07-18-2023, 10:46 PM
Puna Weather Hilo Puna and Hamakua area Forecast 11am
Sunshine early, but clouds will increase today, leading to the first rain and wind from Calvin Tuesday evening, perhaps as early as 5PM. Rainfall will increase rapidly, becoming heavy at times by 10PM and possibly reaching 2 to 3 inches per hour after midnight and continuing like that into early Wednesday morning. Rain should dissipate to showers during the day on Wednesday, with more normal intensity showers continuing Wednesday afternoon into the night, as atmospheric stability returns in the wake of Calvin. Winds will also be increasing through the evening, peaking around 30 to 45 mph just after midnight. Expect slowly diminishing winds Wednesday afternoon and evening to more normal trade wind speeds as they veer to the E to SE. Total rainfall will be between 6 to 12 inches or more overnight Tuesday night into Wednesday morning. More normal trade wind weather will replace Calvin's stormy conditions on Thursday and continue through the coming weekend. Since there is a strong possiblity that winds may increase to 35 to 45 mph with gusts as high as 55mph over the area Tuesday night into Wednesday morning, you still have an opportunity to ascertain that all loose objects are secured or removed from outside the home. Any albezia trees or other loosely rooted or with damaged limbs that may impact your property should already be cut down. Heavy rainfall is expected beginning Tuesday night and coniinuing into Wednesday. This could cause Flash Flooding and ponding of water in all low-lying areas and may make roads impassable at times. Trees my be toppled by the wind and soft soil and may block roads, as well. Listen to all Emergency Managers through this period for updates and Warnings.
Waikoloa Forecast
Sunny morning skies over Waikoloa, with atrengthening winds through Waimea becoming moderate to breezy downslope. Windy dowslope and offshore winds will likley continue on Tuesday, with sea beezes, if any, confined to the more immediate beaches and shorelines. Espect east to northeast downsloping winds to increase today, becoming possibly gale force, 35 to 45 mph gusting to 55mph by nightfall and continuing into Wednesday morning as Calvin approaches and moves by our island over or near South Point. Overcast skies with periods of rain will follow tonight, with some areas of heavy rainfall from Honoka`a, over the Waimea Saddle, to the upper slopes of Waikoloa, mainly to the vicinity of Mamalahoa Highway. Heavy rainfall and possible thunderstorms may also occuraround Hualaloai and vicinity. Rainfall will diminish gradually Wednesday, but with still a chance for some afternoon convective showers over all areas, including the Waikoloa Slope. Winds will remain strong and downslope in the early hours, with some areas like Kawaihae and vicinity receiving downsloping winds in excess or 40 to 50 mph with gusts to 65 mph due to the strong pressure gradient between the departing center of Calvin off our Kona Coast and the building high pressure northeast of our island. Winds will be diminishing by Wednesday night, however, as Calvin moves away.
Waikoloa will see a return of the more normal summer pattern of sunny mornings, with some upslope afternoon cloudiness and isolated showers, leading to clear nighttime skies on Thursday and continuing into the coming weekend. Expect highs in the mid 80s to lower 90s during this period, from the resorts to Waikoloa Village... albeit a bit cooler during the afternoons at the beaches due to the sea brezes and over the upper Waikoloa slope due to cloud cover.
Hawaii Synopsis
Wind speeds will increase rapidly from today through Wednesday as Tropical Storm Calvin produces strong and gusty winds, passing over or near South Point. Damaging wind speeds are possible across many parts of our island as Calvin approaches and passes by. Heavy showers and flooding conditions are expected due to deep unstable tropical moisture forced up the windward mountain slopes of our island. Calvin will likely weaken into a Tropical Depression by Wednesday and maintain a westward track moving away from our island Wednesday and Wednesday night. Expect improving weather and wind conditions statewide by Thursday as we transition back to breezy trade wind pattern.
Big Island Discussion
A high pressure ridge north of the region will drive Tropical Storm Calvin westward into Hawaiian waters later tonight. Weather conditions will change rapidly today through Wednesday as Calvin, currently around 450 miles east-southeast of Hilo Hawaii, continues to quickly move towards the Big Island. The rapid east to west motion of Calvin will tend to limit Tropical Storm impacts to roughly a 12 to 18 hour time period over any one island.
Wind Impacts: Calvin remains on a high confidence westerly track with the ridge north of the islands providing the main steering flow. This storm will continue to weaken as it approaches the Big Island due to cooler water temperatures, the ingest of stable dry air, and some vertical wind shear. However, Tropical Storm Force winds remain in the forecast as the center of the system passes near the south side of the Big Island tonight through early Wednesday morning. A Tropical Storm Warning remains in effect for the Big Island and surrounding waters due to the island's proximity to the Tropical Storm Force wind speeds surrounding the storm. Wind speeds will also increase statewide today through Wednesday as the storm remains on a track passing south of the smaller Hawaiian Islands. These winds will strengthen due to the increasing pressure gradient between the ridge to the north and the low pressure center associated with Calvin passing to the south. This means that wind speeds over the islands in Maui County will at least reach Wind Advisory thresholds and may exceed High Wind Warning criteria in some areas, even as Calvin weakens and passes to the south. Wind speeds will accelerate over and downwind of mountain slopes with stronger gusts expected. A Wind Advisory remains in effect today for all islands in Maui County, A High Wind Watch was also issued for Maui County starting tonight for stronger winds expected on Wednesday. Additional Wind Advisory and High Wind Watch or Warning products may need to be extended to Oahu on Wednesday as Calvin passes to the south. For the moment, Kauai County will see less wind impacts from Calvin based on the latest storm track and intensity.
Rainfall Impacts: Deep unstable tropical moisture surrounding Calvin will be driven up mountain slopes due to the strong wind forcing as the Tropical Storm passes each island. This means the potential for flash flooding remains elevated even for islands not directly in the path of the Tropical Storm. How far north these heavy rainfall impacts will occur is the forecast challenge with this event. The highest potential for heavy rain and flooding are expected along the windward slopes of the Big Island and windward slopes of the eastern half of Maui. Storm total rainfall amounts in the 4 to 8 inch range should be expected for the eastern slopes of the Big Island from North Kohala to the Hamakua Coast to Hilo to South Point, with 1 to 2 inches of rain forecast over the Kona side of the island. Maui may see between 2 to 6 inches of storm total rainfall from the North Shore near Haiku to East Maui near Hana. Other islands will see lower amounts between 0.25 to 2 inches, with locally higher amounts possible favoring windward mountains and slopes. The Flood Watch remains in effect with the potential for flash flooding starting this evening over the Big Island and Maui County. This Flood Watch was expanded in coverage to include Oahu, Kauai and Niihau this morning, with enhanced flood threats to Oahu forecast to start early Wednesday morning potentially impacting the western islands.
By Thursday, Calvin will continue to weaken and pass quickly west of the island chain. High pressure will build in quickly as the storm exits the region, producing more stable breezy trade wind weather with rapidly decreasing shower trends. This trade wind weather will continue through the upcoming weekend with upward trends in shower activity on Saturday and Sunday, mainly along windward and mountain slopes.
Mahalo!
Bob Farrell
Sunshine early, but clouds will increase today, leading to the first rain and wind from Calvin Tuesday evening, perhaps as early as 5PM. Rainfall will increase rapidly, becoming heavy at times by 10PM and possibly reaching 2 to 3 inches per hour after midnight and continuing like that into early Wednesday morning. Rain should dissipate to showers during the day on Wednesday, with more normal intensity showers continuing Wednesday afternoon into the night, as atmospheric stability returns in the wake of Calvin. Winds will also be increasing through the evening, peaking around 30 to 45 mph just after midnight. Expect slowly diminishing winds Wednesday afternoon and evening to more normal trade wind speeds as they veer to the E to SE. Total rainfall will be between 6 to 12 inches or more overnight Tuesday night into Wednesday morning. More normal trade wind weather will replace Calvin's stormy conditions on Thursday and continue through the coming weekend. Since there is a strong possiblity that winds may increase to 35 to 45 mph with gusts as high as 55mph over the area Tuesday night into Wednesday morning, you still have an opportunity to ascertain that all loose objects are secured or removed from outside the home. Any albezia trees or other loosely rooted or with damaged limbs that may impact your property should already be cut down. Heavy rainfall is expected beginning Tuesday night and coniinuing into Wednesday. This could cause Flash Flooding and ponding of water in all low-lying areas and may make roads impassable at times. Trees my be toppled by the wind and soft soil and may block roads, as well. Listen to all Emergency Managers through this period for updates and Warnings.
Waikoloa Forecast
Sunny morning skies over Waikoloa, with atrengthening winds through Waimea becoming moderate to breezy downslope. Windy dowslope and offshore winds will likley continue on Tuesday, with sea beezes, if any, confined to the more immediate beaches and shorelines. Espect east to northeast downsloping winds to increase today, becoming possibly gale force, 35 to 45 mph gusting to 55mph by nightfall and continuing into Wednesday morning as Calvin approaches and moves by our island over or near South Point. Overcast skies with periods of rain will follow tonight, with some areas of heavy rainfall from Honoka`a, over the Waimea Saddle, to the upper slopes of Waikoloa, mainly to the vicinity of Mamalahoa Highway. Heavy rainfall and possible thunderstorms may also occuraround Hualaloai and vicinity. Rainfall will diminish gradually Wednesday, but with still a chance for some afternoon convective showers over all areas, including the Waikoloa Slope. Winds will remain strong and downslope in the early hours, with some areas like Kawaihae and vicinity receiving downsloping winds in excess or 40 to 50 mph with gusts to 65 mph due to the strong pressure gradient between the departing center of Calvin off our Kona Coast and the building high pressure northeast of our island. Winds will be diminishing by Wednesday night, however, as Calvin moves away.
Waikoloa will see a return of the more normal summer pattern of sunny mornings, with some upslope afternoon cloudiness and isolated showers, leading to clear nighttime skies on Thursday and continuing into the coming weekend. Expect highs in the mid 80s to lower 90s during this period, from the resorts to Waikoloa Village... albeit a bit cooler during the afternoons at the beaches due to the sea brezes and over the upper Waikoloa slope due to cloud cover.
Hawaii Synopsis
Wind speeds will increase rapidly from today through Wednesday as Tropical Storm Calvin produces strong and gusty winds, passing over or near South Point. Damaging wind speeds are possible across many parts of our island as Calvin approaches and passes by. Heavy showers and flooding conditions are expected due to deep unstable tropical moisture forced up the windward mountain slopes of our island. Calvin will likely weaken into a Tropical Depression by Wednesday and maintain a westward track moving away from our island Wednesday and Wednesday night. Expect improving weather and wind conditions statewide by Thursday as we transition back to breezy trade wind pattern.
Big Island Discussion
A high pressure ridge north of the region will drive Tropical Storm Calvin westward into Hawaiian waters later tonight. Weather conditions will change rapidly today through Wednesday as Calvin, currently around 450 miles east-southeast of Hilo Hawaii, continues to quickly move towards the Big Island. The rapid east to west motion of Calvin will tend to limit Tropical Storm impacts to roughly a 12 to 18 hour time period over any one island.
Wind Impacts: Calvin remains on a high confidence westerly track with the ridge north of the islands providing the main steering flow. This storm will continue to weaken as it approaches the Big Island due to cooler water temperatures, the ingest of stable dry air, and some vertical wind shear. However, Tropical Storm Force winds remain in the forecast as the center of the system passes near the south side of the Big Island tonight through early Wednesday morning. A Tropical Storm Warning remains in effect for the Big Island and surrounding waters due to the island's proximity to the Tropical Storm Force wind speeds surrounding the storm. Wind speeds will also increase statewide today through Wednesday as the storm remains on a track passing south of the smaller Hawaiian Islands. These winds will strengthen due to the increasing pressure gradient between the ridge to the north and the low pressure center associated with Calvin passing to the south. This means that wind speeds over the islands in Maui County will at least reach Wind Advisory thresholds and may exceed High Wind Warning criteria in some areas, even as Calvin weakens and passes to the south. Wind speeds will accelerate over and downwind of mountain slopes with stronger gusts expected. A Wind Advisory remains in effect today for all islands in Maui County, A High Wind Watch was also issued for Maui County starting tonight for stronger winds expected on Wednesday. Additional Wind Advisory and High Wind Watch or Warning products may need to be extended to Oahu on Wednesday as Calvin passes to the south. For the moment, Kauai County will see less wind impacts from Calvin based on the latest storm track and intensity.
Rainfall Impacts: Deep unstable tropical moisture surrounding Calvin will be driven up mountain slopes due to the strong wind forcing as the Tropical Storm passes each island. This means the potential for flash flooding remains elevated even for islands not directly in the path of the Tropical Storm. How far north these heavy rainfall impacts will occur is the forecast challenge with this event. The highest potential for heavy rain and flooding are expected along the windward slopes of the Big Island and windward slopes of the eastern half of Maui. Storm total rainfall amounts in the 4 to 8 inch range should be expected for the eastern slopes of the Big Island from North Kohala to the Hamakua Coast to Hilo to South Point, with 1 to 2 inches of rain forecast over the Kona side of the island. Maui may see between 2 to 6 inches of storm total rainfall from the North Shore near Haiku to East Maui near Hana. Other islands will see lower amounts between 0.25 to 2 inches, with locally higher amounts possible favoring windward mountains and slopes. The Flood Watch remains in effect with the potential for flash flooding starting this evening over the Big Island and Maui County. This Flood Watch was expanded in coverage to include Oahu, Kauai and Niihau this morning, with enhanced flood threats to Oahu forecast to start early Wednesday morning potentially impacting the western islands.
By Thursday, Calvin will continue to weaken and pass quickly west of the island chain. High pressure will build in quickly as the storm exits the region, producing more stable breezy trade wind weather with rapidly decreasing shower trends. This trade wind weather will continue through the upcoming weekend with upward trends in shower activity on Saturday and Sunday, mainly along windward and mountain slopes.
Mahalo!
Bob Farrell