Flash Flood Warning 4, NWS Honolulu, HI

000
WGHW70 PHFO 041552
FFSHFO

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE HONOLULU HI
550 AM HST SUN NOV 4 2007

HIC003-041700-
/O.CON.PHFO.FF.W.0004.000000T0000Z-071104T1700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
OAHU IN HONOLULU COUNTY-
550 AM HST SUN NOV 4 2007

...A FLASH FLOOD WARNING REMAINS IN EFFECT FOR CENTRAL AND WINDWARD 
OAHU UNTIL 700 AM HST...

LOCATIONS IN THE WARNING INCLUDE THE WINDWARD SIDE FROM LAIE TO 
WAIMANALO...AND CENTRAL OAHU FROM WAHIAWA TO AIEA.

AT 549 AM...RADAR CONTINUED TO SHOW HEAVY SHOWERS AND EMBEDDED 
THUNDERSTORMS...WITH LOCALIZED RAINFALL RATES OF 1 TO 2 INCHES PER 
HOUR....FALLING OVER MUCH OF WINDWARD AND CENTRAL OAHU.

THESE RAINS ARE FALLING OVER AREAS THAT HAVE ALREADY HAD EXCESSIVE 
RAINFALL OVERNIGHT. AMOUNTS OF 3 TO 6 INCHES ARE COMMON. THE HAKIPUU 
MAUKA GAUGE HAS RECIEVED 4 AND A HALF INCHES OF RAIN IN THE PAST 3 
HOURS...AND 7 INCHES OF RAIN IN THE 6 HOUR PERIOD ENDING AT 5 AM.

A FLASH FLOOD WARNING MEANS FLASH FLOODING IS IMMINENT OR OCCURRING
IN STREAMS...ROADS AND LOW LYING AREAS. MOVE TO HIGHER GROUND NOW. 
NEVER DRIVE INTO AREAS WHERE WATER COVERS THE ROAD. ONLY A FEW 
INCHES OF FLOWING WATER CAN MOVE MOST VEHICLES.

THIS WARNING MAY NEED TO BE EXTENDED BEYOND 700 AM HST IF FLASH
FLOODING PERSISTS.

LAT...LON 2139 15801 2158 15813 2169 15792 2146 15772
      2129 15766

$$
R BALLARD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST SUN NOV 4 2007

.SYNOPSIS...
A LOW 400 MILES NORTH NORTHWEST OF KAUAI IS DROPPING SOUTH. THE
APPROACHING LOW WILL PRODUCE UNSETTLED WEATHER WITH A CHANCE OF
HEAVY RAINFALL THROUGH EARLY NEXT WEEK. DRIER...TRADE-WIND WEATHER
WILL RETURN LATER NEXT WEEK.

&&

.DISCUSSION...
SATELLITE IMAGERY SHOWS THICK CLOUDS BLANKETING THE ISLANDS. WITHIN
THE CLOUD AREA RADARS SHOW BANDS OF HEAVY SHOWERS AND
THUNDERSTORMS. AT 300 AM...THE MOST ACTIVE AREA WAS OVER OAHU AND
MOLOKAI WITH RELATIVELY DRY WEATHER FROM LANAI TO THE BIG ISLAND OF
HAWAII.

AT 300 AM A LOW WAS CENTERED 400 MILES NORTH NORTHWEST OF KAUAI.
OVER THE PAST SEVERAL HOURS THE LOW HAS BEEN MOVING SOUTH AT 20 MPH.
A FRONTAL CLOUD BAND CURVING AROUND THE SOUTHEAST SIDE OF THE LOW
HAS BEEN DISSIPATING BUT A 220 MILE WIDE BAND OF OVERCAST LAYERED
CLOUDS WITH EMBEDDED THUNDERSTORMS HAS FORMED CENTERED FROM 28N 155W
OVER OAHU TO 19N 160W.

RECENT RUNS OF THE GFS MODEL SHOW THE LOW CONTINUING TO DROP
SOUTH...REACHING A POINT ABOUT 180 MILES WEST OF KAUAI TOMORROW
NIGHT. MEANWHILE...THE CLOUD BAND CENTERED OVER OAHU WILL MOVE
SOUTHEAST SLOWLY ACROSS THE ISLANDS REACHING THE BIG ISLAND BY
MONDAY. THIS SCENARIO LOOKS PRETTY REASONABLE. A THREAT OF HEAVY
RAIN CONTINUES FOR ALL ISLANDS AND A FLASH FLOOD WATCH WILL REMAIN
IN EFFECT. THE MOST ACTIVE WEATHER IS LIKELY TO BE CONCENTRATED IN
NARROW LINES WITHIN THE BROADER CLOUD BAND. FLASH FLOODING REMAINS
THE GREATEST THREAT...BUT THERE IS A  POSSIBILITY OF SEVERE
THUNDERSTORMS AND FOR SNOW OR FREEZING PRECIPITATION AND STRONG
WINDS ON THE SUMMITS OF MAUNA KEA AND MAUNA LOA.

THE COMPUTER MODELS OFTEN HAVE TROUBLE WITH CUT-OFF LOWS LIKE THE
ONE AFFECTING THE ISLANDS. THE MODELS ARE IN PRETTY GOOD AGREEMENT
OVER THE NEXT 48 HOURS BUT BEGIN TO DIVERGE AFTER THAT. FOR NOW...
WE WILL FOLLOW THE GFS MODEL SHOWING THE LOW WEAKENING AND MOVING
AWAY TO THE WEST SOUTHWEST EARLY NEXT WEEK. THE LOW MAY REMAIN CLOSE
ENOUGH TO MAINTAIN A THREAT OF HEAVY RAIN THROUGH TUESDAY NIGHT. BY
WEDNESDAY THE ATMOSPHERE WILL BE GETTING MORE STABLE AND TRADE WINDS
WILL BE RETURNING.

&&

.MARINE...
A LARGE SOUTH SWELL CONTINUES TO BUILD SO WE HAVE UPGRADED THE HIGH
SURF ADVISORY TO A HIGH SURF WARNING. WE ALSO HAVE ISSUED A MARINE
WEATHER STATEMENT FOR THUNDERSTORMS OVER THE COASTAL WATERS AND FOR
HARBOR SURGES AND WAVES BREAKING IN CHANNEL ENTRANCES.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...

HIGH SURF WARNING FOR SOUTH-FACING SHORES OF ALL ISLANDS.

FLASH FLOOD WATCH FOR ALL ISLANDS.

&&

DONALDSON