High Surf in Hawaii, June 12 to 16, 2008

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1000 AM HST THU JUN 12 2008

.SYNOPSIS...
LIGHT TRADE WINDS WILL CONTINUE THROUGH AT LEAST THE WEEKEND.
SHOWERS WILL CONTINUE TO BE FOCUSED ACROSS WINDWARD AREAS AND THE
LEEWARD BIG ISLAND SLOPES...BUT AN AREA OF LOW PRESSURE ALOFT
LINGERING OVER THE REGION WILL KEEP THE ATMOSPHERE UNSTABLE AND MAY
ENHANCE SHOWERS OVER ALL AREAS.

&&

.DISCUSSION...
BROAD AND COMPLEX LOW PRESSURE ALOFT ACROSS THE CENTRAL PACIFIC WILL
KEEP TRADE WINDS LIGHT AND THE ATMOSPHERE RELATIVELY UNSTABLE
THROUGH AT LEAST THE WEEKEND. THE LOW ALOFT HAS WORKED ITS WAY DOWN
TO THE MID LEVELS OF THE ATMOSPHERE...WHERE IT HAS ERODED THE MID
LEVEL RIDGE OVER THE ISLANDS AND WEAKENED THE SURFACE PRESSURE
GRADIENT AND TRADE WINDS. AS A RESULT...A WEAK MID LEVEL TROUGH
MOVED SLOWLY ACROSS OAHU AND KAUAI OVERNIGHT...CAUSING SURFACE WINDS
TO VEER OUT OF THE EAST SOUTHEAST AND DRAWING THE MOLOKAI PLUME OVER
SOUTHEAST AND WINDWARD OAHU...WHERE 1 TO 3 INCH RAINFALL TOTALS WERE
COMMON LAST NIGHT. ISOLATED RAINFALL IN EXCESS OF 5 INCHES WAS
CREATED BY INSTABILITY CREATED BY THE LOW PRESSURE ALOFT...WHICH HAS
WIPED OUT THE INVERSION OVER THE STATE. SHOWERS HAVE DISSIPATED OVER
OAHU BUT REMAIN ACTIVE NEAR KAUAI AS THE MID LEVEL TROUGH MOVES
THROUGH. WINDS AT THE SURFACE AND MID LEVELS ARE TRENDING MORE
EASTERLY ACROSS THE EASTERN END OF THE STATE AND WILL BACK OUT OF
THE EAST ACROSS OAHU AND KAUAI DURING THE EVENING. THUS...ISOLATED
HEAVY SHOWERS ARE POSSIBLE FOR KAUAI AND OAHU THROUGH THE EVENING
AND OVER THE KONA SLOPES DURING THE AFTERNOON. WE ALSO UPDATED TO
ADD A SLIGHT CHANCE OF THUNDERSTORMS FOR WATERS NORTH OF KAUAI TODAY.

LIGHT TRADE WINDS AND A RELATIVELY UNSTABLE ATMOSPHERE WILL PERSIST
THROUGH AT LEAST THE WEEKEND AS THE LOW ALOFT LINGERS. SHOWERS WILL
BE FOCUSED ACROSS WINDWARD AREAS AND THE KONA SLOPES OF THE BIG
ISLAND...BUT AN ISOLATED HEAVY SHOWER COULD POP UP JUST ABOUT
ANYWHERE AS DAYTIME SEA BREEZES PROMOTE CLOUDS OVER LEEWARD AREAS
EACH AFTERNOON.

IN THE LONG RANGE...FORECAST MODELS SHOW LOW PRESSURE ALOFT
LINGERING ACROSS THE REGION THROUGH THE FIST HALF OF NEXT WEEK BUT
DIFFER ON THE DETAILS. THE GFS AND NOGAPS MAINTAIN THE LIGHT TRADE
WIND FLOW...WHILE THE ECMWF REBUILDS THE MIDLEVEL RIDGE SOMEWHAT AND
BRINGS BACK MODERATE TRADES. THE CURRENT FORECAST BRINGS BACK
MODERATE TRADE WINDS...BUT WE WILL TAKE A CLOSE LOOK AT THE EXTENDED
FORECAST TODAY.

&&

.MARINE...
MODERATE SURF WILL CONTINUE ALONG SOUTH FACING SHORES FOR THE NEXT
COUPLE OF DAYS. A LARGER SOUTH SWELL MAY BOOST SURF TO THE 8 FOOT
ADVISORY LEVEL SATURDAY NIGHT AND SUNDAY.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

WROE