Winter Storm Warning 2, NWS Honolulu, HI

459 
WWHW40 PHFO 191334
WSWHFO

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE HONOLULU HI
334 AM HST WED JAN 19 2011

...WINTER STORM WARNING FOR SUMMITS AND UPPER SLOPES OF HALEAKALA
MAUNA KEA AND MAUNA LOA...

.A COLD LOW ALOFT WILL PASS OVER THE BIG ISLAND AND MAUI TODAY...
BRINGING WINTRY WEATHER TO ELEVATIONS ABOVE 9000 FEET.

HIZ022-028-200245-
/O.CON.PHFO.WS.W.0002.000000T0000Z-110120T0400Z/
HALEAKALA SUMMIT-BIG ISLAND SUMMITS-
INCLUDING...HALEAKALA NATIONAL PARK ABOVE 6000 FEET...
MAUNA LOA AND MAUNA KEA ABOVE 8000 FEET
334 AM HST WED JAN 19 2011

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 PM HST THIS
EVENING...

A WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 PM HST THIS
EVENING. 

THIS MORNING...THE PRIMARY THREAT OVER THE UPPER ELEVATIONS OF
HALEAKALA...MAUNA KEA AND MAUNA LOW WILL BE FREEZING RAIN AND
ICING...WHICH WILL MAKE TRAVEL TO THE SUMMITS VERY DANGEROUS.
SIGNIFICANT SNOWFALL IS ALSO EXPECTED BY THIS AFTERNOON...ESPECIALLY
OVER THE BIG ISLAND SUMMITS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF FREEZING
RAIN...SNOW...AND ICE ARE EXPECTED OR OCCURRING. THIS WILL MAKE
TRAVEL VERY HAZARDOUS OR IMPOSSIBLE.

&&

$$

BIRCHARD

968 
WWHW40 PHFO 200142
WSWHFO

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE HONOLULU HI
342 PM HST WED JAN 19 2011

...WINTER STORM WARNING FOR HALEAKALA...MAUNA LOA AND MAUNA KEA IS
CANCELLED...

HIZ022-028-200245-
/O.CAN.PHFO.WS.W.0002.000000T0000Z-110120T0400Z/
HALEAKALA SUMMIT-BIG ISLAND SUMMITS-
INCLUDING...HALEAKALA NATIONAL PARK ABOVE 6000 FEET...
MAUNA LOA AND MAUNA KEA ABOVE 8000 FEET
342 PM HST WED JAN 19 2011

...WINTER STORM WARNING IS CANCELLED...

THE NATIONAL WEATHER SERVICE IN HONOLULU HAS CANCELLED THE WINTER
STORM WARNING. 

SNOW FLURRIES ARE STILL POSSIBLE OVER THE SUMMITS OF MAUNA LOA AND
MAUNA KEA...BUT SIGNIFICANT SNOW ACCUMULATION IS NOT LIKELY. THE
SUMMIT OF MOUNT HALEAKALA IS CLEARING OUT...AND RAIN OR SNOW IS
NOT EXPECTED THERE.

$$

CRAIG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1022 PM HST TUE JAN 18 2011

.UPDATE...
LIGHT RAIN IS NOW REACHING THE GROUND OVER PORTIONS OF OAHU AND
ADJACENT WATERS...FROM THE PERSISTENT MID AND HIGH LEVEL CLOUD
DECK. UPDATED THE FORECAST FOR TONIGHT TO INCLUDE LIGHT RAIN...
MAINLY ALONG A NNE-SSW BAND CENTERED OVER OAHU AND PORTIONS OF MAUI
COUNTY.

&&

.SYNOPSIS...
AN UPPER LEVEL LOW WILL MOVE SOUTH OVER THE ISLAND CHAIN TONIGHT
AND WEDNESDAY...BRINGING A THREAT OF HEAVY SHOWERS AND A CHANCE OF
THUNDERSTORMS...MAINLY FOR MAUI COUNTY AND THE BIG ISLAND. TRADE
WINDS WILL RETURN THURSDAY...AND LAST INTO EARLY NEXT WEEK. A LARGE
WEST NORTHWEST SWELL WILL BUILD ON WEDNESDAY...PEAK AT WARNING
LEVELS THURSDAY...AND LAST INTO THE WEEKEND.

&&

.DISCUSSION...
AN UPPER LEVEL LOW CURRENTLY CENTERED ABOUT 250 MILES N OF HILO WILL
MOVE SSW AND GRADUALLY WEAKEN OVER THE NEXT COUPLE OF DAYS...WITH
THE CORE OF THE LOW EXPECTED TO PASS OVER MAUI COUNTY ON WEDNESDAY.
THE LOW WILL BRING IT/S DESTABILIZING COLD POOL OVER THE ISLANDS...
AND IS ALREADY MAKING IT/S EFFECTS FELT OVER WINDWARD BIG
ISLAND...WHERE THUNDERSTORMS ARE BEING REPORTED...EVEN THOUGH THE
HIGHEST CLOUD TOPS ARE NEAR 25 THOUSAND FEET. WITH LIGHT WINDS...NOT
MUCH IN THE WAY OF A SURFACE TRIGGER IS EXPECTED OVERNIGHT...SO
FORECASTS WERE UPDATED TO KEEP MOST AREAS DRY AND CLOUDY TONIGHT.
BEST CHANCE FOR HEAVY SHOWERS AND THUNDERSTORMS OVERNIGHT APPEARS TO
BE ALONG THE WINDWARD COAST AND ADJACENT NEAR SHORE WATERS OF THE
BIG ISLAND. ON WEDNESDAY...DAYTIME HEATING AND CONVERGENCE OF SEA
BREEZES OVER THE ISLANDS SEEMS LIKE THE MOST LIKELY TRIGGER FOR
HEAVY SHOWERS AND THUNDERSTORMS...AS THE PRESENCE OF THE LOW ALOFT
WILL KEEP SURFACE WINDS LIGHT AND FROM VARIABLE DIRECTIONS...ASIDE
FOR THE POSSIBILITY OF GUSTY WINDS ASSOCIATED WITH CONVECTION.

THE LOW ALOFT IS ALSO FORECAST TO SHARPEN A SURFACE TROUGH OVER
WATERS EAST OF THE ISLANDS ON WEDNESDAY. THIS TROUGH WILL PASS OVER
THE ISLANDS AND WEAKEN WEDNESDAY NIGHT AND THURSDAY...AND AS IT
PASSES...TRADES WILL INCREASE WITH A BRIEF SURGE IN WINDWARD SHOWERS
EXPECTED.

A STABLE ATMOSPHERE WILL RETURN BY FRIDAY WITH THE UPPER LOW WELL
TO OUR SW AND UPPER RIDGING BUILDING TO OUR N. A SURFACE RIDGE
EXTENDING SW FROM A HIGH OFF THE CALIFORNIA COAST WILL BRING TRADE
WINDS TO THE STATE INTO THE WEEKEND. MODERATE TRADE WINDS LOOK TO
BE PRETTY DRY ON SATURDAY. THE W PACIFIC JET STREAM WILL SHIFT S
EARLY NEXT WEEK...SENDING A WEAKENING FRONT TO NEAR KAUAI ON
MONDAY...WHICH IS EXPECTED TO WEAKEN AND DISPLACE THE SUBTROPICAL
RIDGE CLOSER TO THE ISLANDS...CAUSING A DECREASE IN THE TRADES ON
SUNDAY AND MONDAY. RAINFALL LOOKS TO BE MINIMAL UNTIL THE WEAK FRONT
BRINGS INCREASED WINDWARD SHOWERS TO KAUAI LATE MONDAY.

&&

.MARINE...
LATEST OBSERVATIONS FROM BUOY 51101 NW OF KAUAI SHOW DECLINING SWELL
HEIGHT AND PERIOD...ASSOCIATED WITH THE LAST VESTIGES OF THE LARGE
WNW SWELL THAT PEAKED A COUPLE OF DAYS AGO. LONG-PERIOD FORERUNNERS
ASSOCIATED WITH A NEW...GIANT WNW SWELL ARE EXPECTED TO START MOVING
UNDER THE BUOY LATER TONIGHT...AND THE 8 PM OBSERVATION SHOWED THE
FIRST INDICATIONS OF MINIMAL ENERGY IN THE 24 SECOND PERIOD BAND.
THESE LONG-PERIOD FORERUNNERS WILL ARRIVE IN THE ISLANDS ON
WEDNESDAY...WITH THE SWELL GETTING PROGRESSIVELY LARGER THROUGH THE
DAY. A HIGH SURF WARNING HAS BEEN ISSUED IN ANTICIPATION OF THIS
SWELL/S ARRIVAL DURING THE DAY WEDNESDAY...AND IT/S EVENTUAL PEAK ON
THURSDAY...WITH A LATER ARRIVAL TIME FOR THE BIG ISLAND.

THE SOURCE LOW IS NEARLY STATIONARY...AND THE FETCH EXPANSIVE...SO
SURF WILL REMAIN ELEVATED FOR SEVERAL DAYS. THE RESULTING SWELL
WILL PRODUCE WARNING LEVEL SURF STARTING WEDNESDAY AFTERNOON ON
KAUAI...AND SPREADING DOWN THE ISLAND CHAIN WEDNESDAY NIGHT AND
THURSDAY. THE SURF DISCUSSION /SRDHFO/ WAS UPDATED EARLIER TODAY...
AND CONTAINS ADDITIONAL INSIGHT INTO THE SWELL...AS WELL AS
PROVIDING SOME HISTORICAL CONTEXT.

DUE TO THE BUILDING SWELL...COMBINED SEAS WILL INCREASE ABOVE THE
THRESHOLD FOR THE ISSUANCE OF A SMALL CRAFT ADVISORY /SCA/ WEDNESDAY
AND WEDNESDAY NIGHT...AND THAT WILL BE INCLUDED WITH THE WEDNESDAY/S
EARLY MORNING COASTAL WATERS FORECAST. A MARINE WEATHER STATEMENT
WILL ALSO BE ISSUED AT THAT TIME AS WELL...HIGHLIGHTING THE THREAT
OF STRONG CURRENTS AND WAVES BREAKING IN HARBOR ENTRANCES THAT ARE
EXPOSED TO THE POWERFUL WNW SWELL.

&&

.AVIATION...
THE LOW ALOFT IS RESPONSIBLE FOR DEEP LAYER TURBULENCE NEAR THE
ISLANDS...WITH THE ASSOCIATED MID AND HIGH LEVEL DECK ALSO RESULTING
IN LIGHT RIME ICING OVER THE ISLANDS. THESE HAZARDS TO AVIATION ARE
EXPECTED TO CONTINUE THROUGH WEDNESDAY.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM MIDNIGHT TONIGHT THROUGH WEDNESDAY AFTERNOON
FOR THE BIG ISLAND AND MAUI.

WINTER STORM WATCH FROM 6 AM WEDNESDAY THROUGH WEDNESDAY AFTERNOON
FOR THE BIG ISLAND SUMMITS.

HIGH SURF ADVISORY UNTIL 6 AM WEDNESDAY FOR THE WEST FACING SHORES
OF THE BIG ISLAND.

HIGH SURF WARNING STARTING WEDNESDAY AFTERNOON FOR NORTH AND WEST
FACING SHORES OF NIIHAU KAUAI AND OAHU...NORTH FACING SHORES OF
MOLOKAI AND MAUI.

&&

BIRCHARD