Alert archive / Hawaii / Flash Flood Warnings in 2005

Flash Flood Warning 40, NWS Honolulu, HI

October 31, 2005Honolulu County, Hawaii

NWS Honolulu, HI issued this flash flood warning at Oct 31, 2005, 2:30 AM HST for Honolulu County, Hawaii. It was in force for 3 hr. 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: Oct 31, 2005, 2:30 AM HST (12:30 UTC)
Expired: Oct 31, 2005, 5:30 AM HST
In force: 3 hr
Issued by: NWS Honolulu, HI
Area: Counties, with a storm outline in the text

County Honolulu County, HI

What was reported inside it

Time	Report	Where	Remark
Oct 31, 2:30 AM HST	FLASH FLOOD	Sw Punaluu, HI	WATER FROM A DRAINAGE DITCH OVERFLOWED DURING HEAVY RAINS AND FLOODED A NEARBY RESIDENCE WITH 6 INCHES OF WATER.

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

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched one storm report to this flash flood warning; the first came 0 minutes after it went out.

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 12:00Z, 0.5 hours before the alert went out and 161 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: 242 J/kg
Mixed-layer CIN: -8 J/kg
Mixed-layer LCL: 706 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 11 m²/s²
0-3 km storm-relative helicity: 36 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

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

000
WGHW50 PHFO 311229
FFWHFO
HIC003-311530-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE HONOLULU HI
230 AM HST MON OCT 31 2005

THE NATIONAL WEATHER SERVICE IN HONOLULU HAS ISSUED A

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

* UNTIL 530 AM HST

* AT 225 AM HST...LAW ENFORCEMENT REPORTED FLASH FLOODING FROM HEAVY 
  RAIN NEAR KAHANA BAY...OR ABOUT 18 MILES NORTH OF HONOLULU. THE 
  AREA OF HEAVY RAIN WAS NEARLY STATIONARY.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  PUNALUU...LAIE...KAHUKU AND HAUULA.

AT 225 AM KAHUKU POLICE DEPARTMENT REPORT FLOOD WATERS OVER THE 
KAMEHAMEHA HIGHWAY NEAR KAHANA BAY.

BE ESPECIALLY CAUTIOUS SINCE IT IS HARDER TO SEE FLASH FLOODING IN
THE DARK. AVOID TRAVEL.

DO NOT TRY TO CROSS FAST FLOWING OR RISING WATER IN YOUR VEHICLE OR
ON FOOT. THE WATER MAY BE TOO DEEP TO CROSS SAFELY. TURN AROUND...
DON/T DROWN.

REPORT FLOODING TO POLICE OR CIVIL DEFENSE OFFICIALS FOR RELAY TO THE
NATIONAL WEATHER SERVICE.

THIS FLASH FLOOD WARNING MAY NEED TO BE EXTENDED BEYOND 530 AM HST IF
FLASH FLOODING CONDITIONS PERSIST.

LAT...LON 2139 15782 2138 15777 2152 15782 2170 15792
      2170 15796 2159 15799 2146 15790

$$

PROTON

2 follow-up statements

000
WGHW70 PHFO 311401
FFSHFO

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE HONOLULU HI
357 AM HST MON OCT 31 2005

HIC003-311530-
HONOLULU-
400 AM HST MON OCT 31 2005

...A FLASH FLOOD WARNING CONTINUES UNTIL 530 AM HST FOR THE ISLAND OF
OAHU IN HONOLULU COUNTY...

AT 400 AM HST...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE HEAVY SHOWERS PRODUCING FLASH FLOODING NEAR PUNALUU. THE 
HEAVY SHOWERS WERE REMAINING NEARLY STATIONARY. RADAR AND AUTOMATED 
RAIN GAUGES CONTINUED TO INDICATE THE HEAVIEST SHOWERS STILL HAD 
RAINFALL RATES OF 2 TO 3 INCHES PER HOUR.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO LAIE...KAHUKU
AND HAUULA.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODS AND FLASH FLOODS.

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.

LAT...LON 2139 15782 2138 15777 2152 15782 2170 15792
      2170 15796 2159 15799 2146 15790

$$

PROTON/R BALLARD

000
WGHW70 PHFO 311402 CCA
FFSHFO

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST MON OCT 31 2005

HIC003-311530-
HONOLULU-
400 AM HST MON OCT 31 2005

...A FLASH FLOOD WARNING CONTINUES UNTIL 530 AM HST FOR THE ISLAND OF
OAHU IN HONOLULU COUNTY...

AT 400 AM HST...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE HEAVY SHOWERS PRODUCING FLASH FLOODING NEAR PUNALUU. THE 
HEAVY SHOWERS WERE REMAINING NEARLY STATIONARY. RADAR AND AUTOMATED 
RAIN GAUGES CONTINUED TO INDICATE THE HEAVIEST SHOWERS STILL HAD 
RAINFALL RATES OF 2 TO 3 INCHES PER HOUR.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO LAIE...KAHUKU
AND HAUULA.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODS AND FLASH FLOODS.

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.

LAT...LON 2139 15782 2138 15777 2152 15782 2170 15792
      2170 15796 2159 15799 2146 15790

$$

PROTON/R BALLARD

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 30, 8:30 PM HST, 6 hours earlier.

Area forecast discussion, Oct 30, 8:30 PM HST, 6 hours before

HAWAIIAN ISLANDS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
830 PM HST SUN OCT 30 2005

.SYNOPSIS...
HIGH PRESSURE FROM THE NORTH PACIFIC WILL CONTINUE TO MOVE INTO THE
REGION. THIS WILL INCREASE THE LIGHT TRADES TO MODERATE LEVELS ON
MONDAY. WINDS WILL CONTINUE TO INCREASE TO STRONG LEVELS FOR MID
WEEK. SHOWERS WILL FAVOR WINDWARD AND MAUKA AREAS OVERNIGHT AND THEN
WILL SPREAD TO ALL PARTS OF THE ISLANDS STARTING ON MONDAY.

&&

.DISCUSSION...
AN UPPER TROUGH IS DROPPING INTO THE CENTRAL PACIFIC THIS EVENING
FROM THE NORTHWEST. ANOTHER WEAK UPPER TROUGH REMAINS JUST TO THE
EAST OF THE MAIN HAWAIIAN ISLANDS. THE ZONAL FLOW BETWEEN THE TWO
TROUGHS IS BRINGING CONSIDERABLE HIGH CLOUDINESS TO THE ALOHA STATE
THIS EVENING. TRADE WIND SHOWERS CONTINUE WITHIN IN THE LIGHT TRADE
BACK GROUND WINDS. THIS SHOULD CONTINUE THROUGH THE NIGHT AS THE
UPPER TROUGH FROM THE NORTHWEST CONTINUES TO DIG IN.

ON MONDAY AFTERNOON THE UPPER TROUGH FULLY CUTS OFF AN UPPER LOW TO
THE EAST OF MIDWAY ISLAND OR WELL OFF TO THE NORTHWEST OF KAUAI.
THIS CREATES WEAK UPPER RIDGING OVER THE MAIN HAWAIIAN ISLANDS ON
MONDAY. A MODERATE JET MAX DEVELOPS IN THE LAYER FROM 300 TO 200 MB.
THE RELATIVE SOUTHWEST FLOW WILL CONTINUE TO STREAM UP MOISTURE IN
THE MID TO UPPER LEVELS KEEPING AMPLE AMOUNT OF HIGH CLOUDINESS ON
MONDAY. ON THE SURFACE...HIGH PRESSURE WILL CONTINUE TO BUILD INTO
THE ISLANDS AND WILL START THE RAMPING OF THE TRADE WINDS TOWARDS
STRONG LEVELS BY THE END OF MONDAY. GOING TO STICK WITH A STANDARD
TRADE WIND SHOWER PATTERN FOR THE ISLANDS AND SLIGHTLY BUMP UP POPS
LEEWARD.

TUESDAY THROUGH THURSDAY THE MAIN HAWAIIAN ISLANDS REMAIN IN A
RIDGE BETWEEN THE UPPER LOWS OFF TO THE NORTHWEST AND OFF TO THE
EAST. EACH UPPER LOW EXTENDS DOWN TO THE SURFACE AND THE WESTERN LOW
IS TAKING A /KONA LOW/ LOOK TO IT. ON THE SURFACE THE STRONG HIGH
SETS UP SHOP TO THE NORTH OF THE ISLAND CHAIN. THE NET RESULT FOR
THE ISLANDS WILL BE STRONG TRADES. UPPER LEVELS SHOULD HAVE
STREAMERS OF HIGH CLOUDINESS OVER STATE. IN THE LOWER LEVELS...A
WET TRADE PATTERN WILL DEVELOP BEING ENHANCED BY THE UPPER LEVEL
DYNAMICS. WILL UPDATE THE WINDS AND SWING THE POPS ABOVE CLIMO WITH
FAIR CONFIDENCE FOR THIS PERIOD. MAY HAVE TO LOOK INTO THE SUMMITS
FOR STRONGER WINDS WITH THE BRISK WIND FLOW ALOFT.

THE LONG TERM OUTLOOK FOR NEXT WEEKEND BRINGS A CHANCE FOR THE UPPER
TROUGH TO MOVE CLOSER TO THE ISLANDS POSSIBLY RELAXING THE WINDS AND
TURNING INTO A CONVECTIVE PATTERN. FOR NOW WILL BACK DOWN TO A
MODERATE TRADE PATTERN WITH ALL ELEMENTS AND SEE WHERE THE UPPER
LOWS CUT OFF EARLY NEXT WEEK BEFORE CHANGING THE TREND EITHER WAY.
&&

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

PROTON

The office that day

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

Issued	Product	Office	Counties	Lasted
Oct 30, 11:34 PM HST	Flash Flood Warning	HFO	Honolulu	3 hr
Oct 31, 5:30 AM HST	Flash Flood Warning	HFO	Honolulu	2 hr

Nearby

Flash Flood Warnings in Hawaii, 2005 Every flash flood warning in 2005

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.