AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1000 AM HST MON MAR 28 2011

.SYNOPSIS...
A TROUGH ALOFT WILL KEEP THE ATMOSPHERE A BIT MOIST AND
UNSTABLE...SO IT WILL REMAIN A BIT SHOWERY OVER MAUI COUNTY AND THE
BIG ISLAND THROUGH TOMORROW EVENING. THE WEATHER WILL TURN DRIER
STARTING TOMORROW NIGHT AS THE ATMOSPHERE BECOMES MORE STABLE. HIGH
CLOUDS ASSOCIATED WITH THE TROUGH WILL KEEP SKIES A BIT GRAY OVER
MAUI AND THE BIG ISLAND TODAY...BUT THESE CLOUDS WILL NOT PRODUCE
ANY PRECIPITATION. A RIDGE NORTH OF THE ISLANDS WILL MAINTAIN THE
TRADE WINDS THROUGH FRIDAY. THE WINDS WILL WEAKEN AND SHIFT OUT OF
THE SOUTHEAST THIS WEEKEND AS A FRONT APPROACHES FROM THE NORTHWEST.
THE FRONT MAY BRING SOME WET WEATHER NEXT WEEK BUT IT IS STILL TOO
EARLY TO BE SURE ABOUT THAT.

&&

.DISCUSSION...
WATER VAPOR IMAGERY AND UPPER AIR ANALYSES SHOW A TROUGH ALOFT
RUNNING FROM 30N140W OVER OAHU TO A LOW 470 MILES SOUTHWEST OF
KAUAI. THE TROUGH IS KEEPING THE ATMOSPHERE OVER THE ISLANDS
SOMEWHAT UNSTABLE. THE 200 AM BALLOON SOUNDINGS SHOWED A LIFTED
INDEX OF -1.8 AT HILO AND -2.2 AT LIHUE. SATELLITE SOUNDER DATA
SHOW PRECIPITABLE WATER NEAR .9 INCHES AROUND KAUAI...INCREASING TO
1.2 INCHES AROUND THE BIG ISLAND. IT WILL BE GENERALLY DRY OVER
KAUAI AND OAHU FOR THE NEXT 36 HOURS BUT THERE WILL BE ENOUGH
MOISTURE AND INSTABILITY TO KEEP MAUI COUNTY AND THE BIG ISLAND A
BIT SHOWERY.

THE ATMOSPHERE OVER THE MAIN HAWAIIAN ISLANDS WILL BECOME MORE
STABLE OVER THE NEXT 36 HOURS AS RIDGING ALOFT BUILDS IN FROM THE
WEST. AT LOWER LEVELS DRIER AIR WILL SPREAD OVER THE ISLANDS FROM
THE NORTHEAST. BY TOMORROW NIGHT THE WEATHER SHOULD BECOME RATHER
DRY OVER ALL THE ISLANDS.

THE 1028 MB HIGH NOW NORTHEAST OF THE ISLANDS WILL MOVE EAST
NORTHEAST SLOWLY WITH A SURFACE RIDGE EXTENDING WEST SOUTHWEST FROM
THE HIGH. AS THE HIGH MOVES AWAY...OUR WINDS WILL GRADUALLY
WEAKEN...BUT MAY REMAIN LOCALLY BREEZY THROUGH TOMORROW NIGHT.

THE GLOBAL MODELS CONTINUE TO SHOW A FRONT APPROACHING FROM THE
NORTHWEST NEXT WEEKEND. AS THE SURFACE RIDGE SHIFTS SOUTH AND ERODES
FROM THE WEST...WINDS OVER THE ISLANDS WILL SHIFT OUT OF THE
SOUTHEAST. THE GLOBAL MODELS GENERALLY AGREE THAT THERE MAY BE SOME
WET WEATHER OVER THE ISLANDS NEXT WEEK...BUT DETAILS ARE UNCERTAIN.
THE PATTERN MAY BE COMPLEX WITH A SECOND FRONT PUSHING IN BEHIND THE
FIRST ONE.

&&

.AVIATION...
AIRMET TANGO REMAINS POSTED FOR MODERATE HIGH LEVEL TURBULENCE
ASSOCIATED WITH THE TROUGH ALOFT NEAR THE AREA. THE TERMINALS WILL
REMAIN GENERALLY VFR...ALTHOUGH THERE MAY BE PERIODS OF MVFR
CONDITIONS...ESPECIALLY AT PHNY.

&&

.MARINE...
A SMALL CRAFT ADVISORY CONTINUES FOR STRONG TRADE WINDS OVER MAALAEA
BAY...THE WATERS SOUTH OF THE BIG ISLAND...AND THE PAILOLO AND
ALENUIHAHA CHANNELS THROUGH WEDNESDAY MORNING.

THE WAVE WATCH III MODEL CONTINUES TO SHOW A LARGE NORTHWEST SWELL
ARRIVING WEDNESDAY...WHICH WILL PRODUCE SURF HEIGHTS NEAR THE HIGH
SURF WARNING THRESHOLDS ALONG MOST NORTH AND WEST FACING SHORES OF
THE SMALLER ISLANDS FROM WEDNESDAY NIGHT INTO THURSDAY. THIS SWELL
MAY BE LARGE ENOUGH AND WESTERLY ENOUGH TO PRODUCE SURF HEIGHTS NEAR
THE HIGH SURF ADVISORY THRESHOLD ON WEST FACING SHORES OF THE BIG
ISLAND FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY. A SERIES OF SMALL
TO MODERATE SOUTH SWELLS WILL ROLL IN ALL WEEK.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...

SMALL CRAFT ADVISORY UNTIL 600 AM HST WEDNESDAY MORNING FOR MAALAEA
BAY...THE WATERS SOUTH OF THE BIG ISLAND...AND THE PAILOLO AND
ALENUIHAHA CHANNELS.

&&

$$
DONALDSON