Area Forecast Discussion
Issued by NWS Honolulu, HI
Issued by NWS Honolulu, HI
490 FXHW60 PHFO 240117 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 317 PM HST Thu Jan 23 2025 .SYNOPSIS... Cool and crisp mornings followed by typical daytime high temperatures expected the next couple of days. Moderate trades return this weekend allowing overnight temperatures to rebound toward normal and bringing a chance for rain mainly to windward and mauka areas. && .DISCUSSION... Cool and crisp conditions expected again tonight into Friday morning from Kauai to Maui County. Dewpoints in the low to mid 50s and light winds will allow temperatures to drop into the low 60s and even upper 50s in a few select locales. The front itself has dissipated in the waters of the Alenuihaha Channel between the Big Island and Maui and will support redevelopment of just a few scattered showers within the remnant moisture band tonight. Little if any additional forward progress is expected given the loss of upper-level forcing. A transient period of mid-level ridging over the NE Pacific Basin will allow moderate trades to return for the weekend. The return of easterlies will usher remnant frontal moisture presently in the vicinity of the Big Island westward and will serve as a moisture source for typical trade wind showers Saturday night into the first half of next week. Strong consensus among the extended guidance that renewed troughing within NW flow aloft will favor low pressure development over the lower latitudes of the Central Pacific. The remnant frontal boundary will strengthen in response to developing forcing and will serve as the baroclinic pathway for the surface low to track near or north of the forecast area during the middle to latter portion of next week. Convective feedback is playing some havoc with model solutions at this time, so uncertainty is greater than normal, but the second half of next week seemingly offers the next opportunity for meaningful rainfall across some or all of the island chain. && .AVIATION... Moisture from a dissipated front will remain stalled near northern Big Island and east Maui and will produce isolated MVFR conditions along terrain through the evening. Gradual clearing is expected overnight as land breezes develop. Elsewhere, VFR conditions will prevail under a light, dry, and stable northwest flow. An upper level trough passing over the state will continue to produce moderate turbulence aloft between FL180 and FL380 through the afternoon. Turbulence aloft will diminish from west to east overnight as the upper trough moves eastward. The jet stream may advance toward the state again on Friday and bring moderate turbulence above FL300. && .MARINE... Westerly winds will weaken tonight through early Friday. The ridge will lift northward late Friday into the weekend, which should allow light to moderate trade winds to return. The winds become more uncertain early next week as a trough moves in from the east and a cold front approaches from the northwest. A combination of north northwest and north swells will produce large disorganized surf along north facing shores. The swells are expected to gradually decline Friday through the weekend. A High Surf Advisory remains in effect for north facing exposures through 6 pm HST Friday. A series of moderate northwest and north swells are possible early next week. Aside from areas exposed to wrap from north swells, east shore surf will remain well below normal through the middle of next week. South shore surf will remain at background very small levels through the middle of next week. A Small Craft Advisory (SCA) is now in effect for most marine zones through 6 pm Friday due to 10 foot seas. && .FIRE WEATHER... Afternoon RH values will fall well into the 40s again tomorrow, but winds will fall short of the critical fire behavior threshold. && .HFO WATCHES/WARNINGS/ADVISORIES... High Surf Advisory until 6 PM HST Friday for Niihau-Oahu North Shore-Maui Windward West-Kauai North-Molokai Windward-Molokai North-Maui Central Valley North-Windward Haleakala. Small Craft Advisory until 6 PM HST Friday for Kauai Northwest Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel- Oahu Windward Waters-Oahu Leeward Waters-Kaiwi Channel-Maui County Windward Waters-Alenuihaha Channel-Big Island Windward Waters. && $$ DISCUSSION...JVC AVIATION...Wroe MARINE...Foster FIRE WEATHER...JVC