Flash Flood Warning 100, NWS Honolulu, HI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST SUN MAR 26 2006

.SYNOPSIS...
UNSTABLE WET WEATHER WILL CONTINUE ACROSS THE MAIN HAWAIIAN ISLANDS
TODAY AND THROUGH MOST OF THE NEXT WEEK AS A TROUGH OF LOW PRESSURE
PERSISTS TO OUR WEST. PARTICULARLY HEAVY RAINFALL MAY OCCUR TODAY
THROUGH MONDAY THEN WEDNESDAY THROUGH THURSDAY.

&&

.DISCUSSION...
A DEEP SOUTHWEST TO NORTHEAST ORIENTED TROUGH WEST OF THE MAIN
HAWAIIAN ISLANDS WILL KEEP THE POTENTIAL HIGH FOR HEAVY RAINFALL AT
TIMES THROUGH THE FORECAST PERIOD. SHORT WAVE IMPULSES ROTATE
THROUGH THE BASE OF THE LARGER TROUGH AND MOVE OVER THE
STATE...DRAGGING DEEP TROPICAL MOISTURE INTO THE PERPETUALLY
UNSTABLE ATMOSPHERE OVER THE ISLANDS AND TRIGGERING THE HEAVY
RAINFALL BURSTS.

MODELS SHOW THE NEXT IMPULSE AFFECTING THE ISLANDS TODAY THROUGH
MONDAY...WITH A SECOND IMPULSE EXPECTED WEDNESDAY THROUGH THURSDAY.
SATELLITE AND RADAR SHOW SHOWERS WITH THIS NEXT IMPULSE ARE ALREADY
DEVELOPING OVER THE KAUAI CHANNEL AND ACROSS SOUTHEAST PORTIONS OF
KAUAI. THIS ACTIVITY WILL LIKELY INTENSIFY THROUGH THE DAY TODAY AND
SPREAD EASTWARD. LOW LEVEL FLOW WILL REMAIN SOUTHERLY THROUGH
MIDWEEK...SO HAWAII WEATHER WILL BE WETTER THAN NORMAL EVEN BETWEEN
IMPULSES. THE PALL OF BROKEN TO OVERCAST MIDDLE AND HIGH CLOUDS LIE
ALONG THE EASTERN FLANK OF THE TROUGH AND WILL LIKELY BLOCK THE SUN
INTO EARLY NEXT WEEK.

AFTER THURSDAY...NOGAPS AND GFS WANT TO PUSH THE TROUGH TO THE EAST
OF THE ISLANDS. THIS WOULD BRING DRIER WEATHER TO THE STATE BY NEXT
WEEKEND. TRADE WINDS SHOULD GRADUALLY RETURN BY NEXT WEEKEND...BUT
RAINFALL WILL STILL LIKELY BE A BIT HEAVIER THAN NORMAL AS ALL THE
MOISTURE BROUGHT UP BY THE SOUTHERLIES FROM EARLIER IN THE WEEK GETS
CARRIED BACK WESTWARD OVER THE ISLANDS.

&&

.MARINE...
NEAR HIGH SURF CONDITIONS OF 8 FEET ON THE EAST FACING SHORES
EXPOSED TO THE NORTH SWELL WILL DECREASE SLOWLY THROUGH THE DAY
TODAY.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH SUNDAY AFTERNOON THROUGH LATE MONDAY NIGHT FOR
MAUNA KEA AN MAUNA LOA.
FLASH FLOOD WATCH THROUGH LATE MONDAY NIGHT FOR ALL ISLANDS.

POWELL