Alert archive / Hawaii / Flash Flood Warnings in 2021

Flash Flood Warning 26, NWS Honolulu, HI

March 12, 2021Kauai County, Hawaii

NWS Honolulu, HI issued this flash flood warning at Mar 12, 2021, 5:04 AM HST for Kauai County, Hawaii. It was in force for 2 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 12, 2021, 5:04 AM HST (15:04 UTC)
Expired: Mar 12, 2021, 7:08 AM HST
In force: 2 hr
Issued by: NWS Honolulu, HI
Area: Storm-based polygon
Flood severity: None

County Kauai County, HI

The radar

The South Kauai radar (PHKI), 18 km from the middle of the area, began a volume at 15:06 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, 3.1 hours before the alert went out and 6 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: 476 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 759 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 49 m²/s²
0-3 km storm-relative helicity: 97 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

512 
WGHW50 PHFO 121504
FFWHFO
HIC007-121815-
/O.NEW.PHFO.FF.W.0026.210312T1504Z-210312T1815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Honolulu HI
504 AM HST Fri Mar 12 2021

The National Weather Service in Honolulu has issued a

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

* Until 815 AM HST.

* At 504 AM HST, radar indicated heavy rain over the southeast 
  slopes of Kauai from Waimea to Poipu to Kapaa. Rain was falling at 
  a rate of 1 to 2 inches per hour. Additionally, the South Fork of 
  the Wailua River has risen to a very high level and continues to 
  climb. 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...
  Lihue, Kapaa, Kalaheo, Omao, Lawai, Koloa, Poipu, North Fork 
  Wailua Trails, Wailua Homesteads, Hanapepe, Wailua, Waimea, 
  Anahola, Puhi, Hanamaulu, Wailua River State Park, Eleele, 
  Kaumakani, Pakala Village and Kealia.

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.

Excessive runoff from heavy rainfall will cause flooding of drainage 
ditches and streams, streets, highways, properties, and other low 
lying spots.

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

&&

This warning may need to be extended beyond 815 AM HST if flooding 
persists.

LAT...LON 2215 15928 2205 15932 2196 15932 2195 15934
      2193 15934 2190 15938 2186 15944 2188 15961
      2195 15968

FLASH FLOOD...RADAR INDICATED

$$

JELSEMA

1 follow-up statement

848 
WGHW70 PHFO 121708
FFSHFO

Flash Flood Statement
National Weather Service Honolulu HI
708 AM HST Fri Mar 12 2021

HIC007-121718-
/O.CAN.PHFO.FF.W.0026.000000T0000Z-210312T1815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kauai HI-
708 AM HST Fri Mar 12 2021

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

The heavy rain has ended. Flooding is no longer expected to pose a 
threat.

A Flash Flood Watch remains in effect until 600 AM HST Saturday for 
Kauai County.

LAT...LON 2215 15928 2205 15932 2196 15932 2195 15934
      2193 15934 2190 15938 2186 15944 2188 15961
      2195 15968

$$

KODAMA

The office that day

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

Issued	Product	Office	Counties	Lasted
Mar 11, 2:22 PM HST	Flash Flood Warning	HFO	Honolulu	2 hr
Mar 11, 2:46 PM HST	Areal Flood Advisory	HFO	Kalawao	3 hr
Mar 11, 3:22 PM HST	Special Marine Warning	HFO		22 min
Mar 11, 4:15 PM HST	Flash Flood Warning	HFO	Honolulu	3 hr
Mar 11, 6:09 PM HST	Areal Flood Advisory	HFO	Hawaii	99 min
Mar 11, 7:35 PM HST	Areal Flood Advisory	HFO	Honolulu	81 min
Mar 11, 8:54 PM HST	Areal Flood Advisory	HFO	Kalawao	6 hr
Mar 12, 12:23 AM HST	Special Marine Warning	HFO		112 min
Mar 12, 2:42 AM HST	Areal Flood Advisory	HFO	Kauai	2 hr
Mar 12, 3:56 AM HST	Small Craft Advisory	HFO		10 days
Mar 12, 5:29 AM HST	Areal Flood Advisory	HFO	Honolulu	2 hr
Mar 12, 8:49 AM HST	Special Marine Warning	HFO		41 min
Mar 12, 8:51 AM HST	Areal Flood Advisory	HFO	Kauai	2 hr
Mar 12, 9:45 AM HST	Gale Warning	HFO		6 hr
Mar 12, 11:02 AM HST	Flash Flood Warning Considerable damage threat	HFO	Kauai	3 hr
Mar 12, 11:22 AM HST	Areal Flood Advisory	HFO	Honolulu	68 min
Mar 12, 1:39 PM HST	Flash Flood Warning Considerable damage threat	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; radar from the NEXRAD Level II archive.