Marine Weather and Tide Forecast for Holualoa, HI

DISCUSSION
Bands of clouds are shown on the latest satellite imagery this morning riding the easterly trade winds into the windward mountain slopes of each island. These clouds will continue to produce brief periods of showers mainly over the windward and mountain slopes favoring the overnight to early morning hours. A few bands of high level cirrus, ice crystal clouds, are drifting across the island chain this morning; likely enhancing sunrise and sunset colors.

The wind pattern remains moderate to locally breezy easterly trade winds through Friday. The high pressure ridge will strengthen over the islands this weekend, producing additional drying trends (lower humidity levels), and more stable conditions aloft. Expect breezy to locally windy trade winds by Sunday. The combination of drier humidity levels and stronger winds may elevate fire weather concerns from late Sunday morning through the afternoon hours.

Looking into the cloud and shower activity for the next seven days we continue to see subtle shifts in the day to night diurnal rainfall pattern through Friday. Overall a fairly stable conditions will prevail for the most part through Thursday with some periods of passing showers mainly in the overnight to early morning hours as a few unsettled passing cloud bands are lifted up and rain over windward island mountains. One wrinkle in the latest forecast guidance is the presence of an easterly wave, shown on 700 mb streamlines, moving into the islands on the trade winds from Thursday through Friday. Model cross sections suggest this passing trough will lift the boundary layer with temperature inversion rising into the 8,000 to 9,000 foot range. At this level, deeper clouds will likely increasing shower trends across all islands with some of the stronger showers drifting into the typically drier leeward areas. Rainfall amounts will still remain on the low side with the best chances for shower activity occurring during the typical overnight to early morning hours.

More stable trends develop this weekend as the ridge builds back into the Hawaii Region, decreasing island cloud cover and shower trends. Finally, expect a subtle increase in shower trends by early next week as a combination of upper (500 mb) and lower level (700 mb) troughing move into the region.

AVIATION
Moderate to locally breezy trade winds will continue through Friday. Shower activity will be limited to windward and mountain areas, favoring the overnight to early morning hours.

AIRMET Sierra remains in effect for mountain obscurations along north and east slopes of Maui and the Big Island. These low cloud ceilings will likely diminish later this morning.

AIRMET Tango remains in effect for moderate turbulence over and south through west of island mountains. These stronger winds and turbulent conditions will likely continue through the day.

MARINE
High pressure north of Hawaii will slowly move eastward and drive moderate to locally strong trades across the local waters. The Small Craft Advisory (SCA) for typically windier waters and channels near Maui and the Big Island has been extended through Thursday. Trade winds are forecast to strengthen this weekend, where other zones may need to be added to the SCA.

A small, long period, south swell is starting to slowly filter in early this morning and will peak later tonight into Thursday providing a slight boost in surf along south facing shores through the weeks end. Rough and choppy conditions along east facing shores will pick up a notch or two over the weekend and persist into early next week. Surf will remain nearly flat along north facing shores.

HFO WATCHES/WARNINGS/ADVISORIES
Small Craft Advisory until 6 PM HST Thursday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters.