Alert archive / Hawaii / Flash Flood Warnings in 2021

Flash Flood Warning 35, NWS Honolulu, HI

March 29, 2021Kauai County, Hawaii

NWS Honolulu, HI issued this flash flood warning at Mar 29, 2021, 8:54 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: Mar 29, 2021, 8:54 AM HST (18:54 UTC)
Expired: Mar 29, 2021, 12:00 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 12:00Z, 6.9 hours before the alert went out and 25 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: 36 J/kg
Mixed-layer CIN: -2 J/kg
Mixed-layer LCL: 937 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: -3 m²/s²
0-3 km storm-relative helicity: 51 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

226 
WGHW50 PHFO 291854
FFWHFO
HIC007-292200-
/O.NEW.PHFO.FF.W.0035.210329T1854Z-210329T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Honolulu HI
854 AM 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 noon HST.

* At 854 AM HST, the Hanalei river gage shows the river level is 
  rising rapidly while heavy rainfall continues up in the mountains. 
  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...
  Kapaa, Princeville, Kilauea, Hanalei, Wainiha, Haena, Moloaa, 
  Wailua Homesteads, Alakai Swamp Trails, Anahola, Wailua, Na Pali 
  State Park, Kokee State Park, Kalihiwai 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.

&&

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

LAT...LON 2217 15972 2222 15962 2223 15956 2222 15952
      2224 15950 2224 15947 2224 15943 2225 15941
      2222 15933 2216 15930 2216 15929 2214 15928
      2206 15933

FLASH FLOOD...RADAR INDICATED

$$

LAU

1 follow-up statement

116 
WGHW70 PHFO 292155
FFSHFO

Flash Flood Statement
National Weather Service Honolulu HI
1155 AM HST Mon Mar 29 2021

HIC007-292205-
/O.EXP.PHFO.FF.W.0035.000000T0000Z-210329T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kauai HI-
1155 AM HST Mon Mar 29 2021

...FLASH FLOOD WARNING WILL EXPIRE AT NOON HST TODAY FOR THE ISLAND 
OF KAUAI IN KAUAI COUNTY...

Flood waters have receded. The heavy rain has ended. Flooding is no 
longer expected to pose a threat. Please continue to heed remaining 
road closures.

LAT...LON 2217 15972 2222 15962 2223 15956 2222 15952
      2224 15950 2224 15947 2224 15943 2225 15941
      2222 15933 2216 15930 2216 15929 2214 15928
      2206 15933

$$

LAU

The office that day

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

Issued	Product	Office	Counties	Lasted
Mar 28, 5:15 PM HST	Wind Advisory	HFO	Hawaii	22 hr
Mar 28, 7:06 PM HST	Winter Weather Advisory	HFO	Hawaii	32 hr
Mar 29, 9:53 AM HST	Flash Flood Warning	HFO	Kauai	2 hr
Mar 29, 12:32 PM HST	Flash Flood Watch	HFO	Kauai	20 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.