Hawaii County climate forecast is September 9, 2021

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Photo credit: James Grenz

Hilo

Today: Partly sunny with a few showers. Heights from 78 to 85 near shore to 64 to 72 at 4000 feet. Northeasterly winds of 10 to 15 miles per hour. 50 percent chance of rain.

Tonight: Mostly cloudy. Showers probably in the evening, then isolated showers after midnight. Lows of 63 to 71 near shore to 54 to 59 at 4000 feet. North winds around 10 mph. Chance of rain 60 percent.

Friday: Partly sunny with a few showers. Heights from 78 to 84 near the shore to 63 to 71 at 4000 feet. Northeast winds around 10 mph. Chance of rain 50 percent.

Kona

Today: Sunny in the morning, then mostly cloudy with a few showers in the afternoon. Highs from 82 to 87 near shore to about 68 near 5000 feet. Southwest winds up to 16 km / h, turning west at around 16 km / h in the afternoon. 50 percent chance of rain.

Tonight: Partly cloudy. Isolated showers in the evening, then isolated showers after midnight. Lows of 69 to 74 near shore to 51 to 56 near 5000 feet. Breeze. 50 percent chance of rain.

THE ARTICLE CONTINUES BELOW THE ADVERT

Friday: Sunny with a few showers in the early morning, then partly sunny with a few showers in the late morning and afternoon. Highs from 82 to 88 near shore to about 67 near 5000 feet. Breeze. Chance of rain 40 percent.

Waimea

THE ARTICLE CONTINUES BELOW THE ADVERT

Today: airy. Mostly sunny with a few showers. Highs 65 to 85. Northeasterly winds 10 to 20 miles per hour. Chance of rain 40 percent.

Tonight: Mostly cloudy with a few showers. Lows of 63 to 70 near shore to 56 to 63 near 3000 feet. East winds around 10 mph. Chance of rain 50 percent.

Friday: Partly sunny with a few showers in the morning, then mostly sunny with a few showers in the afternoon. Highs 64 to 84. Northeast winds around 10 mph. Chance of rain 50 percent.

Kohala

THE ARTICLE CONTINUES BELOW THE ADVERT

Today: airy. Mostly sunny with a few showers. Highs 65 to 85. Northeasterly winds 10 to 20 miles per hour. Chance of rain 40 percent.

Tonight: Mostly cloudy with a few showers. Lows of 63 to 70 near shore to 56 to 63 near 3000 feet. East winds around 10 mph. Chance of rain 50 percent.

Friday: Partly sunny with a few showers in the morning, then mostly sunny with a few showers in the afternoon. Highs 64 to 84. Northeast winds around 10 mph. Chance of rain 50 percent.

Southern big island

Today: Sunny in the morning, then mostly cloudy with a few showers in the afternoon. Highs from 84 near shore to 66 near 5000 feet. East wind up to 24 km / h, which increases to 10 to 24 km / h in the afternoon. Chance of rain 20 percent.

Tonight: Mostly clear. Isolated showers in the evening. Lows of 73 near shore to about 53 near 5000 feet. In the evening the northeast wind blows 10 mph and becomes weak. Chance of rain 20 percent.

Friday: Sunny early in the morning, then partly sunny with a few showers in the late morning and afternoon. Altitudes around 83 near shore to about 65 near 5000 feet. In the afternoon, light winds will blow from the east at about 10 miles per hour. Chance of rain 20 percent.

feedback

Today: Partly sunny with a few showers. Heights from 78 to 85 near shore to 64 to 72 at 4000 feet. Northeasterly winds of 10 to 15 miles per hour. 50 percent chance of rain.

Tonight: Mostly cloudy. Showers probably in the evening, then isolated showers after midnight. Lows of 63 to 71 near shore to 54 to 59 at 4000 feet. North winds around 10 mph. Chance of rain 60 percent.

Friday: Partly sunny with a few showers. Heights from 78 to 84 near the shore to 63 to 71 at 4000 feet. Northeast winds around 10 mph. Chance of rain 50 percent.

Waikoloa

Today: sunny and airy. Heights from 83 to 89 near shore to 66 to 73 over 4000 feet. North winds up to 32 km / h, which increases to 10 to 20 km / h in the afternoon.

Tonight: Mostly clear. Lows of 73 near shore to about 53 over 4000 feet. Breeze.

Friday: Mostly sunny. Isolated showers in the late morning. A few showers in the afternoon. Heights from 83 to 89 near shore to 66 to 73 over 4000 feet. Breeze. 50 percent chance of rain.

summary

The moderate to locally stormy trade winds will continue today before weakening tonight and Friday. The trade winds will gradually increase on Saturday before becoming airy again on Sunday. Few windward showers are expected today, but an increase in humidity later tonight and Friday will fuel an increase in windward showers that may last through Saturday.

discussion

Moderate to locally airy trade winds will return nationwide in NE direction today and Friday, as a surface valley to the distant NE is slowly moving west. As the valley approaches, the low pressure gradient across the state becomes weaker – especially across the E end of the chain. As winds tend to be weaker and weaker for most of the state, hitting a minimum on Friday, the gradient appears to remain tight enough to support moderate NE trades across Kauai.
As the trough approaches the islands longitude this weekend, it is expected to weaken as surface hypertension consolidates towards the distant NE. The low-level narrowing pressure gradient is expected to support a trend towards locally breezy ENO trade winds across the state, although continued weakness in the gradient could prevent the winds from getting too strong near the Big Island.
A strong subsidence inversion at a low level will keep the island atmosphere capped for the foreseeable future. Limited humidity immediately upstream of the islands means a mostly dry day and evening with only a few small and short-lived showers over the windward areas. Later that night and Friday, an area of ​​increased low humidity will arrive from the NE, likely driving up inversion heights, fueling an increase in windward showers that may continue through Saturday. The trades can drive some of these showers on the smaller islands in leeward areas. After that, the forecast points to a fairly typical trade wind weather regime well into the next week, with low clouds and showers that occasionally provide a few showers, mainly on windward.

aviation

Moderate trade winds carry scattered clouds and scattered showers to the east-facing slopes and coasts. Local gusty winds are expected to persist through canalized areas until early evening and then ease on Friday. AIRMET Tango for low mechanical turbulence in the lee of higher terrain will likely remain required until at least 0600z.
For Leeward Big Island, the afternoon sea breeze will focus the cloud cover over the south and west facing slopes. Clouds will linger into the evening hours and then move into the sea after midnight. A cutoff inversion of 7 kft will inhibit vertical development so that few associated showers will develop.
Finally, numerical models show a sharp upper level anchored north of the state. SIGMET Tango was issued for severe turbulence at mid to high levels above FL250 north and northeast of the smaller islands. The area of ​​turbulence is expected to shift south later today, possibly hitting Kauai or Oahu this afternoon and the rest of the smaller islands by late evening.

marine

High pressure north of the islands will sustain trade winds throughout the weekend. But a dissolving surface trough approaching the islands from the northeast will result in the locally strong trade flows softening across the eastern half of the island chain today. Moderate to fresh trades will continue elsewhere. The Small Craft Advisory was only extended to 18:00 HST for the Alenuihaha Channel. Although the bottom will dissipate before reaching the islands, the pressure gradient will favor sustained trades in the moderate to fresh areas until early next week.
A number of overlapping long south swells will maintain near-seasonal levels during the forecast period. Along the north-facing coasts, a small surf is expected from a small north and north-east impulse. This northeast swell, which lasts into the weekend, can help maintain small to moderate surf along exposed east coasts. Otherwise, no significant swells are to be expected until the beginning of next week.

HFO watches / warnings / notices

Small Craft Advisory until 6:00 PM HST tonight for the Alenuihaha Channel.

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Data courtesy of NOAA.gov

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