High Surf in Hawaii, August 1 to 3, 2013

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
830 PM HST WED JUL 31 2013

.SYNOPSIS...
A TRADE WIND WEATHER REGIME WILL CONTINUE THROUGH THE NEXT SEVERAL
DAYS. WIND SPEEDS WILL DECREASE A LITTLE ON THURSDAY...THEN EASING
EVEN MORE EARLY NEXT WEEK. DRIER CONDITIONS ARE EXPECTED WITH
PASSING LOW CLOUDS AND BRIEF SHOWERS FAVORING WINDWARD AND MAUKA
AREAS. TRADE SHOWERS WILL BE MORE ACTIVE DURING THE NIGHT AND
MORNING HOURS.

&&

.DISCUSSION...
TRADES ARE GRADUALLY INCREASING ACROSS THE AREA...WITH BREEZY
PERIODS EXPECTED AS HIGH PRESSURE INTENSIFIES FAR TO THE NE OF THE
ALOHA STATE. THIS HIGH WILL ALSO USHER A DRIER AIR MASS INTO THE
REGION DURING THE NEXT COUPLE OF DAYS. LATEST MIMIC/MODEL PWAT
ANALYSES SHOWS A NOTICEABLE DECREASE IN PWAT VALUES JUST E OF THE
ISLANDS...DROPPING TO AROUND 1 INCH OR LESS. SHOWER ACTIVITY WILL
THEN DECREASE AS THE DRIER AIR MASS ESTABLISHES.

A WIND ADVISORY REMAINS IN EFFECT FOR PORTIONS OF MAUI AND THE BIG
ISLAND...INCLUDING THE SUMMITS. THE TRADES WILL WEAKEN A LITTLE AND
DROP BELOW ADVISORY LEVELS BY THU. THE CRITERIA FOR ISSUING WIND
ADVISORIES AND WARNINGS FOR THE SUMMITS IS SET TO CHANGE
TOMORROW...AND AN UPDATED PUBLIC INFORMATION STATEMENT...PNSHFO...
HAS BEEN SENT TO ADDRESS THIS. IF A WIND ADVISORY OR HIGH WIND
WARNING IS IN EFFECT FOR THE SUMMITS WHEN THE CRITERIA ARE SCHEDULED
TO CHANGE...THE EXISTING ADVISORY/WARNING WILL REMAIN IN PLACE UNTIL
WINDS SUBSIDE. SUBSEQUENT ADVISORIES AND WARNINGS WILL THEN BE BASED
ON THE UPDATED CRITERIA.

THE AFOREMENTIONED HIGH FAR NNE OF THE ISLANDS WILL SUPPORT MODERATE
TO LOCALLY FRESH TRADES UNTIL EARLY NEXT WEEK. A FRONT PASSING
FAR N OF THE ISLANDS WILL WEAKEN PRESSURE GRADIENTS ACROSS THE
ISLAND CHAIN AND BRING LIGHTER TRADE WINDS. EXPECT LOW CLOUDS AND
SHOWERS TO FOCUS OVER WINDWARD AND MOUNTAIN AREAS...WITH MORE
ACTIVE PERIODS DURING THE NIGHT AND MORNING HOURS.

THE OFFICIAL FORECAST FROM NHC INDICATES THAT HURRICANE GIL...
CURRENTLY CENTERED ABOUT 2225 MILES ESE OF HILO...WILL BE 1200 MILES
SE OF THE BIG ISLAND AS A WEAKENING TROPICAL STORM ON MONDAY. IT
REMAINS MUCH TOO EARLY TO DETERMINE THE TRACK THAT TROPICAL CYCLONE
GIL MAY TAKE ACROSS THE CENTRAL N PACIFIC NEXT WEEK.

&&

.AVIATION...
GUSTY TRADE WINDS TO CONTINUE WITH LOW LEVEL TURBULENCE ON THE LEE
SIDE OF THE MOUNTAINS. EXPECT ISOL MVFR CONDITIONS ALONG WINDWARD
SLOPES DUE TO CLD AND SHRA. OTHERWISE...VFR CONDITIONS TO PREVAIL AT
THE TERMINALS.

&&

.MARINE...
THE TRADES ARE BRINGING SHORT-PERIOD WIND WAVES TO E FACING
SHORES THROUGH THE WEEKEND...BUT NOW THAT THE SWELL GENERATED BY
FLOSSIE HAS DIMINISHED...HEIGHTS WILL REMAIN BELOW ADVISORY LEVELS
IN MOST AREAS. EARLIER SE BIG ISLAND SURF OBSERVATIONS INDICATED
SURF HEIGHTS AS HIGH AS 10 FEET AT BEACHES S OF CAPE
KUMUKAHI...PROMPTING AND A HIGH SURF ADVISORY. THIS HIGH SURF IS
LIKELY THE RESULT OF A COMBINATION OF TRADE WIND SURF AND LONGER
PERIOD S AND SE SWELLS...AND MAY NEED TO BE EXTENDED.

A LONG-PERIOD SSW SWELL IS EXPECTED TO BUILD INTO TOMORROW...AND
PEAK BELOW ADVISORY LEVELS ON THU...BUT THE SWELL HAS BEEN SLOW
TO ARRIVE THUS FAR. THE SURF DISCUSSION...SRDHFO...HAS BEEN UPDATED
TODAY...AND HAS THE LATEST FORECAST PHILOSOPHY.

AS BREEZY TRADE WINDS PREVAIL ACROSS THE ISLANDS TONIGHT...A SMALL
CRAFT ADVISORY /SCA/ WILL REMAIN IN EFFECT FOR WINDIER COASTAL
WATERS AROUND MAUI AND BIG ISLAND. SOME ZONES MAY BE TRIMMED OUT OF
THE SCA TOMORROW...BUT THE SCA FOR THE WINDIEST ZONES HAS BEEN
EXTENDED.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 6 AM HST THURSDAY FOR LANAI-KAHOOLAWE-
HALEAKALA SUMMIT-SOUTH BIG ISLAND-BIG ISLAND NORTH AND EAST-
KOHALA-BIG ISLAND INTERIOR-BIG ISLAND SUMMITS.

HIGH SURF ADVISORY UNTIL 6 AM HST THURSDAY FOR SOUTH BIG ISLAND-
BIG ISLAND NORTH AND EAST.

SMALL CRAFT ADVISORY UNTIL 6 AM HST THURSDAY FOR KAIWI CHANNEL-
MAUI COUNTY WINDWARD WATERS-BIG ISLAND WINDWARD WATERS.

SMALL CRAFT ADVISORY UNTIL 6 AM HST FRIDAY FOR MAALAEA BAY-
PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND LEEWARD WATERS-BIG
ISLAND SOUTHEAST WATERS.

&&

DISCUSSION/MARINE...REYNES
AVIATION...MORRISON