Special Marine Warning 13, NWS Honolulu, HI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1000 AM HST WED JAN 12 2011

.SYNOPSIS...
A WET AND WINDY WEATHER PATTERN WILL PREVAIL OVER THE STATE THROUGH
MUCH OF THURSDAY. GUSTY SOUTHERLY WINDS...HEAVY RAINS AND EVEN SOME
THUNDERSTORMS ARE EXPECTED AS A COLD FRONT APPROACHES FROM THE WEST.
THE COLD FRONT WILL STALL AND WEAKEN OVER THE WESTERN PORTION OF THE
STATE THURSDAY. AFTER THE FRONT DISSIPATES...CONDITIONS WILL
GRADUALLY BECOME DRIER FRIDAY AND SATURDAY WITH LIGHTER SOUTHERLY
WINDS. ANOTHER COLD FRONT IS FORECAST FOR LATE SUNDAY OR EARLY
MONDAY.

&&

.DISCUSSION...
WATER VAPOR IMAGERY SHOWS A SHARP UPPER LEVEL TROUGH ABOUT 500 MILES
NORTHWEST OF KAUAI...WITH AN ASSOCIATED COLD FRONT ABOUT 300 MILES
NORTHWEST OF KAUAI. WHILE THE FRONT IS WELL WEST OF THE STATE...
MOISTURE LEFT BEHIND BY THE PREVIOUS FRONT LINGERS ACROSS THE
ISLANDS. THE MORNING POES/AMSU BLENDED PRECIPITABLE WATER IMAGERY
SHOWS PW VALUES OF CLOSE TO 2 INCHES ACROSS THE ISLANDS. REGIONAL
RADARS CONTINUE TO SHOW STRONG CONVECTION OVER THE COASTAL WATERS...
WITH SATELLITE IMAGERY SHOWING ADDITIONAL COLD CLOUD TOPS DEVELOPING
UPSTREAM TO THE SOUTH AND WEST OF THE STATE.

THE EARLY MORNING CONVECTION DEVELOPED ALONG THE LEADING EDGE OF THE
MOIST AXIS...IN THE AREA OF STRONGEST MOISTURE ADVECTION. THE
AIRMASS WILL REMAIN MOIST AND UNSTABLE ACROSS THE ISLANDS INTO
TOMORROW. RADAR VAD WIND PROFILES SHOW STRONG SOUTHERLY WINDS OF UP
TO 50 KNOTS IN THE LOW LEVELS. THE UNSTABLE AIRMASS COMBINED WITH
STRONG VERTICAL WIND SHEAR WILL LEAD TO POTENTIAL SEVERE WEATHER.
EARLY MORNING STORMS OVER THE OFFSHORE WATERS SHOWED STRONG ROTATION
AT TIMES. WHILE THE CONVECTION MAY SHOW A DIURNAL DOWNWARD TREND
THIS MORNING...IT MAY FLARE UP AGAIN WITH HEATING THIS AFTERNOON.
THEREFORE WE HAVE ISSUED A SEVERE THUNDERSTORM WATCH THROUGH THIS
AFTERNOON FOR AREAS FROM OAHU WESTWARD.

IN ADDITION TO SEVERE CONVECTION...THE THREAT OF FLASH FLOODING WILL
REMAIN AN ISSUE TODAY THROUGH THURSDAY AS THE MOIST AND UNSTABLE
AIRMASS OVER THE STATE INTERACTS WITH STRONG DYNAMICS ASSOCIATED
WITH THE UPPER TROUGH AND SLOWING COLD FRONT. THE SLOW MOVING COLD
FRONT WILL STALL OVER THE WESTERN PORTION OF THE STATE AND IS ALSO
OF CONCERN AS THIS WILL TEND TO FOCUS HEAVY RAINFALL ACCUMULATIONS
WHERE IT STALLS EARLY THURSDAY. LATEST INDICATIONS THAT THE FRONT
WILL STALL NEAR KAUAI OR POSSIBLY AS FAR EAST AS OAHU BY THURSDAY
MORNING.

STRONG GUSTY WINDS WILL CONTINUE THROUGH TONIGHT AS WELL...AND A
WIND ADVISORY REMAINS IN EFFECT FOR MUCH OF THE STATE. WINDS WILL BE
STRONGEST ACROSS NORTHERN SECTIONS OF THE ISLANDS...WHERE THE
SOUTHERLY WINDS WILL DOWNSLOPE AND ACCELERATE. WIND GUSTS OF 45 TO
50 MPH HAVE BEEN MEASURED FROM KAUAI TO MAUI.

WHILE THE HEAVIEST RAIN HAS BEEN FOCUSED FROM MAUI WESTWARD...MIDDLE
AND HIGH LEVEL CLOUDS ARE ALREADY MOVING ACROSS THE BIG ISLAND.
OBSERVATIONS ATOP MAUNA KEA SHOW SATURATED CONDITIONS WITH
TEMPERATURES AROUND -2C TO -3C. WEB CAMS SHOW CLOUDS AT SUMMIT
LEVEL...WITH POSSIBLE RIME ICING BUT NO PRECIPITATION AT THIS POINT.
WITH HEAVIER SHOWERS EXPECTED TO DEVELOP THIS AFTERNOON AND
TONIGHT...THERE REMAINS THE POTENTIAL FOR SIGNIFICANT SNOWFALL
ACCUMULATIONS GREATER THAN 12 INCHES THROUGH THROUGH THURSDAY.
COMBINED WITH GUSTY WINDS...THIS WILL RESULT IN CONSIDERABLE BLOWING
AND DRIFTING SNOW AND NEAR WHITEOUT CONDITIONS.

THE COLD FRONT WILL WEAKEN THURSDAY AFTERNOON AND NIGHT AS THE STORM
ENERGY QUICKLY LIFTS OFF TO THE NORTHEAST. BY FRIDAY THE SHOWERS AND
WINDS WILL DECREASE GOING INTO THE FIRST HALF OF THE WEEKEND.

THE NEXT COLD FRONT IS FORECAST TO MOVE THROUGH THE ISLAND CHAIN
LATE SUNDAY INTO EARLY MONDAY...BUT APPEARS WEAKER WITH LESS WIND
AND RAINFALL EXPECTED.

&&

.MARINE...
FOR THE NORTHERN OFFSHORE WATERS...THE SOUTHERLY WINDS REACHING 35
KNOTS AHEAD OF THE APPROACHING COLD FRONT TODAY HAS NECESSITATED THE
CONTINUANCE OF THE GALE WARNING.

ACROSS THE COASTAL WATERS...THE STRONG SOUTH SOUTHWEST WINDS UP TO
30 KNOTS WILL RESULT IN SMALL CRAFT ADVISORY CONDITIONS THROUGH
TONIGHT. IN ADDITION TO THE WIND WAVES...A LARGE NORTHWEST SWELL
WILL ALSO CONTRIBUTE TO COMBINED SEAS OF 10 FEET OR GREATER.

THE CURRENT NORTHWEST SWELL WILL BEGIN TO DIMINISH TONIGHT...AND
THE HIGH SURF ADVISORY WILL LIKELY END BY THIS EVENING. A NEW LARGE
WEST NORTHWEST SWELL ARRIVING FRIDAY NIGHT MAY PRODUCE SURF HEIGHTS
NEAR HIGH SURF WARNING THRESHOLDS ALONG NORTH AND WEST FACING SHORES
SATURDAY. ELSEWHERE...THE STRONG SOUTH TO SOUTHWEST WINDS WILL AGAIN
GENERATE ROUGH...SHORT PERIOD SURF ALONG SOUTH AND WEST FACING
SHORES THROUGH THURSDAY.

&&

.AVIATION...
FRONT 225 NM WNW PHBK MOV ESE 25 KT. THICK LAYERED CLOUDS WITH
EMBEDDED CB AHEAD OF THE FRONT COVER THE MAIN HAWAIIAN ISLANDS.
THERE WILL BE SCT TSTMS...STRONG S WINDS...MOD ICE...MOD TURB
WIDESPREAD MVFR AND OCNL IFR COND OVER THE MAIN HAWAIIAN ISLANDS
THROUGH THURSDAY MORNING.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 6 PM HST THURSDAY FOR ALL HAWAIIAN ISLANDS.

WINTER STORM WARNING UNTIL 6 PM HST THURSDAY FOR THE BIG ISLAND
SUMMITS.

WIND ADVISORY UNTIL 6 AM HST THURSDAY FOR HALEAKALA SUMMIT...BIG
ISLAND SUMMITS...AND MOST AREAS OF OTHER ISLANDS EXCEPT WEST AND
SOUTH SHORES OF KAUAI OAHU AND MAUI.

HIGH SURF ADVISORY UNTIL 6 PM HST WEDNESDAY FOR NORTH AND WEST
FACING SHORES OF NIIHAU...KAUAI...OAHU AND MOLOKAI...NORTH FACING
SHORES OF MAUI...AND WEST FACING SHORES OF THE BIG ISLAND.

SMALL CRAFT ADVISORY UNTIL 6 AM HST THURSDAY FOR ALL COASTAL WATERS.

&&

PUBLIC/MARINE...BRAVENDER/BRENCHLEY
AVIATION...DONALDSON

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HONOLULU HI
1027 AM HST WED JAN 12 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0955 AM     HIGH SURF        4 SSE KAILUA-KONA       19.59N 155.97W
01/12/2011                   HAWAII IN HAWAII   HI   EMERGENCY MNGR

            OCEAN SAFETY DIVISION LIFEGUARDS REPORTS THE CLOSURE OF
            KAHALUU AND LAALOA /MAGIC SANDS/ IN KONA DUE TO HIGH
            SURF.

0955 AM     HIGH SURF        4 SSE KAILUA-KONA       19.59N 155.97W
01/12/2011                   HAWAII IN HAWAII   HI   EMERGENCY MNGR

            THE OCEAN SAFETY DIVISION REPORTS THE CLOSURE OF KAHALUU
            AND LAALOA /MAGIC SANDS/ BEACH PARKS IN KONA DUE TO HIGH
            SURF.

&&

RTANABE