Today: Cloudy. Showers in the morning, then numerous showers in the afternoon. Highs around 77 near the shore to 62 to 67 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 90 percent.
Tonight: Cloudy. Numerous showers in the evening, then showers after midnight. Lows around 64 near the shore to around 50 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 90 percent.
Wednesday: Cloudy with numerous showers. Highs around 76 near the shore to 61 to 66 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.
Kona
Today: Mostly sunny with isolated showers in the morning, then cloudy with scattered showers in the afternoon. Highs around 82 near the shore to around 68 near 5000 feet. West winds up to 10 mph. Chance of rain 50 percent.
Tonight: Mostly cloudy. Isolated showers in the evening. Lows around 69 near the shore to around 54 near 5000 feet. Light winds. Chance of rain 20 percent.
ARTICLE CONTINUES BELOW AD
ARTICLE CONTINUES BELOW AD
Wednesday: Partly sunny in the morning, then cloudy with scattered showers in the afternoon. Highs around 83 near the shore to around 69 near 5000 feet. West winds up to 10 mph. Chance of rain 40 percent.
Waimea
Today: Cloudy and windy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 76 near the shore to 66 to 74 near 3000 feet. East winds up to 30 mph increasing to 15 to 30 mph in the afternoon. Chance of rain 70 percent.
Tonight: Breezy. Cloudy with numerous showers. Lows around 63 near the shore to 48 to 60 near 3000 feet. East winds 10 to 25 mph. Chance of rain 70 percent.
Wednesday: Cloudy and breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 58 to 77. East winds 10 to 25 mph. Chance of rain 70 percent.
Kohala
Today: Cloudy and windy. Numerous showers in the morning, then scattered showers in the afternoon. Highs around 76 near the shore to 66 to 74 near 3000 feet. East winds up to 30 mph increasing to 15 to 30 mph in the afternoon. Chance of rain 70 percent.
ARTICLE CONTINUES BELOW AD
Tonight: Breezy. Cloudy with numerous showers. Lows around 63 near the shore to 48 to 60 near 3000 feet. East winds 10 to 25 mph. Chance of rain 70 percent.
Wednesday: Cloudy and breezy. Numerous showers in the morning, then scattered showers in the afternoon. Highs 58 to 77. East winds 10 to 25 mph. Chance of rain 70 percent.
South Big Island
Today: Mostly sunny in the morning then becoming mostly cloudy. Breezy. Isolated showers. Highs around 80 near the shore to around 69 near 5000 feet. East winds up to 25 mph increasing to 10 to 25 mph in the afternoon. Chance of rain 20 percent.
Tonight: Mostly cloudy. Breezy. Isolated showers in the evening. Lows around 68 near the shore to around 53 near 5000 feet. Northeast winds 10 to 25 mph. Chance of rain 20 percent.
Wednesday: Breezy. Partly sunny in the morning, then cloudy with isolated showers in the afternoon. Highs around 81 near the shore to around 70 near 5000 feet. East winds up to 25 mph. Chance of rain 20 percent.
Puna
ARTICLE CONTINUES BELOW AD
Today: Cloudy. Showers in the morning, then numerous showers in the afternoon. Highs around 77 near the shore to 62 to 67 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 90 percent.
Tonight: Cloudy. Numerous showers in the evening, then showers after midnight. Lows around 64 near the shore to around 50 at 4000 feet. Northwest winds up to 10 mph. Chance of rain 90 percent.
Wednesday: Cloudy with numerous showers. Highs around 76 near the shore to 61 to 66 at 4000 feet. Northeast winds up to 15 mph. Chance of rain 70 percent.
Waikoloa
Today: Mostly sunny in the morning then becoming mostly cloudy. Windy. Isolated showers. Highs 77 to 83 near the shore to 64 to 72 above 4000 feet. Northeast winds up to 30 mph. Chance of rain 20 percent.
Tonight: Mostly cloudy. Breezy. Isolated showers in the evening. Lows around 70 near the shore to 48 to 57 above 4000 feet. Southeast winds up to 25 mph. Chance of rain 20 percent.
Wednesday: Mostly sunny in the morning then becoming cloudy. Breezy. Highs 78 to 84 near the shore to 65 to 73 above 4000 feet. Northeast winds up to 25 mph.
Detailed Forecast
Synopsis
A strong high pressure system far north of the Hawaiian Islands will linger through Wednesday with breezy trade winds continuing through mid week. This high will then weaken from Thursday through Saturday producing more moderate trade winds across the island chain. A narrow upper level trough will persist above the islands with embedded upper low centers. This trough will likely enhance overnight to early morning trade wind shower activity, especially over windward and mountain areas into Saturday. Weather conditions will shift to more southeasterly winds with decreasing shower trends on Sunday and Monday.
Discussion
Water vapor satellite imagery this morning shows an interesting upper level pattern with a seasonably strong sub tropical jet stream over the islands along the southern edge of a long and narrow upper level trough. Several weak lows are embedded within this upper trough that will help to weaken the large scale subsidence (downward atmospheric motions) over the region and enhance trade wind shower activity. Trade wind inversion heights from the 2 AM HST upper air balloon soundings range from around 6,000 to 7,000 feet, which is high enough for scattered windward showers in the day becoming numerous showers at night. Leeward areas will see only isolated shower coverage. Local radar imagery this morning confirms scattered to numerous showers moving through the easterly trade wind flow.
Short and medium range guidance remains in good agreement with the breezy trade wind pattern continuing through at least Wednesday, then trade wind speeds will slowly decrease from Thursday through Saturday as the high pressure system far north of the state weakens in response to a passing cold front farther to the north. Rain shower bands will trend higher during the typical overnight to early morning hours and favor windward and mountain sections of each island into Saturday. Rainfall activity was lowered from Kauai to Maui from Thursday through Saturday in this mornings forecast package.
The long range forecast hints at some changes on the horizon. Both the American (GFS) and European (ECMWF) show the high pressure ridge north of the islands breaking down as a low pressure system near the Dateline dives south and sets up northwest of Kauai. Easterly trade winds will veer from a more southeasterly direction from Sunday into Monday and shower activity will decrease west of the Big Island due to the rain shadowing effects of southeasterly winds. Deeper tropical moisture with southerly winds in the mid levels may enhance shower activity over Kauai by late Monday. Stay tuned as models continue to hint at wet weather trends in the extended range forecast around the middle of next week.
Aviation
Strong high pressure far north of the state will bring breezy east north easterly trades through this afternoon. Sufficient moisture in the lower levels will continue to allow for scattered to numerous showers to develop along the windward coasts and slopes. Expect periods of MVFR due to lower ceilings and reduced visibility associated with this activity. Isolated showers elsewhere across the region.
AIRMET Sierra remains in effect for north through east sections of the Big Island and Oahu above 2500 feet due to low clouds and showers.
AIRMET Tango remains in effect below 8000 feet for moderate tempo turbulence over and immediately south through west of mountains.
Marine
Strong high pressure north of the state will remain nearly stationary and drive fresh to locally near gale trades through mid-week. Winds speeds are forecast to peak near gale force in the windiest eastern zones near Maui and the Big Island today into Wednesday, then weaken slightly Thursday through the coming weekend. The Small Craft Advisory (SCA) is in effect through Wednesday afternoon for all coastal waters due to winds and building seas.
A moderate north (350 deg) swell is filling in this morning above model expected guidance. This swell will result in building surf for north facing shores peaking this afternoon. East facing shores will see an increase today for select spots exposed to the north swell and short- period trade wind swell from the fresh to strong trades. Surf will be near High Surf Advisory (HSA) levels for east facing shores and may need to be updated throughout the day. A small, medium- period northwest (320 deg) swell is possible this weekend. South facing shores will continue to have minimal surf due to background long-period energy throughout the week.
HFO Watches/Warnings/Advisories
Small Craft Advisory until 6 PM HST Wednesday for all Hawaiian waters,
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