| Current Conditions | ||
| Temp |  | 2.9 C |
| RH | | 84 % |
| Wind | | NE 1 mph |
| Road | | Open (4x4) |
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Hawaiian Islands Synoptic Discussion and Guidance 365 FXHW60 PHFO 050122 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 322 PM HST Sat Jul 4 2020 .SYNOPSIS... Light to moderate east-southeasterly trades will continue through the holiday weekend. Showers will favor windward and mauka areas, although scattered showers will also affect leeward and interior areas at times. A more typical trade wind pattern will resume on Monday, with showers favoring windward and mauka areas along with the stray leeward spillover. This trade wind pattern will hold through late next week, with breezy conditions expected Tuesday into next weekend. && .DISCUSSION... Currently at the surface, a 1030 mb high is centered around 1600 miles north of Honolulu, while a weak trough of low pressure is located several hundred miles northeast of the state. The resulting gradient is producing light to moderate east- southeasterly trades across the island chain this afternoon. Visible satellite imagery shows partly to mostly cloudy conditions across the state, with radar imagery showing scattered showers, a few of which are fairly heavy. Main short term concerns revolve around rain chances and trade wind trends. The gradient will remain disrupted from the high far north of the islands during the next couple days due to the trough of low pressure northeast of the state which will track steadily westward. The trough should dampen out by Monday, allowing high pressure to become more dominant, with the high then sliding southward and closer to the islands Tuesday through late next week. Light to moderate east-southeasterly winds should hold in place through the remainder of the holiday weekend, with localized sea and land breezes developing in the more sheltered leeward areas. Moderate trades will then return through the day on Monday and become breezy Tuesday through late next week. Shower coverage should diminish this evening as daytime heating is lost and a pocket of lower PW values moves over the islands. Scattered windward showers will remain possible through the night and during the morning hours Sunday, with isolated leeward showers remaining possible mainly near the coast in the east- southeasterly boundary layer flow. Scattered showers are expected to continue to affect windward areas Sunday afternoon, with scattered leeward/interior showers developing as a result of sea breezes and daytime heating influences. Showers should diminish in most leeward/interior areas Sunday evening, with scattered showers continuing in windward locales. As trade winds become more dominant on Monday, we should see a return of more typical trade wind weather, featuring mainly windward/mauka showers and a few leeward spillovers. This pattern appears to hold in place through late next week. && .AVIATION... An area of moist air associated with a low level trough has been moving slowly west across the main Hawaiian Islands while a trough aloft has been making the atmosphere a bit unstable. A band of showery low clouds over the islands has partly broken up since this afternoon and clouds and showers have diminished over east sections of the smaller islands. The low level trough has shifted the winds from south of due east, so more showers than usual have been coming ashore in the Kau district of the Big Island. Lines of showery low clouds coming off Molokai have been moving over Oahu and enhancing showers there. AIRMET Sierra for mountain obscuration is in effect for the Big Island and Oahu. Mountain obscuration is likely to continue tonight and may affect other islands. Drier are will be spreading west over the area later tonight bringing higher cloud ceilings and fewer showers. && .MARINE... A surface trough west of Kauai has weakened the pressure gradient over the state and will maintain light to moderate trades through Sunday. As the surface trough shift further west, a ridge of high pressure will strengthen far north of the state early next week. This will cause the trade winds to gradually strengthen. Therefore, Small Craft Advisory (SCA) conditions will likely develop across the typically windier waters adjacent to the islands of Maui County and the Big Island as early as Monday night, and continue through mid-week. Surf is expected to remain below the High Surf Advisory criteria along all shorelines through early next week. Expect a mix of small background swells from the southeast and south through next week. A slightly larger south swell arriving late Wednesday is expected to gradually build through Thursday. This may cause a slight increase in surf along most south facing shores during the second half of next week. The weak trade wind regime will keep small surf along east facing shores into early next week. As the trade winds strengthen, expect choppy surf to increase along east facing shores from late Tuesday through the end of next week. Surf along most north facing shores will remain nearly flat for the foreseeable future. However, small background easterly trade wind wrap and small northwest swell energy may produce periods of tiny surf along some north facing beaches and reefs. && .HFO WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Jelsema AVIATION...Donaldson MARINE...Kino Bulletins, Forecasts and Observations are courtesy of Honolulu National Weather Service Forecast Office |
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