Photo credit: Brayden Jarvis
west kauai
today: Partly sunny in the morning, then becoming mostly clear. Breeze. Isolated shower. Highs will be around 89 degrees near the coast and around 74 degrees above 3,000 feet. East winds reaching 20 mph. The chance of rain is 20%.
tonight: partly cloudy. Scattered showers in the evening and after midnight. Lows near the coast are about 72 degrees and above 3,000 feet above sea level are about 61 degrees. East winds reaching 15 mph. The chance of rain is 50%.
Sunday: Breeze. Mostly sunny with isolated showers. The highest point near the coast is about 89 degrees and the highest point above 3,000 feet is about 76 degrees. East winds reaching 20 mph. The chance of rain is 20%.
South Kauai
today: Breeze. Partly sunny with scattered showers. The maximum temperature will be 79 to 87 degrees. The chance of rain is 50%.
tonight: Breeze. Mostly cloudy with scattered showers. The lowest temperature is about 72 degrees. The chance of rain is 50%.
Sunday: Breeze. Partly sunny with scattered showers. High temperature 80 to 87 degrees. The chance of rain is 50%.
kauai mountains
today: Mostly cloudy. Breeze. There will be more showers in the morning and scattered showers in the afternoon. Highest temperatures in the valley above 4,000 feet range from 73 to 87 degrees, with highs from 61 to 66 degrees. East winds reaching 20 mph, increasing to 10 to 20 mph in the afternoon. The chance of rain is 70%.
tonight: Breeze. Mostly cloudy with showers. Lowest temperatures range from 66 to 72 degrees in the valley and around 58 degrees above 4,000 feet. East wind 10 to 20 mph. The chance of rain is 70%.
Sunday: Mostly cloudy. Breeze. There will be more showers in the morning and scattered showers in the afternoon. Highest temperatures range from 74 to 87 degrees in the valley and 62 to 67 degrees above 4,000 feet. East wind 10 to 20 mph. The chance of rain is 70%.
North Kauai
today: It will be mostly cloudy in the morning, then becoming sunny. Scattered showers. Highest temperatures will be 77 to 90 degrees. The chance of rain is 50%.
tonight: Mostly cloudy. Scattered showers in the evening, with showers after midnight. Lowest temperature 65 to 74 degrees. The chance of rain is 70%.
Sunday: Partly sunny with scattered showers. Highest temperatures will be 78 to 90 degrees. The chance of rain is 50%.
East Kauai
today: Partly sunny. There will be more showers in the morning and scattered showers in the afternoon. Highest temperature 73 to 85 degrees. The chance of rain is 70%.
tonight: Mostly cloudy. Scattered showers in the evening, with showers after midnight. Lowest temperature 66 to 76 degrees. The chance of rain is 70%.
Sunday: Mostly cloudy. There will be more showers in the morning and scattered showers in the afternoon. Highest temperature 74 to 86 degrees. The chance of rain is 70%.
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.
Data provided by NOAA.gov
