Alert archive / Hawaii / Flash Flood Warnings in 2004

Flash Flood Warning 6, NWS Honolulu, HI

January 25, 2004

NWS Honolulu, HI issued this flash flood warning at Jan 25, 2004, 1:41 PM HST. 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: Jan 25, 2004, 1:41 PM HST (23:41 UTC)
Expired: Jan 25, 2004, 4:45 PM HST
In force: 3 hr
Issued by: NWS Honolulu, HI
Area: Counties, with a storm outline in the text

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 12:00Z, 11.7 hours before the alert went out and 151 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: 1379 J/kg
Mixed-layer CIN: -3 J/kg
Mixed-layer LCL: 692 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 22 m²/s²
0-3 km storm-relative helicity: 102 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.

000 
WGHW50 PHFO 252344
FFWHI 
HIZ002-260245-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE HONOLULU HI
141 PM HST SUN JAN 25 2004

THE NATIONAL WEATHER SERVICE IN HONOLULU HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  OAHU

* UNTIL 445 PM HST

* AT 136 PM HST...THE PUBLIC REPORTED VERY HEAVY RAIN OVER 
  MILILANI.  RADAR SHOWS THE AREA OF HEAVY RAIN WAS NEARLY 
  STATIONARY.

* LOCATIONS IN THE WARNING INCLUDE MILILANI TOWN...PEARL 
  CITY...WAHIAWA...WAIPIO...WHITMORE VILLAGE AND WHEELER
  AFB

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.

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 SEVERE WEATHER TO THE
POLICE FOR IMMEDIATE RELAY TO THE NATIONAL WEATHER SERVICE.

LAT...LON 2149 15810 2135 15799 2144 15784 2159 15795
$$

1 follow-up statement

000 
WGHW70 PHFO 260055
FFSHI 
HIZ002-260110-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE HONOLULU HI
253 PM HST SUN JAN 25 2004

...THE FLASH FLOOD WARNING IS CANCELLED FOR OAHU...

WEATHER RADAR INDICATED THE HEAVY RAINFALL HAS ENDED ACROSS THE
WARNED AREA....AND THERE IS NO LONGER A THREAT FOR SERIOUS FLOODING.

REMINDER...A FLASH FLOOD WATCH REMAINS IN EFFECT FOR ALL HAWAIIAN 
ISLANDS UNTIL 4 PM HST. THIS WILL LIKELY BE EXTENDED.

STAY TUNED TO NOAA WEATHER RADIO...LOCAL TV OR RADIO FOR FURTHER
INFORMATION FROM THE NATIONAL WEATHER SERVICE.

$$
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 Jan 25, 11:00 AM HST, 2 hours 41 minutes earlier.

Area forecast discussion, Jan 25, 11:00 AM HST, 2 hours 41 minutes before

HAWAIIAN ISLANDS FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HONOLULU
11 AM HST SUN JAN 25 2004

UPDATED TO INCLUDE KAUAI AND OAHU TO THE FLASH FLOOD WATCH AREA

.SYNOPSIS...
LINGERING INSTABILITY AND INCREASING MOISTURE WILL PROLONG THE
THREAT OF HEAVY SHOWERS AND THUNDERSTORMS INTO MONDAY AND POSSIBLY
TUESDAY. DRIER TRADE WIND WEATHER IS EXPECTED TO RETURN WEDNESDAY.

&&

.DISCUSSION...
AN UPPER TROUGH JUST WEST OF THE MAIN HAWAIIAN ISLANDS THIS MORNING
WILL MOVE SOUTHEASTWARD...DEEPEN...AND POSSIBLY CUT OFF INTO AN
UPPER LOW JUST SOUTHWEST OF OAHU OVER THE NEXT 48 HOURS. THIS WILL
KEEP THE AIRMASS OVER US UNSTABLE AND PLACE US BENEATH THE
UPLIFT...CONVECTION-INDUCING...PORTION OF THIS FEATURE. OVERNIGHT
SOUNDINGS SHOW THAT THE ATMOSPHERE IS ALREADY QUITE UNSTABLE...WITH
A LIFTED INDEX OF MINUS 9.2 NOTED AT HILO. MOISTURE IS ON THE
INCREASE AS WELL...WITH PRECIPITABLE WATER VALUES RISING AT BOTH
ENDS OF THE ISLAND CHAIN. ITS ALSO QUITE COLD ALOFT...WITH
TEMPERATURES OF MINUS 17 DEGREES C AT 500 MB ABOVE LIHUE. SATELLITE
LOOPS CORROBORATE THE INSTABILITY NOTED IN THE SOUNDING DATA...WITH
SHOWERY LOW CLOUDS AND ISOLATED THUNDERSTORMS SLOWLY WORKING THEIR
WAY WESTWARD ACROSS LOCAL WATERS EAST OF OAHU WITHIN SLUGGISH LOW
LEVEL FLOW. A COLD FRONT APPROACHING FROM THE NORTHWEST HAS A SECOND
AREA OF HEAVY SHOWERS AND THUNDERSTORMS WHICH WILL AFFECT THE
ISLANDS LATER THIS AFTERNOON AND OVERNIGHT TONIGHT. ANOTHER SURFACE
FEATURE IS A RIDGE OF HIGH PRESSURE WHICH EXTENDS WEST ALONG ABOUT
28N...INDUCING A STEEP ENOUGH PRESSURE GRADIENT TO PRODUCE THE WEAK
TRADES WHICH ARE BRINGING MOISTURE BACK INTO OUR WEATHER PICTURE.

IT IS THIS COMBINATION OF INSTABILITY AND INCREASING MOISTURE THAT
WILL LIKELY TRIGGER HEAVY SHOWERS AND THUNDERSTORMS ACROSS THE MAIN
ISLANDS LATER TODAY. THE ADDITIONAL FLOOD THREAT POSED BY THE
APPROACHING COLD FRONT PROMPTED AND EXPANSION OF THE FLOOD WATCH
AREA TO INCLUDE ALL OF THE MAIN HAWAIIAN ISLANDS AS OF 1045 AM HST.

BY WEDNESDAY...THE UPPER TROUGH WILL MOVE EAST OF THE BIG ISLAND AND
BEGIN TO FILL. THE SURFACE RIDGE WILL STRENGTHEN AT THE SAME
TIME...INDUCING DRIER MODERATE TRADE WIND FLOW.

&&

.SURF...
NO CHANGE IS EXPECTED IN THE SURF SITUATION WHERE THE SURF IS
EXPECTED TO REMAIN AT BORDERLINE ADVISORY LEVEL OF 15 FEET TODAY.

&&

.HNL WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH......ALL HAWAIIAN ISLANDS
HIGH SURF ADVISORY.....NORTH AND WEST SHORES KAUAI OAHU MAUI
                       MOLOKAI AND LANAI
                       WEST FACING SHORES OF THE BIG ISLAND

&&

POWELL

The office that day

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

Issued	Product	Office	Counties	Lasted
Jan 25, 12:12 AM HST	Flash Flood Warning	HFO	Kauai	3 hr

Nearby

Flash Flood Warnings in Hawaii, 2004 Every 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.