Alert archive / Hawaii / Flash Flood Warnings in 2021

Flash Flood Warning 43, NWS Honolulu, HI

December 5, 2021Kalawao County, Hawaii

NWS Honolulu, HI issued this flash flood warning at Dec 5, 2021, 6:22 PM HST for Kalawao 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 5, 2021, 6:22 PM HST (04:22 UTC)
Expired: Dec 5, 2021, 9:15 PM HST
In force: 3 hr
Issued by: NWS Honolulu, HI
Area: Storm-based polygon
Flood severity: None

County Kalawao County, HI

The radar

The Molokai radar (PHMO), 14 km from the middle of the area, began a volume at 04:22 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 00:00Z, 4.4 hours before the alert went out and 257 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: 185 J/kg
Mixed-layer CIN: -3 J/kg
Mixed-layer LCL: 995 m above ground
0-6 km bulk shear: 68 kt
0-1 km storm-relative helicity: 15 m²/s²
0-3 km storm-relative helicity: 118 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.4

Open this sounding in Storm Lab

The text

As transmitted.

712 
WGHW50 PHFO 060422
FFWHFO
HIC009-060715-
/O.NEW.PHFO.FF.W.0043.211206T0422Z-211206T0715Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Honolulu HI
622 PM HST Sun Dec 5 2021

The National Weather Service in Honolulu has issued a

* Flash Flood Warning for...
  The island of Molokai in Maui County

* Until 915 PM HST.

* At 622 PM HST, radar indicates heavy rain falling moving over 
  Molokai from the south, with rain rates of 1 to 2 inches per hour. 
  Debris and mud blocking portions of Kamehameha highway have made 
  the roadway impassable, and water levels in streams and rivers 
  continue to rise.

  HAZARD...Flash flooding caused by heavy rain.

  SOURCE...Radar and automated 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...
  Kualapuu, Kaunakakai, Hoolehua, Kalaupapa National Park, Kawela, 
  Kamalo, Maunaloa, Ualapue, Pukoo, Kepuhi, Halawa Valley and 
  Molokai Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

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

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

&&

This warning may need to be extended beyond 915 PM HST if flooding 
persists.

This Flash Flood Warning replaces the previously issued Flood 
Advisory that was in effect for The island of Molokai in Maui County.

LAT...LON 2110 15733 2119 15727 2123 15727 2124 15726
      2120 15701 2123 15699 2123 15697 2119 15693
      2119 15677 2115 15670 2107 15677 2103 15688
      2105 15689 2108 15702 2107 15704 2108 15705
      2109 15709 2107 15725

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

BIRCHARD

The office that day

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

Issued	Product	Office	Counties	Lasted
Dec 5, 2:30 PM HST	Areal Flood Advisory	HFO	Hawaii	86 min
Dec 5, 3:18 PM HST	Areal Flood Advisory	HFO	Kalawao	3 hr
Dec 5, 3:35 PM HST	Coastal Flood Statement	HFO	Hawaii, Honolulu, Kauai, Kalawao	42 hr
Dec 5, 3:56 PM HST	Flash Flood Warning	HFO	Hawaii	5 hr
Dec 5, 4:27 PM HST	Flash Flood Warning	HFO	Kalawao	5 hr
Dec 5, 5:33 PM HST	Areal Flood Advisory	HFO	Kalawao	6 hr
Dec 5, 8:02 PM HST	Gale Warning	HFO		7 hr
Dec 5, 8:02 PM HST	Small Craft Advisory	HFO		10 days
Dec 5, 9:16 PM HST	Flash Flood Warning Considerable damage threat	HFO	Kalawao	12 hr
Dec 5, 9:20 PM HST	Flash Flood Warning	HFO	Kalawao	11 hr
Dec 6, 12:37 AM HST	Areal Flood Advisory	HFO	Hawaii	11 hr
Dec 6, 3:24 AM HST	Winter Weather Advisory	HFO	Hawaii	12 hr
Dec 6, 3:26 AM HST	Gale Warning	HFO		12 hr
Dec 6, 3:37 AM HST	High Surf Advisory	HFO	Hawaii, Honolulu, Kauai, Kalawao	12 hr
Dec 6, 5:54 AM HST	Special Marine Warning	HFO		2 hr
Dec 6, 7:09 AM HST	Special Marine Warning	HFO		51 min
Dec 6, 7:39 AM HST	Special Weather Statement	HFO	Hawaii	51 min
Dec 6, 7:40 AM HST	Areal Flood Advisory	HFO	Honolulu	6 hr
Dec 6, 7:57 AM HST	Areal Flood Advisory	HFO	Kauai	3 hr
Dec 6, 11:30 AM HST	Flash Flood Warning	HFO	Hawaii	2 hr
Dec 6, 12:26 PM HST	Special Marine Warning	HFO		64 min
Dec 6, 1:12 PM HST	Special Weather Statement	HFO	Honolulu	63 min
Dec 6, 1:16 PM HST	Flash Flood Warning	HFO	Honolulu	15 hr
Dec 6, 1:20 PM HST	Special Marine Warning	HFO		55 min
Dec 6, 1:43 PM HST	Areal Flood Advisory	HFO	Hawaii	3 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.