Alert archive / Hawaii / Flash Flood Warnings in 2021

Flash Flood Warning 7, NWS Honolulu, HI

January 26, 2021Hawaii County, Hawaii

NWS Honolulu, HI issued this flash flood warning at Jan 26, 2021, 3:30 AM HST for Hawaii County, Hawaii. It was in force for 2 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Jan 26, 2021, 3:30 AM HST (13:30 UTC)
Expired
Jan 26, 2021, 5:36 AM HST
In force
2 hr
Issued by
NWS Honolulu, HI
Area
Storm-based polygon
Flood severity
None

County Hawaii County, HI

The radar

The South Shore radar (PHWA), 50 km from the middle of the area, began a volume at 13:34 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.

What was reported inside it

TimeReportWhereRemark
Jan 26, 3:30 AM HSTFLASH FLOOD1 Se Mountain View, HILAW ENFORCEMENT REPORTED HIGHWAY 11 WAS CLOSED DUE TO WATER OVER THE ROADWAY BETWEEN ALOHA ESTATES AND MAUNA LOA ROAD.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Hilo, (PITO), launched 12:00Z, 1.5 hours before the alert went out and 44 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.

Skew-T log-pSkew-T log-p diagram, Hilo, at 12:00Z on 2021-01-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 45 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Hilo, at 12:00Z on 2021-01-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 83 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
45 J/kg
Mixed-layer CIN
-46 J/kg
Mixed-layer LCL
556 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
83 m²/s²
0-3 km storm-relative helicity
118 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

611 
WGHW50 PHFO 261330
FFWHFO
HIC001-261630-
/O.NEW.PHFO.FF.W.0007.210126T1330Z-210126T1630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Honolulu HI
330 AM HST Tue Jan 26 2021

The National Weather Service in Honolulu has issued a

* Flash Flood Warning for...
  The island of Hawaii in Hawaii County

* Until 630 AM HST.

* At 330 AM HST, local law enforcement reported highway 11 was 
  closed due to water over the roadway between Aloha Estates and 
  Mauna Loa Road. Rain was falling at a rate of 1 to 2 inches per 
  hour, in areas that are already saturated from recent heavy 
  rainfall. Flash flooding is occurring and is expected to continue.

  HAZARD...Flash flooding caused by heavy rain.

  SOURCE...Law enforcement.

  IMPACT...Flooding in drainages, streams, rivers, roads,
           properties, and other low-lying areas. Public road
           closures possible in some areas. Landslides are
           possible in steep terrain.

* Some locations that will experience flash flooding include...
  Hilo, Hawaiian Paradise Park, Honokaa, Volcano, Glenwood, Hawaii 
  Volcanoes National Park, Mountain View, Pohakuloa Training Area, 
  Pohakuloa Camp, Wood Valley, Hawaiian Acres, Pahala, Keaau, 
  Orchidland Estates, Papaikou, Pepeekeo, Honomu, Punaluu Beach and 
  Hakalau.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Stay away from streams, rivers, drainage ditches, and culverts, even 
if they are currently dry.

Do not cross fast flowing or rising water in your vehicle, or on 
foot. Turn around, don't drown.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

The heavy rains may cause rock and mudslides in steep terrain areas.

&&

This warning may need to be extended beyond 630 AM HST if flooding 
persists.

LAT...LON 1902 15588 1968 15563 2018 15565 2014 15559
      2011 15543 1998 15519 1986 15507 1976 15508
      1975 15500 1964 15497 1952 15479 1945 15483
      1934 15497 1925 15516 1925 15529 1913 15550
      1896 15559 1889 15568 1896 15574

FLASH FLOOD...OBSERVED

$$

JELSEMA
2 follow-up statements
754 
WGHW70 PHFO 261349
FFSHFO

Flash Flood Statement
National Weather Service Honolulu HI
349 AM HST Tue Jan 26 2021

HIC001-261630-
/O.CON.PHFO.FF.W.0007.000000T0000Z-210126T1630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hawaii HI-
349 AM HST Tue Jan 26 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 630 AM HST THIS 
MORNING FOR THE ISLAND OF HAWAII IN HAWAII COUNTY...

At 349 AM HST, radar continued to indicate heavy rain over portions 
of windward Big Island, from the Hamakua Coast southward through the 
Hilo, Puna and Kau Districts. Rain was falling at a rate of 1 to 2 
inches per hour, in areas already saturated from recent heavy 
rainfall. Flash flooding is occurring or expected to begin shortly.

HAZARD...Flash flooding caused by heavy rain.

SOURCE...Radar indicated.

IMPACT...Flooding in drainages, streams, rivers, roads,
         properties, and other low-lying areas. Public road
         closures possible in some areas. Landslides are possible
         in steep terrain.

Some locations that will experience flash flooding include...
  Hilo, Hawaiian Paradise Park, Honokaa, Volcano, Glenwood, Hawaii 
  Volcanoes National Park, Mountain View, Pohakuloa Training Area, 
  Pohakuloa Camp, Wood Valley, Hawaiian Acres, Pahala, Keaau, 
  Orchidland Estates, Papaikou, Pepeekeo, Honomu, Punaluu Beach and 
  Hakalau.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Stay away from streams, rivers, drainage ditches, and culverts, even 
if they are currently dry.

Do not cross fast flowing or rising water in your vehicle, or on 
foot. Turn around, don't drown.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

The heavy rains may cause rock and mudslides in steep terrain areas.

&&

This warning may need to be extended beyond 630 AM HST if flooding 
persists.

LAT...LON 1902 15588 1968 15563 2018 15565 2014 15559
      2011 15543 1998 15519 1986 15507 1976 15508
      1975 15500 1964 15497 1952 15479 1945 15483
      1934 15497 1925 15516 1925 15529 1913 15550
      1896 15559 1889 15568 1896 15574

FLASH FLOOD...RADAR INDICATED

$$

JELSEMA
393 
WGHW70 PHFO 261536
FFSHFO

Flash Flood Statement
National Weather Service Honolulu HI
536 AM HST Tue Jan 26 2021

HIC001-261546-
/O.CAN.PHFO.FF.W.0007.000000T0000Z-210126T1630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hawaii HI-
536 AM HST Tue Jan 26 2021

...FLASH FLOOD WARNING IS CANCELLED FOR THE ISLAND OF HAWAII IN 
HAWAII COUNTY...

The heavy rain has diminished in intensity and no longer poses a 
signicant threat for flooding. Therefore the Flash Flood Warning has 
been cancelled and replaced by a Flood Advisory.

A Flash Flood Watch remains in effect for the Big Island until 600 
PM HST this evening.

LAT...LON 1902 15588 1968 15563 2018 15565 2014 15559
      2011 15543 1998 15519 1986 15507 1976 15508
      1975 15500 1964 15497 1952 15479 1945 15483
      1934 15497 1925 15516 1925 15529 1913 15550
      1896 15559 1889 15568 1896 15574

$$

JELSEMA

The office that day

Everything else NWS Honolulu, HI issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 25, 3:45 PM HSTFlash Flood WarningHFOHonolulu3 hr
Jan 25, 6:40 PM HSTAreal Flood AdvisoryHFOHonolulu2 hr
Jan 26, 12:39 AM HSTAreal Flood AdvisoryHFOHawaii3 hr
Jan 26, 5:33 AM HSTAreal Flood AdvisoryHFOHawaii3 hr

Nearby

Flash Flood Warnings in Hawaii, 2021Every flash flood warning in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.