Light winds and mostly dry weather will prevail for the next couple of days. Strengthening trade winds from Friday into the weekend will bring an increase in showers, some potentially heavy, especially over windward areas.
Light winds and mostly dry weather are on tap the next several days. Trade winds will strengthen from Friday into next week, and may bring an increase in showers, especially to windward areas.
Latest satellite imagery shows that there's been a slight diurnal increase in low cloud cover over waters E of the islands, with areas of scattered low clouds punctuating otherwise nearly clear skies. A few small showers are noted over waters E of Maui and the Big Island, moving generally W near 10 mph. An area of showery low clouds that loitered near Kona airport through the night appears to be dissipating. Land-based observations show light winds mostly blowing downslope and offshore, except at exposed windward locations, where light E trade winds are coming it at speeds less than 10 mph. The trade-wind-supporting ridge to the N, and the local pressure gradient, remains weakened by a slow-moving complex low about 1300 miles NW of Kauai. The subtropical jest S of this feature is sending wispy high clouds over the area from the W, while morning soundings indicated a relatively dry air mass, with PWAT near 1.1".
The slow-moving low to the NW will keep winds light, while a quickly developing low about 1300 miles NE of the islands will also contribute to keep the local pressure gradient loose into Friday. The resultant land and sea breeze weather regime means mostly clear (aside from some high clouds) and cool mornings, with a slight chance of a windward shower. Afternoon clouds over leeward areas will also bring a chance of a shower, especially on the Big Island. A nearby ridge aloft will ensure little to no rainfall accumulation. As mentioned, there will be periods when increased high clouds move over the islands from the W, especially this afternoon and tonight.
Surface high pressure building N of the islands from Friday into early next week will lead to strengthening trade winds that become breezy by Sunday. The ridge aloft will weaken over the weekend as a low aloft moves over the area from the N, but model guidance remains inconsistent as to the timing and location of this low. A slow- moving front will approach the islands from the NE this weekend, and some guidance indicates that this source of increased low- and mid- level moisture will eventually move over the islands with the increasing trade wind flow. The forecast has been indicating the potential for heavy showers (and even snow on the Big Island Summits) this weekend. While this remains in the official forecast for the sake of consistency, it is worth noting that it is not well supported by EPS guidance. Regardless, rainfall would favor windward areas with the trade winds prevailing.
A cold front far north of the state will slowly drift south and keep light winds in the forecast through at least Wednesday. Lighter large scale winds will produce more variable wind directions with afternoon sea breezes and overnight land breezes over all islands. A weak ridge aloft will also produce stable conditions across the state with limited clouds and only a few showers possible.
No AIRMETs in effect and none are expected.
A surface ridge to the north will remain weak for the next several days as broad low pressure meanders well northwest of the state. Expect land and sea breeze conditions near the coasts, with diurnally driven accelerations potentially leading to fresh breezes during the afternoons. A return of fresh to strong easterly trades is possible over the weekend as the ridge strengthens to the north.
Surf along north and east-facing shores will trend up Wednesday through the second half of the week, as a short- to medium- period north-northeast swell arrives from a storm-force low forecast to develop around 1,000 nautical miles to the northeast today through midweek. This will be a long-lived event, as the system slowly evolves and drifts northeastward late in the week. Guidance indicates a reinforcement from this system Friday into Saturday, which may coincide with the peak surf. Heights will near advisory levels for east-facing shores (10 ft faces) from Thursday through Saturday, while north-facing exposures are expected to remain below advisory levels (15 ft faces). For the long-range, guidance shows a gale- to storm-force low tracking eastward from the Bering Sea to the Gulf of Alaska late Wednesday through Friday. If this materializes, a long-period northerly swell could arrive late Sunday into early next week from this feature.
Surf along south facing shores will remain small, with predominantly a mix of short- to medium-period southeast and long- period south to south-southwest swells. A slightly larger south swell is expected this weekend.
None.
