textproduct: Honolulu

SYNOPSIS

Breezy easterly trade winds will continue to gradually veer to the east-southeast over the next day or so as Hurricane Lowell approaches the western islands from the south. Lowell is forecast to pass west of Kauai's coastal waters Monday night. A Hurricane Warning has been issued for Kauai and Niihau. Impacts such as high surf and heavy rain could impact all of the islands.

DISCUSSION

Hurricane Lowell is about 450 miles south-southwest of Kauai this evening and moving northward. Lowell is expected to pass west of the Kauai coastal waters late Monday through Monday night. Lowell's track has nudged to the east, it has raised the possibility of hurricane force winds reaching Kauai and Niihau, as a result a Hurricane Warning has also been issued for both islands.

Additional impacts from Lowell are expected statewide, and a few headlines are in effect as a result. A High Surf Warning for south facing shores for the south swell generated by Lowell for all islands, along with the west facing shores of the Big Island. A High Surf Advisory remains in effect for the east swell generated by former Tropical Storm Karina, which has weakened to a post tropical low.

The Flood Watch for the state continues through Tuesday afternoon. Mosture ahead of Lowell is beginning to lift up from south of the state interacting with terrian and the trade winds resulting in some warnings and advisories already. Have adjusted QPF upward especially across the central part of the state where values were a bit lower, so looking at 4 to 6 inches over most of the state with higher values over Kauai and southeast Big Island. Terrain influence will play a big factor with isolated areas receiving significant amounts through the event. Stay alert for the issuance of any future flood advisories or warnings across the state.

The threat of short-lived, fast-moving tornados/waterspouts will be present mainly near Kauai and Niihau as Lowell makes its closest approach to the islands. These would likely be embedded in rainbands. The threat for tornadoes is lower near the remaining islands, but not zero. The threat for tornadoes should decrease quickly early Tuesday morning.

For surf and other marine impacts, please see the marine section of the discussion below.

Any deviation in track or intensity could also change how these hazards effect the islands.

High pressure is forecast to build back in Thursday through Saturday, bringing in a more typical trade wind pattern with a drier and more stable airmass.

AVIATION

Hurricane Lowell continues its track northward, advecting unstable deep tropical moisture northward into the islands. Shower activity will continue to trend higher over the next 24 hours. MVFR conditions with low cloud ceilings and showers are expected. Heavier showers will produce periods of IFR conditions. Surface winds will strengthen today over the western half of the state, as Hurricane Lowell continues on a northern track.

AIRMET Sierra for mountain obscuration continues for Kauai Oahu Molokai Maui and the Big Island. This AIRMET will likely continue for the next 24 hours.

AIRMET Tango was issued for moderate low level turbulence affecting the island of Kauai over and SW thru NW of island mountains. A strong surface wind AIRMET will likely be issued for Kauai and Niihau on Monday for wind speeds greater than 30 knots due to Hurricane Lowell approaching the islands.

Light icing continues in a layer between 160 and FL220 due to strengthening low level wind speeds as Lowell approaches the island.

MARINE

Hurricane Lowell located southwest of the islands continues to move north-northeast this evening. As it approaches the island chain wind speeds will begin to increase. A Hurricane Warning is now in effect for waters west of Kauai County, while a Tropical Storm Warning remains in effect for Kauai Channel and Kauai Windward Waters through Tuesday afternoon. The Small Craft Advisory remains in effect for all remaining coastal waters for a combination of winds and seas through Monday night. Winds are expected to increasingly veer to the southeast to south as Lowell continues to approach and bring the strongest winds to the western end of the state.

Hurricane conditions are expected in the western offshore waters tonight through Tuesday as the center of the storm is expected to track just west of Niihau. Any slight deviation in the track to the west or east in the next 24 hours will have significant differences in impact for the coastal waters around Kauai County. Post-Tropical Cyclone Karina to the northeast of the islands will continue to weaken and dissipate by Monday.

The High Surf Advisory (HSA) has been upgraded to a High Surf Warning (HSW) for all south facing shores through Monday night. Surf will continue to trend in the HSA range through tonight before the south swell from Hurricane Lowell is expected to rise rapidly Monday, and peak Monday night bringing warning level surf to exposed shorelines. This swell may shift out of the southwest late Monday night. Due to the track of Lowell, a sharp gradient in swell is expected from west to east. Coinciding also with the peak monthly afternoon high tides, this could bring the potential for significant damage to coastal properties and infrastructure, including roadways to portions of Kauai and possibly Oahu. Swell energy is expected to drop off quickly on Tuesday.

A large, medium-period east swell from former Tropical Storm Karina will also continue to produce HSA level surf along east facing shores through Monday night. Surf along north facing shores will remain flat except areas exposed to the storm swells. A small medium period northwest swell is expected on Tuesday as Lowell begins to lift northwest of the islands and will fade through Thursday. By the end of the week, surf along east facing shores could be bolstered by some medium-period swell generated by Tropical Storm Marie in the East Pacific. Otherwise, expect choppy conditions from easterly trade wind swell through the week.

FIRE WEATHER

Fire weather risk will remain low through the forecast period due to increasing moisture moving over the islands in association with Hurricane Lowell. Thunderstorms will be possible through Monday due to the unstable airmass moving overhead. Temperature inversion heights are currently near 11,000 ft from Maui to the Big Island, and are expected to remain elevated during the next few days.

HYDROLOGY

The potential for flooding exists through Tuesday afternoon, and as a result, a Flood Watch is in effect for the entire state. Between now and Tuesday afternoon, Hurricane Lowell is expected to bring additional rain to the islands with 6 to 10 inches for Kauai, with maximum totals of 16 inches possible. For the Big Island, 4 to 8 inches of rain is expected with isolated totals of 12 inches, due to the terrain influence with the southeast flow. Across the remaining islands, rainfall of 4 to 7 inches of rain is expected, with Maui having isolated maximum totals of 9 inches possible. This rainfall may produce significant flash flooding and mudslides, especially across Kauai County and portions of the Big Island.

HFO WATCHES/WARNINGS/ADVISORIES

Flood Watch through Tuesday afternoon for all Hawaii islands-

High Surf Warning until 6 AM HST Tuesday for Niihau-Kauai Leeward-Waianae Coast-Kahoolawe-Maui Leeward West-Kona-Kohala- Kauai East-Kauai South-East Honolulu-Honolulu Metro-Ewa Plain- Molokai Southeast-Molokai West-Molokai Leeward South-Lanai Leeward-Lanai South-Maui Central Valley South-Kipahulu-South Maui/Upcountry-South Haleakala-Big Island South-Big Island Southeast.

High Surf Advisory until 6 AM HST Tuesday for Olomana-Koolau Windward-Molokai Windward-Windward Haleakala-Big Island East-Big Island North.

Hurricane Warning for Niihau-Kauai-

Hurricane Warning for Kauai Northwest Waters-Kauai Leeward Waters.

Tropical Storm Warning for Kauai Windward Waters-Kauai Channel.

Small Craft Advisory until 6 AM HST Tuesday for Oahu Windward Waters-Oahu Leeward Waters-Kaiwi Channel-Maui County Windward Waters-Maui County Leeward Waters-Maalaea Bay-Pailolo Channel- Alenuihaha Channel-Big Island Windward Waters-Big Island Leeward Waters-Big Island Southeast Waters.