Photo credit: James Grenz
Hilo
today: Mostly cloudy. There will be more showers in the morning and scattered showers in the afternoon. Highs near the coast will range from 76 to 86 degrees, with highs around 68 degrees at 4,000 feet. Northeast winds reaching 15 mph. The chance of rain is 70%.
tonight: Mostly cloudy. There will be showers throughout the night, with showers developing after midnight. Low pressure near the coast is 65 to 71 degrees and low pressure at 4,000 feet is 54 to 59 degrees. Northwest winds reaching 10 mph. The chance of rain is 80%.
Sunday: Partly sunny in the morning, then cloudy. Scattered showers. Highs near the coast will range from 77 to 87 degrees, with a high of 69 degrees at about 4,000 feet. Northeast wind, reaching 10 mph. The chance of rain is 50%.
Kona
today: Mostly sunny. Scattered showers in the afternoon. Highs near the coast are 82 to 88 degrees, with highs around 68 degrees near 5,000 feet. West winds reaching 10 mph. The chance of rain is 50%.
tonight: Partly cloudy with some showers. Low pressure near the coast is about 74 degrees and low pressure at 5,000 feet is 50 to 55 degrees. breeze. The chance of rain is 20%.
Sunday: Mostly sunny in the morning, cloudy with scattered showers in the afternoon. Highs near the coast are 83 to 89 degrees, with highs around 69 degrees near 5,000 feet. breeze. The chance of rain is 40%.
water
today: Breeze. Partly sunny with scattered showers. Highs will be 74 to 81 degrees near the coast and 68 to 80 degrees near 3,000 feet. East wind 10 to 25 mph. The chance of rain is 50%.
tonight: Breeze. Mostly cloudy with scattered showers. Low pressure near the coast is 63 to 71 degrees and about 59 degrees near 3,000 feet. East winds reaching 20 mph. The chance of rain is 50%.
Sunday: Breeze. Partly sunny with scattered showers. Highs will be 74 to 81 degrees near the coast and 68 to 80 degrees near 3,000 feet. East winds reaching 20 mph, increasing to 10 to 20 mph in the afternoon. The chance of rain is 50%.
koala
today: Breeze. Partly sunny with scattered showers. Highs will be 74 to 81 degrees near the coast and 68 to 80 degrees near 3,000 feet. East wind 10 to 25 mph. The chance of rain is 50%.
tonight: Breeze. Mostly cloudy with scattered showers. Low pressure near the coast is 63 to 71 degrees and about 59 degrees near 3,000 feet. East winds reaching 20 mph. The chance of rain is 50%.
Sunday: Breeze. Partly sunny with scattered showers. Highs will be 74 to 81 degrees near the coast and 68 to 80 degrees near 3,000 feet. East winds reaching 20 mph, increasing to 10 to 20 mph in the afternoon. The chance of rain is 50%.
south island
today: Mostly sunny. Breeze. There will be isolated showers in the afternoon. Highs near the coast will be about 85 degrees and highs at 5,000 feet will be about 67 degrees. East winds reaching 25 mph. The chance of rain is 20%.
tonight: partly cloudy. Breeze. There will be isolated showers in the evening. The lowest pressure near the coast was around 73 degrees, and the lowest at 5,000 feet was around 52 degrees. Northeast winds reaching 20 mph will become 10 to 15 mph after midnight. The chance of rain is 20%.
Sunday: Breeze. It will be sunny in the morning and partly sunny with showers in the afternoon. Highs near the coast are about 86 degrees and elevations near 5,000 feet are about 68 degrees. East winds reaching 20 mph. The chance of rain is 20%.
Pune
today: Mostly cloudy. There will be more showers in the morning and scattered showers in the afternoon. Highs near the coast will range from 76 to 86 degrees, with highs around 68 degrees at 4,000 feet. Northeast winds reaching 15 mph. The chance of rain is 70%.
tonight: Mostly cloudy. There will be showers throughout the night, with showers developing after midnight. Low pressure near the coast is 65 to 71 degrees, and low pressure at 4,000 feet is 54 to 59 degrees. Northwest winds reaching 10 mph. The chance of rain is 80%.
Sunday: Partly sunny in the morning, then cloudy. Scattered showers. Highs near the coast will range from 77 to 87 degrees, with a high of 69 degrees at about 4,000 feet. Northeast wind, reaching 10 mph. The chance of rain is 50%.
Waikoloa
today: The sun is shining brightly and the breeze is gentle. There will be isolated showers in the afternoon. Highs will be 83 to 89 degrees near the coast and 66 to 74 degrees above 4,000 feet. Northeast winds reaching 25 mph. The chance of rain is 20%.
tonight: Most of it is clear. Breeze. There will be isolated showers in the evening. Lows will be around 74 degrees near the coast and around 55 degrees above 4,000 feet. East winds reaching 20 mph. The chance of rain is 20%.
Sunday: Sunny in the morning, then clear. Breeze. Highs will be 84 to 89 degrees near the coast and 67 to 74 degrees above 4,000 feet. Northeast winds reaching 20 mph.
summary
The high pressure system north of the Hawaiian Islands will continue to gradually weaken and slowly drift westward over the next few days. Trade wind speed trends will remain in the moderate to breezy range through Sunday before decreasing to moderate levels starting Monday. Strong and steady subsidence aloft will limit the chance of showers for much of next week. However, the cloud and shower trend will increase slightly throughout the day today as a weak tropical wave moves from east to west along the island chain.
discuss
Looking at satellite images this morning, we see an area of upper-level cold core low pressure and thunderstorms about 700 to 800 miles northwest of Kauai. High-altitude cirrus clouds surge from the south to the western islands and move along the high-altitude subtropical jet stream. We also see a slight counterclockwise (cyclonic) rotation in the low-level cumulus field, which is associated with a weak trough in the trade winds. This weak tropical wave will continue to slowly move across the islands today, driving a trade wind inversion and increasing cloud and shower trends in the evening. Most intensifying showers will develop during the typical daily rainfall heaviest overnight into early morning hours.
On a larger scale, a strong high pressure system north of the Hawaiian Islands will continue to produce moderate to breezy trade winds in the region today. The high pressure center will continue to weaken and slowly drift westward, with wind trends lowering into the moderate to breezy range Saturday into Sunday, then weakening further to milder levels through much of Monday into next week.
Fairly stable conditions below the upper level ridges are expected to continue limiting vertical cloud heights and shower development through much of next week. One problem with this forecast mentioned above is that tonight's low tide adds some short-term instability. Otherwise, stable and mostly dry weather will occur across the state, with trade wind thermal inversion heights in the 4,000 to 6,000 foot altitude range.
aviation
There will be breezy trade winds today and tonight, with the strongest and strongest gusts from mid-morning to late afternoon. During this period, low clouds and showers will favor windward and mauka areas, bringing MVFR cigs/vsbys at times.
AIRMET Sierra remains effective for mountain screening on windward portions of most islands. Conditions should improve by mid-morning.
AIRMET Tango remains effective for moderate low-level turbulence over all island terrain and downwind. The AIRMET may last all day.
ocean
Strong surface high pressure over the northeastern part of the state will maintain locally strong trading throughout the weekend. A small craft advisory has been extended through Sunday for typically windy areas around Maui County and the Big Island. By early next week, those highs are expected to move westward and ease trading into mild to fresh range.
Overlapping small, medium to long south swells will continue to provide small waves for south facing coasts today. Surfing along the east facing coast will remain choppy due to short term wind conditions. Local wind and waves may affect some north and south facing coasts. Surf along the north coast will remain mostly calm, which is typical for this time of year.
fire weather
Breezier trade winds and lower relative humidity will keep fire weather concerns continuing into Sunday for leeward areas. Sites like west Maui and leeward Kohala on the Big Island are of particular concern. Trade winds will remain in the moderate to breezy range through Sunday, then drop to moderate levels starting Monday as the pressure gradient across the state eases.
Most leeward areas will remain dry. Brief showers will move into windward areas mainly overnight. Humidity levels will return overnight with good to excellent results. The exception to this humidity rule is at altitudes in the 4,000 to 8,000 foot range, where periods of warmer temperatures and dry conditions may occur within or above the subsidence inversion level.
HFO Observations/Warnings/Recommendations
Small craft advisory in Maalaea Bay, Pailolo Channel, Alenuihaha Channel, leeward waters of the Big Island, waters southeast of the Big Island until 6 p.m. HST Sunday.
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Data provided by NOAA.gov
