Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
661 FXHW60 PHFO 081942 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 942 AM HST Fri Nov 8 2024 .SYNOPSIS... A remnant frontal boundary brings increased showers to Molokai and Oahu today and Kauai late tonight into early Saturday. Stable, breezy trades then prevail well into next week. && .DISCUSSION... Remnant frontal zone draped over western Maui County and Oahu this morning presents as a narrow band of shallow moisture existing at the convergent interface of breezy NE trades and building easterlies. Satellite and radar observations confirm model depictions of saturation up to around 8kft in the vicinity of this boundary and low-level forcing remains sufficient to generate widespread light showers along with spotty heavy showers along the convergent boundary itself. This in turn spells a wet morning and early afternoon for Molokai and Oahu, including most leeward areas with the exception of far western Oahu which will likely escape most shower activity given the shallow moisture profile. As governing high pressure migrates eastward, easterlies will gradually build across the area which will usher this band of showers westward with time. Drier upstream air will begin working into Oahu by this afternoon while the band approaches and eventually reaches Kauai late tonight into Saturday. Strong 595dm mid-level ridging is already establishing over western portions of the area and will build eastward during the next 24-48 hours. Consensus is strong among the extended guidance that a stable, breezy, and normal to slightly wetter than normal trade wind pattern will continue well into next week. Further amplification of the resident mid-level ridge axis may allow for a period of strong trades by the end of next week. && .AVIATION... A band of moisture from dissipated front will continue to affect portions of the state within a breezy trade wind flow. As of 930 AM, the band will be clearing Molokai within the next hour or so and will remain focused on Oahu through noon. AIRMET Sierra for MVFR ceilings and VIS in SHRA is posted for windward and mountain sections of these islands, with improvement expected during the afternoon. Expect only isolated MVFR conditions on windward sections of the Big Island, Maui, and Kauai today. For tonight, the moisture band will drift westward and likely impact windward Kauai with MVFR conditions and mountain obscuration. VFR will prevail over leeward areas. The combination of breezy trade winds and an inversion based between 6,000 and 8,000 feet will continue to produce moderate low-level turbulence over and downwind of terrain on all islands through tomorrow. AIRMET Tango is in place for this phenomenon. In addition, a sharp upper level trough just south of the Big Island may produce some moderate turbulence above FL350 through midday. && .MARINE... High pressure to the northwest of the state will gradually shift to the north this weekend and will maintain fresh to locally strong trades through at least early next week. With the high moving north of the state, wind direction will become more easterly by Sunday. Small Craft Advisory (SCA) remains in effect for many areas today and will likely drop off in some areas tonight into Saturday as the trades fluctuate. In the extended, there is growing confidence for trades to strengthen as a strong high sets up NNE of the state. Widespread strong trades are expected during the second half of next week with even gales possible for select channels. A reinforcing medium period NW to NNW (320-340 degree) swell should build in later today, peak tonight into early Saturday, then gradually decline over the weekend. A moderate NW (325 degree) swell is expected to fill in on Monday and will likely peak near advisory levels late Monday. This swell will be followed by a slightly larger NW (320 degree) swell on Wednesday, which should produce advisory level surf for N and W facing shores next week Wednesday. Surf along east-facing shores will remain rough and choppy through the middle of next week due to the breezy trade winds. Long range models are showing a significant increase of windswell towards the end of next week due a large fetch of strong trade winds setting up over and upstream of the state. Surf could reach warning levels (15 ft) along east facing shores towards the end of next week. Surf along south-facing shores will remain small and near the seasonal average through the middle of next week. Also with the peak monthly tides coming up towards the later half of next week (Nov 14th to Nov 18th) we should see coastal inundation impacts during the early morning hours along all coastlines. The large windswell combined with the peak monthly tides could cause greater impacts along windward shores. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 AM HST Saturday for Kauai Northwest Waters-Kauai Leeward Waters-Kauai Channel. Small Craft Advisory until 6 PM HST this evening for Kauai Windward Waters-Oahu Windward Waters-Oahu Leeward Waters-Kaiwi Channel-Maui County Leeward Waters. Small Craft Advisory until 6 PM HST Sunday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. && $$ DISCUSSION...JVC AVIATION...Wroe MARINE...Kino