Alert archive / Hawaii / Flash Flood Warnings in 2004

Flash Flood Warning 69, NWS Honolulu, HI

October 31, 2004Honolulu County, Hawaii

NWS Honolulu, HI issued this flash flood warning at Oct 31, 2004, 2:30 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
Oct 31, 2004, 2:30 PM HST (00:30 UTC)
Expired
Oct 31, 2004, 5:30 PM HST
In force
3 hr
Issued by
NWS Honolulu, HI
Area
Counties, with a storm outline in the text

County Honolulu County, HI

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this flash flood warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Lihue, (PHLI), launched 00:00Z, 0.5 hours before the alert went out and 149 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, Lihue, at 00:00Z on 2004-11-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 675 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lihue, at 00:00Z on 2004-11-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 7 square meters per square second.1939Sfc1 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
675 J/kg
Mixed-layer CIN
-26 J/kg
Mixed-layer LCL
1081 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
7 m²/s²
0-3 km storm-relative helicity
18 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

The text

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

000
WGHW50 PHFO 010029
FFWHFO
HIC003-010330-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE HONOLULU HI
230 PM HST SUN OCT 31 2004

THE NATIONAL WEATHER SERVICE IN HONOLULU HAS ISSUED A

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

* UNTIL 530 PM HST

* AT 218 PM HST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  FLASH FLOODING FROM A STORM OVER WAIPIO...OR 12 MILES NORTHWEST OF
  HONOLULU. THE STORM PRODUCING FLASH FLOODING WAS NEARLY STATIONARY.

* LOCATIONS IMPACTED INCLUDE...
   WHEELER AFB...WAIPAHU...MILILANI...AIEA...PEARL CITY...MAKAKILO 
  CITY...WAHIAWA...WAIPIO...HALAWA...

THIS FLASH FLOOD WARNING REPLACES THE FLOOD ADVISORY THAT WAS IN
EFFECT.

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING OF STREAMS
AND COULD ALSO TRIGGER ROCK AND MUDSLIDES IN STEEP TERRAIN.

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING OF
STREAMS...HIGHWAYS...UNDERPASSES AND LOW LYING AREAS.

MOTORISTS SHOULD BE ALERT FOR FLOODING AND SHOULD NOT ATTEMPT TO
CROSS FAST FLOWING OR RISING WATER...MANY FLASH FLOOD DEATHS OCCUR
WHEN MOTORISTS TRY CROSSING FLOODED ROADWAYS. TURN AROUND...DON/T
DROWN

ESCAPE RISING WATER BY CLIMBING DIRECTLY TO HIGHER GROUND. NEVER TRY
TO OUTRACE A FLOOD...EITHER ON FOOT OR IN YOUR VEHICLE. DO NOT CAMP
NEAR STREAMS OR OTHER AREAS SUBJECT TO FLOODING.

STAY TUNED TO NOAA WEATHER RADIO OR OTHER LOCAL MEDIA SOURCES FOR THE
LATEST SEVERE WEATHER INFORMATION. REPORT FLOODING TO THE POLICE FOR
IMMEDIATE RELAY TO THE NATIONAL WEATHER SERVICE.

LAT...LON 2155 15810 2136 15814 2133 15793 2149 15787

$$

POWELL
1 follow-up statement
000
WGHW70 PHFO 010221
FFSHFO
HIC003-010229-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE HONOLULU HI
419 PM HST SUN OCT 31 2004

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

RADAR SHOWS THAT SHOWERS HAVE RAPIDLY COLLAPSED ACROSS CENTRAL 
OAHU...AND THAT THE THREAT OF FLASH FLOODING HAS DIMINISHED.

STAY TUNED TO NOAA WEATHER RADIO OR OTHER LOCAL MEDIA SOURCES FOR THE
LATEST SEVERE WEATHER INFORMATION. REPORT FLOODING TO THE POLICE FOR
IMMEDIATE RELAY TO THE NATIONAL WEATHER SERVICE.

LAT...LON 2155 15810 2136 15814 2133 15793 2149 15787

$$

POWELL

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Honolulu, HI wrote its last area forecast discussion before this flash flood warning went out at Oct 31, 9:30 AM HST, 5 hours earlier.

Area forecast discussion, Oct 31, 9:30 AM HST, 5 hours before
HAWAIIAN ISLANDS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
930 AM HST SUN OCT 31 2004

.SYNOPSIS...
SHOWERS WILL CONTINUE TO FALL OVER THE ISLANDS OVER THE NEXT COUPLE
OF DAYS. SOUTHEASTERLY WINDS WILL ALLOW THE SHOWERS TO COVER MORE
THAN THE USUAL WINDWARD AND MAUKA AREAS. A TROUGH TO THE NORTHWEST
OF THE ISLANDS WILL ALLOW FOR ISOLATED THUNDERSTORMS TO
DEVELOP...MAINLY DURING THE AFTERNOON HOURS.
&&

.DISCUSSION...
A NORTHEAST TO SOUTHWEST ORIENTED TROUGH IS NORTHWEST OF THE MAIN
HAWAIIAN ISLANDS. THE TROUGH HELPED TO TRIGGER SOME HEAVY RAINS LAST
NIGHT...PARTICULARLY IN THE MANOA AREA. THE HEAVIEST RAIN AT THE
MANOA LYON ARBORETUM GAGE FELL BETWEEN 645 PM AND 730 PM WHEN 3.13
INCHES OF RAIN FELL. THE HEAVIEST 15 MINUTE RAINFALL WAS FROM 7 PM
TO 715 PM WHEN 1.29 INCHES OF RAIN FELL. SEVERAL GAGES ON OAHU
REPORTED 24 HOUR RAINFALL TOTALS OF 4 INCHES OR GREATER BETWEEN 5 AM
SATURDAY AND 5 AM SUNDAY. DURING THAT TIME...THE MANOA LYON
ARBORETUM GAGE REPORTED 9.97 INCHES...THE WILSON TUNNEL GAGE PICKED
UP 6.75 INCHES...LULUKU HAD 6.45...AND ST. STEPHENS HAD 4.68 INCHES
OF RAIN.

THE MODELS SHOW THE UPPER LEVEL TROUGH WEAKENING A BIT TODAY...BUT
ALL ARE DEVELOPING AN UPPER TROUGH FAR TO THE NORTHWEST OF THE
ISLANDS TODAY. THE NOGAPS DEVELOPS THE TROUGH DEEPER THAN THE ECMWF
AND GFS. THE NOGAPS CLOSES THE SYSTEM OFF AT 500 MB BY MONDAY
AFTERNOON ALMOST DUE WEST OF THE ISLANDS. BY MONDAY NIGHT...THE GFS
CLOSES THE SYSTEM OFF NORTH NORTHWEST OF THE ISLANDS. THE ECMWF IS
MORE IN LINE WITH THE GFS. RIGHT NOW WILL FOLLOW CLOSER TO THE GFS
AND ECMWF MODELS.

A COLD FRONT IS FORECAST TO DEVELOP AT THE SURFACE...ASSOCIATED WITH
THE UPPER LEVEL SYSTEM. THE GFS AND ECMWF BOTH RACE THE FRONT OVER
THE ISLANDS NEXT WEEKEND. WILL HOLD OFF MAKING ANY MAJOR CHANGES TO
THE GRIDS FOR NEXT WEEKEND UNTIL FUTURE RUNS COME IN.

HAVE UPPED THE POPS AND SKY OVER SEVERAL LOCATIONS FOR TONIGHT.
BACKED OFF ON THE HEAVY RAINS OVER OAHU FOR THIS AFTERNOON. SHOWERS
WILL DEFINITELY BE AROUND...BUT DIFFICULT TO SAY EXACTLY WHO WILL
SEE ANY HEAVIER SHOWERS. HAVE LEFT ISOLATED THUNDERSTORMS IN THE
FORECAST FOR THE KOOLAU RANGE OF OAHU THIS AFTERNOON. UNSTABLE AIR
AROUND THE STATE COULD LEAD TO DEVELOPMENT ELSEWHERE. VISIBLE
SATELLITE THIS MORNING SHOWS KAUAI MOSTLY CLEAR...SO WILL HAVE TO
MONITOR THE GARDEN ISLE CLOSELY FOR AFTERNOON DEVELOPMENT. HIGH
CLOUDS OVER OAHU AND AREAS EAST HAVE STARTED TO THIN A BIT OVER THE
LAST COUPLE OF HOURS. THROUGH THIN SPOTS IN THE HIGH CLOUDS...CLOUDS
ARE SEEN BUILDING OVER THE KOOLAU AND WAIANAE RANGE ON OAHU.
&&

.HFO WATCHES/WARNINGS/ADVISORIES...NONE.
&&

M BALLARD

Nearby

Flash Flood Warnings in Hawaii, 2004Every flash flood warning in 2004

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.