High Surf in Hawaii, December 2 to 4, 2010

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
438 AM HST THU DEC 2 2010

.SYNOPSIS...
STRONG BREEZES ARE EXPECTED ACROSS THE STATE TODAY THROUGH FRIDAY
NIGHT AS A STRONG SURFACE HIGH FAR TO THE NORTH DIGS SOUTHWARD.
SHOWERS WILL INCREASE TODAY THROUGH EARLY FRIDAY MORNING AS A COLD
FRONT CROSSES THE STATE MOVING FROM NORTHEAST TO SOUTHWEST. SOME
SHOWERS ALONG THE FRONT MAY BE LOCALLY HEAVY AT TIMES. WHILE SHOWERS
WILL FOCUS OVER WINDWARD AND MOUNTAIN AREAS...MANY OF THE SHOWERS
WILL BLOW TO LEEWARD LOCATIONS BY THE BREEZY TRADE WINDS. THE
ATMOSPHERE WILL BE DRIER AND MORE STABLE ON FRIDAY THROUGH NEXT
WEEK...LEADING TO LESS ACTIVE TRADE SHOWERS.

&&

.DISCUSSION...
INFRARED SATELLITE SHOWS A NEARLY STATIONARY UPPER LOW 1275 MILES
WEST OF KAUAI THIS MORNING. A PERSISTENT AREA OF DENSE LAYERED
CLOUDS WITH EMBEDDED THUNDERSTORMS LIES BETWEEN THE LOW AND THE
HAWAIIAN ISLANDS...BUT THIS AREA OF SHOWERS AND THUNDERSTORMS WILL
NOT MOVE ACROSS THE MAIN HAWAIIAN ISLANDS. INSTEAD THEY WILL STAY IN
PLACE THROUGH THE NEXT COUPLE OF DAYS AND PUSH CIRRUS CLOUDS
ACROSS THE STATE FROM THUNDERSTORM TOP BLOW OFF. THIS AREA OF
CONVECTION WILL VERY SLOWLY DRIFT WESTWARD THIS WEEKEND AS THE UPPER
LOW LIFTS FARTHER TO THE NORTHWEST.

A STRONG SURFACE HIGH IS CURRENTLY ABOUT 1240 MILES NORTH OF
OAHU...AND WILL MOVE SLOWLY SOUTHEAST OVER THE NEXT COUPLE DAYS. THE
PRESSURE GRADIENT WILL CONTINUE TO TIGHTEN AS A RESULT...BRINGING
TRADE WINDS UP TO STRONG BREEZES TODAY WHICH WILL LAST THROUGH
FRIDAY NIGHT. A WIND ADVISORY IS IN EFFECT FOR THE TYPICALLY WINDIER
ZONES EXPOSED TO THE TRADES ON MAUI AND THE BIG ISLAND. HALEAKALA
SUMMIT...LANAI AND KAHOOLAWE ARE ALSO INCLUDED. OTHER LAND ZONES
MAY BE CLOSE TO ADVISORY LEVELS AND WILL BE ADDED TO THE
ADVISORY IF CONDITIONS WARRANT. WINDS WILL DECREASE THIS WEEKEND AS
THE HIGH WEAKENS AND MOVES CLOSER TO THE STATE. THE PRESSURE
GRADIENT WILL WEAKEN AS A RESULT...AND TRADES WILL DECREASE TO FRESH
BREEZES BY SATURDAY...AND THEN MODERATE WINDS SUNDAY THROUGH THE
FIRST HALF OF NEXT WEEK.

A COLD FRONT CURRENTLY 150 MILES NORTH OF THE STATE IS APPROACHING
THE ISLANDS AT 15 MPH. SHOWER COVERAGE IS EXPECTED TO CONTINUE TO
TREND WETTER TODAY AS THE LEADING EDGE OF THE ASSOCIATED CLOUD BAND
MOVES ONTO THE ISLANDS THIS MORNING. AMSU/SSMI SATELLITE
PRECIPITABLE WATER /PW/ SHOWS VALUES AROUND 1.6 INCHES JUST
UPSTREAM. THE 12Z SOUNDINGS AT HILO AND LIHUE SHOW PW VALUES OF 1.3
TO 1.5 INCHES. TODAY THROUGH FRIDAY NIGHT...WIDESPREAD SHOWERS ARE
EXPECTED AS THE FRONT MOVES ACROSS THE ISLANDS...WITH SHOWERS
FOCUSING OVER WINDWARD AND MOUNTAIN SECTIONS. EXPECT MANY OF THESE
SHOWERS TO CROSS OVER INTO LEEWARD AREAS AS WELL DUE TO THE STRONG
TRADES. THE ATMOSPHERE IS ALSO SOMEWHAT UNSTABLE...AS INDICATED BY
THE ERODED INVERSIONS ON THE 12Z SOUNDINGS FROM LIHUE AND HILO.
BECAUSE OF THIS...THERE IS A POSSIBILITY OF LOCALLY HEAVY RAINFALL
THROUGH TONIGHT. THE FRONT IS EXPECTED TO PASS SOUTH OF THE ISLANDS
BY EARLY FRIDAY MORNING AND CONDITIONS WILL BEGIN TO DRY OUT DURING
THE DAY FRIDAY.

FRIDAY AFTERNOON INTO NEXT WEEK...CONDITIONS WILL BECOME
DRIER...WITH COMPUTER MODELS SHOWING BELOW NORMAL PRECIPITABLE
WATERS AND RAINFALL COVERAGE. STABILITY WILL ALSO STRENGTHEN ACROSS
THE STATE AS A RIDGE ALOFT WILL DOMINATE. THEREFORE...LESS ACTIVE
TRADE SHOWERS ARE EXPECTED THIS WEEKEND THROUGH EARLY NEXT WEEK.
SHOWERS WILL FOCUS OVER WINDWARD AND MOUNTAIN AREAS WITH THE TRADES
CONTINUING.

&&

.AVIATION...
STRONG HIGH PRES N OF THE AREA WILL MAINTAIN 15-20KT TRADES ACRS THE
AREA THROUGH THE FORECAST PERIOD. A DISSIPATING CDFNT N OF THE STATE
WILL BRING TEMPO MVFR CONDITIONS TO WINDWARD AREAS TODAY AND
TONIGHT. THE TRADES WILL CONTINUE TO PRODUCE LLVL TURB LEE OF THE
MT. ADDITIONALLY HIGH BKN-OVC CI WILL BE AFFECTING THE AREA...MAINLY
W.

&&

.MARINE...
A HIGH SURF ADVISORY IS IN EFFECT FOR EAST FACING SHORES OF ALL
ISLANDS EXCEPT LANAI AND KAHOOLAWE UNTIL SATURDAY MID-MORNING DUE TO
TRADE WIND DRIVEN SURF. WINDS ARE EXPECTED TO INCREASE ENOUGH WHERE
GALES WILL BE POSSIBLE IN THE TYPICALLY WINDY COASTAL WATERS
NEAR MAUI AND THE BIG ISLAND AND A GALE WATCH IS IN EFFECT FOR THESE
AREAS. AT THE VERY LEAST...THESE GALE WATCH ZONES WILL STILL
EXPERIENCE SMALL CRAFT ADVISORY CONDITIONS THROUGH FRIDAY AFTERNOON.
A DECISION WILL BE MADE TODAY WHETHER TO UPGRADE TO WARNINGS FOR
TONIGHT OR PUSH BACK DOWN TO SMALL CRAFT ADVISORIES. ALL OTHER
COASTAL WATER ZONES HAVE SMALL CRAFT ADVISORIES LASTING THROUGH
FRIDAY AFTERNOON.

A SMALL...SHORT PERIOD NORTH SWELL WILL PEAK TODAY AND SLOWLY
DECLINE THROUGH SATURDAY.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY IN EFFECT UNTIL 6 PM HST FRIDAY FOR MAUI LEEWARD
WEST...MAUI CENTRAL VALLEY...LEEWARD HALEAKALA...HALEAKALA
SUMMIT...LANAI...KAHOOLAWE...SOUTH BIG ISLAND...BIG ISLAND NORTH
AND EAST...KOHALA BIG ISLAND AND BIG ISLAND INTERIOR.

HIGH SURF ADVISORY UNTIL 6 AM HST SATURDAY FOR EAST FACING SHORES OF
NIIHAU...KAUAI...OAHU...MOLOKAI...MAUI AND THE BIG ISLAND.

GALE WATCH FROM 6 PM HST TODAY UNTIL 6 PM HST FRIDAY FOR PAILOLO
CHANNEL...MAALAEA BAY...ALENUIHAHA CHANNEL AND WATERS SOUTH OF THE
BIG ISLAND.

SMALL CRAFT ADVISORY UNTIL 6 PM HST TODAY FOR PAILOLO
CHANNEL...MAALAEA BAY...ALENUIHAHA CHANNEL AND WATERS SOUTH OF THE
BIG ISLAND.

SMALL CRAFT ADVISORY UNTIL 6 PM HST FRIDAY FOR ALL OTHER COASTAL
WATERS.

&&

DISCUSSION/MARINE...FOSTER
AVIATION...MORRISON