Current Conditions | ||
Temp | ![]() | 7.7 C |
RH | ![]() | 6 % |
Wind | ![]() | NNE 16 mph |
Road | ![]() | Open (4x4) |
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Hawaiian Islands Synoptic Discussion and Guidance 152 FXHW60 PHFO 051926 AFDHFO Area Forecast Discussion National Weather Service Honolulu HI 926 AM HST Tue Jul 5 2022 .SYNOPSIS... Locally strong trades will continue with wetter than normal conditions through tonight, particularly for the windward slopes of Maui County and Oahu. Trades and shower coverage then trend downward during the latter half of the week. && .DISCUSSION... No changes to the forecast this morning, and not expecting any significant changes with the afternoon package. High pressure to the north of the islands continues to drive locally strong trades to the region. A frontal remnant band caught in the trades continues to bring wet weather to the central islands. As of 9am, the band is focused over Oahu, with some improvement over the islands of Maui County. However additional clouds upstream of Maui County may bring an uptick in shower activity later today and tonight. Drier conditions are expected to continue over Kauai and the Big Island, with the showers there focused over the typical windward areas in the trade wind flow. The morning soundings out of Hilo and Lihue confirmed the arrival of the band of mid-level dry air centered around 700mb. This will ensure continued stability and will limit rainfall amounts away from the most favored locales even as shower coverage remains high. The diurnal heating will bring some improvement by this afternoon, causing showers to trend downward until this evening. Showers then increase in coverage over roughly the same areas again tonight. The high pressure to the north is expected to weaken some during the middle of the week, which will result in a bit of a downward trend in the trades. An upper level trough axis to the northwest of the islands will linger through the week. This is helping to bring some upper level clouds to the region which will also linger through the week. These clouds are expected to be mostly transparent, but batches of these clouds will at times be sufficient to take the edge off of daytime heat. Locally breezy trades will deliver periods of trade wind showers to windward zones for the remainder of the week, but continued stability will help limit rainfall amounts. && .AVIATION... An area of high pressure north of the state will allow for breezy to locally windy trades to persist through the forecast period. This pattern will bring numerous showers to the windward sides of the islands, along with periods of MVFR ceilings and visibility. In addition, isolated showers may pass over the higher terrain and onto leeward areas. AIRMET Sierra remains in effect for mountain obscuration over windward areas of Maui County and Oahu. AIRMET Tango remains in effect for low-level mechanical turbulence leeward of mountains due to strong trades. && .MARINE... Strong surface high pressure will remain located generally northwest to north of the state this week and then build east this weekend. A cold front moving down the eastern flank of this high will briefly weaken the pressure gradient back toward the islands. This will create a period of relatively lighter trade winds Thursday and Friday. The front will wash out this weekend and allow the pressure gradient to re-tighten across the waters upstream of the state. The result will be the return of fresh to strong trades by early next week. A Small Craft Advisory (SCA) is in effect for the windier zones around Maui and Big Island through Friday with the Kaiwi Channel remaining in the SCA through tonight. No significant swells are expected the next several days. Strong trades will support rough and choppy surf along east facing shores through Wednesday. Late week east surf and seas will somewhat ease going into Thursday in response to weakening upstream trades. Deep low pressure passing southeast of New Zealand today will send longer period southwest to south swells our direction. This swell should produce near to above average south facing shore surf early next week. A small, medium period east swell generated by Hurricane Bonnie in the eastern Pacific may arrive early next week. && .HFO WATCHES/WARNINGS/ADVISORIES... Small Craft Advisory until 6 PM HST Friday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters. Small Craft Advisory until 6 AM HST Wednesday for Kaiwi Channel. && $$ DISCUSSION...M Ballard AVIATION...Thomas MARINE...Blood Bulletins, Forecasts and Observations are courtesy of Honolulu National Weather Service Forecast Office |
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