textproduct: Honolulu

SYNOPSIS

A strong high pressure system far north of the Hawaiian Islands will continue to produce moderate to breezy trade winds through today with periods of showers favoring windward mountain areas in the overnight and early morning hours. Hurricane Fausto remains on track to pass north of the Hawaiian Islands on Tuesday and Wednesday as a tropical storm. A drier and breezy trade wind weather pattern will return across the state from Thursday onward as Fausto drifts westward away from the Hawaiian Islands.

DISCUSSION

Currently (3am), satellite and radar imagery shows low clouds and scattered showers moving in on the trades. Showers are primarily impacting windward and mauka spots with a few showers making into leeward locations. High pressure northwest of the state will maintain trades today.

East of the state Hurricane Fausto continues moving west-northwest. Fausto is expected to track north of the state Tuesday into Wednesday. The environment ahead of Fausto grows more unfavorable on approach to the islands and we expect it to weaken into a tropical storm before arrival in the vicinity of the Hawaiian Islands. That said, we remain cautious at this stage that even subtle southern shifts in the track or delayed weakening trends may still produce changes to our island by island impacts. We strongly encourage the public to pay close attention to this passing storm system as weather impacts over the Hawaiian Islands will evolve the closer Fausto gets.

High confidence Fausto impacts include: high surf possibly above warning thresholds for east facing shores today through Tuesday. A High Surf Advisory is already in effect for east facing shores through Wednesday, with the possibility of an upgrade to a warning. Lesser confidence impacts include: strong winds to around 40 mph may develop near and north of the low center and possible heavy rain threats from Tuesday through Wednesday.

No time like the present to review your family hurricane preparedness plans, and ensure every household has at least a 14 day supply of food and water available if needed during this years active hurricane season.

As Fausto continues to move away from the state, a drier and more stable breezy trade wind pattern will fill in from Thursday onward.

AVIATION

Trades will weaken slightly and back towards the northeast today. Low cigs and SHRA possible over windward and mauka locations with some limited spillover into leeward areas. MVFR conds likely in heavier SHRA but VFR should prevail. Hurricane Fausto is east of the state moving WNW and is expected to pass to the north Tuesday into Wednesday. An increase in SHRA and some low cigs will be likely. TC SIGMET Sierra covers Fausto.

AIRMET Sierra is in effect for mtn obsc for windward portions of the smaller islands. Conds may improve in the early morning hours. As Fausto approaches this could be expanded or become an IFR AIRMET.

AIRMET Tango remains in effect for mod low-level turb downwind of island terrain. This AIRMET may likely be dropped this afternoon as winds continue to decline.

MARINE

An overnight ASCAT pass revealed that locally breezy trade winds continue to prevail over the region, especially in the typically winder waters and channels around Maui County and the Big Island. Therefore, a Small Craft Advisory remains in effect for these areas through this afternoon. The fresh to locally breezy trades will gradually shift to the NNE and diminish through the middle of the week in response to what is currently Hurricane Fausto passing north of the islands. However, it is likely that the Small Craft Advisory will need to be expanded due to seas greater than 10 feet for windward waters. The trades will then return to fresh and strong levels late this week into the weekend as the remnants of Fausto continue off to the west-northwest away from the state and strong high pressure builds to the north.

The current long-period south swell will slowly decline for the next couple of days. The High Surf Advisory has been cancelled for south facing shores based on the latest buoy trends and guidance, though some borderline advisory-level surf cannot be ruled out at select top spots along south shores early this morning.

East facing shores will continue to support rough, choppy surf due to the locally breezy trade winds. Additionally, nearshore buoys on the eastern side of the islands have begun to show the long period forerunners of the new easterly swell. A High Surf Advisory for east facing shores is currently in effect through Wednesday afternoon. However, as energy from Hurricane Fausto builds, surf along east facing shores could reach warning levels by tonight through early Wednesday. A Coastal Flood statement may be also be needed during the peak of the large surf for vulnerable low-lying coastal roadways, docks, boat ramps, and other coastal infrastructure exposed to the large east swell. After a brief lull late Wednesday through Thursday, east shore surf will trend back up Friday into the weekend due to a combination of rising trade wind swell and a new long period east swell generated by Hurricane Genevieve.

Surf along N shores could also see some brief increase as Fausto (or its remnants) pass near the region Tuesday and Wednesday, then return to typical flat to tiny levels late Wednesday into the weekend.

HFO WATCHES/WARNINGS/ADVISORIES

High Surf Advisory until 6 PM HST Wednesday for Olomana-Maui Windward West-Kauai East-East Honolulu-Koolau Windward-Molokai Windward-Molokai Southeast-Windward Haleakala-Kipahulu-Big Island Southeast-Big Island East-Big Island North.

Small Craft Advisory until 6 PM HST this evening for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters.