Alert archive / Hawaii / Flash Flood Warnings in 2011

Flash Flood Warning 18, NWS Honolulu, HI

April 6, 2011Honolulu County, Hawaii

NWS Honolulu, HI issued this flash flood warning at Apr 6, 2011, 11:14 PM HST for Honolulu 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: Apr 6, 2011, 11:14 PM HST (09:14 UTC)
Expired: Apr 7, 2011, 2:15 AM HST
In force: 3 hr
Issued by: NWS Honolulu, HI
Area: Storm-based polygon
Flood severity: None

County Honolulu County, HI

The radar

The Molokai radar (PHMO), 91 km from the middle of the area, began a volume at 09:17 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, 9.2 hours before the alert went out and 153 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: 1069 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 882 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: -16 m²/s²
0-3 km storm-relative helicity: 46 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

685 
WGHW50 PHFO 070914
FFWHFO
HIC003-071115-
/O.NEW.PHFO.FF.W.0018.110407T0914Z-110407T1115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE HONOLULU HI
1114 PM HST WED APR 6 2011

THE NATIONAL WEATHER SERVICE IN HONOLULU HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  THE ISLAND OF OAHU IN HONOLULU COUNTY

* UNTIL 115 AM HST

* AT 1107 PM HST...RADAR SHOWED HEAVY RAIN NEAR PEARL CITY...OR ABOUT
  12 MILES NORTHWEST OF HONOLULU. THE AREA OF HEAVY RAIN WAS MOVING 
  WEST SLOWLY.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  KAILUA...HONOLULU...PEARL CITY...MILILANI AND WAIPAHU.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WARNING MEANS FLASH FLOODING IS IMMINENT OR OCCURRING
IN STREAMS...ROADS AND LOW LYING AREAS. MOVE TO HIGHER GROUND NOW.

DO NOT CROSS FAST FLOWING OR RISING WATER IN YOUR VEHICLE OR ON FOOT.
TURN AROUND...DON/T DROWN.

&&

THIS FLASH FLOOD WARNING REPLACES THE FLOOD ADVISORY THAT WAS IN
EFFECT FOR THE ISLAND OF OAHU IN HONOLULU COUNTY.

THIS WARNING MAY NEED TO BE EXTENDED BEYOND 115 AM HST IF FLASH
FLOODING PERSISTS.

LAT...LON 2158 15826 2171 15795 2153 15784 2131 15764
      2125 15781 2131 15809

$$
DONALDSON

3 follow-up statements

791 
WGHW70 PHFO 071011
FFSHFO

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE HONOLULU HI
1211 AM HST THU APR 7 2011

HIC003-071115-
/O.CON.PHFO.FF.W.0018.000000T0000Z-110407T1115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
OAHU IN HONOLULU COUNTY-
1211 AM HST THU APR 7 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT FOR THE ISLAND OF OAHU IN
HONOLULU COUNTY UNTIL 115 AM HST...

RADARS SHOW THAT THE HEAVIEST RAIN HAS SHIFTED FARTHER SOUTHEAST TO 
THE LEEWARD SLOPES OF THE KOOLAU MOUNTAINS FROM MANOA TO HALAWA. 
THIS HEAVY RAIN COULD PRODUCE FLOODING ON THE MOANALUA FREEWAY.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO HONOLULU... 
MANOA VALLEY...MOANALUA VALLEY AND HALAWA VALLEY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WARNING MEANS FLASH FLOODING IS IMMINENT OR OCCURRING
IN STREAMS...ROADS AND LOW LYING AREAS. MOVE TO HIGHER GROUND NOW.

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 115 AM HST IF FLASH
FLOODING PERSISTS.

LAT...LON 2158 15826 2171 15795 2153 15784 2131 15764
      2125 15781 2131 15809

$$
DONALDSON

216 
WGHW50 PHFO 071059
FFWHFO
HIC003-071215-
/O.EXT.PHFO.FF.W.0018.000000T0000Z-110407T1215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE HONOLULU HI
1259 AM HST THU APR 7 2011

THE NATIONAL WEATHER SERVICE IN HONOLULU HAS EXTENDED THE

* FLASH FLOOD WARNING FOR...
  THE ISLAND OF OAHU IN HONOLULU COUNTY

* UNTIL 215 AM HST

* AT 1248 AM HST...RAIN GAGES AT MILILANI AND PACIFIC PALISADES 
  SHOWED HEAVY RAIN FALLING AT OVER AN INCH PER HOUR. THE AREA OF 
  HEAVY RAIN WAS MOVING NORTHWEST AT 20 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  HONOLULU...PEARL CITY...MILILANI TOWN...AND WAHIAWA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WARNING MEANS FLASH FLOODING IS IMMINENT OR OCCURRING
IN STREAMS...ROADS AND LOW LYING AREAS. MOVE TO HIGHER GROUND NOW.

DO NOT CROSS FAST FLOWING OR RISING WATER IN YOUR VEHICLE OR ON FOOT.
TURN AROUND...DON/T DROWN.

&&

THIS FLASH FLOOD WARNING REPLACES THE PRE-EXISTING WARNING THAT WAS
IN EFFECT FOR THE ISLAND OF OAHU IN HONOLULU COUNTY.

THIS WARNING MAY NEED TO BE EXTENDED BEYOND 215 AM HST IF FLASH
FLOODING PERSISTS.

LAT...LON 2158 15826 2171 15795 2153 15784 2131 15764
      2125 15781 2131 15809

$$
DONALDSON

729 
WGHW70 PHFO 071211
FFSHFO

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE HONOLULU HI
211 AM HST THU APR 7 2011

HIC003-071220-
/O.EXP.PHFO.FF.W.0018.000000T0000Z-110407T1215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
OAHU IN HONOLULU COUNTY-
211 AM HST THU APR 7 2011

...THE FLASH FLOOD WARNING HAS EXPIRED FOR THE ISLAND OF OAHU IN
HONOLULU COUNTY...

THE HEAVY RAINS AND FLOODING HAVE SUBSIDED...BUT RUNOFF IS STILL
OCCURRING AND STREAMS WILL REMAIN HIGH FOR SEVERAL HOURS.

A FLASH FLOOD WATCH FOR ALL ISLANDS CONTINUES THROUGH EARLY FRIDAY 
MORNING.

LAT...LON 2158 15826 2171 15795 2153 15784 2131 15764
      2125 15781 2131 15809

$$
DONALDSON

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 6, 2:53 PM HST	Areal Flood Advisory	HFO	Hawaii	3 hr
Apr 6, 3:27 PM HST	High Surf Advisory	HFO	Honolulu, Kalawao	48 hr
Apr 6, 3:54 PM HST	Winter Storm Warning	HFO	Hawaii	60 hr
Apr 6, 4:06 PM HST	Special Marine Warning	HFO		54 min
Apr 6, 4:20 PM HST	Flash Flood Warning	HFO	Hawaii	89 min
Apr 6, 4:49 PM HST	Areal Flood Advisory	HFO	Kalawao	37 min
Apr 6, 4:52 PM HST	Areal Flood Advisory	HFO	Kauai	54 min
Apr 6, 5:42 PM HST	Special Marine Warning	HFO		39 min
Apr 6, 6:44 PM HST	Special Marine Warning	HFO		61 min
Apr 6, 7:43 PM HST	Special Marine Warning	HFO		32 min
Apr 6, 8:39 PM HST	Special Marine Warning	HFO		51 min
Apr 6, 10:55 PM HST	Areal Flood Advisory	HFO	Honolulu	3 hr
Apr 7, 12:19 AM HST	Areal Flood Advisory	HFO	Hawaii	58 min
Apr 7, 2:18 AM HST	Areal Flood Advisory	HFO	Kauai	39 min
Apr 7, 8:46 AM HST	Areal Flood Advisory	HFO	Kauai	3 hr

Nearby

Flash Flood Warnings in Hawaii, 2011 Every flash flood warning in 2011

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.