####018007226#### WTHW80 PHFO 190907 HLSHFO HIZ023-026>028-051>054-191715- Tropical Storm Calvin Local Statement Advisory Number 31 National Weather Service Honolulu HI EP032023 1107 PM HST Tue Jul 18 2023 This product covers the Hawaiian islands **TROPICAL STORM CALVIN BEGINNING TO PASS SOUTH OF THE BIG ISLAND** NEW INFORMATION --------------- * CHANGES TO WATCHES AND WARNINGS: - None * CURRENT WATCHES AND WARNINGS: - A Tropical Storm Warning is in effect for Hawaii County * STORM INFORMATION: - About 305 miles southeast of Honolulu or about 140 miles south of Hilo - 17.7N 155.2W - Storm Intensity 50 mph - Movement West or 275 degrees at 20 mph SITUATION OVERVIEW ------------------ Tropical Storm Calvin, currently located southeast of South Point, will continue westward through the overnight hours, then pass well south of the smaller islands through the day Wednesday. Periods of heavy rainfall, damaging winds, and life threatening surf along exposed east facing shores will continue through Wednesday. Bands of heavy rainfall will continue to move ashore and impact portions of the Big Island overnight through Wednesday morning. Streams have already begun to respond on the Big Island, and with rainfall totals expected to climb into the 4 to 8 inch range with locally higher amounts possible, the potential for flash flooding will quickly increase through the late evening and overnight hours. Similar conditions are expected to begin for portions of Maui County through the late night hours, which will likely continue well into Wednesday. Rainfall totals are expected to climb into the 3 to 6 inch range for Maui County and 2 to 4 inches for Oahu and Kauai County, mainly over windward and mountain locations. Damaging winds are expected to continue overnight into Wednesday for the Big Island and Maui County, which may lead to power outages, downed trees and powerlines, potentially leading to impassable roads. Advisory-level winds are anticipated for Oahu and Kauai, especially through the day Wednesday as Calvin passes to the south. This is especially the case in areas over and downwind of terrain. Significant coastal impacts will continue overnight through Wednesday morning along exposed east facing shores of the Big Island and Maui due to a combination of damaging onshore winds and life- threatening surf. Surf at this level combined with water levels running higher than predicted and surge associated with Calvin will will produce significant beach erosion, with water potentially inundating vulnerable coastal areas and roadways. For Oahu and Kauai, expect the surf to rapidly build to advisory levels overnight, then remain up through the day Wednesday. The threat of coastal impacts will begin to lower quickly through the day Wednesday for he Big Island as Calvin continues westward, then for the smaller islands by Wednesday night into Thursday. POTENTIAL IMPACTS ----------------- * WIND: Protect against hazardous wind having possible limited impacts across the Hawaiian islands. Potential impacts include: - Damage to porches, awnings, carports, sheds, and unanchored mobile homes. Unsecured lightweight objects blown about. - Many large tree limbs broken off. A few trees snapped or uprooted, but with greater numbers in places where trees are shallow rooted. Some fences and roadway signs blown over. - A few roads impassable from debris, particularly within urban or heavily wooded places. Hazardous driving conditions on bridges and other elevated roadways. - Scattered power and communications outages. * SURGE: Protect against locally hazardous surge having possible limited impacts across portions of windward and southeast Big Island. Potential impacts in this area include: - Localized inundation with storm surge flooding mainly along immediate shorelines and in low-lying spots, or in areas farther inland near where higher surge waters move ashore. - Sections of near-shore roads and parking lots become overspread with surge water. Driving conditions dangerous in places where surge water covers the road. - Moderate beach erosion. Heavy surf also breaching dunes, mainly in usually vulnerable locations. Strong rip currents. - Minor to locally moderate damage to marinas, docks, boardwalks, and piers. A few small craft broken away from moorings. * FLOODING RAIN: Protect against dangerous rainfall flooding having possible significant impacts across across Maui and windward and southeastern portions of the Big Island. Potential impacts include: - Moderate rainfall flooding may prompt several evacuations and rescues. - Rivers and tributaries may quickly become swollen with swifter currents and overspill their banks in a few places, especially in usually vulnerable spots. Small streams, creeks, canals, arroyos, and ditches overflow. - Flood waters can enter some structures or weaken foundations. Several places may experience expanded areas of rapid inundation at underpasses, low-lying spots, and poor drainage areas. Some streets and parking lots take on moving water as storm drains and retention ponds overflow. Driving conditions become hazardous. Some road and bridge closures. * TORNADOES: Protect against a tornado event having possible limited impacts across the Hawaiian islands. Potential impacts include: - The occurrence of isolated tornadoes can hinder the execution of emergency plans during tropical events. - A few places may experience tornado damage, along with power and communications disruptions. - Locations could realize roofs peeled off buildings, chimneys toppled, mobile homes pushed off foundations or overturned, large tree tops and branches snapped off, shallow-rooted trees knocked over, moving vehicles blown off roads, and small boats pulled from moorings. PRECAUTIONARY/PREPAREDNESS ACTIONS ---------------------------------- Listen to local official for recommended preparedness actions. Listen for updates and be ready in case you lose electrical power. Keep a battery-powered radio, charged cell phone and flashlight handy. Keep your cell phone charged and in power-saving mode. If you lose power, use it sparingly and mainly for personal emergencies and check- ins. * ADDITIONAL SOURCES OF INFORMATION: - For information on appropriate preparations see ready.gov - For information on creating an emergency plan see getagameplan.org - For additional disaster preparedness information see redcross.org NEXT UPDATE ----------- The next local statement will be issued by the National Weather Service in Honolulu HI around 530 AM HST, or sooner if conditions warrant. $$ Shigesato / Gibbs