High Surf in Hawaii, November 27 to 28, 2011

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 PM HST SUN NOV 27 2011

.SYNOPSIS...
A HIGH FAR NORTH OF THE AREA WILL PRODUCE LOCALLY BREEZY TRADE WINDS
THROUGH MONDAY...WHILE A RIDGE ALOFT WILL KEEP RAINFALL LIGHT
THROUGH MID-WEEK. THE WINDS WILL BECOME GENTLE BY TUESDAY NIGHT AS
THE HIGH MOVES AWAY TO THE EAST. TRADE WINDS WILL STRENGTHEN...AND
SHOWERS WILL INCREASE LATER IN THE WEEK AS A SURFACE TROUGH
APPROACHES FROM THE EAST.

&&

.DISCUSSION...
A RELATIVELY STRONG 1032 MB HIGH LIES ABOUT 1400 MILES NORTH
NORTHEAST OF HONOLULU NEAR 38N143W. THIS HIGH...AND THE SURFACE
RIDGE EXTENDING SOUTHWEST FROM THE HIGH...WILL MAINTAIN A RELATIVELY
TIGHT PRESSURE GRADIENT TONIGHT. A STRONG TEMPERATURE INVERSION
NEAR 5500 FT WILL FORM A CAP THAT WILL HELP FORCE THE LOW LEVEL FLOW
TO FUNNEL AROUND THE MOUNTAINOUS TERRAIN OF THE ISLANDS. WINDS WILL
BE STRONG ENOUGH TO KEEP GALES IN THE ALENUIHAHA CHANNELS.

THE GLOBAL MODELS ARE IN CLOSE AGREEMENT FOR THE NEXT SEVERAL DAYS.
THE SURFACE HIGH IS FORECAST TO MOVE OFF TO THE EAST FAIRLY RAPIDLY
SO OUR SURFACE WINDS WILL WEAKEN THROUGH TUESDAY NIGHT. MEANWHILE...
A RIDGE ALOFT WILL BUILD OVER THE AREA FROM THE WEST...KEEPING THE
ATMOSPHERE STABLE AND RAINFALL LIGHT THROUGH MID-WEEK.

A NORTHEAST TO SOUTHWEST SURFACE TROUGH ABOUT 1000 MILES EAST OF THE
BIG ISLAND IS FORECAST TO MOVE WEST AT AROUND 10 MPH. THIS TROUGH
WILL COLLECT SOME MOISTURE FROM THE FRONT THAT CROSSED THE ISLANDS
YESTERDAY AND FROM THE REMNANT OF HURRICANE KENNETH. AS THE TROUGH
APPROACHES FROM THE EAST THE TRADE WINDS WILL BACK TO A MORE
NORTHERLY DIRECTION AND STRENGTHEN ON WEDNESDAY. LOW LEVEL MOISTURE
FROM THE TROUGH WILL MOVE OVER THE ISLANDS AS EARLY AS WEDNESDAY
NIGHT AND RAINFALL WILL INCREASE. AT THE SAME TIME...A FRONT WILL
APPROACH FROM THE NORTHWEST. THE ECMWF SHOWS THE TRAILING END OF THE
FRONTAL BAND REACHING THE ISLANDS THURSDAY...WHILE THE GFS SHOWS THE
BAND STALLING NORTHWEST OF KAUAI. BOTH MODELS SHOW THE DRY WEATHER
ENDING BY THURSDAY NIGHT.

WINDS OVER THE MAIN HAWAIIAN ISLANDS MAY WEAKEN AND SHIFT OUT OF THE
SOUTHEAST NEXT WEEKEND AS ANOTHER FRONT APPROACHES FROM THE
NORTHWEST. THAT IS STILL FAR ENOUGH OUT TO HAVE MUCH CONFIDENCE IN
THE COMPUTER MODEL SOLUTIONS.

&&

.MARINE...
WINDS WILL REMAIN ABOVE THE 25 KT THRESHOLD FOR ALL COASTAL WATERS
AND AT GALE FORCE IN THE ALENUIHAHA CHANNEL TONIGHT. WINDS WILL
DIMINISH FAIRLY RAPIDLY STARTING TONIGHT AS THE SURFACE HIGH MOVES
RAPIDLY EAST. WE EXPECT TO DROP THE GALE WARNING TOMORROW MORNING...
WHILE SMALL CRAFT ADVISORIES WILL LIKELY CONTINUE FOR THE WINDIER
ZONES AROUND THE BIG ISLAND AND MAUI THROUGH EARLY TUESDAY MORNING.

A LARGE NORTH NORTHWEST SWELL WILL CONTINUE TO PRODUCE HIGH SURF
ALONG NORTH AND WEST FACING SHORES OVERNIGHT. THE SWELL SHOULD
DIMINISH FAIRLY QUICKLY OVERNIGHT SO WE EXPECT TO BE ABLE TO DROP
THE HIGH SURF ADVISORY FOR NORTH FACING SHORES TOMORROW MORNING. THE
STRONG NORTHEAST WINDS WILL CONTINUE TO PRODUCE ROUGH SURF ALONG
EAST FACING SHORES THROUGH MONDAY EVENING...SO THE ADVISORY WILL
LIKELY CONTINUE FOR EAST FACING SHORES TILL THEN.

&&

.AVIATION...
AIRMET TANGO WILL LIKELY REMAIN UP TONIGHT...AND POSSIBLY LONGER...
FOR MODERATE LOW LEVEL TURBULENCE SOUTH THROUGH WEST OF THE
MOUNTAINS. THE TERMINALS SHOULD REMAIN VFR TONIGHT.

&&

.FIRE WEATHER...
STRONG NORTHEAST WINDS AND DRY AIR ARE LIKELY TO PRODUCE CONDITIONS
FAVORABLE FOR RAPID FIRE GROWTH TODAY...SO THE RED FLAG WARNING
THROUGH 600 PM TODAY HAS A GOOD CHANCE OF VERIFYING.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING THROUGH 600 PM THIS EVENING.

HIGH SURF ADVISORY TILL 600 PM THIS EVENING FOR NORTH AND EAST
FACING SHORES OF LANAI AND THE BIG ISLAND AND NORTH...EAST AND
WEST FACING SHORES OF THE OTHER ISLANDS.

GALE WARNING THROUGH EARLY MONDAY MORNING FOR THE ALENUIHAHA CHANNEL.

SMALL CRAFT ADVISORY THROUGH EARLY MONDAY EVENING FOR THE REST OF
THE HAWAIIAN WATERS.

&&

DONALDSON