A significant pattern change is then expected by Tuesday as an upper level trough and surface low pressure evolve northwest of the islands. This system is expected to draw deep tropical moisture northward over the state, leading to an extended period of strong southerly winds, increased chances for widespread rainfall and thunderstorms, and renewed flooding concerns from from the middle of the week through this weekend.
Trades will continue to weaken heading into the evening as an upper-level disturbance moves in and initiates a wet week across the islands. VFR conditions are expected to prevail through at least sunrise tomorrow, however rain may start to move in for Kauai and even Hilo by late morning Tuesday. Rain is then expected to slowly spread across the islands afterward.
AIRMET Tango remains in effect for upper level turbulence between FL300 and FL350 over the islands and is expected to continue through the period. AIRMET Sierra was dropped for windward Oahu, but another may be issued for other islands as this aforementioned disturbance moves in with more moisture.
Moderate to locally fresh trades will gradually ease and shift southeasterly tonight through Wednesday as a front stalls just west of the islands and high pressure far north of the islands moves slowly eastward. The winds will turn more southerly and increase to moderate and strong levels on Thursday as a low pressure system develops along the stalled frontal boundary.
Small northwest swells will keep some small surf along north facing shores through this evening. A moderate long-period northwest swell will fill in tonight and Tuesday, giving more of a boost to north shore surf late Tuesday through Wednesday. A small, short- period north-northeast swell will fill in during the day Tuesday before peaking Wednesday and subsiding Thursday. This overlap will make for some rough choppy conditions along north facing shores.
A small southerly swell will keep some small surf in place along south facing shores through this evening. A slightly larger, long- period south swell, will fill in tonight, giving a more noticeable increase to south shore surf Tuesday. Surf could reach advisory levels by Wednesday before slowly easing Thursday into the weekend. Strengthening southerly winds will make for rough and choppy surf by late next week.
East shore surf will remain small and below the seasonal average due to a lack of strong trade winds over and upstream of the islands, except for some wrap from the northerly swells.
Flood Watch from Wednesday morning 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 Wednesday morning through Friday afternoon for Big Island Summits.
