windward portions of
Kauai...Oahu and Molokai by the afternoon. Any rainfall
accumulations will be light.
At the upper levels...water vapor imagery shows a positively-
tilted trough just west of Kauai this morning. Soundings show a
nearly absent inversion at Lihue with a strong one at 8000 feet at
Hilo. Precipitable water values are slightly below normal at
around 1.2 inches.
Moderate to locally fresh trade winds will prevail through
Thursday...with a brief strengthening Friday and Saturday across
the southern half of the state as Tropical Depression Genevieve
passes by to the south. While the main activity with Genevieve will
remain well south of Hawaii...moisture along the far-northern
fringes of the depression will get caught up in the trade winds in
the next day or so. The trades will push this tropical moisture
towards the southern end of the state.
These is model discrepancy between the GFS and European model (ecmwf) as to how far
up the island chain the moisture will reach...and will depend on
the path Genevieve takes. The primary impact of this moisture
will be heavy rain which seems to have the best shot at reaching
The Big Island on Friday...but too close to call for Maui County
and Oahu. Kauai is likely too far north to be impacted by the
Trade winds should maintain moderate strength on Sunday through
the first half of next week. Drier air will also move in Sunday
moderate and locally breezy trades continue over the islands today.
An airmet for low level turb has been issued for areas over and imt
S through west of terrain.
Throughout the islands...VFR conditions will prevail. Trades will
carry passing showers. Some showers may produce brief MVFR
conditions...mainly affecting windward and Mauka slopes.
a Small Craft Advisory /sca/ is in effect for typically windy
waters around Maui County and The Big Island. Small Craft Advisory winds will
likely linger into the long term portion of the forecast period.
A small to moderate swell from the south-southwest is expected
this weekend. Otherwise...a series of small south swells will
continue through next week. Prevailing trade winds will continue
to produce short period...choppy surf along east facing shores.
Small Craft Advisory until 6 PM HST Friday for Maalaea Bay-
Pailolo Channel-Alenuihaha Channel-Big Island leeward waters-Big
Island southeast waters.