Lighter background winds will support daytime sea breezes and nighttime land breezes today through Friday. Thus, most cloud cover and shower activity will favor interior and mountain areas during the afternoons. Deeper moisture associated with a weak trough will move northward from the southeast through Friday, and will briefly increase shower chances island- by-island as it weakens. A more typical trade wind pattern will return late this weekend.
Latest satellite and radar imagery shows isolated to scattered showers across the region. More persistent showers are moving onto and over the Big Island as a weak trough continues its March up the island chain. The trough should be near Maui tonight and possibly near or over Oahu on Thursday afternoon. As this weakening trough moves up the island chain expect a slight increase in showers before the trough moves away.
A series of fronts will move across the North Pacific well north of the island chain. This should disrupt the moderate trades weakening them through Friday. This should lead to sea/land breezes for the next few days. Clouds and showers should mainly be limited to over the island interiors and mountainous terrain, particularly during the day. The exception being the previously discussed weakening trough moving across the island chain.
After a brief period of east-southeasterly flow Saturday, moderate easterly trades will return during the second half of the weekend. Some light windward and mauka showers will return but fairly dry conditions will keep the showers limited.
An oncoming surface trough moving through the Big Island early this morning will make for weakened trades across most sites. Expect light to moderate land/sea breezes to prevail as a result, with increasing cloud cover and moisture moving from the Big Island northwestward through the period. Any rain that results from this system is primarily expected to impact windward sites, but MVFR conditions may still spill over to leeward sites at times. IFR is possible as well under heavier showers.
AIRMET Sierra is currently in effect for mountain obscuration across windward Big Island due to oncoming showers. This may spread to other islands later in the period.
A ridge of high pressure north of the state is driving gentle to locally moderate easterly trades as a front to the northwest pushes the ridge east of the coastal waters. The ridge will strengthen north of the area over weekend as the trough weakens and lifts far north, allowing moderate to fresh trades to return.
Surf along south facing shores will remain elevated as the current swell gradually declines through the evening. The High Surf Advisory (HSA) has been cancelled this morning but may need to be reissued Thursday as another moderate, long period south southwest swell is expected to fill in tonight and peak Thursday before slowly fading Friday through the weekend. Surf along north facing shores will remain flat to tiny through the forecast period. Surf along east facing shores will remain below average as easterly trade winds ease through the end of the week.
The Coastal Flood Statement has been cancelled this morning as the peak high tides and the south swell have begun to decline. The Marine Weather Statement has also been cancelled due to the declining south swell.
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