Alert archive / Hawaii / Flash Flood Warnings in 2021

Flash Flood Warning 42, NWS Honolulu, HI

December 5, 2021Kalawao County, Hawaii

NWS Honolulu, HI issued this flash flood warning at Dec 5, 2021, 4:27 PM HST for Kalawao County, Hawaii. It was in force for 5 hr. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Dec 5, 2021, 4:27 PM HST (02:27 UTC)
Expired
Dec 5, 2021, 9:30 PM HST
In force
5 hr
Issued by
NWS Honolulu, HI
Area
Storm-based polygon
Flood severity
None

County Kalawao County, HI

The radar

The Molokai radar (PHMO), 91 km from the middle of the area, began a volume at 02:31 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.

What was reported inside it

TimeReportWhereRemark
Dec 5, 9:10 PM HSTFLASH FLOODKihei, HIMAUI EMERGENCY MANAGEMENT AGENCY REPORTS SEVERAL HOMES FLOODED IN THE MAUI MEADOWS SUBDIVISION. VEHICLES HAVE BEEN WASHED AWAY WHILE OTHERS WERE STRANDED BETWEEN FLOODED CULVERTS.
Dec 5, 9:40 PM HSTFLASH FLOODKula, HIKULA HWY FLOODING AT LOWER KULA RD.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Hilo, (PITO), launched 00:00Z, 2.5 hours before the alert went out and 188 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-pSkew-T log-p diagram, Hilo, at 00:00Z on 2021-12-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 154 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Hilo, at 00:00Z on 2021-12-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 192 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
154 J/kg
Mixed-layer CIN
-7 J/kg
Mixed-layer LCL
626 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
192 m²/s²
0-3 km storm-relative helicity
307 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.9

Open this sounding in Storm Lab

The text

As transmitted.

827 
WGHW50 PHFO 060227
FFWHFO
HIC009-060430-
/O.NEW.PHFO.FF.W.0042.211206T0227Z-211206T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Honolulu has issued a

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

* Until 630 PM HST.

* At 427 PM HST, radar indicated rainfall increasing over the slopes 
  of Haleakala with higher rain rates of 2 to 3 inches per hour 
  approaching Maui from the south. Rainfall is expected to spread 
  westward over the next several hours and affect central and west 
  Maui.

  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. Flooding may close Piilani
           Highway at low water crossings such as at Kalepa Gulch
           and at Hawelewele Gulch near Mile Marker 31.

* Some locations that will experience flash flooding include...
  Kahului, Kihei, Lahaina, Kula, Pukalani, Makawao, Keokea, 
  Haliimaile, Paia, Puunene, Haiku-Pauwela, Pauwela, Wailea, 
  Maalaea, Huelo, Ulupalakua, Makena, Waikapu, Wailuku and Waiehu.

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 PM HST if flooding 
persists.

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

LAT...LON 2093 15672 2102 15668 2105 15660 2100 15652
      2091 15647 2096 15633 2095 15624 2087 15612
      2084 15611 2081 15599 2077 15597 2071 15598
      2064 15604 2063 15609 2057 15642 2063 15647
      2077 15648 2078 15650 2076 15654 2080 15663

FLASH FLOOD...RADAR INDICATED

$$

KODAMA
2 follow-up statements
304 
WGHW50 PHFO 060425
FFWHFO
HIC009-060730-
/O.EXT.PHFO.FF.W.0042.000000T0000Z-211206T0730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Honolulu has extended the

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

* Until 930 PM HST.

* At 625 PM HST, radar indicated rainfall continuing to move over 
  the slopes of Haleakala from the south. Rain rates of 2 to 3 
  inches per hour were occurring over the Kaupo Gap area, and 1 to 2 
  inches per hour near Oheo Gulch. Heavy rainfall will also be 
  moving over central and west Maui during the next several 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.

* This warning includes the entire island of Maui.

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 PM HST if flooding 
persists.

LAT...LON 2093 15672 2102 15668 2105 15660 2100 15652
      2091 15647 2096 15633 2095 15624 2087 15612
      2084 15611 2081 15599 2077 15597 2071 15598
      2064 15604 2063 15609 2057 15642 2063 15647
      2077 15648 2078 15650 2076 15654 2080 15663

FLASH FLOOD...RADAR INDICATED

$$

KODAMA
602 
WGHW70 PHFO 060524
FFSHFO

Flash Flood Statement
National Weather Service Honolulu HI
724 PM HST Sun Dec 5 2021

HIC009-060730-
/O.CON.PHFO.FF.W.0042.000000T0000Z-211206T0730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maui HI-
724 PM HST Sun Dec 5 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 930 PM HST THIS 
EVENING FOR THE ISLAND OF MAUI IN MAUI COUNTY...

At 724 PM HST, radar indicated heavy rain over all of Maui, with 
rainfall especially heavy over the slopes of Haleakala, where rain 
has been falling at a rate of 2 to 3 inches per hour. Rapid rises in 
water levels are occurring in streams and rivers. Runoff through 
Wailea and Makena is expected to impactful.

HAZARD...Heavy rain producing life threatening flash flooding.

SOURCE...Radar.

IMPACT...Significant and life threatening flooding in drainages,
         streams, rivers, roads, properties, and other low lying
         areas. Multiple public road closures expected, as well
         as landslides in steep terrain.

This warning includes the entire island of Maui.

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 2093 15672 2102 15668 2105 15660 2100 15652
      2091 15647 2096 15633 2095 15624 2087 15612
      2084 15611 2081 15599 2077 15597 2071 15598
      2064 15604 2063 15609 2057 15642 2063 15647
      2077 15648 2078 15650 2076 15654 2080 15663

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

BIRCHARD

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 5, 2:30 PM HSTAreal Flood AdvisoryHFOHawaii86 min
Dec 5, 3:18 PM HSTAreal Flood AdvisoryHFOKalawao3 hr
Dec 5, 3:35 PM HSTCoastal Flood StatementHFOHawaii, Honolulu, Kauai, Kalawao42 hr
Dec 5, 3:56 PM HSTFlash Flood WarningHFOHawaii5 hr
Dec 5, 5:33 PM HSTAreal Flood AdvisoryHFOKalawao6 hr
Dec 5, 6:22 PM HSTFlash Flood WarningHFOKalawao3 hr
Dec 5, 8:02 PM HSTGale WarningHFO7 hr
Dec 5, 8:02 PM HSTSmall Craft AdvisoryHFO10 days
Dec 5, 9:16 PM HSTFlash Flood Warning Considerable damage threatHFOKalawao12 hr
Dec 5, 9:20 PM HSTFlash Flood WarningHFOKalawao11 hr
Dec 6, 12:37 AM HSTAreal Flood AdvisoryHFOHawaii11 hr
Dec 6, 3:24 AM HSTWinter Weather AdvisoryHFOHawaii12 hr
Dec 6, 3:26 AM HSTGale WarningHFO12 hr
Dec 6, 3:37 AM HSTHigh Surf AdvisoryHFOHawaii, Honolulu, Kauai, Kalawao12 hr
Dec 6, 5:54 AM HSTSpecial Marine WarningHFO2 hr
Dec 6, 7:09 AM HSTSpecial Marine WarningHFO51 min
Dec 6, 7:39 AM HSTSpecial Weather StatementHFOHawaii51 min
Dec 6, 7:40 AM HSTAreal Flood AdvisoryHFOHonolulu6 hr
Dec 6, 7:57 AM HSTAreal Flood AdvisoryHFOKauai3 hr
Dec 6, 11:30 AM HSTFlash Flood WarningHFOHawaii2 hr
Dec 6, 12:26 PM HSTSpecial Marine WarningHFO64 min
Dec 6, 1:12 PM HSTSpecial Weather StatementHFOHonolulu63 min
Dec 6, 1:16 PM HSTFlash Flood WarningHFOHonolulu15 hr
Dec 6, 1:20 PM HSTSpecial Marine WarningHFO55 min
Dec 6, 1:43 PM HSTAreal Flood AdvisoryHFOHawaii3 hr

Nearby

Flash Flood Warnings in Hawaii, 2021Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.