Alert archive / Hawaii / Flash Flood Warnings in 2021

Flash Flood Warning 14, NWS Honolulu, HI

March 9, 2021Honolulu County, Hawaii

NWS Honolulu, HI issued this flash flood warning at Mar 9, 2021, 8:33 AM HST for Honolulu County, Hawaii. It was in force for 117 min. 1 report 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: Mar 9, 2021, 8:33 AM HST (18:33 UTC)
Expired: Mar 9, 2021, 10:30 AM HST
In force: 117 min
Issued by: NWS Honolulu, HI
Area: Storm-based polygon
Flood severity: None

County Honolulu County, HI

The radar

The Molokai radar (PHMO), 75 km from the middle of the area, began a volume at 18:34 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

Time	Report	Where	Remark
Mar 9, 10:35 AM HST	FLASH FLOOD	Kaneohe, HI	FOUR FEET OF WATER AT WILLIAN HENRY ROAD IN KANEOHE. BLOCKED DRAIN IN AREA. WATER GOING INTO HOUSES.

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

The nearest sounding before it

Lihue, (PHLI), launched 12:00Z, 6.6 hours before the alert went out and 169 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: 198 J/kg
Mixed-layer CIN: -3 J/kg
Mixed-layer LCL: 585 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: 29 m²/s²
0-3 km storm-relative helicity: 39 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

046 
WGHW50 PHFO 091833
FFWHFO
HIC003-091930-
/O.NEW.PHFO.FF.W.0014.210309T1833Z-210309T1930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Honolulu HI
833 AM HST Tue Mar 9 2021

The National Weather Service in Honolulu has issued a

* Flash Flood Warning for...
  The island of Oahu in Honolulu County

* Until 930 AM HST.

* At 833 AM HST, radar indicated heavy rain over Kaneohe on Oahu. 
  Rain was falling at a rate of 2 to 3 inches per hour. 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...
  Waikane, Waiahole, Kahaluu, Kaaawa, Ahuimanu, Punaluu, Hauula, 
  Kaneohe, Kaneohe Marine Base, Wahiawa, Laie, Kalihi, Maunawili, 
  Kailua, Manoa, Kahuku, Palolo, Waimanalo, Haleiwa and Hawaii Kai.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

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

LAT...LON 2162 15811 2173 15800 2173 15797 2155 15783
      2147 15783 2143 15779 2144 15778 2146 15779
      2147 15778 2147 15771 2141 15772 2134 15768
      2133 15763 2131 15763 2126 15768 2125 15771

FLASH FLOOD...RADAR INDICATED

$$

DONALDSON

1 follow-up statement

976 
WGHW50 PHFO 091913
FFWHFO
HIC003-092030-
/O.EXT.PHFO.FF.W.0014.000000T0000Z-210309T2030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Honolulu HI
913 AM HST Tue Mar 9 2021

The National Weather Service in Honolulu has extended the

* Flash Flood Warning for...
  The island of Oahu in Honolulu County

* Until 1030 AM HST.

* At 913 AM HST, radar and automated rain gauges indicated heavy 
  rain falling over windward Oahu. Rain was falling at a rate of 3 
  to 4 inches per hour. Flash flooding is occurring or expected to 
  begin shortly.

  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...
  Waikane, Waiahole, Kahaluu, Kaaawa, Ahuimanu, Punaluu, Hauula, 
  Kaneohe, Kaneohe Marine Base, Wahiawa, Laie, Kalihi, Maunawili, 
  Kailua, Manoa, Kahuku, Palolo, Waimanalo, Haleiwa and Hawaii Kai.

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.

The heavy rains may cause rock and mudslides in steep terrain areas.

&&

This warning may need to be extended beyond 1030 AM HST if flooding 
persists.

LAT...LON 2162 15811 2173 15800 2173 15797 2155 15783
      2147 15783 2143 15779 2144 15778 2146 15779
      2147 15778 2147 15771 2141 15772 2134 15768
      2133 15763 2131 15763 2126 15768 2125 15771

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

DONALDSON

The office that day

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

Issued	Product	Office	Counties	Lasted
Mar 8, 2:42 PM HST	Flash Flood Warning Considerable damage threat	HFO	Kalawao	5 hr
Mar 8, 8:07 PM HST	High Surf Advisory	HFO	Honolulu, Kalawao	19 hr
Mar 8, 9:32 PM HST	Areal Flood Advisory	HFO	Kalawao	33 min
Mar 8, 10:05 PM HST	Flash Flood Warning	HFO	Kalawao	5 hr
Mar 8, 10:55 PM HST	Areal Flood Advisory	HFO	Kauai	6 hr
Mar 9, 5:02 AM HST	Areal Flood Advisory	HFO	Honolulu	3 hr
Mar 9, 8:05 AM HST	Areal Flood Advisory	HFO	Honolulu	28 min
Mar 9, 8:09 AM HST	Special Marine Warning	HFO		2 hr
Mar 9, 8:22 AM HST	Special Weather Statement	HFO	Honolulu	53 min
Mar 9, 9:15 AM HST	Special Weather Statement	HFO	Honolulu	30 min
Mar 9, 9:59 AM HST	Special Weather Statement	HFO	Honolulu	61 min
Mar 9, 10:03 AM HST	Special Marine Warning	HFO		54 min
Mar 9, 10:31 AM HST	Flash Flood Warning	HFO	Honolulu	6 hr
Mar 9, 10:55 AM HST	Areal Flood Advisory	HFO	Hawaii	11 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.