Alert archive / Hawaii / Flash Flood Warnings in 2021

Flash Flood Warning 37, NWS Honolulu, HI

March 29, 2021Kauai County, Hawaii

NWS Honolulu, HI issued this flash flood warning at Mar 29, 2021, 4:56 PM 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: Mar 29, 2021, 4:56 PM HST (02:56 UTC)
Expired: Mar 29, 2021, 8:00 PM HST
In force: 3 hr
Issued by: NWS Honolulu, HI
Area: Storm-based polygon
Flood severity: None

County Kauai County, HI

The nearest sounding before it

Lihue, (PHLI), launched 00:00Z, 2.9 hours before the alert went out and 10 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 234 J/kg
Mixed-layer CIN: -2 J/kg
Mixed-layer LCL: 836 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 10 m²/s²
0-3 km storm-relative helicity: 14 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.2

Open this sounding in Storm Lab

The text

As transmitted.

931 
WGHW50 PHFO 300256
FFWHFO
HIC007-300600-
/O.NEW.PHFO.FF.W.0037.210330T0256Z-210330T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Honolulu HI
456 PM HST Mon Mar 29 2021

The National Weather Service in Honolulu has issued a

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

* Until 800 PM HST.

* At 456 PM HST, the river gauge at the Hanalei bridge is at a 
  dangerous level.


  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...
  Lihue, Kapaa, Kalaheo, Princeville, Kilauea, North Fork Wailua 
  Trails, Wailua Homesteads, Wailua, Omao, Lawai, Koloa, Anahola, 
  Hanalei, Moloaa, Poipu, Wainiha, Hanapepe, Wailua River State 
  Park, Puhi and Hanamaulu.

A Flash Flood Watch remains in effect through Tuesday afternoon for 
the entire island.

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 800 PM HST if flooding 
persists.

LAT...LON 2188 15958 2223 15955 2222 15952 2225 15949
      2224 15943 2225 15940 2222 15933 2216 15930
      2216 15929 2214 15928 2205 15932 2196 15932
      2195 15932 2195 15934 2193 15934 2189 15938
      2186 15944

FLASH FLOOD...GAUGE INDICATED

$$

LAU

1 follow-up statement

715 
WGHW70 PHFO 300421
FFSHFO

Flash Flood Statement
National Weather Service Honolulu HI
621 PM HST Mon Mar 29 2021

HIC007-300600-
/O.CON.PHFO.FF.W.0037.000000T0000Z-210330T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kauai HI-
621 PM HST Mon Mar 29 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 8 PM HST THIS EVENING 
FOR THE ISLAND OF KAUAI IN KAUAI COUNTY...

At 621 PM HST, Kauai Emergency Management reported that the Kuhio 
Highway is closed in the vicinity of the Hanalei River Bridge due to 
water over the roadway.  Rainfall intensity has decreased during the 
last hour however, although moderate showers continue to affect 
windward sections of Kauai with rainfall rates up to 1 inch per 
hour. Flash flooding is already occurring.

HAZARD...Flash flooding caused by heavy rain.

SOURCE...Emergency management.

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...
  Lihue, Kapaa, Kalaheo, Princeville, Kilauea, North Fork Wailua 
  Trails, Wailua Homesteads, Wailua, Omao, Lawai, Koloa, Anahola, 
  Hanalei, Moloaa, Poipu, Wainiha, Hanapepe, Wailua River State 
  Park, Puhi and Hanamaulu.

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 800 PM HST if flooding 
persists.

LAT...LON 2188 15958 2223 15955 2222 15952 2225 15949
      2224 15943 2225 15940 2222 15933 2216 15930
      2216 15929 2214 15928 2205 15932 2196 15932
      2195 15932 2195 15934 2193 15934 2189 15938
      2186 15944

FLASH FLOOD...OBSERVED

$$

JELSEMA

The office that day

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

Issued	Product	Office	Counties	Lasted
Mar 29, 3:39 PM HST	Small Craft Advisory	HFO		12 hr
Mar 29, 4:15 PM HST	Areal Flood Advisory	HFO	Kauai	3 hr
Mar 30, 9:05 AM HST	Flash Flood Watch	HFO	Kauai	6 hr

Nearby

Flash Flood Warnings in Hawaii, 2021 Every 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.