Flash Flood Warning 11, NWS Honolulu, HI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
830 PM HST MON FEB 20 2006

.SYNOPSIS...
A JETSTREAM ACROSS THE ISLANDS WILL KEEP CONDITIONS RIPE FOR
LOCALIZED HEAVY RAINFALL AND ISOLATED THUNDERSTORMS OVERNIGHT. TRADE
WINDS ARE BLOWING NOW...BUT A TROUGH EXPECTED TO FORM EAST OF THE
BIG ISLAND BY MIDWEEK WILL CAUSE WINDS TO WEAKEN AND BECOME
NORTHERLY. HOWEVER...DRIER CONDITIONS ARE EXPECTED TUESDAY INTO NEXT
WEEKEND AS A RIDGE DEVELOPS OVERHEAD. A FRONT IS EXPECTED SUNDAY AND
MONDAY.

&&

.DISCUSSION...
A 130 MPH JETSTREAM BLOWING FROM WEST SOUTHWEST TO EAST NORTHEAST
ACROSS THE MAIN HAWAIIAN ISLANDS CONTINUES TO ENCOURAGE DEEP
CONVECTION ACROSS THE WESTERN HALF OF THE ISLAND CHAIN THIS EVENING.
HEAVY SHOWERS ARE OCCURRING ACROSS THE SOUTHEAST PORTION OF
KAUAI...WITH RADAR-DERIVED RAINFALL RATES IN EXCESS OF 4 INCHES PER
HOUR NOTED NEAR KOLOA. SO FAR THIS EVENING...THE REMAINING ISLANDS
HAVE SEEN FAR LESS ACTIVITY AFTER A FAIRLY BUSY AFTERNOON. SATELLITE
IMAGERY SHOWS AN AREA OF INCREASED LOW CLOUDS AND MOISTURE MOVING
TOWARDS THE SMALLER ISLANDS FROM THE NORTHEAST. WE WILL SEE IF THE
ADDITION OF THIS MOISTURE TRIGGERS AN UPSURGE IN SHOWER ACTIVITY
EAST OF KAUAI TONIGHT. WE WILL EXTEND THE FLOOD WATCH FOR
KAUAI...OAHU AND MOLOKAI UNTIL 4 AM HST TUESDAY.

WE ARE IN THE PROCESS OF CHANGING THE GRIDDED DATABASE TO ACCOUNT
FOR A TROUGH EXPECTED TO DEVELOP EAST OF THE BIG ISLAND AT MIDWEEK
AND FOR A FRONTAL BOUNDARY TO REACH THE ISLANDS LATE NEXT WEEKEND.
SO FAR...THE MAJOR IMPACT THIS TROUGH WILL HAVE WILL BE TO DECREASE
OUR SURFACE WINDS AND SWING THEM TO NORTHERLIES. ZONAL FLOW ALOFT
EXPECTED WEDNESDAY WILL BECOME ANTICYCLONICALLY CURVED BY FRIDAY AS
AN UPPER RIDGE DEVELOPS. MODELS ACTUALLY KEEP THE ISLANDS RATHER DRY
FROM LATE WEDNESDAY INTO NEXT WEEKEND. HOWEVER...A FRONTAL BAND IS
EXPECTED TO REACH THE ISLANDS SUNDAY...STALLING ACROSS THE CENTRAL
ISLANDS MONDAY. GFS75 INCREASES RAINFALL AMOUNTS DURING THIS
TIME...AND INTRODUCES STRONGER POSTFRONTAL NORTHEAST WINDS TO FINISH
THE FORECAST PERIOD.

LATEST WEB CAMS AND OBSERVATIONS FROM SURFACE AND UPPER AIR STATIONS
INDICATE THE THREAT OF CONTINUOUS DENSE FOG ON THE BIG ISLAND
SUMMITS HAS PASSED. THEREFORE...THE DENSE FOG ADVISORY IS CANCELLED
EFFECTIVE 815 PM HST.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH UNTIL 4 AM TUESDAY FOR KAUAI OAHU AND MOLOKAI.
&&

POWELL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HONOLULU HI
900 PM HST MON FEB 20 2006

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0807 PM     FLASH FLOOD      WAILUA                  22.06N 159.34W
02/20/2006                   KAUAI IN KAUAI     HI   LAW ENFORCEMENT

            LOOP ROAD CLOSURE, WAILUA HOMESTEADS

0807 PM     FLASH FLOOD      2 S KALAHEO             21.89N 159.53W
02/20/2006                   KAUAI IN KAUAI     HI   LAW ENFORCEMENT

            WAHA RD NOT PASSABLE

0807 PM     FLASH FLOOD      5 S LIHUE               21.90N 159.35W
02/20/2006                   PHZ113             HI   LAW ENFORCEMENT

            HEAVY RUNOFF NEAR PUO.

0807 PM     FLASH FLOOD      KAPAA                   22.10N 159.35W
02/20/2006                   KAUAI              HI   LAW ENFORCEMENT

            KEAPANA BRIDGE CLOSURE DUE TO FLOODING

&&

HFO