Low pressure will draw deep tropical moisture over the state today. Waves of heavy rain capable of producing flash flooding are expected Wednesday through the end of the week. SE winds may become strong as well.
Issued at 836 PM HST Tue Apr 7 2026
Latest radar imagery shows a band of showers and isolated thunderstorms moving through Maui County, with orographic showers also impacting the southeast portion of the Big Island. Clearing conditions prevail behind this rain band for Kauai and Oahu. Under the current weather pattern, however, the islands are expected to be under the threat of showers for at least the next several days, potentially longer.
Hilo in particular may see prolonged degraded conditions as the weather pattern favors persistent orographic showers for the rest of the week and even into the weekend. As for the rest of the sites, confidence is low to moderate on when exactly the next wave of rain will occur, but high resolution weather models suggest Wednesday evening may see shower redevelopment. Winds are expected to be relatively light over the next 24 hours as this pattern weakens the trades.
AIRMET Sierra remains in effect for mountain obscuration for Maui, Molokai, Lanai, and Oahu. Oahu in particular is expected to improve overnight, however Maui County may see low ceilings prevail, and will likely need to consider extension of this AIRMET into SE Big Island given current observations.
Issued at 836 PM HST Tue Apr 7 2026
South to southeast winds are expected to steadily increase late tomorrow into Thursday, as a low pressure system develops just west of the state. Showers, some locally heavy, will be possible through Friday as a result of the southerly winds bringing tropical moisture to the north over the islands. As the low pressure system further deepens Thursday into Friday, we will likely see a greater coverage of thunderstorms and winds are expected to increase to gale force across many coastal waters. Very rough boating conditions are expected late Thursday into Friday as seas quickly rise in response to the strong to gale force southerly winds.
Latest offshore buoys and near-shore buoys are showing a steady rise in the 18 to 22 second energy bands this evening and surf will continue to rise tonight and peak on Wednesday above advisory thresholds. A High Surf Advisory has been issued for all south facing shores of the Hawaiian Islands through Wednesday night. Along north facing shores, a new moderate long-period northwest (310-320 degree) swell continues to fill in this evening and will peak on Wednesday below advisory thresholds. A small, short- period north-northeast swell will also fill in this evening before peaking tomorrow and subsiding Thursday.
As the long-period south swell declines on Thursday, strong to near gale force southerly winds are expected to develop on Thursday and strengthen even further Thursday night into Friday. This increase of southerly winds will bring a rapid increase of short-period energy Thursday into Friday and will once again bring surf heights above the advisory thresholds. Large disorganized surf is expected along many south facing shores Thursday into Friday.
High Surf Advisory until 6 AM HST Thursday for Big Island South- Big Island Southeast-East Honolulu-Ewa Plain-Honolulu Metro- Kahoolawe-Kauai South-Kauai Southwest-Kona-Lanai Leeward-Lanai South-Maui Central Valley South-Maui Leeward West-Molokai Leeward South-Molokai West-Niihau-South Haleakala-South Maui/Upcountry-Waianae Coast.
Flood Watch from 6 AM HST Wednesday through Friday afternoon for Big Island East-Big Island Interior-Big Island North-Big Island South-Big Island Southeast-Big Island Summits-Central Oahu-East Honolulu-Ewa Plain-Haleakala Summit-Honolulu Metro-Kahoolawe- Kauai East-Kauai Mountains-Kauai North-Kauai South-Kauai Southwest-Kipahulu-Kohala-Kona-Koolau Leeward-Koolau Windward- Lanai Leeward-Lanai Mauka-Lanai South-Lanai Windward-Maui Central Valley North-Maui Central Valley South-Maui Leeward West- Maui Windward West-Molokai Leeward South-Molokai North-Molokai Southeast-Molokai West-Molokai Windward-Niihau-Oahu North Shore- Olomana-South Haleakala-South Maui/Upcountry-Waianae Coast- Waianae Mountains-Windward Haleakala.
Winter Storm Watch from 6 AM HST Wednesday through Friday afternoon for Big Island Summits.
