WEATHER UPDATE: A final round of moderate to heavy rain will move across the islands on Sunday and Monday before more favorable conditions settle in for the rest of the week
Our take
As we navigate the ever-changing climate of our beautiful islands, the recent weather update brings both a sense of urgency and an opportunity for reflection. A significant upper-level trough is currently directing deep tropical moisture toward our shores, leading to anticipated heavy rainfall and potential thunderstorms across Oʻahu, Molokaʻi, and Kauaʻi. Residents and visitors alike are advised to stay alert, especially as the National Weather Service has extended the Flash Flood Watch until Monday afternoon due to already saturated ground conditions. This weather system follows a series of heavy rains detailed in previous articles, such as WEATHER UPDATE: Conditions will gradually improve as a cold front moves eastward across the islands today, but additional rain is possible on Sunday and Monday and WEATHER UPDATE: Another kona storm may bring periods of moderate or heavy rain throughout the week, bringing renewed concerns for flooding across the islands.
Rain is a double-edged sword for our islands. While it replenishes our lush landscapes and supports the diverse ecosystems that thrive here, excessive rain can lead to challenges such as flash flooding, road closures, and damage to property. The immediate impact of this weather pattern on Oʻahu and Molokaʻi is a reminder of nature's power, but it also underscores the importance of preparedness. With the ground already saturated and the potential for more heavy rainfall, residents should remain vigilant and heed safety advisories. This is especially crucial for those who may be exploring or engaging in outdoor activities in these regions.
In the coming days, we can expect a shift towards more favorable weather conditions as light trades develop. However, the humidity will linger, reminding us that the tropical climate we cherish is still very much in play. As we transition into this new phase, it offers a moment to appreciate the delicate balance of our environment. The islands are a living tapestry of culture and nature, each thread woven together by the weather that shapes them. This week’s rain serves as a powerful reminder of our connection to the land and the necessity of respecting the forces that govern it.
Looking ahead, it will be interesting to see how these weather patterns evolve and influence local life. Will the anticipated warm and humid conditions foster a vibrant resurgence of our community activities, or will they encourage a retreat indoors as we wait for clearer skies? The impact of weather extends beyond immediate safety concerns; it influences everything from tourism to agriculture, shaping the rhythm of life here in Hawaii. As we ride out the rain, let’s embrace the spirit of adventure that defines us, exploring how we can adapt and thrive amid nature’s unpredictable moods. What will the next few days reveal about our resilience and appreciation for the beautiful yet powerful environment we call home?
Background
As of 6:00 AM HST on Sunday, April 12:
An upper-level trough approaching the islands from the northwest has restarted the flow of deep tropical moisture over the islands this morning and will likely lead to several bands of moderate to heavy rain showers and a few thunderstorms over the next couple of days. The heaviest rain will likely set up over Oʻahu and Molokaʻi today and will slowly retrograde back toward Kauaʻi on Monday. Later in the week, light trades will develop, but conditions will remain warm and very humid until stronger trades set up midway through the following week.
The National Weather Service has extended the Flash Flood Watch until Monday afternoon, as the ground remains saturated from recent heavy rainfall.
Key points
As of 6:00 AM HST on Sunday, April 12:
On Sunday, the heaviest rainfall will likely impact Oʻahu, Molokaʻi, and Lanaʻi.
On Monday, the heaviest rainfall will shift back toward Kauaʻi.
Maui and Hawaiʻi will largely avoid the worst impacts, but flash flooding is still possible with afternoon showers.
Conditions will slowly improve on Tuesday, with light trades setting back up.
Warm and humid conditions will continue through early next week.
Forecast synopsis
As of 3:49 AM HST on Sunday, April 12:
From the National Weather Service office in Honolulu:
Showers and isolated thunderstorms will spread over the western half of the state becoming heavy over central portions of the state through tonight. The heaviest rain bands are anticipated over Oahu and Molokai, and possibly spread westward over Kauai. Because of the latest rainfall over the last few days, flash flooding is possible. Light and variable winds are expected to prevail through the first half of the week, with light trades returning to the state thereafter.
Weather risk outlook
As of 7:00 AM HST on Sunday, April 12:
NOTE: An updated risk outlook will be posted later this morning.
| County | SUN AM | SUN PM | MON | TUE | WED |
|---|---|---|---|---|---|
| Overall risk: | 2 | 2 | 2 | · | · |
| Kauaʻi | 2 | 2 | 2 | · | · |
| Oʻahu | 2 | 2 | 2 | · | · |
| Maui | 1 | 2 | 1 | · | · |
| Hawaiʻi | 1 | 1 | 1 | · | · |
Key: · - little to none; 1 - minor; 2 - moderate; 3 - major; 4 - extreme
Projected rainfall totals:
As of 6:00 AM HST on Friday, April 10:
Below are projections for the remainder of the rainfall expected between now and midnight on Tuesday from the National Weather Service’s National Digital Forecast Database (NDFD), the ECMWF model, and the GFS model. The NDFD values can be viewed using the NWS’s IDSS Forecast Points tool.
| City | NWS | ECMWF | GFS |
|---|---|---|---|
| Lihue | 2.3 | 2.1 | 1.0 |
| Honolulu | 5.8 | 1.1 | 2.1 |
| Wahiawa | 6.1 | 2.1 | 2.5 |
| Kaneohe | 6.0 | 1.4 | 2.3 |
| Kahului | 0.8 | 0.2 | 0.8 |
| Hana | 1.0 | 0.6 | 0.7 |
| Molokai | 2.8 | 0.8 | 1.1 |
| Lanai | 0.5 | 0.8 | 0.7 |
| Hilo | 0.0 | 0.1 | 0.0 |
| Kona | 0.1 | 0.2 | 0.2 |
More information
For more information on the impacts of this system as it develops, please check out these links:
National Weather Service
- NWS Honolulu homepage
- NWS Honolulu Area Forecast Discussion
- NWS Honolulu on Facebook
- NWS Honolulu on X
Hawaii Emergency Management Agency
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