Light winds are expected across the state today as a front approaches from the northwest, allowing for sea breeze development and limited shower activity over leeward and interior areas. The front will move north to south across the islands chain this weekend into early next week, bringing increased rainfall that will be primarily focused along windward slopes. Breezy to windy trades will follow the front, persisting through much of next week.
Current radar and infrared satellite imagery show some layered high clouds continuing to stream over the islands, with very sparse low cloud and shower coverage across the island chain. These upper-level clouds, tied to jet dynamics aloft, are expected to taper off later today. The trade winds have been mostly cut off thanks to a broad low pressure system to the northeast and its associated cold front approaching the state from the north. In this lighter flow, sea breezes will likely form, bringing low clouds and isolated to scattered showers to island interiors as well as along any weak convergent boundaries. Despite the slight weakening of the mid level ridge over the region, generally stable conditions will remain in place in advance of the front`s arrival in Hawaii, so any showers that do form will likely be light.
The latest model guidance has come into better agreement on the pattern for this weekend and into next week, gradually increasing forecast confidence. The aforementioned cold front is expected to approach the western end of the state on Saturday and pass over the eastern end by sometime on Sunday. Light winds can be expected to prevail ahead of the front with breezy to windy east- northeasterly winds in its wake. Modest low level moisture pooling ahead of and along this boundary will increase rain chances as the front progresses down the island chain, but with mid level ridging still in place, rainfall rates should be limited. The relatively quick-moving nature of the front will serve as an additional limiting factor for flooding concerns.
Breezy to windy east-northeasterly trades will become established across the state early next week as high pressure builds to the north. Another reinforcing front with an even stronger high pressure system (1036 mb) will arrive midweek, providing another boost in the east-northeasterly trades. With mid level ridging persisting over the region, inversion heights will remain low, keeping the moisture confined to lower levels and focusing clouds and showers over windward and mauka areas.
Light and variable winds are expected today, allowing for daytime sea breezes as light background winds shift out of the north around Kauai and Oahu. The atmosphere will remain stable, and aside from isolated MVFR ceilings over interior terrain, VFR conditions will prevail. A cold front will approach Kauai by Saturday morning, bringing breezy to windy northeasterly winds and increasing shower coverage near the frontal boundary.
Flow will become light and variable today as an area of low pressure moves north of the Hawaiian Islands and an associated cold front approaches from the northwest. The front is forecast to pass across the island chain late Saturday into Sunday. Behind the front, expect fresh to locally strong north northeast trades to fill in. These winds should last into early to mid next week as high pressure builds north of the state. Small Craft Advisories will likely be needed during this time.
The current small to moderate, medium period, northwest swell (320-330) will slowly subside through early Saturday and keep surf size near seasonal normals along north facing shores. A deep low pressure system can be noted on last nights ASCAT pass well north of the state with a north to south fetch pointed directly towards the islands. This low will generate a large, short to medium period, northerly swell that will help to bump surf heights up late Saturday into Sunday that will likely exceed the High Surf Advisory threshold for north facing shores. This fetch will also favor harbor surges in N facing harbors such as Kahului and Hilo on Sunday. Additional north northeast swell should continue elevated swell conditions along north and east facing beaches through early next week.
Surf will remain small along east facing shores today as trade flow weakens to light and variable. As a front presses southward across the island chain Saturday into Sunday, winds will shift northeasterly and increase in strength. This, combined with a large, moderate period, north or north northeast swell will bring high surf and choppy conditions to east facing shores late Saturday through Monday. A High Surf Advisory will likely be needed during the peak of the event.
A small, long period, south southwest swell will boost surf heights later today into Saturday to near seasonal normals along south facing shores. Several more similarly sized southerly swell will enter the waters Sunday into early next week.
Peak monthly tides combined with water levels that are running higher than predicted will lead to minor flooding along the shoreline and in low-lying coastal areas for the next several mornings. Thus, the Coastal Flood Statement has been extended through noon on Saturday.
None.
