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Next 12 Hours

Forecast data from the National Digital Forecast Database.

5 Day Forecast

• Wednesday
• 
• High: 82 °
• Low: 72 °
• Rain Showers

• Thursday
• 
• High: 84 °
• Low: 72 °
• Rain Showers

• Friday
• 
• High: 82 °
• Low: 72 °
• Mostly Cloudy

• Saturday
• 
• High: 82 °
• Low: 72 °
• Fog

• Sunday
• 
• High: 86 °
• Low: 72 °
• Partly Cloudy

Area forecast discussion 
National Weather Service Honolulu HI 
400 am HST Wednesday may 16 2012 


Synopsis... 
a weak front will dissipate over Kauai this morning. As light trade 
winds strengthen through the day...showers and cloud cover will 
increase across the rest of the state...especially windward. From 
Thursday through Saturday...both trades and showers will diminish 
gradually...only to recover again next week. 


&& 


Discussion... 
remnants of a dissipating frontal cloud band streamed over Kauai 
County from the northeast...while cloud cover upwind of the other 
islands trended toward trade-wind norms. Satellite estimates of 
atmospheric moisture hovered near seasonable values over most of the 
state...but unsurprisingly averaged one quarter or a third above 
climatology around Kauai. Rainfall accumulation overnight on Kauai 
was highest at mount Waialeale...where orographic forcing was 
maximized...with the rest of the island receiving only a smattering. 
Elsewhere....a cluster of marine cumuli that developed under the 
influence of troughing aloft to the east of The Big Island moved 
ashore around Cape Kumukahi...but pre-frontal subsidence still 
prevailed across the rest of the state. Increasing...though still 
sparse...trade shower activity should start to reach windward slopes 
through the day. 


Surface observations around the islands already reported light trade 
winds blowing...and pressure trends supported a significant increase 
in wind speed from the stagnant conditions on Tuesday. As the front 
dissipates completely...its remnant moisture will be blown away 
toward the southwest and away from the state. 


As the middle-level trough to the east weakens...and ridging edges in 
from the northwest...the subtropical ridge at the surface will 
rebuild...boosting trade wind speeds through the next 12 to 18 
hours. Guidance as a whole is somewhat ambivalent on the question of 
whether wind speeds at their peak tonight will reach the lower 
threshold for a Small Craft Advisory...though certainly such a 
scenario remains possible. In any case...this peak will not persist 
for long...as ridging is expected to flatten out both aloft and at 
the surface...allowing the trades to weaken gradually at least 
through Saturday. Windward showers also will diminish through the 
first half of the weekend with unimpressive orographic forcing and 
under weak subsidence. 


Solutions trend toward climatology again through the middle of next 
week. 


&& 


Marine... 
as the trade winds increase by tonight...speeds in the typically 
windier areas around Maui and The Big Island may approach 25 
knots...possibly requiring a Small Craft Advisory. 


&& 


Hfo watches/warnings/advisories... 
none. 


&& 


$$ 


Ryshko