Alert archive / Hawaii / Flash Flood Warnings in 2021

Flash Flood Warning 45, NWS Honolulu, HI

December 5, 2021Kalawao County, Hawaii

NWS Honolulu, HI issued this flash flood warning at Dec 5, 2021, 9:20 PM HST for Kalawao County, Hawaii. It was in force for 11 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, 9:20 PM HST (07:20 UTC)
Expired: Dec 6, 2021, 8:15 AM HST
In force: 11 hr
Issued by: NWS Honolulu, HI
Area: Storm-based polygon
Flood severity: None

County Kalawao County, HI

The radar

The Molokai radar (PHMO), 15 km from the middle of the area, began a volume at 07:21 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, 7.3 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.

337 
WGHW50 PHFO 060720
FFWHFO
HIC009-061030-
/O.NEW.PHFO.FF.W.0045.211206T0720Z-211206T1030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Honolulu HI
920 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 1230 AM HST.

* At 920 PM HST, radar indicates heavy rain falling moving over 
  Molokai from the south, with rain rates of 1 to 2 inches per hour. 
  Waters in streams and rivers remain high, with additional rain 
  approaching form the south.

  HAZARD...Flash flooding caused by heavy rain.

  SOURCE...Radar.

  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...
  all of Molokai.

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 1230 AM HST if flooding 
persists.

LAT...LON 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 2109 15709 2107 15725
      2110 15733

FLASH FLOOD...RADAR INDICATED

$$

BIRCHARD

5 follow-up statements

079 
WGHW50 PHFO 061018
FFWHFO
HIC009-061330-
/O.EXT.PHFO.FF.W.0045.000000T0000Z-211206T1330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Honolulu HI
1218 AM HST Mon Dec 6 2021

The National Weather Service in Honolulu has extended the

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

* Until 330 AM HST.

* At 1218 AM HST, radar indicated that heavy rain had temporarily 
  eased in intensity and coverage over Molokai, but runoff from 
  earlier heavy rain continues. Molokai Police Department reports 
  that Kamehameha Five Highway remains closed near mile marker 8 due 
  to mud and debris on the roadway. Satellite shows more heavy 
  showers developing a little further out that may move over the 
  island by approximately 1 am.

  HAZARD...Flash flooding caused by heavy rain.

  SOURCE...Radar.

  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...
  all of Molokai.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

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 330 AM HST if flooding 
persists.

LAT...LON 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 2109 15709 2107 15725
      2110 15733

FLASH FLOOD...RADAR INDICATED

$$

Birchard

482 
WGHW70 PHFO 061106
FFSHFO

Flash Flood Statement
National Weather Service Honolulu HI
106 AM HST Mon Dec 6 2021

HIC009-061330-
/O.CON.PHFO.FF.W.0045.000000T0000Z-211206T1330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maui HI-
106 AM HST Mon Dec 6 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 330 AM HST EARLY THIS 
MORNING FOR THE ISLAND OF MOLOKAI IN MAUI COUNTY...

At 106 AM HST, radar indicated areas of moderate rain moving over 
Molokai from the south, with runoff from earlier heavy rain 
continuing. Kamehameha Five Highway remains closed near mile marker 
8 due to mud and debris on the roadway. Additional heavy showers 
forming to the south of the island will likely move ashore through 
the early morning hours.

HAZARD...Flash flooding caused by heavy rain.

SOURCE...Radar.

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...
all of Molokai.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

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 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 2109 15709 2107 15725
      2110 15733

FLASH FLOOD...RADAR INDICATED

$$

BIRCHARD

906 
WGHW50 PHFO 061323
FFWHFO
HIC009-061630-
/O.EXT.PHFO.FF.W.0045.000000T0000Z-211206T1630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Honolulu HI
323 AM HST Mon Dec 6 2021

The National Weather Service in Honolulu has extended the

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

* Until 630 AM HST.

* At 323 AM HST, radar indicated some decrease in rainfall moving 
  over Molokai from the south, but runoff from earlier heavy rain 
  continues. Kamehameha Five Highway remains closed near mile marker 
  8 due to mud and debris on the roadway. Additional heavy showers 
  forming to the south of the island will likely move ashore through 
  the early morning hours.

  HAZARD...Flash flooding caused by heavy rain.

  SOURCE...Radar.

  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...
  all of Molokai.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

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 630 AM HST if flooding 
persists.

LAT...LON 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 2109 15709 2107 15725
      2110 15733

FLASH FLOOD...RADAR INDICATED

$$

Birchard

074 
WGHW50 PHFO 061616
FFWHFO
HIC009-061930-
/O.EXT.PHFO.FF.W.0045.000000T0000Z-211206T1930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Honolulu HI
616 AM HST Mon Dec 6 2021

The National Weather Service in Honolulu has extended the

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

* Until 930 AM HST.

* At 616 AM HST, radar indicated rainfall has eased but runoff 
  levels remain high. Kamehameha Five Highway remains closed near 
  mile marker 8 due to mud and debris on the roadway. Additional 
  rainfall will be moving over Molokai from the south during the 
  early morning hours.

  HAZARD...Flash flooding caused by heavy rain.

  SOURCE...Radar.

  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.

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 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 2109 15709 2107 15725
      2110 15733

FLASH FLOOD...RADAR INDICATED

$$

KODAMA

492 
WGHW70 PHFO 061815
FFSHFO

Flash Flood Statement
National Weather Service Honolulu HI
815 AM HST Mon Dec 6 2021

HIC009-061825-
/O.CAN.PHFO.FF.W.0045.000000T0000Z-211206T1930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maui HI-
815 AM HST Mon Dec 6 2021

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

Flood waters have receded and heavy rainfall has ended. Maui 
Emergency Management reported that Kamehameha Five Highway has been 
reopened.

A Flood Watch remains in effect for Maui County through Tuesday 
afternoon.

LAT...LON 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 2109 15709 2107 15725
      2110 15733

$$

KODAMA

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, 6:22 PM HST	Flash Flood Warning	HFO	Kalawao	3 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 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.