Alert archive / Hawaii / Flash Flood Watches in 2018
Flash Flood Watch 13, NWS Honolulu, HI
NWS Honolulu, HI issued this flash flood watch at Aug 21, 2018, 5:39 AM HST for 4 counties in Hawaii. It took effect at Aug 22, 2018, 6:00 AM HST. It was in force for 4 days.
The area
The counties it named.
The facts
- Issued
- Aug 21, 2018, 5:39 AM HST (15:39 UTC)
- In effect from
- Aug 22, 2018, 6:00 AM HST
- Expired
- Aug 26, 2018, 3:23 PM HST
- In force
- 4 days
- Issued by
- NWS Honolulu, HI
- Flood severity
- None
Counties Hawaii County, HI, Honolulu County, HI, Kalawao County, HI, Kauai County, HI
The radar
The Molokai radar (PHMO), 38 km from the middle of the area, began a volume at 15:39 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Lihue, (PHLI), launched 12:00Z, 3.7 hours before the alert went out and 214 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 392 J/kg
- Mixed-layer CIN
- -91 J/kg
- Mixed-layer LCL
- 795 m above ground
- 0-6 km bulk shear
- 6 kt
- 0-1 km storm-relative helicity
- -17 m²/s²
- 0-3 km storm-relative helicity
- 14 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
058 WGHW60 PHFO 211539 FFAHFO URGENT - IMMEDIATE BROADCAST REQUESTED Flood Watch National Weather Service Honolulu HI 539 AM HST Tue Aug 21 2018 ...FLOOD WATCH FOR ALL HAWAIIAN ISLAND FROM WEDNESDAY... .As Hurricane Lane approaches the islands from the south, deep tropical moisture associated with Lane will spread across the island chain from the east, with increased potential for heavy rainfall. HIZ001>028-220445- /O.NEW.PHFO.FF.A.0013.180822T1600Z-180825T0400Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Niihau-Kauai Windward-Kauai Leeward-Kauai Mountains- Oahu South Shore-Waianae Coast-Oahu North Shore-Oahu Koolau- Olomana-Central Oahu-Waianae Mountains-Molokai Windward- Molokai Leeward-Lanai Makai-Lanai Mauka-Kahoolawe- Maui Windward West-Maui Leeward West-Maui Central Valley- Windward Haleakala-Leeward Haleakala-Haleakala Summit-Kona- South Big Island-Big Island North and East-Kohala- Big Island Interior-Big Island Summits- 539 AM HST Tue Aug 21 2018 ...FLASH FLOOD WATCH IN EFFECT FROM WEDNESDAY MORNING THROUGH FRIDAY AFTERNOON... The National Weather Service in Honolulu has issued a * Flash Flood Watch for Kahoolawe, Kauai, Lanai, Maui, Molokai, Niihau, Oahu and the Big Island. * From Wednesday morning through Friday afternoon * Abundant moisture from Hurricane Lane is expected to move over the Big Island late Wednesday and spreading to the rest of the islands through Friday. Intense rainfall will be possible, especially along southeast and east facing slopes. The risk of flooding will only increase as Hurricane Lane approaches. * In addition to flood prone areas, heavy rain events of this size may cause flooding in areas outside of designated flood zones. Low spots in roads will become dangerous and impassible due to severe runoff. High amounts of debris in streams and gulches may clog bridges and culverts resulting in dangerous flooding outside the normal channels and significant property damage. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a VERY DANGEROUS SITUATION. You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$
13 follow-up statements
345 WGHW60 PHFO 220332 FFAHFO Flood Watch National Weather Service Honolulu HI 532 PM HST Tue Aug 21 2018 ...FLOOD WATCH FOR ALL HAWAIIAN ISLAND FROM WEDNESDAY... .As Hurricane Lane approaches the islands from the south, deep tropical moisture associated with Lane will spread across the island chain from the east, with increased potential for heavy rainfall. HIZ001>028-221645- /O.CON.PHFO.FF.A.0013.180822T1600Z-180825T0400Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Niihau-Kauai Windward-Kauai Leeward-Kauai Mountains- Oahu South Shore-Waianae Coast-Oahu North Shore-Oahu Koolau- Olomana-Central Oahu-Waianae Mountains-Molokai Windward- Molokai Leeward-Lanai Makai-Lanai Mauka-Kahoolawe- Maui Windward West-Maui Leeward West-Maui Central Valley- Windward Haleakala-Leeward Haleakala-Haleakala Summit-Kona- South Big Island-Big Island North and East-Kohala- Big Island Interior-Big Island Summits- 532 PM HST Tue Aug 21 2018 ...FLASH FLOOD WATCH REMAINS IN EFFECT FROM WEDNESDAY MORNING THROUGH FRIDAY AFTERNOON... The Flash Flood Watch continues for * Kahoolawe, Kauai, Lanai, Maui, Molokai, Niihau, Oahu and the Big Island. * From Wednesday morning through Friday afternoon * Abundant moisture from Hurricane Lane is expected to move over the Big Island late Wednesday and spread to the rest of the islands through Friday. Intense rainfall will be possible, especially along southeast and east facing slopes. Storm total rainfall amounts greater than 20 inches are possible. The risk of flooding will increase as Hurricane Lane approaches. * In addition to flood prone areas, heavy rain events of this size may cause flooding in areas outside of designated flood zones. Low spots in roads will become dangerous and impassible due to severe runoff. High amounts of debris in streams and gulches may clog bridges and culverts resulting in dangerous flooding outside the normal channels and significant property damage. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a VERY DANGEROUS SITUATION. You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$
894 WGHW60 PHFO 221511 FFAHFO URGENT - IMMEDIATE BROADCAST REQUESTED Flood Watch National Weather Service Honolulu HI 511 AM HST Wed Aug 22 2018 ...FLOOD WATCH FOR ALL HAWAIIAN ISLANDS THROUGH FRIDAY NIGHT... .As Hurricane Lane approaches the islands from the south, deep tropical moisture associated with Lane will spread across the island chain from the southeast, with increased potential for heavy rainfall and flooding. HIZ001>028-230415- /O.EXT.PHFO.FF.A.0013.180822T1600Z-180825T1600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Niihau-Kauai Windward-Kauai Leeward-Kauai Mountains- Oahu South Shore-Waianae Coast-Oahu North Shore-Oahu Koolau- Olomana-Central Oahu-Waianae Mountains-Molokai Windward- Molokai Leeward-Lanai Makai-Lanai Mauka-Kahoolawe- Maui Windward West-Maui Leeward West-Maui Central Valley- Windward Haleakala-Leeward Haleakala-Haleakala Summit-Kona- South Big Island-Big Island North and East-Kohala- Big Island Interior-Big Island Summits- 511 AM HST Wed Aug 22 2018 ...FLASH FLOOD WATCH IN EFFECT THROUGH FRIDAY NIGHT... The Flash Flood Watch is now in effect for * All Hawaiian Islands * Through late Friday night * Abundant moisture from Hurricane Lane is expected to move over the Big Island this afternoon and spread northward to the rest of the islands through Friday. Heavy rainfall is expected, especially along southeast and east facing slopes. Storm total rainfall amounts greater than 20 inches are possible. The flooding threat will increase as Hurricane Lane approaches. * In addition to flood prone areas, heavy rain events of this size may cause flooding in areas outside of designated flood zones. Low spots in roads will become dangerous and impassible due to severe runoff. High amounts of debris in streams and gulches may clog bridges and culverts resulting in dangerous flooding outside the normal channels and significant property damage. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a VERY DANGEROUS SITUATION. You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$ RCB
087 WGHW60 PHFO 230332 FFAHFO Flood Watch National Weather Service Honolulu HI 532 PM HST Wed Aug 22 2018 ...FLOOD WATCH FOR ALL HAWAIIAN ISLANDS THROUGH FRIDAY NIGHT... .As Hurricane Lane approaches the islands from the south, deep tropical moisture associated with Lane will spread across the island chain from the southeast, with increased potential for heavy rainfall and flooding. HIZ001>028-231645- /O.CON.PHFO.FF.A.0013.000000T0000Z-180825T1600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Niihau-Kauai Windward-Kauai Leeward-Kauai Mountains- Oahu South Shore-Waianae Coast-Oahu North Shore-Oahu Koolau- Olomana-Central Oahu-Waianae Mountains-Molokai Windward- Molokai Leeward-Lanai Makai-Lanai Mauka-Kahoolawe- Maui Windward West-Maui Leeward West-Maui Central Valley- Windward Haleakala-Leeward Haleakala-Haleakala Summit-Kona- South Big Island-Big Island North and East-Kohala- Big Island Interior-Big Island Summits- 532 PM HST Wed Aug 22 2018 ...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH LATE FRIDAY NIGHT... The Flash Flood Watch continues for * Kahoolawe, Kauai, Lanai, Maui, Molokai, Niihau, Oahu and the Big Island. * Through late Friday night * Abundant moisture from Hurricane Lane is expected to move over the Big Island this afternoon and spread northward to the rest of the islands through Friday. Heavy rainfall is expected, especially along southeast and east facing slopes. Storm total rainfall amounts greater than 20 inches are possible. The flooding threat will increase as Hurricane Lane approaches. * In addition to flood prone areas, heavy rain events of this size may cause flooding in areas outside of designated flood zones. Low spots in roads will become dangerous and impassible due to severe runoff. High amounts of debris in streams and gulches may clog bridges and culverts resulting in dangerous flooding outside the normal channels and significant property damage. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a VERY DANGEROUS SITUATION. You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$
653 WGHW60 PHFO 231601 FFAHFO Flood Watch National Weather Service Honolulu HI 601 AM HST Thu Aug 23 2018 ...FLOOD WATCH FOR ALL HAWAIIAN ISLANDS THROUGH FRIDAY NIGHT... .Deep tropical moisture associated with Lane will continue to spread across the island chain from the southeast, with increased potential for heavy rainfall and flooding. HIZ001>028-240515- /O.CON.PHFO.FF.A.0013.000000T0000Z-180825T1600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Niihau-Kauai Windward-Kauai Leeward-Kauai Mountains- Oahu South Shore-Waianae Coast-Oahu North Shore-Oahu Koolau- Olomana-Central Oahu-Waianae Mountains-Molokai Windward- Molokai Leeward-Lanai Makai-Lanai Mauka-Kahoolawe- Maui Windward West-Maui Leeward West-Maui Central Valley- Windward Haleakala-Leeward Haleakala-Haleakala Summit-Kona- South Big Island-Big Island North and East-Kohala- Big Island Interior-Big Island Summits- 601 AM HST Thu Aug 23 2018 ...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH LATE FRIDAY NIGHT... The Flash Flood Watch continues for * Entire State of Hawaii. * Through late Friday night * Abundant moisture from Hurricane Lane is moving across the Big Island and Maui, and will continue to spread across the rest of the islands through Friday. Heavy rainfall is expected, especially along southeast and east facing slopes. Storm total rainfall amounts greater than 20 inches are possible. The flooding threat will increase as Hurricane Lane approaches. * In addition to flood prone areas, heavy rain events of this size may cause flooding in areas outside of designated flood zones. Low spots in roads will become dangerous and impassible due to severe runoff. High amounts of debris in streams and gulches may clog bridges and culverts resulting in dangerous flooding outside the normal channels and significant property damage. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a VERY DANGEROUS SITUATION. You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$
258 WGHW60 PHFO 240314 FFAHFO Flood Watch National Weather Service Honolulu HI 514 PM HST Thu Aug 23 2018 ...FLOOD WATCH FOR ALL HAWAIIAN ISLANDS THROUGH FRIDAY NIGHT... .Deep tropical moisture associated with Lane will maintain the threat for heavy rainfall and flooding. HIZ001>028-241615- /O.CON.PHFO.FF.A.0013.000000T0000Z-180825T1600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Niihau-Kauai Windward-Kauai Leeward-Kauai Mountains- Oahu South Shore-Waianae Coast-Oahu North Shore-Oahu Koolau- Olomana-Central Oahu-Waianae Mountains-Molokai Windward- Molokai Leeward-Lanai Makai-Lanai Mauka-Kahoolawe- Maui Windward West-Maui Leeward West-Maui Central Valley- Windward Haleakala-Leeward Haleakala-Haleakala Summit-Kona- South Big Island-Big Island North and East-Kohala- Big Island Interior-Big Island Summits- 514 PM HST Thu Aug 23 2018 ...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH LATE FRIDAY NIGHT... The Flash Flood Watch continues for * Kahoolawe, Kauai, Lanai, Maui, Molokai, Niihau, Oahu and the Big Island. * Through late Friday night * Abundant moisture from Hurricane Lane will maintain heavy rainfall, especially along southeast and east facing slopes through Friday night. Storm total rainfall amounts greater than 20 inches remains possible. * In addition to flood prone areas, heavy rain events of this size may cause flooding in areas outside of designated flood zones. Low spots in roads will become dangerous and impassible due to severe runoff. High amounts of debris in streams and gulches may clog bridges and culverts resulting in dangerous flooding outside the normal channels and significant property damage. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a VERY DANGEROUS SITUATION. You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. && $$
461 WGHW60 PHFO 241648 FFAHFO URGENT - IMMEDIATE BROADCAST REQUESTED Flood Watch National Weather Service Honolulu HI 648 AM HST Fri Aug 24 2018 ...FLOOD WATCH FOR ALL HAWAIIAN ISLANDS THROUGH SATURDAY NIGHT... .Moisture associated with Hurricane Lane will maintain the threat for flooding rain. HIZ001>028-250600- /O.EXT.PHFO.FF.A.0013.000000T0000Z-180826T0400Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Niihau-Kauai Windward-Kauai Leeward-Kauai Mountains- Oahu South Shore-Waianae Coast-Oahu North Shore-Oahu Koolau- Olomana-Central Oahu-Waianae Mountains-Molokai Windward- Molokai Leeward-Lanai Makai-Lanai Mauka-Kahoolawe- Maui Windward West-Maui Leeward West-Maui Central Valley- Windward Haleakala-Leeward Haleakala-Haleakala Summit-Kona- South Big Island-Big Island North and East-Kohala- Big Island Interior-Big Island Summits- 648 AM HST Fri Aug 24 2018 ...FLASH FLOOD WATCH NOW IN EFFECT THROUGH SATURDAY AFTERNOON... The Flash Flood Watch is now in effect for * All Hawaiian islands. * Through Saturday afternoon. * Moisture from Hurricane Lane will produce heavy rainfall, through Saturday. Additional rainfall amounts greater than 20 inches are possible over some areas. * Rain events of this size cause widespread flooding and can affect areas that do not usually flood. Low spots in roads will become dangerous and impassible due to severe runoff. Debris in streams and gulches may clog bridges and culverts resulting in dangerous flooding. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a VERY DANGEROUS SITUATION. Monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. If you experience heavy rain or rising water, head to higher ground immediately. && $$ Donaldson
897 WGHW60 PHFO 241707 CCA FFAHFO URGENT - IMMEDIATE BROADCAST REQUESTED Flood Watch...CORRECTED National Weather Service Honolulu HI 707 AM HST Fri Aug 24 2018 ...FLOOD WATCH FOR ALL HAWAIIAN ISLANDS TROUGH SATURDAY AFTERNOON... .Moisture associated with Hurricane Lane will maintain the threat for flooding rain. HIZ001>028-250600- /O.EXT.PHFO.FF.A.0013.000000T0000Z-180826T0400Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Niihau-Kauai Windward-Kauai Leeward-Kauai Mountains- Oahu South Shore-Waianae Coast-Oahu North Shore-Oahu Koolau- Olomana-Central Oahu-Waianae Mountains-Molokai Windward- Molokai Leeward-Lanai Makai-Lanai Mauka-Kahoolawe- Maui Windward West-Maui Leeward West-Maui Central Valley- Windward Haleakala-Leeward Haleakala-Haleakala Summit-Kona- South Big Island-Big Island North and East-Kohala- Big Island Interior-Big Island Summits- 707 AM HST Fri Aug 24 2018 ...FLASH FLOOD WATCH NOW IN EFFECT THROUGH SATURDAY AFTERNOON... The Flash Flood Watch is now in effect for * All Hawaiian islands. * Through Saturday afternoon. * Moisture from Hurricane Lane will produce heavy rainfall, through Saturday. Additional rainfall amounts greater than 20 inches are possible over some areas. * Rain events of this size cause widespread flooding and can affect areas that do not usually flood. Low spots in roads will become dangerous and impassible due to severe runoff. Debris in streams and gulches may clog bridges and culverts resulting in dangerous flooding. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a VERY DANGEROUS SITUATION. Monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. If you experience heavy rain or rising water, head to higher ground immediately. && $$ Donaldson
508 WGHW60 PHFO 250239 FFAHFO Flood Watch National Weather Service Honolulu HI 439 PM HST Fri Aug 24 2018 ...FLOOD WATCH FOR ALL HAWAIIAN ISLANDS TROUGH SATURDAY AFTERNOON... .Moisture associated with Hurricane Lane will maintain the threat for flooding rain. HIZ001>028-251630- /O.CON.PHFO.FF.A.0013.000000T0000Z-180826T0400Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Niihau-Kauai Windward-Kauai Leeward-Kauai Mountains- Oahu South Shore-Waianae Coast-Oahu North Shore-Oahu Koolau- Olomana-Central Oahu-Waianae Mountains-Molokai Windward- Molokai Leeward-Lanai Makai-Lanai Mauka-Kahoolawe- Maui Windward West-Maui Leeward West-Maui Central Valley- Windward Haleakala-Leeward Haleakala-Haleakala Summit-Kona- South Big Island-Big Island North and East-Kohala- Big Island Interior-Big Island Summits- 439 PM HST Fri Aug 24 2018 ...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH SATURDAY AFTERNOON... The Flash Flood Watch continues for * All Hawaiian islands * Through Saturday afternoon * Moisture from Hurricane Lane will produce heavy rainfall, through Saturday. Additional rainfall amounts greater than 20 inches are possible over some areas. * Rain events of this size cause widespread flooding and can affect areas that do not usually flood. Low spots in roads will become dangerous and impassible due to severe runoff. Debris in streams and gulches may clog bridges and culverts resulting in dangerous flooding. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is LIFE THREATENING. Do not cross fast flowing water in your vehicle, or on foot. Monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. If you experience heavy rain or rising water, head to higher ground immediately. && $$ Kodama
417 WGHW60 PHFO 251723 FFAHFO URGENT - IMMEDIATE BROADCAST REQUESTED Flood Watch National Weather Service Honolulu HI 723 AM HST Sat Aug 25 2018 ...FLOOD WATCH FOR ALL HAWAIIAN ISLANDS TROUGH SATURDAY AFTERNOON... .Moisture associated with Hurricane Lane will maintain the threat for flooding rain. HIZ001>028-260630- /O.EXT.PHFO.FF.A.0013.000000T0000Z-180826T1600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Niihau-Kauai Windward-Kauai Leeward-Kauai Mountains- Oahu South Shore-Waianae Coast-Oahu North Shore-Oahu Koolau- Olomana-Central Oahu-Waianae Mountains-Molokai Windward- Molokai Leeward-Lanai Makai-Lanai Mauka-Kahoolawe- Maui Windward West-Maui Leeward West-Maui Central Valley- Windward Haleakala-Leeward Haleakala-Haleakala Summit-Kona- South Big Island-Big Island North and East-Kohala- Big Island Interior-Big Island Summits- 723 AM HST Sat Aug 25 2018 ...FLASH FLOOD WATCH NOW IN EFFECT THROUGH LATE TONIGHT... The Flash Flood Watch is now in effect for * Kahoolawe, Kauai, Lanai, Maui, Molokai, Niihau, Oahu and the Big Island. * Through late tonight * Moisture from Hurricane Lane will produce heavy rainfall, through Saturday. Additional rainfall amounts greater than 20 inches are possible over some areas. * Rain events of this size cause widespread flooding and can affect areas that do not usually flood. Low spots in roads will become dangerous and impassible due to severe runoff. Debris in streams and gulches may clog bridges and culverts resulting in dangerous flooding. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is LIFE THREATENING. Do not cross fast flowing water in your vehicle, or on foot. Monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. If you experience heavy rain or rising water, head to higher ground immediately. && $$
803 WGHW60 PHFO 252009 CCA FFAHFO URGENT - IMMEDIATE BROADCAST REQUESTED Flood Watch...CORRECTED National Weather Service Honolulu HI 1009 AM HST Sat Aug 25 2018 ...FLOOD WATCH FOR ALL HAWAIIAN ISLANDS THROUGH LATE TONIGHT... .Moisture associated with Hurricane Lane will maintain the threat for flooding rain. HIZ001>028-260630- /O.COR.PHFO.FF.A.0013.000000T0000Z-180826T1600Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Niihau-Kauai Windward-Kauai Leeward-Kauai Mountains- Oahu South Shore-Waianae Coast-Oahu North Shore-Oahu Koolau- Olomana-Central Oahu-Waianae Mountains-Molokai Windward- Molokai Leeward-Lanai Makai-Lanai Mauka-Kahoolawe- Maui Windward West-Maui Leeward West-Maui Central Valley- Windward Haleakala-Leeward Haleakala-Haleakala Summit-Kona- South Big Island-Big Island North and East-Kohala- Big Island Interior-Big Island Summits- 1009 AM HST Sat Aug 25 2018 ...FLASH FLOOD WATCH NOW IN EFFECT THROUGH LATE TONIGHT... The Flash Flood Watch is now in effect for * Kahoolawe, Kauai, Lanai, Maui, Molokai, Niihau, Oahu and the Big Island. * Through late tonight * Moisture from Hurricane Lane will produce heavy rainfall, through Saturday. Additional rainfall amounts greater than 20 inches are possible over some areas. * Rain events of this size cause widespread flooding and can affect areas that do not usually flood. Low spots in roads will become dangerous and impassible due to severe runoff. Debris in streams and gulches may clog bridges and culverts resulting in dangerous flooding. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is LIFE THREATENING. Do not cross fast flowing water in your vehicle, or on foot. Monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. If you experience heavy rain or rising water, head to higher ground immediately. && $$
114 WGHW60 PHFO 260148 FFAHFO URGENT - IMMEDIATE BROADCAST REQUESTED Flood Watch National Weather Service Honolulu HI 348 PM HST Sat Aug 25 2018 ...FLOOD WATCH FOR ALL HAWAIIAN ISLANDS THROUGH SUNDAY AFTERNOON... .Moisture remaining over the islands as Tropical Storm Lane departs will maintain the threat for flooding rain. HIZ001>028-261500- /O.EXT.PHFO.FF.A.0013.000000T0000Z-180827T0400Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Niihau-Kauai Windward-Kauai Leeward-Kauai Mountains- Oahu South Shore-Waianae Coast-Oahu North Shore-Oahu Koolau- Olomana-Central Oahu-Waianae Mountains-Molokai Windward- Molokai Leeward-Lanai Makai-Lanai Mauka-Kahoolawe- Maui Windward West-Maui Leeward West-Maui Central Valley- Windward Haleakala-Leeward Haleakala-Haleakala Summit-Kona- South Big Island-Big Island North and East-Kohala- Big Island Interior-Big Island Summits- 348 PM HST Sat Aug 25 2018 ...FLASH FLOOD WATCH NOW IN EFFECT THROUGH SUNDAY AFTERNOON... The Flash Flood Watch is now in effect for * Kahoolawe, Kauai, Lanai, Maui, Molokai, Niihau, Oahu and the Big Island. * Through Sunday afternoon * Moisture remaining over the islands as Tropical Storm Lane departs will bring the potential for heavy rainfall through Sunday. Additional rain of 5 to 10 inches over windward Big Island and Maui, and 3 to 5 inches elsewhere through the weekend. * Rain events of this size cause widespread flooding and can affect areas that do not usually flood. Low spots in roads will become dangerous and impassible due to severe runoff. Debris in streams and gulches may clog bridges and culverts resulting in dangerous flooding. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is LIFE THREATENING. Do not cross fast flowing water in your vehicle, or on foot. Monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. If you experience heavy rain or rising water, head to higher ground immediately. && $$ Foster
338 WGHW60 PHFO 261342 FFAHFO Flood Watch National Weather Service Honolulu HI 342 AM HST Sun Aug 26 2018 ...FLASH FLOOD WATCH FOR OAHU, MAUI COUNTY AND THE BIG ISLAND THROUGH THIS AFTERNOON... HIZ001>004-261445- /O.CAN.PHFO.FF.A.0013.000000T0000Z-180827T0400Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Niihau-Kauai Windward-Kauai Leeward-Kauai Mountains- 342 AM HST Sun Aug 26 2018 ...FLASH FLOOD WATCH IS CANCELLED... Some locally heavy showers may continue to affect Niihau and Kauai today, but the threat for flash flooding has diminished. Therefore the Flash Flood Watch has been cancelled. $$ HIZ005>028-270400- /O.CON.PHFO.FF.A.0013.000000T0000Z-180827T0400Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Oahu South Shore-Waianae Coast-Oahu North Shore-Oahu Koolau- Olomana-Central Oahu-Waianae Mountains-Molokai Windward- Molokai Leeward-Lanai Makai-Lanai Mauka-Kahoolawe- Maui Windward West-Maui Leeward West-Maui Central Valley- Windward Haleakala-Leeward Haleakala-Haleakala Summit-Kona- South Big Island-Big Island North and East-Kohala- Big Island Interior-Big Island Summits- 342 AM HST Sun Aug 26 2018 ...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH THIS AFTERNOON... The Flash Flood Watch continues for * Kahoolawe, Lanai, Maui, Molokai, Oahu and the Big Island. * Through this afternoon * Moisture remaining over the islands as Tropical Storm Lane departs will bring the potential for additionally heavy rainfall today. Any additional heavy rainfall over these highly saturated grounds could quickly lead to flash flooding. * Heavy rainfall could result in low spots in roads becoming dangerous and impassible due to severe runoff. Debris in streams and gulches may clog bridges and culverts resulting in dangerous flooding. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is LIFE THREATENING. Do not cross fast flowing water in your vehicle, or on foot. Monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued. If you experience heavy rain or rising water, head to higher ground immediately. && $$
932 WGHW60 PHFO 270123 FFAHFO Flood Watch National Weather Service Honolulu HI 323 PM HST Sun Aug 26 2018 HIZ005>028-270230- /O.CAN.PHFO.FF.A.0013.000000T0000Z-180827T0400Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Oahu South Shore-Waianae Coast-Oahu North Shore-Oahu Koolau- Olomana-Central Oahu-Waianae Mountains-Molokai Windward- Molokai Leeward-Lanai Makai-Lanai Mauka-Kahoolawe- Maui Windward West-Maui Leeward West-Maui Central Valley- Windward Haleakala-Leeward Haleakala-Haleakala Summit-Kona- South Big Island-Big Island North and East-Kohala- Big Island Interior-Big Island Summits- 323 PM HST Sun Aug 26 2018 ...FLASH FLOOD WATCH IS CANCELLED... The Flash Flood Watch for Kahoolawe, Lanai, Maui, Molokai, Oahu and the Big Island has been cancelled. While showers continue, the threat for flooding has diminished. Some briefly heavy showers are possible tonight and tomorrow. $$
What forecasters said that day
The local office's own words before this flash flood watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Honolulu, HI wrote its last area forecast discussion before this flash flood watch went out at Aug 21, 4:00 AM HST, 1 hour 39 minutes earlier.
Area forecast discussion, Aug 21, 4:00 AM HST, 1 hour 39 minutes before
Area Forecast Discussion National Weather Service Honolulu HI 400 AM HST Tue Aug 21 2018 .SYNOPSIS... High pressure north of the state will provide for a typical trade wind weather pattern across the area today. Clouds and passing showers will favor windward and mauka areas with just a few brief showers expected over select leeward locations. For Wednesday through the remainder of the week into the weekend, our weather pattern will be highly dependent on the track and intensity of Hurricane Lane. && .DISCUSSION... Please note that tropical cyclone operations are in effect. So as to incorporate the latest forecast information from the Central Pacific Hurricane Center (CPHC), public forecast updates from the Honolulu Forecast Office will come shortly after forecast updates are received from CPHC. Typical trade wind weather continues over the islands today, with passing low clouds and showers affecting mainly windward and mountain areas. Both early morning Lihue and Hilo soundings showed a typical trade wind profile, with low level moisture extending to around 6 thousand feet. Trades will still increase slightly as highs far northeast and northwest consolidate with Hurricane Lane to the south. A mid level ridge over the area is bringing a rather stable airmass to area. An almost west to east oriented area of low clouds has reached the Big Island and Maui county overnight, and will bring more clouds and showers to the windward and mountain areas. Weather for the early part of Wednesday across the islands will still pretty much be trade wind weather, though a further increase in low clouds as well as trade winds are expected for the islands as more moisture will reach the area from the east while Land edges closer. As for Wednesday night through the rest of the week time frame, our weather will be highly dependent on the track and intensity of Hurricane Lane. It is still too early to determine the extend of the weather impacts that Lane may have on the state. The latest forecast track from the Central Pacific Hurricane Center still has Lane passing south of the main Hawaiian Islands, but its track has nudged closer to the state. If this track holds, the potential impacts on our islands weather could include an increase in wind speeds due to a tightened pressure gradient, between high pressure north of the state and Lane traversing to our south. Moisture associated with Lane would likely bring increased shower activity with locally heavy rain possible over the Big Island, mainly east and southeast and then eventually spreading up the island chain through the remainder of the week. Also swell generated by Lane could bring very large surf to the islands. Everyone is encouraged to monitor the latest advisories on Hurricane Lane from the Central Pacific Hurricane Center. && .AVIATION... Trade winds will strengthen as surface high pressure builds north of the area and Hurricane Lane approaches from the southeast. Stronger trade winds will cause moderate mechanical turbulence to develop over and along leeward slopes of mountains across the state. AIRMET Tango remains in effect for low level moderate turbulence. Drier and more stable air will produce decreasing cloud and showers trends with VFR conditions prevailing today. Clouds and showers are likely to increase later in the week as Hurricane Lane approaches the Hawaiian Islands. The weather conditions across the Hawaii region are greatly dependent on the track of hurricane. && .MARINE... Please note that tropical cyclone operations are in effect. So as to incorporate the latest forecast information from the Central Pacific Hurricane Center (CPHC), marine forecast updates from the Honolulu Forecast Office will come shortly after forecast updates from CPHC, namely shortly after 5 and 11 am/pm, instead of the normal 4 and 10 am/pm. A weak surface trough W of Kauai will move W away from the area today as high pressure builds to the N. This will result in a gradually increasing trade wind flow through today. A Small Craft Advisory (SCA) remains in effect for the windier areas around Maui and the Big Island for these stronger winds. As Hurricane Lane moves into an area S of the islands by mid-week, the pressure gradient will likely increase further, potentially requiring an expansion of the SCA. More significantly, a Tropical Storm Watch remains in effect for the coastal waters south of the Big Island. This may need to be upgraded to a Tropical Storm Warning or Hurricane Watch/Warning as the storm gets closer. There is significant uncertainty regarding the position and intensity of Lane later in the week, so it is too early to determine what impacts Lane may eventually bring, and mariners need to continue to closely monitor forecasts. A High Surf Advisory for E facing shores of Maui and the Big Island remains in effect. As Hurricane Lane moves into an area S of the islands later this week, S swell will likely increase, with a wide variety of wave periods and directions leading to rough and potentially damaging surf. There is still significant uncertainty and it is difficult to know the level of impacts, but there is potential for large seas/swells from Lane leading to warning-level surf along E through S facing shores of the islands. Otherwise, a small NNW swell is expected to peak today before gradually diminishing Wednesday and Thursday. See the latest Oahu Surf Discussion (SRDHFO) for more details on surf and swell. && .HFO WATCHES/WARNINGS/ADVISORIES... High Surf Advisory until 6 PM HST this evening for Windward Haleakala-South Big Island-Big Island North and East. Tropical Storm Watch for Big Island Leeward Waters-Big Island Southeast Waters. Small Craft Advisory until 6 PM HST this evening for Maalaea Bay-Pailolo Channel-Alenuihaha Channel. && SYNOPSIS/DISCUSSION...Hui AVIATION...BOHLIN MARINE...POWELL
The office that day
Everything else NWS Honolulu, HI issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 21, 4:48 AM HST | Hurricane Watch | HFO | Hawaii, Honolulu, Kauai, Kalawao | 3 days |
Nearby
Flash Flood Watches in Hawaii, 2018Every flash flood watch in 2018
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.