Alert archive / Hawaii / Flash Flood Warnings in 2021

Flash Flood Warning 1, NWS Honolulu, HI

January 18, 2021Kalawao County, Hawaii

NWS Honolulu, HI issued this flash flood warning at Jan 18, 2021, 12:51 AM HST for Kalawao County, Hawaii. It was in force for 6 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: Jan 18, 2021, 12:51 AM HST (10:51 UTC)
Expired: Jan 18, 2021, 6:45 AM HST
In force: 6 hr
Issued by: NWS Honolulu, HI
Area: Storm-based polygon
Flood severity: None

County Kalawao County, HI

The radar

The Molokai radar (PHMO), 31 km from the middle of the area, began a volume at 10:53 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

Hilo, (PITO), launched 00:00Z, 10.9 hours before the alert went out and 251 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: 116 J/kg
Mixed-layer CIN: -8 J/kg
Mixed-layer LCL: 1002 m above ground
0-6 km bulk shear: 11 kt
0-1 km storm-relative helicity: 4 m²/s²
0-3 km storm-relative helicity: 5 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

560 
WGHW50 PHFO 181051
FFWHFO
HIC009-181345-
/O.NEW.PHFO.FF.W.0001.210118T1051Z-210118T1345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Honolulu HI
1251 AM HST Mon Jan 18 2021

The National Weather Service in Honolulu has issued a

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

* Until 345 AM HST.

* At 1251 AM HST, radar indicated heavy rain over 2 inches has 
  fallen over a large area in eastern Molokai. Rain was falling at a 
  rate of 1 to 3 inches per hour. Flash flooding is occurring or 
  expected to begin shortly.

  HAZARD...Flash flooding caused by heavy rain over eastern
           Molokai. The stream gauge along Kawela Gulch has
           exceeded Flash Flood Warning thresholds. Flood waters
           may block portions of Kamehameha highway near mile
           marker 4.

  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...
  Kalaupapa National Park, Kamalo, Ualapue, Kawela, Pukoo, 
  Kaunakakai, Halawa Valley and Kualapuu.

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 345 AM HST if flooding 
persists.

LAT...LON 2107 15704 2120 15704 2120 15701 2123 15699
      2123 15697 2123 15696 2119 15693 2119 15677
      2116 15671 2116 15669 2115 15669 2114 15669
      2107 15677 2104 15685 2104 15686 2103 15688
      2105 15688 2108 15702

FLASH FLOOD...RADAR INDICATED

$$

RCB

4 follow-up statements

931 
WGHW70 PHFO 181129
FFSHFO

Flash Flood Statement
National Weather Service Honolulu HI
129 AM HST Mon Jan 18 2021

HIC009-181345-
/O.CON.PHFO.FF.W.0001.000000T0000Z-210118T1345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maui HI-
129 AM HST Mon Jan 18 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 345 AM HST EARLY THIS 
MORNING FOR THE ISLAND OF MOLOKAI IN MAUI COUNTY...

At 129 AM HST, radar indicated heavy rain over eastern Molokai. Rain 
was falling at a rate of 1 to 2 inches per hour. Flash flooding is 
occurring or expected to begin shortly. Flood waters may block 
portions of Kamehameha highway.

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...
  Kalaupapa National Park, Kamalo, Ualapue, Kawela, Pukoo, 
  Kaunakakai, Halawa Valley and Kualapuu.

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 345 AM HST if flooding 
persists.

LAT...LON 2107 15704 2120 15704 2120 15701 2123 15699
      2123 15697 2123 15696 2119 15693 2119 15677
      2116 15671 2116 15669 2115 15669 2114 15669
      2107 15677 2104 15685 2104 15686 2103 15688
      2105 15688 2108 15702

FLASH FLOOD...RADAR INDICATED

$$

RCB

663 
WGHW50 PHFO 181319
FFWHFO
HIC009-181645-
/O.EXT.PHFO.FF.W.0001.000000T0000Z-210118T1645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Honolulu HI
319 AM HST Mon Jan 18 2021

The National Weather Service in Honolulu has extended the

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

* Until 645 AM HST.

* At 319 AM HST, radar indicated heavy rain over eastern Molokai. 
  Rain was falling at a rate of 1 to 2 inches per hour. Flash 
  flooding is occurring or expected to begin shortly. Stream gauges 
  at Kawela Gulch and Kaunakakai Gulch are exceeding flash flood 
  thresholds. Flood waters may block portions of Kamehameha highway 
  this morning.

  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...
  Kamalo, Kalaupapa National Park, Ualapue, Kawela, Pukoo, Halawa 
  Valley, Kaunakakai and Kualapuu.

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 645 AM HST if flooding 
persists.

LAT...LON 2107 15704 2120 15704 2120 15701 2123 15697
      2123 15696 2119 15693 2119 15677 2116 15669
      2114 15669 2107 15677 2103 15687 2103 15688
      2105 15688 2108 15702

FLASH FLOOD...RADAR INDICATED

$$

RCB

199 
WGHW70 PHFO 181441
FFSHFO

Flash Flood Statement
National Weather Service Honolulu HI
441 AM HST Mon Jan 18 2021

HIC009-181645-
/O.CON.PHFO.FF.W.0001.000000T0000Z-210118T1645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maui HI-
441 AM HST Mon Jan 18 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 645 AM HST THIS 
MORNING FOR THE ISLAND OF MOLOKAI IN MAUI COUNTY...

At 441 AM HST, radar indicated heavy rain has diminished over east 
Molokai this morning. Expect continued elevated water levels in area 
streams and gulches, with water flowing over low lying roadways.

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...
  Kamalo, Kalaupapa National Park, Ualapue, Kawela, Pukoo, Halawa 
  Valley, Kaunakakai and Kualapuu.

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 645 AM HST if flooding 
persists.

LAT...LON 2107 15704 2120 15704 2120 15701 2123 15697
      2123 15696 2119 15693 2119 15677 2116 15669
      2114 15669 2107 15677 2103 15687 2103 15688
      2105 15688 2108 15702

FLASH FLOOD...RADAR INDICATED

$$

RCB

096 
WGHW70 PHFO 181636
FFSHFO

Flash Flood Statement
National Weather Service Honolulu HI
636 AM HST Mon Jan 18 2021

HIC009-181646-
/O.EXP.PHFO.FF.W.0001.000000T0000Z-210118T1645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maui HI-
636 AM HST Mon Jan 18 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 645 AM HST THIS MORNING FOR 
THE ISLAND OF MOLOKAI IN MAUI COUNTY...

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

A Flash Flood Watch remains in effect until 600 PM HST Tuesday for 
portions of Kahoolawe Hawaii...Lanai Hawaii...Maui Hawaii...Molokai 
Hawaii and Oahu Hawaii.

LAT...LON 2107 15704 2120 15704 2120 15701 2123 15697
      2123 15696 2119 15693 2119 15677 2116 15669
      2114 15669 2107 15677 2103 15687 2103 15688
      2105 15688 2108 15702

$$

KINO

The office that day

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

Issued	Product	Office	Counties	Lasted
Jan 17, 3:37 PM HST	Wind Advisory	HFO	Honolulu, Kauai, Kalawao	48 hr
Jan 17, 3:45 PM HST	Gale Warning	HFO		36 hr
Jan 17, 3:45 PM HST	Small Craft Advisory	HFO		24 hr
Jan 17, 4:37 PM HST	Areal Flood Advisory	HFO	Kauai	3 hr
Jan 17, 7:07 PM HST	Areal Flood Advisory	HFO	Hawaii	3 hr
Jan 17, 7:17 PM HST	Areal Flood Advisory	HFO	Kauai	2 hr
Jan 18, 12:06 AM HST	Areal Flood Advisory	HFO	Kalawao	3 hr
Jan 18, 3:03 AM HST	Areal Flood Advisory	HFO	Kalawao	3 hr
Jan 18, 3:49 AM HST	Winter Weather Advisory	HFO	Hawaii	36 hr
Jan 18, 5:16 AM HST	Areal Flood Advisory	HFO	Kalawao	3 hr
Jan 18, 8:53 AM HST	Areal Flood Advisory	HFO	Hawaii	3 hr
Jan 18, 10:17 AM HST	Areal Flood Advisory	HFO	Honolulu	3 hr
Jan 18, 10:50 AM HST	Areal Flood Advisory	HFO	Kalawao	6 hr
Jan 18, 11:50 AM HST	Areal Flood Advisory	HFO	Kalawao	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.