Alert archive / Hawaii / Flash Flood Warnings in 2021

Flash Flood Warning 50, NWS Honolulu, HI

December 31, 2021Kauai County, Hawaii

NWS Honolulu, HI issued this flash flood warning at Dec 31, 2021, 6:26 AM HST for Kauai County, Hawaii. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Dec 31, 2021, 6:26 AM HST (16:26 UTC)
Expired
Dec 31, 2021, 9:20 AM HST
In force
3 hr
Issued by
NWS Honolulu, HI
Area
Storm-based polygon
Flood severity
None

County Kauai County, HI

The radar

The South Kauai radar (PHKI), 35 km from the middle of the area, began a volume at 16:27 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, 4.4 hours before the alert went out and 31 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, Lihue, at 12:00Z on 2021-12-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 302 joules per kilogram.LCLEL10008507005003002001001 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, Lihue, at 12:00Z on 2021-12-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 77 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
302 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
593 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
77 m²/s²
0-3 km storm-relative helicity
93 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

917 
WGHW50 PHFO 311626
FFWHFO
HIC007-311930-
/O.NEW.PHFO.FF.W.0050.211231T1626Z-211231T1930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Honolulu HI
626 AM HST Fri Dec 31 2021

The National Weather Service in Honolulu has issued a

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

* Until 930 AM HST.

* At 626 AM HST, the Hanalei River gauge reported a rapid rise in 
  water level, even though rainfall upstream has decreased, and 
  Kauai Emergency Management reports that Kuhio Highway has been 
  closed at the Hanalei River.

  HAZARD...Flash flooding caused by heavy rain.

  SOURCE...Stream Gauges.

  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...
  Princeville, Hanalei, Wainiha, Haena, Alakai Swamp Trails, Na Pali 
  State Park and Kalihiwai.

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.

&&

This warning may need to be extended beyond 930 AM HST if flooding 
persists.

LAT...LON 2224 15959 2224 15958 2222 15952 2224 15950
      2225 15949 2224 15943 2212 15946 2212 15958

FLASH FLOOD...GAUGE INDICATED

$$

WROE
2 follow-up statements
417 
WGHW70 PHFO 311808
FFSHFO

Flash Flood Statement
National Weather Service Honolulu HI
808 AM HST Fri Dec 31 2021

HIC007-311930-
/O.CON.PHFO.FF.W.0050.000000T0000Z-211231T1930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kauai HI-
808 AM HST Fri Dec 31 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 930 AM HST THIS 
MORNING FOR THE ISLAND OF KAUAI IN KAUAI COUNTY...

At 808 AM HST, the stream gauge at the Hanalei River Bridge has been 
showing that elevated water levels are declining, and little shower 
activity is occurring on Kauai. Kauai Emergency Management reports 
that Kuhio Highway remains closed at the Hanalei River.

HAZARD...Flash flooding caused by heavy rain.

SOURCE...Stream Gauges.

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...
  Princeville, Hanalei, Wainiha, Haena, Alakai Swamp Trails, Na Pali 
  State Park and Kalihiwai.

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.

&&

LAT...LON 2224 15959 2224 15958 2222 15952 2224 15950
      2225 15949 2224 15943 2212 15946 2212 15958

FLASH FLOOD...GAUGE INDICATED

$$

WROE
746 
WGHW70 PHFO 311920
FFSHFO

Flash Flood Statement
National Weather Service Honolulu HI
920 AM HST Fri Dec 31 2021

HIC007-311930-
/O.CAN.PHFO.FF.W.0050.000000T0000Z-211231T1930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kauai HI-
920 AM HST Fri Dec 31 2021

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

Heavy showers have decreased, and flood waters are receding. Kauai 
Emergency Management reports that Kuhio Hwy remains closed at the 
Hanalei River, though water on the road is decreasing.

LAT...LON 2224 15959 2224 15958 2222 15952 2224 15950
      2225 15949 2224 15943 2212 15946 2212 15958

$$

WROE

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 30, 3:04 PM HSTAreal Flood AdvisoryHFOKalawao3 hr
Dec 30, 3:07 PM HSTWinter Weather AdvisoryHFOHawaii19 hr
Dec 30, 3:42 PM HSTAreal Flood AdvisoryHFOHawaii3 hr
Dec 30, 7:34 PM HSTAreal Flood AdvisoryHFOHonolulu55 min
Dec 30, 8:29 PM HSTFlash Flood WarningHFOHonolulu3 hr
Dec 31, 4:52 AM HSTAreal Flood AdvisoryHFOKauai3 hr
Dec 31, 9:11 AM HSTAreal Flood AdvisoryHFOHawaii6 hr
Dec 31, 12:18 PM HSTAreal Flood AdvisoryHFOKalawao4 hr
Dec 31, 1:28 PM HSTAreal Flood AdvisoryHFOKalawao3 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.