Photo Credit: Brendan Stephen
West Kaua'i
Today: Partly sunny. Scattered showers in the morning, then isolated light showers in the afternoon. Highs 81 to 86 near the shore to around 71 above 3000 feet. Southeast winds up to 15 mph shifting to the south in the afternoon. Chance of rain 30 percent.
Tonight: Partly cloudy. Lows around 69 near the shore to around 59 above 3000 feet. Light winds.
Tuesday: Mostly sunny. Isolated light showers in the morning. Highs 82 to 87 near the shore to around 74 above 3000 feet. East winds up to 10 mph shifting to the south in the afternoon. Chance of rain 20 percent.
South Kauai
Today: Mostly sunny with isolated light showers. Highs 78 to 85. Southwest winds up to 15 mph increasing to 10 to 15 mph in the afternoon. Chance of rain 20 percent.
Tonight: Partly cloudy. Lows around 70. West winds around 10 mph in the evening becoming light.
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ARTICLE CONTINUES BELOW AD
Tuesday: Mostly sunny. Isolated light showers in the morning. Highs 78 to 86. Southwest winds 10 to 15 mph. Chance of rain 20 percent.
Kauai Mountains
Today: Mostly sunny in the morning then becoming partly sunny. Isolated light showers. Highs 73 to 81 in the valleys to around 65 above 4000 feet. Southwest winds up to 10 mph. Chance of rain 20 percent.
Tonight: Partly cloudy. Lows 60 to 68 in the valleys to around 57 above 4000 feet. Light winds.
Tuesday: Mostly sunny. Isolated light showers in the afternoon. Highs 73 to 82 in the valleys to around 66 above 4000 feet. Light winds. Chance of rain 20 percent.
North Kaua'i
Today: Mostly sunny with isolated light showers. Highs 75 to 84. South winds up to 15 mph shifting to the northeast in the afternoon. Chance of rain 20 percent.
Tonight: Mostly clear. Lows 63 to 70. South winds up to 10 mph in the evening becoming light.
Tuesday: Mostly sunny. Highs 75 to 85. South winds up to 10 mph shifting to the north in the afternoon.
East Kauai
Today: Mostly sunny with isolated light showers. Highs 73 to 85. Southwest winds up to 15 mph. Chance of rain 20 percent.
Tonight: Partly cloudy. Lows 62 to 73. Southwest winds up to 15 mph.
Tuesday: Mostly sunny. Highs 74 to 86. Southwest winds up to 15 mph.
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Synopsis
Relatively dry and stable conditions will persist through mid week with light winds that will allow for sea breezes each day and land breezes overnight. A cold front will move through the western end of the state on Thursday and then dissipate across Maui County, increasing the chance of rain ahead of and along the frontal boundary and bringing moderate to breezy northeast winds in its wake. Forecast details for next weekend become a bit murky due to significant model differences.
Discussion
Relatively dry and stable conditions will continue through the first half of the week as ridging aloft and at the surface dominate and moisture remains limited. Upper air soundings from early this morning at Hilo and Lihue confirm these conditions with temperature inversion heights around 5000 to 5500 feet and precipitable water values only near an inch. The orientation of a surface ridge centered to the east-northeast of Hawaii along with a cold front approaching from the northwest will maintain light southerly winds through Wednesday, ahead of the front. This lighter flow will allow for the development of afternoon sea breezes that will bring clouds and isolated showers over island interiors and for overnight land breezes that will help to clear out these interior clouds and showers.
The aforementioned cold front is expected to reach Kauai’s doorstep sometime late Wednesday night into Thursday morning, with decent agreement amongst the deterministic GFS and ECMWF in this timing. Some prefrontal moisture looks to stream across the western half of the state on Wednesday, possibly bringing a little boost to the diurnal sea breeze showers. Then rain chances will increase along the frontal boundary as it moves down the island chain on Thursday and dissipates somewhere in the vicinity of Maui County. Moderate to breezy northeast winds will fill in behind the front on Thursday, then moderate easterly trades will persist Friday into Saturday morning with high pressure dominating to the far northeast.
The forecast details become a bit murkier Saturday and beyond as the global model solutions begin to diverge more significantly. The ECMWF has a fairly strong cold front barge through the island chain on Sunday, bringing some gusty northerly winds and increasing rain chances across the state. At the same time, it also has a deep upper level trough dig in across the state and increase instability. While the 06Z GFS now has a slightly more similar solution to the ECMWF, it has a slower cold front that gets pushed westward by a trough, possibly before it even reaches the state. As such, forecast confidence remains on the lower side for this weekend and beyond.
Aviation
A stubborn ridge of high pressure to the northeast of the state will keep trade winds at bay through most of the week. Low level flow will remain weak but sufficient to steer occasional bands of light showers towards south and east facing coasts of the Big Island and Maui. Elsewhere, daytime sea breezes and nighttime land breezes will drive local weather patterns. Expect cumulus build- ups over island interiors during the afternoon and early evening hours. Clear skies will prevail overnight, especially along west and northwest facing slopes and coasts.
No AIRMETs are in effect or anticipated at this time.
Marine
A ridge of high pressure over the state which will maintain gentle south to southeast winds through Wednesday as the front passes north of the state. A second front may move into the northwest offshore boundary Wednesday and then move down the state through Thursday before stalling near Maui and the Big island and dissipating Friday. Northerly winds behind the front will quickly become northeasterly as the front weakens and a weak high develops northwest of the state.
A series of northwest swells generated by a complex gale low system south of the Aleutian Islands will keep surf elevated along north and west facing shores throughout the week. A moderate, medium period northwest (320-330 degree) is expected to fill in this afternoon and peak late night into Tuesday. A second, overlapping moderate, and slightly longer period northwest swell is expected to fill in Tuesday morning. Latest model guidance is slightly larger that last model run. Surf heights are thus anticipated to peak near advisory levels Tuesday then hold just below advisory levels through Wednesday. A couple of larger northwest swells (310-330 degree) may further boost surf well above advisory levels later in the week Thursday into Friday. The compounding swells may also elevate significant wave heights above small craft thresholds of 10 feet during this time.
An out of season long period, small south swell will peak today, generating near summertime average surf along south facing shores. This swell will slowly trend down through Wednesday. The next small, long period south swell is expected slowly fill in during the second half of the week and peak over the weekend.
Surf along east facing shores will decline as a lingering small, short period north-northeast swell fades through today and wind swells remain small due to light southerly flow during the first half of the week.
Fire weather
Critical fire weather conditions are not expected through the week. Even though daytime relative humidity values may briefly approach critical levels early in the week, winds will remain light and preclude any fire weather concerns. Increasing moisture and rainfall trends will develop Thursday into next weekend as a weakening cold front moves down the island chain, then dissipates near Maui County.
HFO Watches/Warnings/Advisories
None.
Kauai Now Weather is brought to you by Blue Hawaiian Helicopters.
Data Courtesy of NOAA.gov
