High Surf in Hawaii, February 15 to 18, 2012

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
323 PM HST WED FEB 15 2012

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN IN CONTROL AT THE SURFACE AND ALOFT
THROUGH THE WEEKEND. THE TRADE WINDS WILL RETURN AS THE RIDGE SLIDES
TO THE NORTH OF THE STATE AND STRENGTHENS OVERNIGHT. WINDWARD
FOCUSED SHOWERS WILL RETURN WITH THE TRADE WINDS. AN UPPER-LEVEL
LOW WILL ENHANCE SHOWER ACTIVITY FRIDAY INTO THE WEEKEND.

&&

.DISCUSSION...
THE OVERALL WEATHER PATTERN REMAINS UNCHANGED THIS AFTERNOON WITH
HIGH PRESSURE DOMINATING THE SCENE AT BOTH THE SURFACE AND ALOFT.
THE STRONG UPPER-LEVEL RIDGING TO THE NORTH AND NORTHEAST OF THE
STATE CONTINUES TO STEER THE LOW PRESSURE SYSTEMS STREAMING OFF OF
THE ASIAN CONTINENT TO THE NORTH OF HAWAII...AND THE SURFACE RIDGE
IS KEEPING THE AIRMASS QUITE STABLE. LIGHT SURFACE WINDS OVER THE
SMALLER ISLANDS IS ALLOWING FOR SEA BREEZE DEVELOPMENT AND
INTERIOR ISLAND CLOUD BUILD-UPS THIS AFTERNOON. ISOLATED SHOWERS
REMAIN A POSSIBILITY...HOWEVER...PRECIPITATION ACCUMULATIONS WILL
BE LIGHT.

OVERNIGHT THE SURFACE RIDGE IS EXPECTED TO BEGIN SLIDING TO THE
NORTH ALLOWING FOR A RETURN OF TRADE WIND FLOW BY EARLY THURSDAY.
THE TRADES WILL STRENGTHEN INTO THE WEEKEND WITH SPEEDS MOVING
INTO THE FRESH RANGE BY FRIDAY. THE RETURN OF TRADES WILL USHER IN
ENHANCED WINDWARD AND MAUKA SHOWERS TO ALL ISLANDS. BY FRIDAY AN
UPPER-LEVEL LOW WILL BEGIN TO MIGRATE EAST TO WEST AND APPROACH
THE BIG ISLAND. THIS LOW...ALTHOUGH MODELS ARE HAVING DIFFICULTY
AGREEING ON HOW WELL IT WILL PULL TOGETHER...WILL ENHANCE UPPER-
LEVEL INSTABILITY AND THUS SHOWER ACTIVITY INTO THE WEEKEND. TRADE
WINDS WILL CONTINUE THROUGHOUT THE WEEKEND...SO EVEN WITH THE
UPPER-LOW IN PLACE...PRECIPITATION WILL FAVOR WINDWARD AND MAUKA
AREAS. TEMPERATURES ALOFT WILL BE LOW ENOUGH THAT THE BIG ISLAND
SUMMITS WILL STAND THE CHANCE OF WINTRY PRECIPITATION THROUGHOUT
THE WEEKEND.

BY EARLY NEXT WEEK THERE ARE SOME HINTS THAT THE SURFACE RIDGE
WILL SHIFT SLIGHTLY TO THE EAST ALLOWING FOR A MORE SOUTHEAST
SHIFT IN THE TRADES. IN THE UPPER-LEVELS...THE LOW WILL LINGER IN
THE VICINITY OF HAWAII.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL OVER THE AREA THROUGH TOMORROW. ISOL
MVFR CIGS WILL BE CONFINED TO MAUKA AREAS. NO AIRMETS ARE IN
EFFECT...BUT A STRENGTHENING TRADE WIND FLOW ON THURSDAY MAY
REQUIRE AN AIRMET TANGO SERIES FOR LOW LEVEL TURB.

&&

.MARINE...
A LARGE NORTHWEST SWELL WILL CONTINUE TO BUILD THIS EVENING AND
INTO TOMORROW. A HIGH SURF ADVISORY HAS BEEN ISSUED FOR NORTH AND
WEST SHORES OF NIIHAU KAUAI OAHU AND NORTH SHORES OF MOLOKAI AND
MAUI. THIS SWELL IS EXPECTED TO BE A HIGH END ADVISORY LEVEL SURF
EVENT. ENOUGH WEST COMPONENT IS PRESENT IN THE SWELL TO GENERATE
ADVISORY LEVEL SURF FOR WEST FACING SHORES OF THE BIG ISLAND
BEGINNING AFTER MIDNIGHT TONIGHT.

STRENGTHENING TRADE WINDS TOMORROW COULD ALSO PLAY A FACTOR OVER
THE NEXT FEW DAYS. ROUGH WIND DRIVEN WAVES ALONG EAST FACING SHORES
COULD ALSO PRODUCE HIGH SURF LEVELS.

A SMALL CRAFT ADVISORY /SCA/ REMAINS IN EFFECT AND HAS BEEN
EXTENDED THROUGH FRIDAY FOR ALL HAWAIIAN COASTAL WATERS EXCEPT
MAALAEA BAY DUE TO THE INCOMING SWELL AND INCREASING TRADES. MAALAEA
BAY WILL LIKELY BE ADDED TOMORROW AS THE TRADES STRENGTHEN.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY THROUGH FRIDAY FOR NORTH AND WEST SHORES OF
NIIHAU KAUAI OAHU AND NORTH SHORES OF MOLOKAI AND MAUI.

HIGH SURF ADVISORY FROM MIDNIGHT TONIGHT THROUGH FRIDAY FOR WEST
FACING SHORES OF THE BIG ISLAND.

WIND ADVISORY UNTIL 4 AM HST THURSDAY FOR HALEAKALA SUMMIT.

SMALL CRAFT ADVISORY UNTIL 6 PM HST FRIDAY FOR ALL HAWAIIAN WATERS
EXCEPT MAALAEA BAY-

&&

DISCUSSION/MARINE...CANTIN
AVIATION...WROE