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000
FXHW60 PHFO 191959
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
959 AM HST FRI DEC 19 2014

.SYNOPSIS...
TRADES WILL WEAKEN TO A LAND AND SEA BREEZE PATTERN THIS WEEKEND
AS A COLD FRONT AND UPPER TROUGH APPROACH FROM THE NORTHWEST.
NORTH TO NORTHEAST WINDS AND RAINFALL WILL INCREASE SUNDAY NIGHT
WITH THE POTENTIAL FOR HEAVY RAIN AND THUNDERSTORMS MONDAY INTO
TUESDAY. A GRADUAL RETURN TO TRADE WIND WEATHER IS EXPECTED LATE
NEXT WEEK.

&&

.DISCUSSION...
SATELLITE IMAGERY SHOWS A POSITIVELY-TILTED UPPER LEVEL TROUGH
OVER HAWAII WITH A WEST TO EAST ORIENTED JET STREAM RUNNING JUST
SOUTH OF THE BIG ISLAND INDICATED BY A SWATH OF CIRRUS CLOUDS. AT
THE SURFACE...HIGH PRESSURE IS CENTERED TO THE EAST-NORTHEAST OF
THE STATE PRODUCING MODERATE TO LOCALLY FRESH TRADE WINDS...WITH
THE STRONGEST WINDS NEAR MAUI COUNTY AND THE BIG ISLAND. RADAR IS
SHOWING A FEW PASSING WINDWARD SHOWERS ACROSS OAHU AND MAUI COUNTY
THIS MORNING.

THE SURFACE HIGH IS EXPECTED TO MOVE EAST...AWAY FROM HAWAII...OVER
THE NEXT DAY AND WILL RESULT IN PROGRESSIVELY LESS INFLUENCE ON
OUR WINDS. MEANWHILE...A STRONG COLD FRONT IS APPROXIMATELY 1400
MILES NORTHWEST OF KAUAI MOVING TOWARD US. THE FRONT IS SUPPORTED
BY AN UPPER TROUGH WHICH WILL STAY WITH IT AS APPROACHES THE
HAWAIIAN ISLANDS. WINDS WILL WEAKEN AND VEER SOUTHEASTERLY ON
SATURDAY AHEAD OF THIS SYSTEM...RESULTING IN A SHIFT TO MORE WARM
AND MUGGY CONDITIONS THIS WEEKEND. WINDS WILL LIKELY STAY TOO
EASTERLY NEAR THE BIG ISLAND TO BRING VOG UP TO THE SMALLER
ISLANDS OVER THE WEEKEND. THE WEAKENING FLOW WILL ALSO ALLOW A
SEA AND LAND BREEZE PATTERN TO SET UP SATURDAY AND
SUNDAY...RESULTING IN DAYTIME CLOUD BUILD UPS OVER THE ISLANDS AND
CLEARING OUT AT NIGHT.

THE COLD FRONT WILL ARRIVE SUNDAY NIGHT...FOLLOWED BY THE COLD
POOL ALOFT FROM THE UPPER TROUGH ON MONDAY. NORTHEAST SURFACE
WINDS WILL DRASTICALLY STRENGTHEN ALONG THE FRONTAL BOUNDARY
BEGINNING ON KAUAI SUNDAY NIGHT AND SPREADING EASTWARD DOWN THE
ISLAND CHAIN THROUGH TUESDAY NIGHT. WITH SIGNIFICANT SUPPORT FROM
THE TROUGH ALOFT...THE FRONT WILL HAVE THE OPPORTUNITY TO PRODUCE
LOCALLY HEAVY RAIN AND THUNDERSTORMS.

THE GFS AND ECMWF MODELS ARE NOT CONSISTENT WITH THE AMOUNT OF
INSTABILITY THAT WILL BE PRESENT TO TRIGGER THUNDERSTORMS...LET
ALONE PINPOINTING LOCATIONS ON THE ISLANDS. BOTH MODELS BRING THE
TROUGH AXIS ACROSS KAUAI MONDAY NIGHT...WITH 500 MB TEMPERATURES
NEAR -14 DEGREES CELSIUS FOR THE GFS AND -17 DEGREES CELSIUS FOR
THE ECMWF. AFTER THIS POINT...THE GFS QUICKLY SHIFT THE TROUGH
EASTWARD WHILE THE ECMWF KEEP THE UPPER TROUGH IN THE VICINITY OF
KAUAI AND OAHU THROUGH WEDNESDAY MORNING. FOR NOW...IT LOOKS LIKE
THE NORTHWESTERN END OF THE STATE...NAMELY KAUAI AND OAHU...WOULD
HAVE THE BEST CHANCES FOR THUNDERSTORMS AND HEAVY RAINFALL MONDAY
AND TUESDAY. THE STRONG VERTICAL WIND SHEAR WILL IMPROVE THE
VENTILATION OF ANY THUNDERSTORMS THAT DO DEVELOP...POTENTIALLY
ALLOWING SOME TO BECOME SEVERE...THOUGH REMAINS A BIT EARLY TO
CONSIDER A SEVERE THUNDERSTORM WATCH.

THE UPPER TROUGH AND DEEP MOISTURE ALSO INVITES THE POTENTIAL FOR
SNOW OVER THE SUMMITS OF MAUNA KEA AND MAUNA LOA MONDAY NIGHT
THROUGH TUESDAY.

FROM WEDNESDAY INTO FRIDAY OF NEXT WEEK...THE TROUGH ALOFT WILL LIFT
OUT TOWARD THE NORTHEAST...AND CONDITIONS WILL RETURN TOWARD
CLIMATOLOGY. AS MENTIONED...MODEL SOLUTIONS SHOW THIS PROCESS MAY
BE DRAWN OUT...SO THE RELATIVELY QUICK RETURN OF TRADE-WIND
WEATHER IN THE FORECAST MAY BE TOO OPTIMISTIC...AND SHOULD BE
REEVALUATED AS MORE RUNS BECOME AVAILABLE. TRADE-WIND WEATHER
SHOULD RETURN BY LATE NEXT WEEK.

&&

.AVIATION...
WITH A FRONT APPROACHING AND HIGH PRESSURE NORTH OF THE ISLANDS
BEING PUSHED EASTWARD...TRADES WILL BE REPLACED WITH A MORE
SOUTHEAST WIND FLOW BEGINNING TODAY INTO SATURDAY. BUT THE FRONT
WILL BE WEAKENING AS IT NEARS THE STATE THUS INSTEAD OF STRONG SE
WINDS...MAY SEE MORE LAND/SEA BREEZES FROM TIME TO TIME. THUS EXPECT
MORE INTERIOR CLOUDINESS DURING THE AFTERNOONS ALONG WITH CLEARING
AT NIGHT WITH SLIGHTLY LESS WINDWARD CLOUDINESS. BOTTOM LINE...EXPECT
MOSTLY VFR CONDITIONS TO PREVAIL THROUGH TONIGHT.

MODERATE AND GUSTY TRADE WINDS WILL START TO EASE TODAY THUS WILL BE
ABLE TO DROP THE AIRMET TANGO FOR LOW LEVEL TURB JUST OVER AND LEE
OF MOUNTAINS SOMETIME TODAY. UPPER JET STREAM NEAR AND JUST SOUTH
OF BIG ISLAND DROPPING SOUTHWARD SO WILL ALSO CEASE MENTION OF
POSSIBLE HIGH LEVEL TURB FROM THE TURB SECTION OF AIRMET IN THE NEAR
FUTURE AS WELL.

&&

.MARINE...
THE HIGH SURF ADVISORY FOR NORTH AND WEST FACING SHORES HAS BEEN
CANCELLED THIS MORNING AS OBSERVATIONS AND BUOY REPORTS SHOW BELOW
ADVISORY FACE HEIGHTS. THE NORTHWEST SWELL PEAKED OVERNIGHT AND IS
EXPECTED TO DECLINE TODAY AND SATURDAY...THOUGH CONDITIONS MAY STILL
REMAIN CLOSE TO ADVISORY LEVELS THROUGH THIS AFTERNOON.

A LARGER NORTHWEST SWELL IS EXPECTED TO ARRIVE ON SUNDAY AND WILL
LIKELY BUILD TO HIGH SURF WARNING LEVEL HEIGHTS FOR NORTH AND WEST
FACING SHORES BY LATE IN THE DAY. THIS SWELL SHOULD HAVE ENOUGH
WESTERLY COMPONENT TO IMPACT THE WEST SIDE OF THE BIG ISLAND AS
WELL.

EASTERLY WINDS ARE EXPECTED TO TAPER OFF TONIGHT AND SATURDAY AS A
COLD FRONT APPROACHES THE STATE FROM THE NORTHWEST AND FORCES THE
SUBTROPICAL HIGH FURTHER AWAY FROM HAWAII. WINDS WILL REMAIN
LIGHT ON SUNDAY AS THE NORTHWEST SWELL BUILDS...BUT NORTH TO
NORTHEAST WINDS WILL DRASTICALLY INCREASE SUNDAY NIGHT INTO MONDAY
AS THE SWELL PEAKS. A SMALL CRAFT ADVISORY /SCA/ IS IN EFFECT
THROUGH 6 PM TODAY FOR THE EASTERN HALF OF THE STATE FOR WINDS AND
SEAS. WITH THE SWELL ON THE DECLINE TODAY...THE SCA WILL LIKELY BE
TRIMMED BACK TO SOME OF THE WINDY ZONES AROUND MAUI COUNTY AND THE
BIG ISLAND THROUGH SATURDAY MORNING...THEN DROPPED ALTOGETHER.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 6 PM HST THIS EVENING FOR KAIWI
CHANNEL-MAUI COUNTY WINDWARD WATERS- MAUI COUNTY LEEWARD WATERS-
MAALAEA BAY-PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND WINDWARD
WATERS-BIG ISLAND LEEWARD WATERS-BIG ISLAND SOUTHEAST WATERS.


&&

$$

DISCUSSION/MARINE...FOSTER
AVIATION...FUJII







000
FXHW60 PHFO 191959
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
959 AM HST FRI DEC 19 2014

.SYNOPSIS...
TRADES WILL WEAKEN TO A LAND AND SEA BREEZE PATTERN THIS WEEKEND
AS A COLD FRONT AND UPPER TROUGH APPROACH FROM THE NORTHWEST.
NORTH TO NORTHEAST WINDS AND RAINFALL WILL INCREASE SUNDAY NIGHT
WITH THE POTENTIAL FOR HEAVY RAIN AND THUNDERSTORMS MONDAY INTO
TUESDAY. A GRADUAL RETURN TO TRADE WIND WEATHER IS EXPECTED LATE
NEXT WEEK.

&&

.DISCUSSION...
SATELLITE IMAGERY SHOWS A POSITIVELY-TILTED UPPER LEVEL TROUGH
OVER HAWAII WITH A WEST TO EAST ORIENTED JET STREAM RUNNING JUST
SOUTH OF THE BIG ISLAND INDICATED BY A SWATH OF CIRRUS CLOUDS. AT
THE SURFACE...HIGH PRESSURE IS CENTERED TO THE EAST-NORTHEAST OF
THE STATE PRODUCING MODERATE TO LOCALLY FRESH TRADE WINDS...WITH
THE STRONGEST WINDS NEAR MAUI COUNTY AND THE BIG ISLAND. RADAR IS
SHOWING A FEW PASSING WINDWARD SHOWERS ACROSS OAHU AND MAUI COUNTY
THIS MORNING.

THE SURFACE HIGH IS EXPECTED TO MOVE EAST...AWAY FROM HAWAII...OVER
THE NEXT DAY AND WILL RESULT IN PROGRESSIVELY LESS INFLUENCE ON
OUR WINDS. MEANWHILE...A STRONG COLD FRONT IS APPROXIMATELY 1400
MILES NORTHWEST OF KAUAI MOVING TOWARD US. THE FRONT IS SUPPORTED
BY AN UPPER TROUGH WHICH WILL STAY WITH IT AS APPROACHES THE
HAWAIIAN ISLANDS. WINDS WILL WEAKEN AND VEER SOUTHEASTERLY ON
SATURDAY AHEAD OF THIS SYSTEM...RESULTING IN A SHIFT TO MORE WARM
AND MUGGY CONDITIONS THIS WEEKEND. WINDS WILL LIKELY STAY TOO
EASTERLY NEAR THE BIG ISLAND TO BRING VOG UP TO THE SMALLER
ISLANDS OVER THE WEEKEND. THE WEAKENING FLOW WILL ALSO ALLOW A
SEA AND LAND BREEZE PATTERN TO SET UP SATURDAY AND
SUNDAY...RESULTING IN DAYTIME CLOUD BUILD UPS OVER THE ISLANDS AND
CLEARING OUT AT NIGHT.

THE COLD FRONT WILL ARRIVE SUNDAY NIGHT...FOLLOWED BY THE COLD
POOL ALOFT FROM THE UPPER TROUGH ON MONDAY. NORTHEAST SURFACE
WINDS WILL DRASTICALLY STRENGTHEN ALONG THE FRONTAL BOUNDARY
BEGINNING ON KAUAI SUNDAY NIGHT AND SPREADING EASTWARD DOWN THE
ISLAND CHAIN THROUGH TUESDAY NIGHT. WITH SIGNIFICANT SUPPORT FROM
THE TROUGH ALOFT...THE FRONT WILL HAVE THE OPPORTUNITY TO PRODUCE
LOCALLY HEAVY RAIN AND THUNDERSTORMS.

THE GFS AND ECMWF MODELS ARE NOT CONSISTENT WITH THE AMOUNT OF
INSTABILITY THAT WILL BE PRESENT TO TRIGGER THUNDERSTORMS...LET
ALONE PINPOINTING LOCATIONS ON THE ISLANDS. BOTH MODELS BRING THE
TROUGH AXIS ACROSS KAUAI MONDAY NIGHT...WITH 500 MB TEMPERATURES
NEAR -14 DEGREES CELSIUS FOR THE GFS AND -17 DEGREES CELSIUS FOR
THE ECMWF. AFTER THIS POINT...THE GFS QUICKLY SHIFT THE TROUGH
EASTWARD WHILE THE ECMWF KEEP THE UPPER TROUGH IN THE VICINITY OF
KAUAI AND OAHU THROUGH WEDNESDAY MORNING. FOR NOW...IT LOOKS LIKE
THE NORTHWESTERN END OF THE STATE...NAMELY KAUAI AND OAHU...WOULD
HAVE THE BEST CHANCES FOR THUNDERSTORMS AND HEAVY RAINFALL MONDAY
AND TUESDAY. THE STRONG VERTICAL WIND SHEAR WILL IMPROVE THE
VENTILATION OF ANY THUNDERSTORMS THAT DO DEVELOP...POTENTIALLY
ALLOWING SOME TO BECOME SEVERE...THOUGH REMAINS A BIT EARLY TO
CONSIDER A SEVERE THUNDERSTORM WATCH.

THE UPPER TROUGH AND DEEP MOISTURE ALSO INVITES THE POTENTIAL FOR
SNOW OVER THE SUMMITS OF MAUNA KEA AND MAUNA LOA MONDAY NIGHT
THROUGH TUESDAY.

FROM WEDNESDAY INTO FRIDAY OF NEXT WEEK...THE TROUGH ALOFT WILL LIFT
OUT TOWARD THE NORTHEAST...AND CONDITIONS WILL RETURN TOWARD
CLIMATOLOGY. AS MENTIONED...MODEL SOLUTIONS SHOW THIS PROCESS MAY
BE DRAWN OUT...SO THE RELATIVELY QUICK RETURN OF TRADE-WIND
WEATHER IN THE FORECAST MAY BE TOO OPTIMISTIC...AND SHOULD BE
REEVALUATED AS MORE RUNS BECOME AVAILABLE. TRADE-WIND WEATHER
SHOULD RETURN BY LATE NEXT WEEK.

&&

.AVIATION...
WITH A FRONT APPROACHING AND HIGH PRESSURE NORTH OF THE ISLANDS
BEING PUSHED EASTWARD...TRADES WILL BE REPLACED WITH A MORE
SOUTHEAST WIND FLOW BEGINNING TODAY INTO SATURDAY. BUT THE FRONT
WILL BE WEAKENING AS IT NEARS THE STATE THUS INSTEAD OF STRONG SE
WINDS...MAY SEE MORE LAND/SEA BREEZES FROM TIME TO TIME. THUS EXPECT
MORE INTERIOR CLOUDINESS DURING THE AFTERNOONS ALONG WITH CLEARING
AT NIGHT WITH SLIGHTLY LESS WINDWARD CLOUDINESS. BOTTOM LINE...EXPECT
MOSTLY VFR CONDITIONS TO PREVAIL THROUGH TONIGHT.

MODERATE AND GUSTY TRADE WINDS WILL START TO EASE TODAY THUS WILL BE
ABLE TO DROP THE AIRMET TANGO FOR LOW LEVEL TURB JUST OVER AND LEE
OF MOUNTAINS SOMETIME TODAY. UPPER JET STREAM NEAR AND JUST SOUTH
OF BIG ISLAND DROPPING SOUTHWARD SO WILL ALSO CEASE MENTION OF
POSSIBLE HIGH LEVEL TURB FROM THE TURB SECTION OF AIRMET IN THE NEAR
FUTURE AS WELL.

&&

.MARINE...
THE HIGH SURF ADVISORY FOR NORTH AND WEST FACING SHORES HAS BEEN
CANCELLED THIS MORNING AS OBSERVATIONS AND BUOY REPORTS SHOW BELOW
ADVISORY FACE HEIGHTS. THE NORTHWEST SWELL PEAKED OVERNIGHT AND IS
EXPECTED TO DECLINE TODAY AND SATURDAY...THOUGH CONDITIONS MAY STILL
REMAIN CLOSE TO ADVISORY LEVELS THROUGH THIS AFTERNOON.

A LARGER NORTHWEST SWELL IS EXPECTED TO ARRIVE ON SUNDAY AND WILL
LIKELY BUILD TO HIGH SURF WARNING LEVEL HEIGHTS FOR NORTH AND WEST
FACING SHORES BY LATE IN THE DAY. THIS SWELL SHOULD HAVE ENOUGH
WESTERLY COMPONENT TO IMPACT THE WEST SIDE OF THE BIG ISLAND AS
WELL.

EASTERLY WINDS ARE EXPECTED TO TAPER OFF TONIGHT AND SATURDAY AS A
COLD FRONT APPROACHES THE STATE FROM THE NORTHWEST AND FORCES THE
SUBTROPICAL HIGH FURTHER AWAY FROM HAWAII. WINDS WILL REMAIN
LIGHT ON SUNDAY AS THE NORTHWEST SWELL BUILDS...BUT NORTH TO
NORTHEAST WINDS WILL DRASTICALLY INCREASE SUNDAY NIGHT INTO MONDAY
AS THE SWELL PEAKS. A SMALL CRAFT ADVISORY /SCA/ IS IN EFFECT
THROUGH 6 PM TODAY FOR THE EASTERN HALF OF THE STATE FOR WINDS AND
SEAS. WITH THE SWELL ON THE DECLINE TODAY...THE SCA WILL LIKELY BE
TRIMMED BACK TO SOME OF THE WINDY ZONES AROUND MAUI COUNTY AND THE
BIG ISLAND THROUGH SATURDAY MORNING...THEN DROPPED ALTOGETHER.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 6 PM HST THIS EVENING FOR KAIWI
CHANNEL-MAUI COUNTY WINDWARD WATERS- MAUI COUNTY LEEWARD WATERS-
MAALAEA BAY-PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND WINDWARD
WATERS-BIG ISLAND LEEWARD WATERS-BIG ISLAND SOUTHEAST WATERS.


&&

$$

DISCUSSION/MARINE...FOSTER
AVIATION...FUJII








000
FXHW60 PHFO 191959
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
959 AM HST FRI DEC 19 2014

.SYNOPSIS...
TRADES WILL WEAKEN TO A LAND AND SEA BREEZE PATTERN THIS WEEKEND
AS A COLD FRONT AND UPPER TROUGH APPROACH FROM THE NORTHWEST.
NORTH TO NORTHEAST WINDS AND RAINFALL WILL INCREASE SUNDAY NIGHT
WITH THE POTENTIAL FOR HEAVY RAIN AND THUNDERSTORMS MONDAY INTO
TUESDAY. A GRADUAL RETURN TO TRADE WIND WEATHER IS EXPECTED LATE
NEXT WEEK.

&&

.DISCUSSION...
SATELLITE IMAGERY SHOWS A POSITIVELY-TILTED UPPER LEVEL TROUGH
OVER HAWAII WITH A WEST TO EAST ORIENTED JET STREAM RUNNING JUST
SOUTH OF THE BIG ISLAND INDICATED BY A SWATH OF CIRRUS CLOUDS. AT
THE SURFACE...HIGH PRESSURE IS CENTERED TO THE EAST-NORTHEAST OF
THE STATE PRODUCING MODERATE TO LOCALLY FRESH TRADE WINDS...WITH
THE STRONGEST WINDS NEAR MAUI COUNTY AND THE BIG ISLAND. RADAR IS
SHOWING A FEW PASSING WINDWARD SHOWERS ACROSS OAHU AND MAUI COUNTY
THIS MORNING.

THE SURFACE HIGH IS EXPECTED TO MOVE EAST...AWAY FROM HAWAII...OVER
THE NEXT DAY AND WILL RESULT IN PROGRESSIVELY LESS INFLUENCE ON
OUR WINDS. MEANWHILE...A STRONG COLD FRONT IS APPROXIMATELY 1400
MILES NORTHWEST OF KAUAI MOVING TOWARD US. THE FRONT IS SUPPORTED
BY AN UPPER TROUGH WHICH WILL STAY WITH IT AS APPROACHES THE
HAWAIIAN ISLANDS. WINDS WILL WEAKEN AND VEER SOUTHEASTERLY ON
SATURDAY AHEAD OF THIS SYSTEM...RESULTING IN A SHIFT TO MORE WARM
AND MUGGY CONDITIONS THIS WEEKEND. WINDS WILL LIKELY STAY TOO
EASTERLY NEAR THE BIG ISLAND TO BRING VOG UP TO THE SMALLER
ISLANDS OVER THE WEEKEND. THE WEAKENING FLOW WILL ALSO ALLOW A
SEA AND LAND BREEZE PATTERN TO SET UP SATURDAY AND
SUNDAY...RESULTING IN DAYTIME CLOUD BUILD UPS OVER THE ISLANDS AND
CLEARING OUT AT NIGHT.

THE COLD FRONT WILL ARRIVE SUNDAY NIGHT...FOLLOWED BY THE COLD
POOL ALOFT FROM THE UPPER TROUGH ON MONDAY. NORTHEAST SURFACE
WINDS WILL DRASTICALLY STRENGTHEN ALONG THE FRONTAL BOUNDARY
BEGINNING ON KAUAI SUNDAY NIGHT AND SPREADING EASTWARD DOWN THE
ISLAND CHAIN THROUGH TUESDAY NIGHT. WITH SIGNIFICANT SUPPORT FROM
THE TROUGH ALOFT...THE FRONT WILL HAVE THE OPPORTUNITY TO PRODUCE
LOCALLY HEAVY RAIN AND THUNDERSTORMS.

THE GFS AND ECMWF MODELS ARE NOT CONSISTENT WITH THE AMOUNT OF
INSTABILITY THAT WILL BE PRESENT TO TRIGGER THUNDERSTORMS...LET
ALONE PINPOINTING LOCATIONS ON THE ISLANDS. BOTH MODELS BRING THE
TROUGH AXIS ACROSS KAUAI MONDAY NIGHT...WITH 500 MB TEMPERATURES
NEAR -14 DEGREES CELSIUS FOR THE GFS AND -17 DEGREES CELSIUS FOR
THE ECMWF. AFTER THIS POINT...THE GFS QUICKLY SHIFT THE TROUGH
EASTWARD WHILE THE ECMWF KEEP THE UPPER TROUGH IN THE VICINITY OF
KAUAI AND OAHU THROUGH WEDNESDAY MORNING. FOR NOW...IT LOOKS LIKE
THE NORTHWESTERN END OF THE STATE...NAMELY KAUAI AND OAHU...WOULD
HAVE THE BEST CHANCES FOR THUNDERSTORMS AND HEAVY RAINFALL MONDAY
AND TUESDAY. THE STRONG VERTICAL WIND SHEAR WILL IMPROVE THE
VENTILATION OF ANY THUNDERSTORMS THAT DO DEVELOP...POTENTIALLY
ALLOWING SOME TO BECOME SEVERE...THOUGH REMAINS A BIT EARLY TO
CONSIDER A SEVERE THUNDERSTORM WATCH.

THE UPPER TROUGH AND DEEP MOISTURE ALSO INVITES THE POTENTIAL FOR
SNOW OVER THE SUMMITS OF MAUNA KEA AND MAUNA LOA MONDAY NIGHT
THROUGH TUESDAY.

FROM WEDNESDAY INTO FRIDAY OF NEXT WEEK...THE TROUGH ALOFT WILL LIFT
OUT TOWARD THE NORTHEAST...AND CONDITIONS WILL RETURN TOWARD
CLIMATOLOGY. AS MENTIONED...MODEL SOLUTIONS SHOW THIS PROCESS MAY
BE DRAWN OUT...SO THE RELATIVELY QUICK RETURN OF TRADE-WIND
WEATHER IN THE FORECAST MAY BE TOO OPTIMISTIC...AND SHOULD BE
REEVALUATED AS MORE RUNS BECOME AVAILABLE. TRADE-WIND WEATHER
SHOULD RETURN BY LATE NEXT WEEK.

&&

.AVIATION...
WITH A FRONT APPROACHING AND HIGH PRESSURE NORTH OF THE ISLANDS
BEING PUSHED EASTWARD...TRADES WILL BE REPLACED WITH A MORE
SOUTHEAST WIND FLOW BEGINNING TODAY INTO SATURDAY. BUT THE FRONT
WILL BE WEAKENING AS IT NEARS THE STATE THUS INSTEAD OF STRONG SE
WINDS...MAY SEE MORE LAND/SEA BREEZES FROM TIME TO TIME. THUS EXPECT
MORE INTERIOR CLOUDINESS DURING THE AFTERNOONS ALONG WITH CLEARING
AT NIGHT WITH SLIGHTLY LESS WINDWARD CLOUDINESS. BOTTOM LINE...EXPECT
MOSTLY VFR CONDITIONS TO PREVAIL THROUGH TONIGHT.

MODERATE AND GUSTY TRADE WINDS WILL START TO EASE TODAY THUS WILL BE
ABLE TO DROP THE AIRMET TANGO FOR LOW LEVEL TURB JUST OVER AND LEE
OF MOUNTAINS SOMETIME TODAY. UPPER JET STREAM NEAR AND JUST SOUTH
OF BIG ISLAND DROPPING SOUTHWARD SO WILL ALSO CEASE MENTION OF
POSSIBLE HIGH LEVEL TURB FROM THE TURB SECTION OF AIRMET IN THE NEAR
FUTURE AS WELL.

&&

.MARINE...
THE HIGH SURF ADVISORY FOR NORTH AND WEST FACING SHORES HAS BEEN
CANCELLED THIS MORNING AS OBSERVATIONS AND BUOY REPORTS SHOW BELOW
ADVISORY FACE HEIGHTS. THE NORTHWEST SWELL PEAKED OVERNIGHT AND IS
EXPECTED TO DECLINE TODAY AND SATURDAY...THOUGH CONDITIONS MAY STILL
REMAIN CLOSE TO ADVISORY LEVELS THROUGH THIS AFTERNOON.

A LARGER NORTHWEST SWELL IS EXPECTED TO ARRIVE ON SUNDAY AND WILL
LIKELY BUILD TO HIGH SURF WARNING LEVEL HEIGHTS FOR NORTH AND WEST
FACING SHORES BY LATE IN THE DAY. THIS SWELL SHOULD HAVE ENOUGH
WESTERLY COMPONENT TO IMPACT THE WEST SIDE OF THE BIG ISLAND AS
WELL.

EASTERLY WINDS ARE EXPECTED TO TAPER OFF TONIGHT AND SATURDAY AS A
COLD FRONT APPROACHES THE STATE FROM THE NORTHWEST AND FORCES THE
SUBTROPICAL HIGH FURTHER AWAY FROM HAWAII. WINDS WILL REMAIN
LIGHT ON SUNDAY AS THE NORTHWEST SWELL BUILDS...BUT NORTH TO
NORTHEAST WINDS WILL DRASTICALLY INCREASE SUNDAY NIGHT INTO MONDAY
AS THE SWELL PEAKS. A SMALL CRAFT ADVISORY /SCA/ IS IN EFFECT
THROUGH 6 PM TODAY FOR THE EASTERN HALF OF THE STATE FOR WINDS AND
SEAS. WITH THE SWELL ON THE DECLINE TODAY...THE SCA WILL LIKELY BE
TRIMMED BACK TO SOME OF THE WINDY ZONES AROUND MAUI COUNTY AND THE
BIG ISLAND THROUGH SATURDAY MORNING...THEN DROPPED ALTOGETHER.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 6 PM HST THIS EVENING FOR KAIWI
CHANNEL-MAUI COUNTY WINDWARD WATERS- MAUI COUNTY LEEWARD WATERS-
MAALAEA BAY-PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND WINDWARD
WATERS-BIG ISLAND LEEWARD WATERS-BIG ISLAND SOUTHEAST WATERS.


&&

$$

DISCUSSION/MARINE...FOSTER
AVIATION...FUJII







000
FXHW60 PHFO 191959
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
959 AM HST FRI DEC 19 2014

.SYNOPSIS...
TRADES WILL WEAKEN TO A LAND AND SEA BREEZE PATTERN THIS WEEKEND
AS A COLD FRONT AND UPPER TROUGH APPROACH FROM THE NORTHWEST.
NORTH TO NORTHEAST WINDS AND RAINFALL WILL INCREASE SUNDAY NIGHT
WITH THE POTENTIAL FOR HEAVY RAIN AND THUNDERSTORMS MONDAY INTO
TUESDAY. A GRADUAL RETURN TO TRADE WIND WEATHER IS EXPECTED LATE
NEXT WEEK.

&&

.DISCUSSION...
SATELLITE IMAGERY SHOWS A POSITIVELY-TILTED UPPER LEVEL TROUGH
OVER HAWAII WITH A WEST TO EAST ORIENTED JET STREAM RUNNING JUST
SOUTH OF THE BIG ISLAND INDICATED BY A SWATH OF CIRRUS CLOUDS. AT
THE SURFACE...HIGH PRESSURE IS CENTERED TO THE EAST-NORTHEAST OF
THE STATE PRODUCING MODERATE TO LOCALLY FRESH TRADE WINDS...WITH
THE STRONGEST WINDS NEAR MAUI COUNTY AND THE BIG ISLAND. RADAR IS
SHOWING A FEW PASSING WINDWARD SHOWERS ACROSS OAHU AND MAUI COUNTY
THIS MORNING.

THE SURFACE HIGH IS EXPECTED TO MOVE EAST...AWAY FROM HAWAII...OVER
THE NEXT DAY AND WILL RESULT IN PROGRESSIVELY LESS INFLUENCE ON
OUR WINDS. MEANWHILE...A STRONG COLD FRONT IS APPROXIMATELY 1400
MILES NORTHWEST OF KAUAI MOVING TOWARD US. THE FRONT IS SUPPORTED
BY AN UPPER TROUGH WHICH WILL STAY WITH IT AS APPROACHES THE
HAWAIIAN ISLANDS. WINDS WILL WEAKEN AND VEER SOUTHEASTERLY ON
SATURDAY AHEAD OF THIS SYSTEM...RESULTING IN A SHIFT TO MORE WARM
AND MUGGY CONDITIONS THIS WEEKEND. WINDS WILL LIKELY STAY TOO
EASTERLY NEAR THE BIG ISLAND TO BRING VOG UP TO THE SMALLER
ISLANDS OVER THE WEEKEND. THE WEAKENING FLOW WILL ALSO ALLOW A
SEA AND LAND BREEZE PATTERN TO SET UP SATURDAY AND
SUNDAY...RESULTING IN DAYTIME CLOUD BUILD UPS OVER THE ISLANDS AND
CLEARING OUT AT NIGHT.

THE COLD FRONT WILL ARRIVE SUNDAY NIGHT...FOLLOWED BY THE COLD
POOL ALOFT FROM THE UPPER TROUGH ON MONDAY. NORTHEAST SURFACE
WINDS WILL DRASTICALLY STRENGTHEN ALONG THE FRONTAL BOUNDARY
BEGINNING ON KAUAI SUNDAY NIGHT AND SPREADING EASTWARD DOWN THE
ISLAND CHAIN THROUGH TUESDAY NIGHT. WITH SIGNIFICANT SUPPORT FROM
THE TROUGH ALOFT...THE FRONT WILL HAVE THE OPPORTUNITY TO PRODUCE
LOCALLY HEAVY RAIN AND THUNDERSTORMS.

THE GFS AND ECMWF MODELS ARE NOT CONSISTENT WITH THE AMOUNT OF
INSTABILITY THAT WILL BE PRESENT TO TRIGGER THUNDERSTORMS...LET
ALONE PINPOINTING LOCATIONS ON THE ISLANDS. BOTH MODELS BRING THE
TROUGH AXIS ACROSS KAUAI MONDAY NIGHT...WITH 500 MB TEMPERATURES
NEAR -14 DEGREES CELSIUS FOR THE GFS AND -17 DEGREES CELSIUS FOR
THE ECMWF. AFTER THIS POINT...THE GFS QUICKLY SHIFT THE TROUGH
EASTWARD WHILE THE ECMWF KEEP THE UPPER TROUGH IN THE VICINITY OF
KAUAI AND OAHU THROUGH WEDNESDAY MORNING. FOR NOW...IT LOOKS LIKE
THE NORTHWESTERN END OF THE STATE...NAMELY KAUAI AND OAHU...WOULD
HAVE THE BEST CHANCES FOR THUNDERSTORMS AND HEAVY RAINFALL MONDAY
AND TUESDAY. THE STRONG VERTICAL WIND SHEAR WILL IMPROVE THE
VENTILATION OF ANY THUNDERSTORMS THAT DO DEVELOP...POTENTIALLY
ALLOWING SOME TO BECOME SEVERE...THOUGH REMAINS A BIT EARLY TO
CONSIDER A SEVERE THUNDERSTORM WATCH.

THE UPPER TROUGH AND DEEP MOISTURE ALSO INVITES THE POTENTIAL FOR
SNOW OVER THE SUMMITS OF MAUNA KEA AND MAUNA LOA MONDAY NIGHT
THROUGH TUESDAY.

FROM WEDNESDAY INTO FRIDAY OF NEXT WEEK...THE TROUGH ALOFT WILL LIFT
OUT TOWARD THE NORTHEAST...AND CONDITIONS WILL RETURN TOWARD
CLIMATOLOGY. AS MENTIONED...MODEL SOLUTIONS SHOW THIS PROCESS MAY
BE DRAWN OUT...SO THE RELATIVELY QUICK RETURN OF TRADE-WIND
WEATHER IN THE FORECAST MAY BE TOO OPTIMISTIC...AND SHOULD BE
REEVALUATED AS MORE RUNS BECOME AVAILABLE. TRADE-WIND WEATHER
SHOULD RETURN BY LATE NEXT WEEK.

&&

.AVIATION...
WITH A FRONT APPROACHING AND HIGH PRESSURE NORTH OF THE ISLANDS
BEING PUSHED EASTWARD...TRADES WILL BE REPLACED WITH A MORE
SOUTHEAST WIND FLOW BEGINNING TODAY INTO SATURDAY. BUT THE FRONT
WILL BE WEAKENING AS IT NEARS THE STATE THUS INSTEAD OF STRONG SE
WINDS...MAY SEE MORE LAND/SEA BREEZES FROM TIME TO TIME. THUS EXPECT
MORE INTERIOR CLOUDINESS DURING THE AFTERNOONS ALONG WITH CLEARING
AT NIGHT WITH SLIGHTLY LESS WINDWARD CLOUDINESS. BOTTOM LINE...EXPECT
MOSTLY VFR CONDITIONS TO PREVAIL THROUGH TONIGHT.

MODERATE AND GUSTY TRADE WINDS WILL START TO EASE TODAY THUS WILL BE
ABLE TO DROP THE AIRMET TANGO FOR LOW LEVEL TURB JUST OVER AND LEE
OF MOUNTAINS SOMETIME TODAY. UPPER JET STREAM NEAR AND JUST SOUTH
OF BIG ISLAND DROPPING SOUTHWARD SO WILL ALSO CEASE MENTION OF
POSSIBLE HIGH LEVEL TURB FROM THE TURB SECTION OF AIRMET IN THE NEAR
FUTURE AS WELL.

&&

.MARINE...
THE HIGH SURF ADVISORY FOR NORTH AND WEST FACING SHORES HAS BEEN
CANCELLED THIS MORNING AS OBSERVATIONS AND BUOY REPORTS SHOW BELOW
ADVISORY FACE HEIGHTS. THE NORTHWEST SWELL PEAKED OVERNIGHT AND IS
EXPECTED TO DECLINE TODAY AND SATURDAY...THOUGH CONDITIONS MAY STILL
REMAIN CLOSE TO ADVISORY LEVELS THROUGH THIS AFTERNOON.

A LARGER NORTHWEST SWELL IS EXPECTED TO ARRIVE ON SUNDAY AND WILL
LIKELY BUILD TO HIGH SURF WARNING LEVEL HEIGHTS FOR NORTH AND WEST
FACING SHORES BY LATE IN THE DAY. THIS SWELL SHOULD HAVE ENOUGH
WESTERLY COMPONENT TO IMPACT THE WEST SIDE OF THE BIG ISLAND AS
WELL.

EASTERLY WINDS ARE EXPECTED TO TAPER OFF TONIGHT AND SATURDAY AS A
COLD FRONT APPROACHES THE STATE FROM THE NORTHWEST AND FORCES THE
SUBTROPICAL HIGH FURTHER AWAY FROM HAWAII. WINDS WILL REMAIN
LIGHT ON SUNDAY AS THE NORTHWEST SWELL BUILDS...BUT NORTH TO
NORTHEAST WINDS WILL DRASTICALLY INCREASE SUNDAY NIGHT INTO MONDAY
AS THE SWELL PEAKS. A SMALL CRAFT ADVISORY /SCA/ IS IN EFFECT
THROUGH 6 PM TODAY FOR THE EASTERN HALF OF THE STATE FOR WINDS AND
SEAS. WITH THE SWELL ON THE DECLINE TODAY...THE SCA WILL LIKELY BE
TRIMMED BACK TO SOME OF THE WINDY ZONES AROUND MAUI COUNTY AND THE
BIG ISLAND THROUGH SATURDAY MORNING...THEN DROPPED ALTOGETHER.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 6 PM HST THIS EVENING FOR KAIWI
CHANNEL-MAUI COUNTY WINDWARD WATERS- MAUI COUNTY LEEWARD WATERS-
MAALAEA BAY-PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND WINDWARD
WATERS-BIG ISLAND LEEWARD WATERS-BIG ISLAND SOUTHEAST WATERS.


&&

$$

DISCUSSION/MARINE...FOSTER
AVIATION...FUJII








000
FXHW60 PHFO 191331 AAA
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST FRI DEC 19 2014

.SYNOPSIS...
MODERATE TRADE WINDS WILL KEEP MOSTLY LIGHT SHOWERS FOCUSED OVER
WINDWARD SLOPES INTO THE WEEKEND. FROM SUNDAY NIGHT INTO MONDAY...A
FRONT WILL SPREAD RAIN...COLD AIR...AND STRONG NORTHERLY WINDS
ACROSS THE STATE FROM THE NORTHWEST. UNSETTLED WEATHER WILL CONTINUE
THROUGH ABOUT TUESDAY...BEFORE RETURNING GRADUALLY TO TRADE-WIND
CONDITIONS BY THE END OF NEXT WEEK.

&&

.DISCUSSION...
SURFACE OBSERVATIONS AROUND THE MAIN HAWAIIAN ISLANDS REPORTED
MOSTLY MODERATE TRADE WINDS. GUIDANCE STRONGLY SUPPORTED A DECREASE
IN WIND SPEEDS THROUGH THE DAY...BUT A FEW OUTLYING OBSERVATIONS
SUGGESTED THAT THIS PROCESS MAY TAKE LONGER THAN CURRENTLY EXPECTED.
FOR NOW...WE WILL FOLLOW PRIOR THINKING.

THE INVERSION HEIGHT AND STRENGTH...CLOUD COVER...AND SHOWER
ACTIVITY STILL APPROXIMATED CLIMATOLOGY. RADAR DETECTED SLIGHTLY
FEWER SHOWERS OVER THE COASTAL WATERS...BUT OROGRAPHIC LIFTING
CONTINUED TO SQUEEZE OUT WIDESPREAD...IF GENERALLY LIGHT...
ACCUMULATION OVER RAIN GAUGES...DESPITE PERSISTENTLY LOW
PRECIPITABLE WATER. ALOFT...STRONG AND BROAD RIDGING KEPT CIRRUS
LAYERS FROM THE ITCZ SOUTH OF THE BIG ISLAND...BUT ONLY JUST.

GUIDANCE STILL AGREED FAIRLY WELL THAT A LONG-WAVE MID-LEVEL TROUGH
WILL DIG TOWARD THE STATE FROM THE NORTHWEST THROUGH THE WEEKEND...
EFFECTIVELY DISPLACING THE RIDGE BY SUNDAY EVENING...AND THEN
SHARPENING TOWARD THE SOUTHWEST INTO TUESDAY. THIS DEVELOPMENT ALOFT
WILL SUPPORT THE APPROACH OF A COLD FRONT AT THE SURFACE. THROUGH
ABOUT SUNDAY...THE SUBTROPICAL RIDGE WILL RECEDE TOWARD THE EAST
AHEAD OF THE FRONT...CAUSING SURFACE WINDS AROUND THE ISLANDS TO
DIMINISH AND BECOME MORE SOUTHEASTERLY. FROM SUNDAY NIGHT INTO NEXT
WEEK...THE FRONT WILL WORK ITS WAY SOUTHEAST ACROSS THE STATE. WITH
SIGNIFICANT SUPPORT FROM THE DIGGING TROUGH ALOFT...THE FRONT WILL
HAVE THE OPPORTUNITY TO PRODUCE WIDESPREAD RAIN. THE PUSH OF COLD
AIR AT LOW LEVELS BEHIND THE FRONT ALSO WILL BRING STRONG NORTHERLY
WINDS.

PERHAPS MOST IMPORTANTLY...A VERY COLD POOL OF AIR ALOFT WILL
ACCOMPANY THE MID-LEVEL TROUGH. THIS COLD POOL WILL DESTABILIZE THE
ATMOSPHERE SIGNIFICANTLY...INTRODUCING A NON-TRIVIAL RISK OF
THUNDERSTORMS AROUND MONDAY...MAINLY FROM MOLOKAI NORTHWEST. A
SLIGHT CHANCE OF THUNDERSTORMS HAS BEEN INTRODUCED INTO THE FORECAST
FOLLOWING THE LOCAL TOOL RUN OFF OF MODEL CONSENSUS. STRONG VERTICAL
WIND SHEAR WILL IMPROVE THE VENTILATION OF ANY THUNDERSTORMS THAT DO
DEVELOP...POTENTIALLY ALLOWING SOME TO BECOME SEVERE. IT REMAINED
MUCH TOO EARLY TO CONSIDER A SEVERE THUNDERSTORM WATCH...BUT
POSSIBLE HIGH IMPACTS REQUIRED CONTINUED VIGILANCE WITH RESPECT TO
THIS MATTER.

THE COLD POOL ALSO WILL INTRODUCE THE POSSIBILITY OF WINTER WEATHER
OVER HIGHER ELEVATIONS OF MAUI AND THE BIG ISLAND. THIS FAR OUT...
MUCH REMAINED UNCERTAIN...BUT GENERALLY SPEAKING THE AVAILABLE
MOISTURE APPEARED LIMITED LARGELY TO BELOW THE SUMMITS THROUGH MOST
OF THE FORECAST PERIOD. WHERE BOTH COLD TEMPERATURES AND AVAILABLE
MOISTURE COINCIDED...A SLIGHT CHANCE OF LIGHT SNOW HAS BEEN INCLUDED
IN THE FORECAST AS A PLACE HOLDER. DEEPER MOISTURE...OR
THUNDERSTORMS DEVELOPING FURTHER SOUTH THAN EXPECTED...COULD
INCREASE THE RISK OF WINTER WEATHER OVER THE SUMMITS DRAMATICALLY.

FROM WEDNESDAY INTO FRIDAY OF NEXT WEEK...THE TROUGH ALOFT WILL LIFT
OUT TOWARD THE NORTHEAST...AND CONDITIONS WILL RETURN TOWARD
CLIMATOLOGY. RECENT SOLUTIONS TENDED TO DRAW OUT THIS PROCESS...SO
THE RELATIVELY QUICK RETURN OF TRADE-WIND WEATHER IN THE FORECAST
MAY BE TOO OPTIMISTIC...AND SHOULD BE REEVALUATED AS MORE RUNS
BECOME AVAILABLE. ON THE WHOLE THOUGH...TRADE-WIND WEATHER SHOULD
RETURN BY NEXT WEEKEND.

&&

.AVIATION...
WINDWARD AND MAUKA AREAS WILL CONTINUE TO EXPERIENCE PASSING SHOWERS
WITH EMBEDDED ISOL MVFR CONDITIONS. HEAVIER CLOUD COVER AND SHOWERS
REMAIN OVER KAUAI AND BIG ISLAND THIS MORNING...THEREFORE AIRMET
SIERRA CONTINUES. ELSEWHERE...AIRMET SIERRA HAS BEEN CANCELLED.

MODERATE AND GUSTY TRADE WINDS WILL START TO EASE TODAY AS A RIDGE
BEGINS TO BUILD JUST NORTH OF THE ISLANDS. THIS WILL LIKELY ALLOW
FOR THE CANCELLATION OF AIRMET TANGO FOR LOW LEVEL TURB.

THERE IS ALSO MENTION FOR POSSIBLE UPPER LEVEL TURB BETWEEN FL280
AND FL420. A JET...WITH MAX WINDS TO 100 KT...SITS JUST SOUTH OF
HAWAII. AT THIS TIME HAVE NOT RECEIVED ANY PIREPS...THIS WILL BE
UPGRADED TO AN OFFICIAL AIRMET IF REPORTS ARE RECEIVED.

&&

.MARINE...
WITH WINDS EXPECTED TO DIMINISH TODAY...AND THE LARGE NORTHWEST
SWELL SLOWLY PASSING THE STATE...WATERS AROUND KAUAI AND MOST OF
OAHU SHOULD FALL BELOW THE CRITERIA FOR A SMALL CRAFT ADVISORY
/SCA/ THIS MORNING. ELSEWHERE...THE ADVISORY WILL REMAIN IN EFFECT
THROUGH 6 PM HST TODAY. CONDITIONS SHOULD SUBSIDE FURTHER THIS
EVENING...BUT THEN ANOTHER LARGE NORTHWEST WILL PRODUCE SCA
CONDITIONS AGAIN BY SATURDAY NIGHT.

AN EVEN LARGER NW SWELL IS EXPECTED TO ARRIVE ON SUNDAY...LIKELY
PUSHING SURF HEIGHTS INTO WARNING LEVELS OVER BOTH NORTH- AND
WEST-FACING SHORES OF MOST ISLANDS. DEEP LOW PRESSURE FAR NORTH OF
THE STATE MAY CONTINUE TO PRODUCE SWELLS KEEPING SURF ELEVATED TO
NEAR THE ADVISORY LEVELS THROUGH THE SECOND HALF OF NEXT WEEK.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 PM HST THIS EVENING FOR NIIHAU-KAUAI
WINDWARD-KAUAI LEEWARD-WAIANAE COAST-OAHU NORTH SHORE-OAHU
KOOLAU-MOLOKAI-MAUI WINDWARD WEST-WINDWARD HALEAKALA.

SMALL CRAFT ADVISORY UNTIL 6 PM HST THIS EVENING FOR KAIWI
CHANNEL-MAUI COUNTY WINDWARD WATERS-MAUI COUNTY LEEWARD WATERS-
MAALAEA BAY-PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND
WINDWARD WATERS-BIG ISLAND LEEWARD WATERS-BIG ISLAND SOUTHEAST
WATERS.

&&

$$

AVIATION...EATON
REST...RYSHKO






000
FXHW60 PHFO 191331 AAA
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST FRI DEC 19 2014

.SYNOPSIS...
MODERATE TRADE WINDS WILL KEEP MOSTLY LIGHT SHOWERS FOCUSED OVER
WINDWARD SLOPES INTO THE WEEKEND. FROM SUNDAY NIGHT INTO MONDAY...A
FRONT WILL SPREAD RAIN...COLD AIR...AND STRONG NORTHERLY WINDS
ACROSS THE STATE FROM THE NORTHWEST. UNSETTLED WEATHER WILL CONTINUE
THROUGH ABOUT TUESDAY...BEFORE RETURNING GRADUALLY TO TRADE-WIND
CONDITIONS BY THE END OF NEXT WEEK.

&&

.DISCUSSION...
SURFACE OBSERVATIONS AROUND THE MAIN HAWAIIAN ISLANDS REPORTED
MOSTLY MODERATE TRADE WINDS. GUIDANCE STRONGLY SUPPORTED A DECREASE
IN WIND SPEEDS THROUGH THE DAY...BUT A FEW OUTLYING OBSERVATIONS
SUGGESTED THAT THIS PROCESS MAY TAKE LONGER THAN CURRENTLY EXPECTED.
FOR NOW...WE WILL FOLLOW PRIOR THINKING.

THE INVERSION HEIGHT AND STRENGTH...CLOUD COVER...AND SHOWER
ACTIVITY STILL APPROXIMATED CLIMATOLOGY. RADAR DETECTED SLIGHTLY
FEWER SHOWERS OVER THE COASTAL WATERS...BUT OROGRAPHIC LIFTING
CONTINUED TO SQUEEZE OUT WIDESPREAD...IF GENERALLY LIGHT...
ACCUMULATION OVER RAIN GAUGES...DESPITE PERSISTENTLY LOW
PRECIPITABLE WATER. ALOFT...STRONG AND BROAD RIDGING KEPT CIRRUS
LAYERS FROM THE ITCZ SOUTH OF THE BIG ISLAND...BUT ONLY JUST.

GUIDANCE STILL AGREED FAIRLY WELL THAT A LONG-WAVE MID-LEVEL TROUGH
WILL DIG TOWARD THE STATE FROM THE NORTHWEST THROUGH THE WEEKEND...
EFFECTIVELY DISPLACING THE RIDGE BY SUNDAY EVENING...AND THEN
SHARPENING TOWARD THE SOUTHWEST INTO TUESDAY. THIS DEVELOPMENT ALOFT
WILL SUPPORT THE APPROACH OF A COLD FRONT AT THE SURFACE. THROUGH
ABOUT SUNDAY...THE SUBTROPICAL RIDGE WILL RECEDE TOWARD THE EAST
AHEAD OF THE FRONT...CAUSING SURFACE WINDS AROUND THE ISLANDS TO
DIMINISH AND BECOME MORE SOUTHEASTERLY. FROM SUNDAY NIGHT INTO NEXT
WEEK...THE FRONT WILL WORK ITS WAY SOUTHEAST ACROSS THE STATE. WITH
SIGNIFICANT SUPPORT FROM THE DIGGING TROUGH ALOFT...THE FRONT WILL
HAVE THE OPPORTUNITY TO PRODUCE WIDESPREAD RAIN. THE PUSH OF COLD
AIR AT LOW LEVELS BEHIND THE FRONT ALSO WILL BRING STRONG NORTHERLY
WINDS.

PERHAPS MOST IMPORTANTLY...A VERY COLD POOL OF AIR ALOFT WILL
ACCOMPANY THE MID-LEVEL TROUGH. THIS COLD POOL WILL DESTABILIZE THE
ATMOSPHERE SIGNIFICANTLY...INTRODUCING A NON-TRIVIAL RISK OF
THUNDERSTORMS AROUND MONDAY...MAINLY FROM MOLOKAI NORTHWEST. A
SLIGHT CHANCE OF THUNDERSTORMS HAS BEEN INTRODUCED INTO THE FORECAST
FOLLOWING THE LOCAL TOOL RUN OFF OF MODEL CONSENSUS. STRONG VERTICAL
WIND SHEAR WILL IMPROVE THE VENTILATION OF ANY THUNDERSTORMS THAT DO
DEVELOP...POTENTIALLY ALLOWING SOME TO BECOME SEVERE. IT REMAINED
MUCH TOO EARLY TO CONSIDER A SEVERE THUNDERSTORM WATCH...BUT
POSSIBLE HIGH IMPACTS REQUIRED CONTINUED VIGILANCE WITH RESPECT TO
THIS MATTER.

THE COLD POOL ALSO WILL INTRODUCE THE POSSIBILITY OF WINTER WEATHER
OVER HIGHER ELEVATIONS OF MAUI AND THE BIG ISLAND. THIS FAR OUT...
MUCH REMAINED UNCERTAIN...BUT GENERALLY SPEAKING THE AVAILABLE
MOISTURE APPEARED LIMITED LARGELY TO BELOW THE SUMMITS THROUGH MOST
OF THE FORECAST PERIOD. WHERE BOTH COLD TEMPERATURES AND AVAILABLE
MOISTURE COINCIDED...A SLIGHT CHANCE OF LIGHT SNOW HAS BEEN INCLUDED
IN THE FORECAST AS A PLACE HOLDER. DEEPER MOISTURE...OR
THUNDERSTORMS DEVELOPING FURTHER SOUTH THAN EXPECTED...COULD
INCREASE THE RISK OF WINTER WEATHER OVER THE SUMMITS DRAMATICALLY.

FROM WEDNESDAY INTO FRIDAY OF NEXT WEEK...THE TROUGH ALOFT WILL LIFT
OUT TOWARD THE NORTHEAST...AND CONDITIONS WILL RETURN TOWARD
CLIMATOLOGY. RECENT SOLUTIONS TENDED TO DRAW OUT THIS PROCESS...SO
THE RELATIVELY QUICK RETURN OF TRADE-WIND WEATHER IN THE FORECAST
MAY BE TOO OPTIMISTIC...AND SHOULD BE REEVALUATED AS MORE RUNS
BECOME AVAILABLE. ON THE WHOLE THOUGH...TRADE-WIND WEATHER SHOULD
RETURN BY NEXT WEEKEND.

&&

.AVIATION...
WINDWARD AND MAUKA AREAS WILL CONTINUE TO EXPERIENCE PASSING SHOWERS
WITH EMBEDDED ISOL MVFR CONDITIONS. HEAVIER CLOUD COVER AND SHOWERS
REMAIN OVER KAUAI AND BIG ISLAND THIS MORNING...THEREFORE AIRMET
SIERRA CONTINUES. ELSEWHERE...AIRMET SIERRA HAS BEEN CANCELLED.

MODERATE AND GUSTY TRADE WINDS WILL START TO EASE TODAY AS A RIDGE
BEGINS TO BUILD JUST NORTH OF THE ISLANDS. THIS WILL LIKELY ALLOW
FOR THE CANCELLATION OF AIRMET TANGO FOR LOW LEVEL TURB.

THERE IS ALSO MENTION FOR POSSIBLE UPPER LEVEL TURB BETWEEN FL280
AND FL420. A JET...WITH MAX WINDS TO 100 KT...SITS JUST SOUTH OF
HAWAII. AT THIS TIME HAVE NOT RECEIVED ANY PIREPS...THIS WILL BE
UPGRADED TO AN OFFICIAL AIRMET IF REPORTS ARE RECEIVED.

&&

.MARINE...
WITH WINDS EXPECTED TO DIMINISH TODAY...AND THE LARGE NORTHWEST
SWELL SLOWLY PASSING THE STATE...WATERS AROUND KAUAI AND MOST OF
OAHU SHOULD FALL BELOW THE CRITERIA FOR A SMALL CRAFT ADVISORY
/SCA/ THIS MORNING. ELSEWHERE...THE ADVISORY WILL REMAIN IN EFFECT
THROUGH 6 PM HST TODAY. CONDITIONS SHOULD SUBSIDE FURTHER THIS
EVENING...BUT THEN ANOTHER LARGE NORTHWEST WILL PRODUCE SCA
CONDITIONS AGAIN BY SATURDAY NIGHT.

AN EVEN LARGER NW SWELL IS EXPECTED TO ARRIVE ON SUNDAY...LIKELY
PUSHING SURF HEIGHTS INTO WARNING LEVELS OVER BOTH NORTH- AND
WEST-FACING SHORES OF MOST ISLANDS. DEEP LOW PRESSURE FAR NORTH OF
THE STATE MAY CONTINUE TO PRODUCE SWELLS KEEPING SURF ELEVATED TO
NEAR THE ADVISORY LEVELS THROUGH THE SECOND HALF OF NEXT WEEK.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 PM HST THIS EVENING FOR NIIHAU-KAUAI
WINDWARD-KAUAI LEEWARD-WAIANAE COAST-OAHU NORTH SHORE-OAHU
KOOLAU-MOLOKAI-MAUI WINDWARD WEST-WINDWARD HALEAKALA.

SMALL CRAFT ADVISORY UNTIL 6 PM HST THIS EVENING FOR KAIWI
CHANNEL-MAUI COUNTY WINDWARD WATERS-MAUI COUNTY LEEWARD WATERS-
MAALAEA BAY-PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND
WINDWARD WATERS-BIG ISLAND LEEWARD WATERS-BIG ISLAND SOUTHEAST
WATERS.

&&

$$

AVIATION...EATON
REST...RYSHKO







000
FXHW60 PHFO 191330
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST FRI DEC 19 2014

.SYNOPSIS...
MODERATE TRADE WINDS WILL KEEP MOSTLY LIGHT SHOWERS FOCUSED OVER
WINDWARD SLOPES INTO THE WEEKEND. FROM SUNDAY NIGHT INTO MONDAY...A
FRONT WILL SPREAD RAIN...COLD AIR...AND STRONG NORTHERLY WINDS
ACROSS THE STATE FROM THE NORTHWEST. UNSETTLED WEATHER WILL CONTINUE
THROUGH ABOUT TUESDAY...BEFORE RETURNING GRADUALLY TO TRADE-WIND
CONDITIONS BY THE END OF NEXT WEEK.

&&

.DISCUSSION...
SURFACE OBSERVATIONS AROUND THE MAIN HAWAIIAN ISLANDS REPORTED
MOSTLY MODERATE TRADE WINDS. GUIDANCE STRONGLY SUPPORTED A DECREASE
IN WIND SPEEDS THROUGH THE DAY...BUT A FEW OUTLYING OBSERVATIONS
SUGGESTED THAT THIS PROCESS MAY TAKE LONGER THAN CURRENTLY EXPECTED.
FOR NOW...WE WILL FOLLOW PRIOR THINKING.

THE INVERSION HEIGHT AND STRENGTH...CLOUD COVER...AND SHOWER
ACTIVITY STILL APPROXIMATED CLIMATOLOGY. RADAR DETECTED SLIGHTLY
FEWER SHOWERS OVER THE COASTAL WATERS...BUT OROGRAPHIC LIFTING
CONTINUED TO SQUEEZE OUT WIDESPREAD...IF GENERALLY LIGHT...
ACCUMULATION OVER RAIN GAUGES...DESPITE PERSISTENTLY LOW
PRECIPITABLE WATER. ALOFT...STRONG AND BROAD RIDGING KEPT CIRRUS
LAYERS FROM THE ITCZ SOUTH OF THE BIG ISLAND...BUT ONLY JUST.

GUIDANCE STILL AGREED FAIRLY WELL THAT A LONG-WAVE MID-LEVEL TROUGH
WILL DIG TOWARD THE STATE FROM THE NORTHWEST THROUGH THE WEEKEND...
EFFECTIVELY DISPLACING THE RIDGE BY SUNDAY EVENING...AND THEN
SHARPENING TOWARD THE SOUTHWEST INTO TUESDAY. THIS DEVELOPMENT ALOFT
WILL SUPPORT THE APPROACH OF A COLD FRONT AT THE SURFACE. THROUGH
ABOUT SUNDAY...THE SUBTROPICAL RIDGE WILL RECEDE TOWARD THE EAST
AHEAD OF THE FRONT...CAUSING SURFACE WINDS AROUND THE ISLANDS TO
DIMINISH AND BECOME MORE SOUTHEASTERLY. FROM SUNDAY NIGHT INTO NEXT
WEEK...THE FRONT WILL WORK ITS WAY SOUTHEAST ACROSS THE STATE. WITH
SIGNIFICANT SUPPORT FROM THE DIGGING TROUGH ALOFT...THE FRONT WILL
HAVE THE OPPORTUNITY TO PRODUCE WIDESPREAD RAIN. THE PUSH OF COLD
AIR AT LOW LEVELS BEHIND THE FRONT ALSO WILL BRING STRONG NORTHERLY
WINDS.

PERHAPS MOST IMPORTANTLY...A VERY COLD POOL OF AIR ALOFT WILL
ACCOMPANY THE MID-LEVEL TROUGH. THIS COLD POOL WILL DESTABILIZE THE
ATMOSPHERE SIGNIFICANTLY...INTRODUCING A NON-TRIVIAL RISK OF
THUNDERSTORMS AROUND MONDAY...MAINLY FROM MOLOKAI NORTHWEST. A
SLIGHT CHANCE OF THUNDERSTORMS HAS BEEN INTRODUCED INTO THE FORECAST
FOLLOWING THE LOCAL TOOL RUN OFF OF MODEL CONSENSUS. STRONG VERTICAL
WIND SHEAR WILL IMPROVE THE VENTILATION OF ANY THUNDERSTORMS THAT DO
DEVELOP...POTENTIALLY ALLOWING SOME TO BECOME SEVERE. IT REMAINED
MUCH TOO EARLY TO CONSIDER A SEVERE THUNDERSTORM WATCH...BUT
POSSIBLE HIGH IMPACTS REQUIRED CONTINUED VIGILANCE WITH RESPECT TO
THIS MATTER.

THE COLD POOL ALSO WILL INTRODUCE THE POSSIBILITY OF WINTER WEATHER
OVER HIGHER ELEVATIONS OF MAUI AND THE BIG ISLAND. THIS FAR OUT...
MUCH REMAINED UNCERTAIN...BUT GENERALLY SPEAKING THE AVAILABLE
MOISTURE APPEARED LIMITED LARGELY TO BELOW THE SUMMITS THROUGH MOST
OF THE FORECAST PERIOD. WHERE BOTH COLD TEMPERATURES AND AVAILABLE
MOISTURE COINCIDED...A SLIGHT CHANCE OF LIGHT SNOW HAS BEEN INCLUDED
IN THE FORECAST AS A PLACE HOLDER. DEEPER MOISTURE...OR
THUNDERSTORMS DEVELOPING FURTHER SOUTH THAN EXPECTED...COULD
INCREASE THE RISK OF WINTER WEATHER OVER THE SUMMITS DRAMATICALLY.

FROM WEDNESDAY INTO FRIDAY OF NEXT WEEK...THE TROUGH ALOFT WILL LIFT
OUT TOWARD THE NORTHEAST...AND CONDITIONS WILL RETURN TOWARD
CLIMATOLOGY. RECENT SOLUTIONS TENDED TO DRAW OUT THIS PROCESS...SO
THE RELATIVELY QUICK RETURN OF TRADE-WIND WEATHER IN THE FORECAST
MAY BE TOO OPTIMISTIC...AND SHOULD BE REEVALUATED AS MORE RUNS
BECOME AVAILABLE. ON THE WHOLE THOUGH...TRADE-WIND WEATHER SHOULD
RETURN BY NEXT WEEKEND.

&&

.AVIATION...
WINDWARD AND MAUKA AREAS WILL CONTINUE TO EXPERIENCE PASSING SHOWERS
WITH EMBEDDED ISOL MVFR CONDITIONS. HEAVIER CLOUD COVER REMAINS OVER
KAUAI THIS MORNING...THEREFORE AIRMET SIERRA CONTINUES.
ELSEWHERE...AIRMET SIERRA HAS BEEN CANCELLED.

MODERATE AND GUSTY TRADE WINDS WILL START TO EASE TODAY AS A RIDGE
BEGINS TO BUILD JUST NORTH OF THE ISLANDS. THIS WILL LIKELY ALLOW
FOR THE CANCELLATION OF AIRMET TANGO FOR LOW LEVEL TURB.

THERE IS ALSO MENTION FOR POSSIBLE UPPER LEVEL TURB BETWEEN FL280
AND FL420. A JET...WITH MAX WINDS TO 100 KT...SITS JUST SOUTH OF
HAWAII. AT THIS TIME HAVE NOT RECEIVED ANY PIREPS...THIS WILL BE
UPGRADED TO AN OFFICIAL AIRMET IF REPORTS ARE RECEIVED.

&&

.MARINE...
WITH WINDS EXPECTED TO DIMINISH TODAY...AND THE LARGE NORTHWEST
SWELL SLOWLY PASSING THE STATE...WATERS AROUND KAUAI AND MOST OF
OAHU SHOULD FALL BELOW THE CRITERIA FOR A SMALL CRAFT ADVISORY
/SCA/ THIS MORNING. ELSEWHERE...THE ADVISORY WILL REMAIN IN EFFECT
THROUGH 6 PM HST TODAY. CONDITIONS SHOULD SUBSIDE FURTHER THIS
EVENING...BUT THEN ANOTHER LARGE NORTHWEST WILL PRODUCE SCA
CONDITIONS AGAIN BY SATURDAY NIGHT.

AN EVEN LARGER NW SWELL IS EXPECTED TO ARRIVE ON SUNDAY...LIKELY
PUSHING SURF HEIGHTS INTO WARNING LEVELS OVER BOTH NORTH- AND
WEST-FACING SHORES OF MOST ISLANDS. DEEP LOW PRESSURE FAR NORTH OF
THE STATE MAY CONTINUE TO PRODUCE SWELLS KEEPING SURF ELEVATED TO
NEAR THE ADVISORY LEVELS THROUGH THE SECOND HALF OF NEXT WEEK.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 PM HST THIS EVENING FOR NIIHAU-KAUAI
WINDWARD-KAUAI LEEWARD-WAIANAE COAST-OAHU NORTH SHORE-OAHU
KOOLAU-MOLOKAI-MAUI WINDWARD WEST-WINDWARD HALEAKALA.

SMALL CRAFT ADVISORY UNTIL 6 PM HST THIS EVENING FOR KAIWI
CHANNEL-MAUI COUNTY WINDWARD WATERS-MAUI COUNTY LEEWARD WATERS-
MAALAEA BAY-PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND
WINDWARD WATERS-BIG ISLAND LEEWARD WATERS-BIG ISLAND SOUTHEAST
WATERS.

&&

$$

AVIATION...EATON
REST...RYSHKO






000
FXHW60 PHFO 191330
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST FRI DEC 19 2014

.SYNOPSIS...
MODERATE TRADE WINDS WILL KEEP MOSTLY LIGHT SHOWERS FOCUSED OVER
WINDWARD SLOPES INTO THE WEEKEND. FROM SUNDAY NIGHT INTO MONDAY...A
FRONT WILL SPREAD RAIN...COLD AIR...AND STRONG NORTHERLY WINDS
ACROSS THE STATE FROM THE NORTHWEST. UNSETTLED WEATHER WILL CONTINUE
THROUGH ABOUT TUESDAY...BEFORE RETURNING GRADUALLY TO TRADE-WIND
CONDITIONS BY THE END OF NEXT WEEK.

&&

.DISCUSSION...
SURFACE OBSERVATIONS AROUND THE MAIN HAWAIIAN ISLANDS REPORTED
MOSTLY MODERATE TRADE WINDS. GUIDANCE STRONGLY SUPPORTED A DECREASE
IN WIND SPEEDS THROUGH THE DAY...BUT A FEW OUTLYING OBSERVATIONS
SUGGESTED THAT THIS PROCESS MAY TAKE LONGER THAN CURRENTLY EXPECTED.
FOR NOW...WE WILL FOLLOW PRIOR THINKING.

THE INVERSION HEIGHT AND STRENGTH...CLOUD COVER...AND SHOWER
ACTIVITY STILL APPROXIMATED CLIMATOLOGY. RADAR DETECTED SLIGHTLY
FEWER SHOWERS OVER THE COASTAL WATERS...BUT OROGRAPHIC LIFTING
CONTINUED TO SQUEEZE OUT WIDESPREAD...IF GENERALLY LIGHT...
ACCUMULATION OVER RAIN GAUGES...DESPITE PERSISTENTLY LOW
PRECIPITABLE WATER. ALOFT...STRONG AND BROAD RIDGING KEPT CIRRUS
LAYERS FROM THE ITCZ SOUTH OF THE BIG ISLAND...BUT ONLY JUST.

GUIDANCE STILL AGREED FAIRLY WELL THAT A LONG-WAVE MID-LEVEL TROUGH
WILL DIG TOWARD THE STATE FROM THE NORTHWEST THROUGH THE WEEKEND...
EFFECTIVELY DISPLACING THE RIDGE BY SUNDAY EVENING...AND THEN
SHARPENING TOWARD THE SOUTHWEST INTO TUESDAY. THIS DEVELOPMENT ALOFT
WILL SUPPORT THE APPROACH OF A COLD FRONT AT THE SURFACE. THROUGH
ABOUT SUNDAY...THE SUBTROPICAL RIDGE WILL RECEDE TOWARD THE EAST
AHEAD OF THE FRONT...CAUSING SURFACE WINDS AROUND THE ISLANDS TO
DIMINISH AND BECOME MORE SOUTHEASTERLY. FROM SUNDAY NIGHT INTO NEXT
WEEK...THE FRONT WILL WORK ITS WAY SOUTHEAST ACROSS THE STATE. WITH
SIGNIFICANT SUPPORT FROM THE DIGGING TROUGH ALOFT...THE FRONT WILL
HAVE THE OPPORTUNITY TO PRODUCE WIDESPREAD RAIN. THE PUSH OF COLD
AIR AT LOW LEVELS BEHIND THE FRONT ALSO WILL BRING STRONG NORTHERLY
WINDS.

PERHAPS MOST IMPORTANTLY...A VERY COLD POOL OF AIR ALOFT WILL
ACCOMPANY THE MID-LEVEL TROUGH. THIS COLD POOL WILL DESTABILIZE THE
ATMOSPHERE SIGNIFICANTLY...INTRODUCING A NON-TRIVIAL RISK OF
THUNDERSTORMS AROUND MONDAY...MAINLY FROM MOLOKAI NORTHWEST. A
SLIGHT CHANCE OF THUNDERSTORMS HAS BEEN INTRODUCED INTO THE FORECAST
FOLLOWING THE LOCAL TOOL RUN OFF OF MODEL CONSENSUS. STRONG VERTICAL
WIND SHEAR WILL IMPROVE THE VENTILATION OF ANY THUNDERSTORMS THAT DO
DEVELOP...POTENTIALLY ALLOWING SOME TO BECOME SEVERE. IT REMAINED
MUCH TOO EARLY TO CONSIDER A SEVERE THUNDERSTORM WATCH...BUT
POSSIBLE HIGH IMPACTS REQUIRED CONTINUED VIGILANCE WITH RESPECT TO
THIS MATTER.

THE COLD POOL ALSO WILL INTRODUCE THE POSSIBILITY OF WINTER WEATHER
OVER HIGHER ELEVATIONS OF MAUI AND THE BIG ISLAND. THIS FAR OUT...
MUCH REMAINED UNCERTAIN...BUT GENERALLY SPEAKING THE AVAILABLE
MOISTURE APPEARED LIMITED LARGELY TO BELOW THE SUMMITS THROUGH MOST
OF THE FORECAST PERIOD. WHERE BOTH COLD TEMPERATURES AND AVAILABLE
MOISTURE COINCIDED...A SLIGHT CHANCE OF LIGHT SNOW HAS BEEN INCLUDED
IN THE FORECAST AS A PLACE HOLDER. DEEPER MOISTURE...OR
THUNDERSTORMS DEVELOPING FURTHER SOUTH THAN EXPECTED...COULD
INCREASE THE RISK OF WINTER WEATHER OVER THE SUMMITS DRAMATICALLY.

FROM WEDNESDAY INTO FRIDAY OF NEXT WEEK...THE TROUGH ALOFT WILL LIFT
OUT TOWARD THE NORTHEAST...AND CONDITIONS WILL RETURN TOWARD
CLIMATOLOGY. RECENT SOLUTIONS TENDED TO DRAW OUT THIS PROCESS...SO
THE RELATIVELY QUICK RETURN OF TRADE-WIND WEATHER IN THE FORECAST
MAY BE TOO OPTIMISTIC...AND SHOULD BE REEVALUATED AS MORE RUNS
BECOME AVAILABLE. ON THE WHOLE THOUGH...TRADE-WIND WEATHER SHOULD
RETURN BY NEXT WEEKEND.

&&

.AVIATION...
WINDWARD AND MAUKA AREAS WILL CONTINUE TO EXPERIENCE PASSING SHOWERS
WITH EMBEDDED ISOL MVFR CONDITIONS. HEAVIER CLOUD COVER REMAINS OVER
KAUAI THIS MORNING...THEREFORE AIRMET SIERRA CONTINUES.
ELSEWHERE...AIRMET SIERRA HAS BEEN CANCELLED.

MODERATE AND GUSTY TRADE WINDS WILL START TO EASE TODAY AS A RIDGE
BEGINS TO BUILD JUST NORTH OF THE ISLANDS. THIS WILL LIKELY ALLOW
FOR THE CANCELLATION OF AIRMET TANGO FOR LOW LEVEL TURB.

THERE IS ALSO MENTION FOR POSSIBLE UPPER LEVEL TURB BETWEEN FL280
AND FL420. A JET...WITH MAX WINDS TO 100 KT...SITS JUST SOUTH OF
HAWAII. AT THIS TIME HAVE NOT RECEIVED ANY PIREPS...THIS WILL BE
UPGRADED TO AN OFFICIAL AIRMET IF REPORTS ARE RECEIVED.

&&

.MARINE...
WITH WINDS EXPECTED TO DIMINISH TODAY...AND THE LARGE NORTHWEST
SWELL SLOWLY PASSING THE STATE...WATERS AROUND KAUAI AND MOST OF
OAHU SHOULD FALL BELOW THE CRITERIA FOR A SMALL CRAFT ADVISORY
/SCA/ THIS MORNING. ELSEWHERE...THE ADVISORY WILL REMAIN IN EFFECT
THROUGH 6 PM HST TODAY. CONDITIONS SHOULD SUBSIDE FURTHER THIS
EVENING...BUT THEN ANOTHER LARGE NORTHWEST WILL PRODUCE SCA
CONDITIONS AGAIN BY SATURDAY NIGHT.

AN EVEN LARGER NW SWELL IS EXPECTED TO ARRIVE ON SUNDAY...LIKELY
PUSHING SURF HEIGHTS INTO WARNING LEVELS OVER BOTH NORTH- AND
WEST-FACING SHORES OF MOST ISLANDS. DEEP LOW PRESSURE FAR NORTH OF
THE STATE MAY CONTINUE TO PRODUCE SWELLS KEEPING SURF ELEVATED TO
NEAR THE ADVISORY LEVELS THROUGH THE SECOND HALF OF NEXT WEEK.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 PM HST THIS EVENING FOR NIIHAU-KAUAI
WINDWARD-KAUAI LEEWARD-WAIANAE COAST-OAHU NORTH SHORE-OAHU
KOOLAU-MOLOKAI-MAUI WINDWARD WEST-WINDWARD HALEAKALA.

SMALL CRAFT ADVISORY UNTIL 6 PM HST THIS EVENING FOR KAIWI
CHANNEL-MAUI COUNTY WINDWARD WATERS-MAUI COUNTY LEEWARD WATERS-
MAALAEA BAY-PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND
WINDWARD WATERS-BIG ISLAND LEEWARD WATERS-BIG ISLAND SOUTHEAST
WATERS.

&&

$$

AVIATION...EATON
REST...RYSHKO







000
FXHW60 PHFO 190614
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
830 PM HST THU DEC 18 2014

.SYNOPSIS...
MODERATE TRADE WINDS WILL KEEP MOSTLY LIGHT SHOWERS FOCUSED OVER
WINDWARD SLOPES INTO THE WEEKEND. FROM SUNDAY NIGHT INTO MONDAY...A
FRONT WILL SPREAD RAIN...COLD AIR...AND STRONG NORTHERLY WINDS
ACROSS THE STATE FROM THE NORTHWEST. UNSETTLED WEATHER WILL CONTINUE
THROUGH ABOUT TUESDAY...BEFORE RETURNING GRADUALLY TO TRADE-WIND
CONDITIONS BY THE END OF NEXT WEEK.

&&

.DISCUSSION...
SURFACE OBSERVATIONS AROUND THE MAIN HAWAIIAN ISLANDS REPORTED
MOSTLY MODERATE TO STRONG TRADE WINDS. UNDER A FAIRLY TYPICAL
INVERSION...CLOUD COVER AND SHOWER ACTIVITY APPROXIMATED
CLIMATOLOGY...EXCEPT FOR ENHANCED STRATOCUMULUS AND STRATUS COVER
PULSING UP NORTHWEST OF OAHU UNDER THE INFLUENCE OF A PASSING
GRAVITY WAVE. RADAR DETECTED SCATTERED SHOWERS OVER THE COASTAL
WATERS...BUT ACCUMULATION OVER LAND REMAINED GENERALLY LIGHT...AND
LIMITED MAINLY TO WINDWARD SLOPES. A PASSING CLUMP OF CIRRUS OVER
MAUI COUNTY SHOULD DISSIPATE PROMPTLY...THOUGH MORE LAYERS MOVING
NORTH OUT OF THE ITCZ MAY SHADE THE STATE INTO FRIDAY. ALOFT...
STRONG AND BROAD RIDGING PREVAILED OVER THE ISLANDS...SUPPORTING THE
SUBTROPICAL RIDGE AT THE SURFACE TO THE NORTH.

GUIDANCE AGREED FAIRLY WELL THAT A LONG-WAVE MID-LEVEL TROUGH WILL
DIG TOWARD THE STATE FROM THE NORTHWEST THROUGH THE WEEKEND...
EFFECTIVELY DISPLACING THE RIDGE BY SUNDAY EVENING...AND THEN
SHARPENING TOWARD THE SOUTHWEST INTO TUESDAY. THIS DEVELOPMENT ALOFT
WILL SUPPORT THE APPROACH OF A FRONT AT THE SURFACE. THROUGH ABOUT
SUNDAY...THE SUBTROPICAL RIDGE WILL RECEDE TOWARD THE EAST AHEAD OF
THE FRONT...CAUSING SURFACE WINDS AROUND THE ISLANDS TO DIMINISH AND
BECOME MORE SOUTHEASTERLY. FROM SUNDAY NIGHT INTO NEXT WEEK...THE
FRONT WILL WORKS ITS WAY SOUTHEAST ACROSS THE STATE. WITH
SIGNIFICANT SUPPORT FROM THE DIGGING TROUGH ALOFT...THE FRONT WILL
HAVE THE OPPORTUNITY TO PRODUCE WIDESPREAD RAIN. THE PUSH OF COLD
AIR AT LOW LEVELS BEHIND THE FRONT ALSO WILL BRING STRONG NORTHERLY
WINDS.

PERHAPS MOST IMPORTANTLY...A VERY COLD POOL OF AIR ALOFT WILL
ACCOMPANY THE MID-LEVEL TROUGH. THIS COLD POOL WILL DESTABILIZE THE
ATMOSPHERE SIGNIFICANTLY...INTRODUCING A NON-TRIVIAL RISK OF
THUNDERSTORMS AROUND MONDAY...ESPECIALLY FROM MOLOKAI NORTHWEST.
STRONG VERTICAL WIND SHEAR WILL IMPROVE THE VENTILATION OF ANY
THUNDERSTORMS THAT DO DEVELOP...POTENTIALLY ALLOWING SOME TO BECOME
SEVERE. WHILE MODEL DIFFERENCES CAST SOME DOUBT ON THE LIKELIHOOD OF
SUCH AN OUTCOME THAT FAR OUT...POSSIBLE HIGH IMPACTS REQUIRED
CONTINUED VIGILANCE. AT THE VERY LEAST...IF CONSENSUS CONTINUES DOWN
THIS ROAD...THEN IT WILL BECOME PRUDENT SOON TO MENTION IN THE
OFFICIAL FORECAST A SLIGHT CHANCE OF THUNDERSTORMS AROUND MONDAY FOR
KAUAI AND OAHU.

FROM WEDNESDAY INTO FRIDAY OF NEXT WEEK...THE TROUGH ALOFT WILL LIFT
OUT TOWARD THE NORTHEAST...AND CONDITIONS WILL RETURN TOWARD
CLIMATOLOGY...THOUGH THIS PROCESS REMAINED SLIGHTLY SLOWER IN ECMWF
SOLUTIONS. MOST MODELS ALSO KEPT LOCAL SURFACE WINDS MORE NORTHERLY
THAN USUAL AS LATE AS FRIDAY. ON THE WHOLE THOUGH...TRADE-WIND
WEATHER WILL PREVAIL BY NEXT WEEKEND.

&&

.MARINE...
A COMBINATION OF INCREASING NORTHWEST SWELL AND STRONG WINDS
CONTINUED TO REQUIRE A SMALL CRAFT ADVISORY /SCA/ FOR NEARLY ALL
COASTAL WATERS THROUGH 6 PM HST FRIDAY. CONDITIONS SHOULD SUBSIDE
FRIDAY EVENING...BUT THEN ANOTHER LARGE NORTHWEST WILL PRODUCE SCA
CONDITIONS AGAIN BY SATURDAY NIGHT.

AN EVEN LARGER NW SWELL IS EXPECTED TO ARRIVE ON SUNDAY...LIKELY
PUSHING SURF HEIGHTS INTO WARNING LEVELS OVER BOTH NORTH- AND
WEST-FACING SHORES OF MOST ISLANDS. DEEP LOW PRESSURE FAR NORTH OF
THE STATE MAY CONTINUE TO PRODUCE SWELLS KEEPING SURF ELEVATED TO
NEAR THE ADVISORY LEVELS THROUGH THE SECOND HALF OF NEXT WEEK.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 PM HST FRIDAY FOR NIIHAU-KAUAI
WINDWARD-KAUAI LEEWARD-WAIANAE COAST-OAHU NORTH SHORE-OAHU
KOOLAU-MOLOKAI-MAUI WINDWARD WEST-WINDWARD HALEAKALA.

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

&&

$$

RYSHKO







000
FXHW60 PHFO 190614
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
830 PM HST THU DEC 18 2014

.SYNOPSIS...
MODERATE TRADE WINDS WILL KEEP MOSTLY LIGHT SHOWERS FOCUSED OVER
WINDWARD SLOPES INTO THE WEEKEND. FROM SUNDAY NIGHT INTO MONDAY...A
FRONT WILL SPREAD RAIN...COLD AIR...AND STRONG NORTHERLY WINDS
ACROSS THE STATE FROM THE NORTHWEST. UNSETTLED WEATHER WILL CONTINUE
THROUGH ABOUT TUESDAY...BEFORE RETURNING GRADUALLY TO TRADE-WIND
CONDITIONS BY THE END OF NEXT WEEK.

&&

.DISCUSSION...
SURFACE OBSERVATIONS AROUND THE MAIN HAWAIIAN ISLANDS REPORTED
MOSTLY MODERATE TO STRONG TRADE WINDS. UNDER A FAIRLY TYPICAL
INVERSION...CLOUD COVER AND SHOWER ACTIVITY APPROXIMATED
CLIMATOLOGY...EXCEPT FOR ENHANCED STRATOCUMULUS AND STRATUS COVER
PULSING UP NORTHWEST OF OAHU UNDER THE INFLUENCE OF A PASSING
GRAVITY WAVE. RADAR DETECTED SCATTERED SHOWERS OVER THE COASTAL
WATERS...BUT ACCUMULATION OVER LAND REMAINED GENERALLY LIGHT...AND
LIMITED MAINLY TO WINDWARD SLOPES. A PASSING CLUMP OF CIRRUS OVER
MAUI COUNTY SHOULD DISSIPATE PROMPTLY...THOUGH MORE LAYERS MOVING
NORTH OUT OF THE ITCZ MAY SHADE THE STATE INTO FRIDAY. ALOFT...
STRONG AND BROAD RIDGING PREVAILED OVER THE ISLANDS...SUPPORTING THE
SUBTROPICAL RIDGE AT THE SURFACE TO THE NORTH.

GUIDANCE AGREED FAIRLY WELL THAT A LONG-WAVE MID-LEVEL TROUGH WILL
DIG TOWARD THE STATE FROM THE NORTHWEST THROUGH THE WEEKEND...
EFFECTIVELY DISPLACING THE RIDGE BY SUNDAY EVENING...AND THEN
SHARPENING TOWARD THE SOUTHWEST INTO TUESDAY. THIS DEVELOPMENT ALOFT
WILL SUPPORT THE APPROACH OF A FRONT AT THE SURFACE. THROUGH ABOUT
SUNDAY...THE SUBTROPICAL RIDGE WILL RECEDE TOWARD THE EAST AHEAD OF
THE FRONT...CAUSING SURFACE WINDS AROUND THE ISLANDS TO DIMINISH AND
BECOME MORE SOUTHEASTERLY. FROM SUNDAY NIGHT INTO NEXT WEEK...THE
FRONT WILL WORKS ITS WAY SOUTHEAST ACROSS THE STATE. WITH
SIGNIFICANT SUPPORT FROM THE DIGGING TROUGH ALOFT...THE FRONT WILL
HAVE THE OPPORTUNITY TO PRODUCE WIDESPREAD RAIN. THE PUSH OF COLD
AIR AT LOW LEVELS BEHIND THE FRONT ALSO WILL BRING STRONG NORTHERLY
WINDS.

PERHAPS MOST IMPORTANTLY...A VERY COLD POOL OF AIR ALOFT WILL
ACCOMPANY THE MID-LEVEL TROUGH. THIS COLD POOL WILL DESTABILIZE THE
ATMOSPHERE SIGNIFICANTLY...INTRODUCING A NON-TRIVIAL RISK OF
THUNDERSTORMS AROUND MONDAY...ESPECIALLY FROM MOLOKAI NORTHWEST.
STRONG VERTICAL WIND SHEAR WILL IMPROVE THE VENTILATION OF ANY
THUNDERSTORMS THAT DO DEVELOP...POTENTIALLY ALLOWING SOME TO BECOME
SEVERE. WHILE MODEL DIFFERENCES CAST SOME DOUBT ON THE LIKELIHOOD OF
SUCH AN OUTCOME THAT FAR OUT...POSSIBLE HIGH IMPACTS REQUIRED
CONTINUED VIGILANCE. AT THE VERY LEAST...IF CONSENSUS CONTINUES DOWN
THIS ROAD...THEN IT WILL BECOME PRUDENT SOON TO MENTION IN THE
OFFICIAL FORECAST A SLIGHT CHANCE OF THUNDERSTORMS AROUND MONDAY FOR
KAUAI AND OAHU.

FROM WEDNESDAY INTO FRIDAY OF NEXT WEEK...THE TROUGH ALOFT WILL LIFT
OUT TOWARD THE NORTHEAST...AND CONDITIONS WILL RETURN TOWARD
CLIMATOLOGY...THOUGH THIS PROCESS REMAINED SLIGHTLY SLOWER IN ECMWF
SOLUTIONS. MOST MODELS ALSO KEPT LOCAL SURFACE WINDS MORE NORTHERLY
THAN USUAL AS LATE AS FRIDAY. ON THE WHOLE THOUGH...TRADE-WIND
WEATHER WILL PREVAIL BY NEXT WEEKEND.

&&

.MARINE...
A COMBINATION OF INCREASING NORTHWEST SWELL AND STRONG WINDS
CONTINUED TO REQUIRE A SMALL CRAFT ADVISORY /SCA/ FOR NEARLY ALL
COASTAL WATERS THROUGH 6 PM HST FRIDAY. CONDITIONS SHOULD SUBSIDE
FRIDAY EVENING...BUT THEN ANOTHER LARGE NORTHWEST WILL PRODUCE SCA
CONDITIONS AGAIN BY SATURDAY NIGHT.

AN EVEN LARGER NW SWELL IS EXPECTED TO ARRIVE ON SUNDAY...LIKELY
PUSHING SURF HEIGHTS INTO WARNING LEVELS OVER BOTH NORTH- AND
WEST-FACING SHORES OF MOST ISLANDS. DEEP LOW PRESSURE FAR NORTH OF
THE STATE MAY CONTINUE TO PRODUCE SWELLS KEEPING SURF ELEVATED TO
NEAR THE ADVISORY LEVELS THROUGH THE SECOND HALF OF NEXT WEEK.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 PM HST FRIDAY FOR NIIHAU-KAUAI
WINDWARD-KAUAI LEEWARD-WAIANAE COAST-OAHU NORTH SHORE-OAHU
KOOLAU-MOLOKAI-MAUI WINDWARD WEST-WINDWARD HALEAKALA.

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

&&

$$

RYSHKO






000
FXHW60 PHFO 190208
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
345 PM HST THU DEC 18 2014

.SYNOPSIS...
HIGH PRESSURE CENTERED NORTH OF THE ISLANDS WILL MAINTAIN LOCALLY
BREEZY TRADE WINDS THROUGH FRIDAY. SHOWERS WILL CONTINUE OVER MOST
WINDWARD AND MOUNTAIN AREAS TONIGHT...WITH ISOLATED SHOWERS POSSIBLE
OVER LEEWARD LOCATIONS INCLUDING THE HONOLULU METRO AREA. THE TRADES
ARE EXPECTED TO DECREASE DURING THE WEEKEND AS THE HIGH MOVES
FURTHER AWAY FROM THE ALOHA STATE AND A COLD FRONT APPROACHES THE
ISLANDS FROM THE NORTHWEST. THE FRONT WILL REACH THE ISLAND CHAIN ON
MONDAY AND LINGER THROUGH TUESDAY WITH INCREASING SHOWERS AND
POTENTIAL FOR LOCALIZED HEAVY RAIN. STRONG NORTHERLY WINDS ARE
EXPECTED BEHIND THE FRONT BY THE MIDDLE OF NEXT WEEK.

&&

.DISCUSSION...
HIGH PRESSURE NE OF THE ISLANDS WILL CONTINUE TO MIGRATE E DURING
THE WEEKEND AS A SHORT WAVE TROUGH FAR NW OF THE AREA PUSHES A COLD
FRONT BOUNDARY TOWARDS THE ISLANDS. AS THE HIGH MOVES FURTHER
AWAY...EXPECT THE TRADES TO GRADUALLY DIMINISH AND ALLOWING FOR
PERIODS OF SEA/LAND BREEZES TO DEVELOP SAT...SUN AND POSSIBLY ON
MON. SHOWERS WILL CONTINUE TO AFFECT WINDWARD AREAS...WITH LEEWARD
AND INTERIOR AREAS EXPERIENCING PERIODS OF CLOUDY SKIES AND
SCATTERED SHOWERS AS SEA BREEZES PUSH INLAND EACH AFTERNOON.
HOWEVER...SOUNDING/MODEL SOLUTIONS SUGGEST A RELATIVELY DRY AIRMASS
PERSISTING ALOFT DURING THE NEXT COUPLE OF DAYS...KEEPING VERTICAL
DEVELOPMENT OF SHOWERS TO A MINIMUM.

AS THE TROUGH/FRONT COMPLEX APPROACHES THE ISLANDS...INTENSITY
DIFFERENCES BETWEEN THE GLOBAL MODELS...MAINLY GFS AND ECMWF...ARE
MAKING THE FORECAST FOR MON AND MON NIGHT RATHER DIFFICULT. TIMING
WISE...BOTH ARE GRADUALLY BECOMING IN BETTER AGREEMENT IN TERMS OF
BRINGING THE BASE OF THE TROUGH INTO THE W HALF OF THE ISLAND CHAIN
LATE MON INTO TUE. THE SFC FRONT...HOWEVER...IS LOOKING WEAKER ON
GFS. 500 MB TEMPS ON GFS FOR THAT TIME PERIOD ARE AROUND -13C...
WHILE ECMWF SHOWS A LITTLE BETTER UPPER LVL SUPPORT WITH TEMPS
AROUND -17C.

REGARDLESS OF THE FINAL OUTCOME...THERE WILL BE AN INCREASE IN
SHOWER ACTIVITY ACROSS THE ALOHA STATE WITH THE FROPA STARTING MON
EVENING...AND POTENTIAL FOR LOCALIZED HEAVY RAIN. WILL LEAVE MENTION
OF THUNDERSTORMS OUT OF THE FORECAST ATTM...BUT UPCOMING GUIDANCE
WILL LIKELY SUPPORT MODIFYING THE FORECAST TO INCLUDE MENTION OF
SLIGHT CHANCES OF THUNDERSTORMS FOR MON NIGHT.

FOR THE LONG TERM FORECAST...THE MODELS REMAIN IN DISAGREEMENT
REGARDING THE SOLUTION FOR THE UPPER TROUGH. ECMWF KEEPS THE TROUGH
AXIS CLOSER OR OVER THE ISLANDS THROUGH LATE TUE WITH CHANCES OF
ENHANCED SHOWERS AND MAYBE SLIGHT CHANCES OF THUNDERSTORMS. GFS HAS
A FASTER SOLUTION...PUSHING THE TROUGH FURTHER TO THE NE OF THE
ISLANDS BY LATE TUE...SUGGESTING A DECREASE IN SHOWERS AND LITTLE
OR NO SUPPORT FOR DEEP CONVECTION BY THAT TIME. HOWEVER...BOTH
MODELS SHOW THE SFC FRONTAL BOUNDARY LINGERING ACROSS THE CENTRAL
PORTIONS OF THE STATE ON TUE...MAYBE REACHING MAUI COUNTY IN THE
AFTERNOON HOURS. THEREFORE...EXPECT AT LEAST A WETTER PATTERN
STARTING MON AFTERNOON AND EVENING...CONTINUING THROUGH TUE.

ONCE THE FRONTAL BOUNDARY AND THE TROUGH CLEAR THE AREA...MUCH
STRONGER N WINDS ARE ANTICIPATED...BRINGING PERIODS OF BREEZY TO
POSSIBLY WINDY CONDITIONS ACROSS THE ISLANDS FOR THE MIDDLE OF NEXT
WEEK. THE SITUATION WILL CONTINUE TO BE CLOSELY MONITORED AND
CHANGES TO THE FORECAST WILL CERTAINLY BE INCORPORATED AS NEW MODEL
GUIDANCE BECOMES AVAILABLE.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL OVER LEEWARD AREAS. WINDWARD AND
MAUKA...CLOUDS AND SHOWERS WILL MOVE IN WITH THE TRADE WINDS ARE
CAUSING ISOL MVFR CIGS AND MTN OBSC. COVERAGE MAY INCREASE TONIGHT
AND MAY REQUIRE AN AIRMET FOR MTN OBSC.

BREEZY TRADE WINDS ARE ALSO RESULTING IN LEEWARD MECHANICAL
TURBULENCE OVER ALL ISLANDS. AIRMET TANGO IS IN EFFECT FOR THIS...
AND WILL LIKELY CARRY ON THROUGH THE DAY FRIDAY.

&&

.MARINE...
THE SMALL CRAFT ADVISORY /SCA/ HAS BEEN EXPANDED TO INCLUDE
BASICALLY ALL COASTAL WATERS THROUGH FRIDAY 6 PM HST FOR A
COMBINATION OF INCREASING NORTHWEST SWELL AND STRONG WINDS
PERSISTING OVER THE SOUTHERN WATERS. CONDITIONS SHOULD THEN SUBSIDE
FRIDAY EVENING...THEN ANOTHER LARGE NORTHWEST SHOULD BRING BACK SCA
CONDITIONS BY SATURDAY NIGHT.

AN EVEN LARGER NW SWELL IS EXPECTED TO ARRIVE ON SUNDAY...LIKELY
PUSHING SURF HEIGHTS INTO WARNING LEVELS OVER BOTH NORTH AND WEST
FACING SHORES OF MOST ISLANDS. THE SOURCE OF THIS SWELL IS FROM A
RATHER BROAD STORM LOW CURRENTLY LOCATED OFF THE EAST COAST OF
JAPAN. IN ADDITION...A LOW PRESSURE SYSTEM FAR NORTH OF THE ALOHA
STATE MAY KEEP SURF ELEVATED OVER THE NORTH FACING SHORES...PROBABLY
AT ADVISORY LEVELS...THROUGH THE SECOND HALF OF NEXT WEEK.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 PM HST FRIDAY FOR NIIHAU-KAUAI
WINDWARD-KAUAI LEEWARD-WAIANAE COAST-OAHU NORTH SHORE-OAHU
KOOLAU-MOLOKAI-MAUI WINDWARD WEST-WINDWARD HALEAKALA.

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

&&

$$

DISCUSSION/MARINE...REYNES
AVIATION...FOSTER








000
FXHW60 PHFO 190208
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
345 PM HST THU DEC 18 2014

.SYNOPSIS...
HIGH PRESSURE CENTERED NORTH OF THE ISLANDS WILL MAINTAIN LOCALLY
BREEZY TRADE WINDS THROUGH FRIDAY. SHOWERS WILL CONTINUE OVER MOST
WINDWARD AND MOUNTAIN AREAS TONIGHT...WITH ISOLATED SHOWERS POSSIBLE
OVER LEEWARD LOCATIONS INCLUDING THE HONOLULU METRO AREA. THE TRADES
ARE EXPECTED TO DECREASE DURING THE WEEKEND AS THE HIGH MOVES
FURTHER AWAY FROM THE ALOHA STATE AND A COLD FRONT APPROACHES THE
ISLANDS FROM THE NORTHWEST. THE FRONT WILL REACH THE ISLAND CHAIN ON
MONDAY AND LINGER THROUGH TUESDAY WITH INCREASING SHOWERS AND
POTENTIAL FOR LOCALIZED HEAVY RAIN. STRONG NORTHERLY WINDS ARE
EXPECTED BEHIND THE FRONT BY THE MIDDLE OF NEXT WEEK.

&&

.DISCUSSION...
HIGH PRESSURE NE OF THE ISLANDS WILL CONTINUE TO MIGRATE E DURING
THE WEEKEND AS A SHORT WAVE TROUGH FAR NW OF THE AREA PUSHES A COLD
FRONT BOUNDARY TOWARDS THE ISLANDS. AS THE HIGH MOVES FURTHER
AWAY...EXPECT THE TRADES TO GRADUALLY DIMINISH AND ALLOWING FOR
PERIODS OF SEA/LAND BREEZES TO DEVELOP SAT...SUN AND POSSIBLY ON
MON. SHOWERS WILL CONTINUE TO AFFECT WINDWARD AREAS...WITH LEEWARD
AND INTERIOR AREAS EXPERIENCING PERIODS OF CLOUDY SKIES AND
SCATTERED SHOWERS AS SEA BREEZES PUSH INLAND EACH AFTERNOON.
HOWEVER...SOUNDING/MODEL SOLUTIONS SUGGEST A RELATIVELY DRY AIRMASS
PERSISTING ALOFT DURING THE NEXT COUPLE OF DAYS...KEEPING VERTICAL
DEVELOPMENT OF SHOWERS TO A MINIMUM.

AS THE TROUGH/FRONT COMPLEX APPROACHES THE ISLANDS...INTENSITY
DIFFERENCES BETWEEN THE GLOBAL MODELS...MAINLY GFS AND ECMWF...ARE
MAKING THE FORECAST FOR MON AND MON NIGHT RATHER DIFFICULT. TIMING
WISE...BOTH ARE GRADUALLY BECOMING IN BETTER AGREEMENT IN TERMS OF
BRINGING THE BASE OF THE TROUGH INTO THE W HALF OF THE ISLAND CHAIN
LATE MON INTO TUE. THE SFC FRONT...HOWEVER...IS LOOKING WEAKER ON
GFS. 500 MB TEMPS ON GFS FOR THAT TIME PERIOD ARE AROUND -13C...
WHILE ECMWF SHOWS A LITTLE BETTER UPPER LVL SUPPORT WITH TEMPS
AROUND -17C.

REGARDLESS OF THE FINAL OUTCOME...THERE WILL BE AN INCREASE IN
SHOWER ACTIVITY ACROSS THE ALOHA STATE WITH THE FROPA STARTING MON
EVENING...AND POTENTIAL FOR LOCALIZED HEAVY RAIN. WILL LEAVE MENTION
OF THUNDERSTORMS OUT OF THE FORECAST ATTM...BUT UPCOMING GUIDANCE
WILL LIKELY SUPPORT MODIFYING THE FORECAST TO INCLUDE MENTION OF
SLIGHT CHANCES OF THUNDERSTORMS FOR MON NIGHT.

FOR THE LONG TERM FORECAST...THE MODELS REMAIN IN DISAGREEMENT
REGARDING THE SOLUTION FOR THE UPPER TROUGH. ECMWF KEEPS THE TROUGH
AXIS CLOSER OR OVER THE ISLANDS THROUGH LATE TUE WITH CHANCES OF
ENHANCED SHOWERS AND MAYBE SLIGHT CHANCES OF THUNDERSTORMS. GFS HAS
A FASTER SOLUTION...PUSHING THE TROUGH FURTHER TO THE NE OF THE
ISLANDS BY LATE TUE...SUGGESTING A DECREASE IN SHOWERS AND LITTLE
OR NO SUPPORT FOR DEEP CONVECTION BY THAT TIME. HOWEVER...BOTH
MODELS SHOW THE SFC FRONTAL BOUNDARY LINGERING ACROSS THE CENTRAL
PORTIONS OF THE STATE ON TUE...MAYBE REACHING MAUI COUNTY IN THE
AFTERNOON HOURS. THEREFORE...EXPECT AT LEAST A WETTER PATTERN
STARTING MON AFTERNOON AND EVENING...CONTINUING THROUGH TUE.

ONCE THE FRONTAL BOUNDARY AND THE TROUGH CLEAR THE AREA...MUCH
STRONGER N WINDS ARE ANTICIPATED...BRINGING PERIODS OF BREEZY TO
POSSIBLY WINDY CONDITIONS ACROSS THE ISLANDS FOR THE MIDDLE OF NEXT
WEEK. THE SITUATION WILL CONTINUE TO BE CLOSELY MONITORED AND
CHANGES TO THE FORECAST WILL CERTAINLY BE INCORPORATED AS NEW MODEL
GUIDANCE BECOMES AVAILABLE.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL OVER LEEWARD AREAS. WINDWARD AND
MAUKA...CLOUDS AND SHOWERS WILL MOVE IN WITH THE TRADE WINDS ARE
CAUSING ISOL MVFR CIGS AND MTN OBSC. COVERAGE MAY INCREASE TONIGHT
AND MAY REQUIRE AN AIRMET FOR MTN OBSC.

BREEZY TRADE WINDS ARE ALSO RESULTING IN LEEWARD MECHANICAL
TURBULENCE OVER ALL ISLANDS. AIRMET TANGO IS IN EFFECT FOR THIS...
AND WILL LIKELY CARRY ON THROUGH THE DAY FRIDAY.

&&

.MARINE...
THE SMALL CRAFT ADVISORY /SCA/ HAS BEEN EXPANDED TO INCLUDE
BASICALLY ALL COASTAL WATERS THROUGH FRIDAY 6 PM HST FOR A
COMBINATION OF INCREASING NORTHWEST SWELL AND STRONG WINDS
PERSISTING OVER THE SOUTHERN WATERS. CONDITIONS SHOULD THEN SUBSIDE
FRIDAY EVENING...THEN ANOTHER LARGE NORTHWEST SHOULD BRING BACK SCA
CONDITIONS BY SATURDAY NIGHT.

AN EVEN LARGER NW SWELL IS EXPECTED TO ARRIVE ON SUNDAY...LIKELY
PUSHING SURF HEIGHTS INTO WARNING LEVELS OVER BOTH NORTH AND WEST
FACING SHORES OF MOST ISLANDS. THE SOURCE OF THIS SWELL IS FROM A
RATHER BROAD STORM LOW CURRENTLY LOCATED OFF THE EAST COAST OF
JAPAN. IN ADDITION...A LOW PRESSURE SYSTEM FAR NORTH OF THE ALOHA
STATE MAY KEEP SURF ELEVATED OVER THE NORTH FACING SHORES...PROBABLY
AT ADVISORY LEVELS...THROUGH THE SECOND HALF OF NEXT WEEK.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 PM HST FRIDAY FOR NIIHAU-KAUAI
WINDWARD-KAUAI LEEWARD-WAIANAE COAST-OAHU NORTH SHORE-OAHU
KOOLAU-MOLOKAI-MAUI WINDWARD WEST-WINDWARD HALEAKALA.

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

&&

$$

DISCUSSION/MARINE...REYNES
AVIATION...FOSTER









000
FXHW60 PHFO 190151
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
345 PM HST THU DEC 18 2014

.SYNOPSIS...
HIGH PRESSURE CENTERED NORTH OF THE ISLANDS WILL MAINTAIN LOCALLY
BREEZY TRADE WINDS THROUGH FRIDAY. SHOWERS WILL CONTINUE OVER MOST
WINDWARD AND MOUNTAIN AREAS TONIGHT...WITH ISOLATED SHOWERS POSSIBLE
OVER LEEWARD LOCATIONS INCLUDING THE HONOLULU METRO AREA. THE TRADES
ARE EXPECTED TO DECREASE DURING THE WEEKEND AS THE HIGH MOVES
FURTHER AWAY FROM THE ALOHA STATE AND A COLD FRONT APPROACHES THE
ISLANDS FROM THE NORTHWEST. THE FRONT WILL REACH THE ISLAND CHAIN ON
MON AND LINGER THROUGH TUESDAY WITH INCREASING SHOWERS AND POTENTIAL
FOR LOCALIZED HEAVY RAIN. STRONG NORTHERLY WINDS ARE EXPECTED BEHIND
THE FRONT BY THE MIDDLE OF NEXT WEEK.

&&

.DISCUSSION...
HIGH PRESSURE NE OF THE ISLANDS WILL CONTINUE TO MIGRATE E DURING
THE WEEKEND AS A SHORT WAVE TROUGH FAR NW OF THE AREA PUSHES A COLD
FRONT BOUNDARY TOWARDS THE ISLANDS. AS THE HIGH MOVES FURTHER
AWAY...EXPECT THE TRADES TO GRADUALLY DIMINISH AND ALLOWING FOR
PERIODS OF SEA/LAND BREEZES TO DEVELOP SAT...SUN AND POSSIBLY ON
MON. SHOWERS WILL CONTINUE TO AFFECT WINDWARD AREAS...WITH LEEWARD
AND INTERIOR AREAS EXPERIENCING PERIODS OF CLOUDY SKIES AND
SCATTERED SHOWERS AS SEA BREEZES PUSH INLAND EACH AFTERNOON.
HOWEVER...SOUNDING/MODEL SOLUTIONS SUGGEST A RELATIVELY DRY AIRMASS
PERSISTING ALOFT DURING THE NEXT COUPLE OF DAYS...KEEPING VERTICAL
DEVELOPMENT OF SHOWERS TO A MINIMUM.

AS THE TROUGH/FRONT COMPLEX APPROACHES THE ISLANDS...INTENSITY
DIFFERENCES BETWEEN THE GLOBAL MODELS...MAINLY GFS AND ECMWF...ARE
MAKING THE FORECAST FOR MON AND MON NIGHT RATHER DIFFICULT. TIMING
WISE...BOTH ARE GRADUALLY BECOMING IN BETTER AGREEMENT IN TERMS OF
BRINGING THE BASE OF THE TROUGH INTO THE W HALF OF THE ISLAND CHAIN
LATE MON INTO TUE. THE SFC FRONT...HOWEVER...IS LOOKING WEAKER ON
GFS. 500 MB TEMPS ON GFS FOR THAT TIME PERIOD ARE AROUND -13C...
WHILE ECMWF SHOWS A LITTLE BETTER UPPER LVL SUPPORT WITH TEMPS
AROUND -17C.

REGARDLESS OF THE FINAL OUTCOME...THERE WILL BE AN INCREASE IN
SHOWER ACTIVITY ACROSS THE ALOHA STATE WITH THE FROPA STARTING MON
EVENING...AND POTENTIAL FOR LOCALIZED HEAVY RAIN. WILL LEAVE MENTION
OF THUNDERSTORMS OUT OF THE FORECAST ATTM...BUT UPCOMING GUIDANCE
WILL LIKELY SUPPORT MODIFYING THE FORECAST TO INCLUDE MENTION OF
SLIGHT CHANCES OF THUNDERSTORMS FOR MON NIGHT.

FOR THE LONG TERM FORECAST...THE MODELS REMAIN IN DISAGREEMENT
REGARDING THE SOLUTION FOR THE UPPER TROUGH. ECMWF KEEPS THE TROUGH
AXIS CLOSER OR OVER THE ISLANDS THROUGH LATE TUE WITH CHANCES OF
ENHANCED SHOWERS AND MAYBE SLIGHT CHANCES OF THUNDERSTORMS. GFS HAS
A FASTER SOLUTION...PUSHING THE TROUGH FURTHER TO THE NE OF THE
ISLANDS BY LATE TUE...SUGGESTING A DECREASE IN SHOWERS AND LITTLE
OR NO SUPPORT FOR DEEP CONVECTION BY THAT TIME. HOWEVER...BOTH
MODELS SHOW THE SFC FRONTAL BOUNDARY LINGERING ACROSS THE CENTRAL
PORTIONS OF THE STATE ON TUE...MAYBE REACHING MAUI COUNTY IN THE
AFTERNOON HOURS. THEREFORE...EXPECT AT LEAST A WETTER PATTERN
STARTING MON AFTERNOON AND EVENING...CONTINUING THROUGH TUE.

ONCE THE FRONTAL BOUNDARY AND THE TROUGH CLEAR THE AREA...MUCH
STRONGER N WINDS ARE ANTICIPATED...BRINGING PERIODS OF BREEZY TO
POSSIBLY WINDY CONDITIONS ACROSS THE ISLANDS FOR THE MIDDLE OF NEXT
WEEK. THE SITUATION WILL CONTINUE TO BE CLOSELY MONITORED AND
CHANGES TO THE FORECAST WILL CERTAINLY BE INCORPORATED AS NEW MODEL
GUIDANCE BECOMES AVAILABLE.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL OVER LEEWARD AREAS. WINDWARD AND
MAUKA...CLOUDS AND SHOWERS WILL MOVE IN WITH THE TRADE WINDS ARE
CAUSING ISOL MVFR CIGS AND MTN OBSC. COVERAGE MAY INCREASE TONIGHT
AND MAY REQUIRE AN AIRMET FOR MTN OBSC.

BREEZY TRADE WINDS ARE ALSO RESULTING IN LEEWARD MECHANICAL
TURBULENCE OVER ALL ISLANDS. AIRMET TANGO IS IN EFFECT FOR THIS...
AND WILL LIKELY CARRY ON THROUGH THE DAY FRIDAY.

&&

.MARINE...
THE SMALL CRAFT ADVISORY /SCA/ HAS BEEN EXPANDED TO INCLUDE
BASICALLY ALL COASTAL WATERS THROUGH FRIDAY 6 PM HST FOR A
COMBINATION OF INCREASING NORTHWEST SWELL AND STRONG WINDS
PERSISTING OVER THE SOUTHERN WATERS. CONDITIONS SHOULD THEN SUBSIDE
FRIDAY EVENING...THEN ANOTHER LARGE NORTHWEST SHOULD BRING BACK SCA
CONDITIONS BY SATURDAY NIGHT.

AN EVEN LARGER NW SWELL IS EXPECTED TO ARRIVE ON SUNDAY...LIKELY
PUSHING SURF HEIGHTS INTO WARNING LEVELS OVER BOTH NORTH AND WEST
FACING SHORES OF MOST ISLANDS. THE SOURCE OF THIS SWELL IS FROM A
RATHER BROAD STORM LOW CURRENTLY LOCATED OFF THE EAST COAST OF
JAPAN. IN ADDITION...A LOW PRESSURE SYSTEM FAR NORTH OF THE ALOHA
STATE MAY KEEP SURF ELEVATED OVER THE NORTH FACING SHORES...PROBABLY
AT ADVISORY LEVELS...THROUGH THE SECOND HALF OF NEXT WEEK.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 PM HST FRIDAY FOR NIIHAU-KAUAI
WINDWARD-KAUAI LEEWARD-WAIANAE COAST-OAHU NORTH SHORE-OAHU
KOOLAU-MOLOKAI-MAUI WINDWARD WEST-WINDWARD HALEAKALA.

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

&&

$$

DISCUSSION/MARINE...REYNES
AVIATION...FOSTER







000
FXHW60 PHFO 190151
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
345 PM HST THU DEC 18 2014

.SYNOPSIS...
HIGH PRESSURE CENTERED NORTH OF THE ISLANDS WILL MAINTAIN LOCALLY
BREEZY TRADE WINDS THROUGH FRIDAY. SHOWERS WILL CONTINUE OVER MOST
WINDWARD AND MOUNTAIN AREAS TONIGHT...WITH ISOLATED SHOWERS POSSIBLE
OVER LEEWARD LOCATIONS INCLUDING THE HONOLULU METRO AREA. THE TRADES
ARE EXPECTED TO DECREASE DURING THE WEEKEND AS THE HIGH MOVES
FURTHER AWAY FROM THE ALOHA STATE AND A COLD FRONT APPROACHES THE
ISLANDS FROM THE NORTHWEST. THE FRONT WILL REACH THE ISLAND CHAIN ON
MON AND LINGER THROUGH TUESDAY WITH INCREASING SHOWERS AND POTENTIAL
FOR LOCALIZED HEAVY RAIN. STRONG NORTHERLY WINDS ARE EXPECTED BEHIND
THE FRONT BY THE MIDDLE OF NEXT WEEK.

&&

.DISCUSSION...
HIGH PRESSURE NE OF THE ISLANDS WILL CONTINUE TO MIGRATE E DURING
THE WEEKEND AS A SHORT WAVE TROUGH FAR NW OF THE AREA PUSHES A COLD
FRONT BOUNDARY TOWARDS THE ISLANDS. AS THE HIGH MOVES FURTHER
AWAY...EXPECT THE TRADES TO GRADUALLY DIMINISH AND ALLOWING FOR
PERIODS OF SEA/LAND BREEZES TO DEVELOP SAT...SUN AND POSSIBLY ON
MON. SHOWERS WILL CONTINUE TO AFFECT WINDWARD AREAS...WITH LEEWARD
AND INTERIOR AREAS EXPERIENCING PERIODS OF CLOUDY SKIES AND
SCATTERED SHOWERS AS SEA BREEZES PUSH INLAND EACH AFTERNOON.
HOWEVER...SOUNDING/MODEL SOLUTIONS SUGGEST A RELATIVELY DRY AIRMASS
PERSISTING ALOFT DURING THE NEXT COUPLE OF DAYS...KEEPING VERTICAL
DEVELOPMENT OF SHOWERS TO A MINIMUM.

AS THE TROUGH/FRONT COMPLEX APPROACHES THE ISLANDS...INTENSITY
DIFFERENCES BETWEEN THE GLOBAL MODELS...MAINLY GFS AND ECMWF...ARE
MAKING THE FORECAST FOR MON AND MON NIGHT RATHER DIFFICULT. TIMING
WISE...BOTH ARE GRADUALLY BECOMING IN BETTER AGREEMENT IN TERMS OF
BRINGING THE BASE OF THE TROUGH INTO THE W HALF OF THE ISLAND CHAIN
LATE MON INTO TUE. THE SFC FRONT...HOWEVER...IS LOOKING WEAKER ON
GFS. 500 MB TEMPS ON GFS FOR THAT TIME PERIOD ARE AROUND -13C...
WHILE ECMWF SHOWS A LITTLE BETTER UPPER LVL SUPPORT WITH TEMPS
AROUND -17C.

REGARDLESS OF THE FINAL OUTCOME...THERE WILL BE AN INCREASE IN
SHOWER ACTIVITY ACROSS THE ALOHA STATE WITH THE FROPA STARTING MON
EVENING...AND POTENTIAL FOR LOCALIZED HEAVY RAIN. WILL LEAVE MENTION
OF THUNDERSTORMS OUT OF THE FORECAST ATTM...BUT UPCOMING GUIDANCE
WILL LIKELY SUPPORT MODIFYING THE FORECAST TO INCLUDE MENTION OF
SLIGHT CHANCES OF THUNDERSTORMS FOR MON NIGHT.

FOR THE LONG TERM FORECAST...THE MODELS REMAIN IN DISAGREEMENT
REGARDING THE SOLUTION FOR THE UPPER TROUGH. ECMWF KEEPS THE TROUGH
AXIS CLOSER OR OVER THE ISLANDS THROUGH LATE TUE WITH CHANCES OF
ENHANCED SHOWERS AND MAYBE SLIGHT CHANCES OF THUNDERSTORMS. GFS HAS
A FASTER SOLUTION...PUSHING THE TROUGH FURTHER TO THE NE OF THE
ISLANDS BY LATE TUE...SUGGESTING A DECREASE IN SHOWERS AND LITTLE
OR NO SUPPORT FOR DEEP CONVECTION BY THAT TIME. HOWEVER...BOTH
MODELS SHOW THE SFC FRONTAL BOUNDARY LINGERING ACROSS THE CENTRAL
PORTIONS OF THE STATE ON TUE...MAYBE REACHING MAUI COUNTY IN THE
AFTERNOON HOURS. THEREFORE...EXPECT AT LEAST A WETTER PATTERN
STARTING MON AFTERNOON AND EVENING...CONTINUING THROUGH TUE.

ONCE THE FRONTAL BOUNDARY AND THE TROUGH CLEAR THE AREA...MUCH
STRONGER N WINDS ARE ANTICIPATED...BRINGING PERIODS OF BREEZY TO
POSSIBLY WINDY CONDITIONS ACROSS THE ISLANDS FOR THE MIDDLE OF NEXT
WEEK. THE SITUATION WILL CONTINUE TO BE CLOSELY MONITORED AND
CHANGES TO THE FORECAST WILL CERTAINLY BE INCORPORATED AS NEW MODEL
GUIDANCE BECOMES AVAILABLE.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL OVER LEEWARD AREAS. WINDWARD AND
MAUKA...CLOUDS AND SHOWERS WILL MOVE IN WITH THE TRADE WINDS ARE
CAUSING ISOL MVFR CIGS AND MTN OBSC. COVERAGE MAY INCREASE TONIGHT
AND MAY REQUIRE AN AIRMET FOR MTN OBSC.

BREEZY TRADE WINDS ARE ALSO RESULTING IN LEEWARD MECHANICAL
TURBULENCE OVER ALL ISLANDS. AIRMET TANGO IS IN EFFECT FOR THIS...
AND WILL LIKELY CARRY ON THROUGH THE DAY FRIDAY.

&&

.MARINE...
THE SMALL CRAFT ADVISORY /SCA/ HAS BEEN EXPANDED TO INCLUDE
BASICALLY ALL COASTAL WATERS THROUGH FRIDAY 6 PM HST FOR A
COMBINATION OF INCREASING NORTHWEST SWELL AND STRONG WINDS
PERSISTING OVER THE SOUTHERN WATERS. CONDITIONS SHOULD THEN SUBSIDE
FRIDAY EVENING...THEN ANOTHER LARGE NORTHWEST SHOULD BRING BACK SCA
CONDITIONS BY SATURDAY NIGHT.

AN EVEN LARGER NW SWELL IS EXPECTED TO ARRIVE ON SUNDAY...LIKELY
PUSHING SURF HEIGHTS INTO WARNING LEVELS OVER BOTH NORTH AND WEST
FACING SHORES OF MOST ISLANDS. THE SOURCE OF THIS SWELL IS FROM A
RATHER BROAD STORM LOW CURRENTLY LOCATED OFF THE EAST COAST OF
JAPAN. IN ADDITION...A LOW PRESSURE SYSTEM FAR NORTH OF THE ALOHA
STATE MAY KEEP SURF ELEVATED OVER THE NORTH FACING SHORES...PROBABLY
AT ADVISORY LEVELS...THROUGH THE SECOND HALF OF NEXT WEEK.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 PM HST FRIDAY FOR NIIHAU-KAUAI
WINDWARD-KAUAI LEEWARD-WAIANAE COAST-OAHU NORTH SHORE-OAHU
KOOLAU-MOLOKAI-MAUI WINDWARD WEST-WINDWARD HALEAKALA.

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

&&

$$

DISCUSSION/MARINE...REYNES
AVIATION...FOSTER







000
FXHW60 PHFO 190151
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
345 PM HST THU DEC 18 2014

.SYNOPSIS...
HIGH PRESSURE CENTERED NORTH OF THE ISLANDS WILL MAINTAIN LOCALLY
BREEZY TRADE WINDS THROUGH FRIDAY. SHOWERS WILL CONTINUE OVER MOST
WINDWARD AND MOUNTAIN AREAS TONIGHT...WITH ISOLATED SHOWERS POSSIBLE
OVER LEEWARD LOCATIONS INCLUDING THE HONOLULU METRO AREA. THE TRADES
ARE EXPECTED TO DECREASE DURING THE WEEKEND AS THE HIGH MOVES
FURTHER AWAY FROM THE ALOHA STATE AND A COLD FRONT APPROACHES THE
ISLANDS FROM THE NORTHWEST. THE FRONT WILL REACH THE ISLAND CHAIN ON
MON AND LINGER THROUGH TUESDAY WITH INCREASING SHOWERS AND POTENTIAL
FOR LOCALIZED HEAVY RAIN. STRONG NORTHERLY WINDS ARE EXPECTED BEHIND
THE FRONT BY THE MIDDLE OF NEXT WEEK.

&&

.DISCUSSION...
HIGH PRESSURE NE OF THE ISLANDS WILL CONTINUE TO MIGRATE E DURING
THE WEEKEND AS A SHORT WAVE TROUGH FAR NW OF THE AREA PUSHES A COLD
FRONT BOUNDARY TOWARDS THE ISLANDS. AS THE HIGH MOVES FURTHER
AWAY...EXPECT THE TRADES TO GRADUALLY DIMINISH AND ALLOWING FOR
PERIODS OF SEA/LAND BREEZES TO DEVELOP SAT...SUN AND POSSIBLY ON
MON. SHOWERS WILL CONTINUE TO AFFECT WINDWARD AREAS...WITH LEEWARD
AND INTERIOR AREAS EXPERIENCING PERIODS OF CLOUDY SKIES AND
SCATTERED SHOWERS AS SEA BREEZES PUSH INLAND EACH AFTERNOON.
HOWEVER...SOUNDING/MODEL SOLUTIONS SUGGEST A RELATIVELY DRY AIRMASS
PERSISTING ALOFT DURING THE NEXT COUPLE OF DAYS...KEEPING VERTICAL
DEVELOPMENT OF SHOWERS TO A MINIMUM.

AS THE TROUGH/FRONT COMPLEX APPROACHES THE ISLANDS...INTENSITY
DIFFERENCES BETWEEN THE GLOBAL MODELS...MAINLY GFS AND ECMWF...ARE
MAKING THE FORECAST FOR MON AND MON NIGHT RATHER DIFFICULT. TIMING
WISE...BOTH ARE GRADUALLY BECOMING IN BETTER AGREEMENT IN TERMS OF
BRINGING THE BASE OF THE TROUGH INTO THE W HALF OF THE ISLAND CHAIN
LATE MON INTO TUE. THE SFC FRONT...HOWEVER...IS LOOKING WEAKER ON
GFS. 500 MB TEMPS ON GFS FOR THAT TIME PERIOD ARE AROUND -13C...
WHILE ECMWF SHOWS A LITTLE BETTER UPPER LVL SUPPORT WITH TEMPS
AROUND -17C.

REGARDLESS OF THE FINAL OUTCOME...THERE WILL BE AN INCREASE IN
SHOWER ACTIVITY ACROSS THE ALOHA STATE WITH THE FROPA STARTING MON
EVENING...AND POTENTIAL FOR LOCALIZED HEAVY RAIN. WILL LEAVE MENTION
OF THUNDERSTORMS OUT OF THE FORECAST ATTM...BUT UPCOMING GUIDANCE
WILL LIKELY SUPPORT MODIFYING THE FORECAST TO INCLUDE MENTION OF
SLIGHT CHANCES OF THUNDERSTORMS FOR MON NIGHT.

FOR THE LONG TERM FORECAST...THE MODELS REMAIN IN DISAGREEMENT
REGARDING THE SOLUTION FOR THE UPPER TROUGH. ECMWF KEEPS THE TROUGH
AXIS CLOSER OR OVER THE ISLANDS THROUGH LATE TUE WITH CHANCES OF
ENHANCED SHOWERS AND MAYBE SLIGHT CHANCES OF THUNDERSTORMS. GFS HAS
A FASTER SOLUTION...PUSHING THE TROUGH FURTHER TO THE NE OF THE
ISLANDS BY LATE TUE...SUGGESTING A DECREASE IN SHOWERS AND LITTLE
OR NO SUPPORT FOR DEEP CONVECTION BY THAT TIME. HOWEVER...BOTH
MODELS SHOW THE SFC FRONTAL BOUNDARY LINGERING ACROSS THE CENTRAL
PORTIONS OF THE STATE ON TUE...MAYBE REACHING MAUI COUNTY IN THE
AFTERNOON HOURS. THEREFORE...EXPECT AT LEAST A WETTER PATTERN
STARTING MON AFTERNOON AND EVENING...CONTINUING THROUGH TUE.

ONCE THE FRONTAL BOUNDARY AND THE TROUGH CLEAR THE AREA...MUCH
STRONGER N WINDS ARE ANTICIPATED...BRINGING PERIODS OF BREEZY TO
POSSIBLY WINDY CONDITIONS ACROSS THE ISLANDS FOR THE MIDDLE OF NEXT
WEEK. THE SITUATION WILL CONTINUE TO BE CLOSELY MONITORED AND
CHANGES TO THE FORECAST WILL CERTAINLY BE INCORPORATED AS NEW MODEL
GUIDANCE BECOMES AVAILABLE.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL OVER LEEWARD AREAS. WINDWARD AND
MAUKA...CLOUDS AND SHOWERS WILL MOVE IN WITH THE TRADE WINDS ARE
CAUSING ISOL MVFR CIGS AND MTN OBSC. COVERAGE MAY INCREASE TONIGHT
AND MAY REQUIRE AN AIRMET FOR MTN OBSC.

BREEZY TRADE WINDS ARE ALSO RESULTING IN LEEWARD MECHANICAL
TURBULENCE OVER ALL ISLANDS. AIRMET TANGO IS IN EFFECT FOR THIS...
AND WILL LIKELY CARRY ON THROUGH THE DAY FRIDAY.

&&

.MARINE...
THE SMALL CRAFT ADVISORY /SCA/ HAS BEEN EXPANDED TO INCLUDE
BASICALLY ALL COASTAL WATERS THROUGH FRIDAY 6 PM HST FOR A
COMBINATION OF INCREASING NORTHWEST SWELL AND STRONG WINDS
PERSISTING OVER THE SOUTHERN WATERS. CONDITIONS SHOULD THEN SUBSIDE
FRIDAY EVENING...THEN ANOTHER LARGE NORTHWEST SHOULD BRING BACK SCA
CONDITIONS BY SATURDAY NIGHT.

AN EVEN LARGER NW SWELL IS EXPECTED TO ARRIVE ON SUNDAY...LIKELY
PUSHING SURF HEIGHTS INTO WARNING LEVELS OVER BOTH NORTH AND WEST
FACING SHORES OF MOST ISLANDS. THE SOURCE OF THIS SWELL IS FROM A
RATHER BROAD STORM LOW CURRENTLY LOCATED OFF THE EAST COAST OF
JAPAN. IN ADDITION...A LOW PRESSURE SYSTEM FAR NORTH OF THE ALOHA
STATE MAY KEEP SURF ELEVATED OVER THE NORTH FACING SHORES...PROBABLY
AT ADVISORY LEVELS...THROUGH THE SECOND HALF OF NEXT WEEK.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 PM HST FRIDAY FOR NIIHAU-KAUAI
WINDWARD-KAUAI LEEWARD-WAIANAE COAST-OAHU NORTH SHORE-OAHU
KOOLAU-MOLOKAI-MAUI WINDWARD WEST-WINDWARD HALEAKALA.

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

&&

$$

DISCUSSION/MARINE...REYNES
AVIATION...FOSTER








000
FXHW60 PHFO 190151
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
345 PM HST THU DEC 18 2014

.SYNOPSIS...
HIGH PRESSURE CENTERED NORTH OF THE ISLANDS WILL MAINTAIN LOCALLY
BREEZY TRADE WINDS THROUGH FRIDAY. SHOWERS WILL CONTINUE OVER MOST
WINDWARD AND MOUNTAIN AREAS TONIGHT...WITH ISOLATED SHOWERS POSSIBLE
OVER LEEWARD LOCATIONS INCLUDING THE HONOLULU METRO AREA. THE TRADES
ARE EXPECTED TO DECREASE DURING THE WEEKEND AS THE HIGH MOVES
FURTHER AWAY FROM THE ALOHA STATE AND A COLD FRONT APPROACHES THE
ISLANDS FROM THE NORTHWEST. THE FRONT WILL REACH THE ISLAND CHAIN ON
MON AND LINGER THROUGH TUESDAY WITH INCREASING SHOWERS AND POTENTIAL
FOR LOCALIZED HEAVY RAIN. STRONG NORTHERLY WINDS ARE EXPECTED BEHIND
THE FRONT BY THE MIDDLE OF NEXT WEEK.

&&

.DISCUSSION...
HIGH PRESSURE NE OF THE ISLANDS WILL CONTINUE TO MIGRATE E DURING
THE WEEKEND AS A SHORT WAVE TROUGH FAR NW OF THE AREA PUSHES A COLD
FRONT BOUNDARY TOWARDS THE ISLANDS. AS THE HIGH MOVES FURTHER
AWAY...EXPECT THE TRADES TO GRADUALLY DIMINISH AND ALLOWING FOR
PERIODS OF SEA/LAND BREEZES TO DEVELOP SAT...SUN AND POSSIBLY ON
MON. SHOWERS WILL CONTINUE TO AFFECT WINDWARD AREAS...WITH LEEWARD
AND INTERIOR AREAS EXPERIENCING PERIODS OF CLOUDY SKIES AND
SCATTERED SHOWERS AS SEA BREEZES PUSH INLAND EACH AFTERNOON.
HOWEVER...SOUNDING/MODEL SOLUTIONS SUGGEST A RELATIVELY DRY AIRMASS
PERSISTING ALOFT DURING THE NEXT COUPLE OF DAYS...KEEPING VERTICAL
DEVELOPMENT OF SHOWERS TO A MINIMUM.

AS THE TROUGH/FRONT COMPLEX APPROACHES THE ISLANDS...INTENSITY
DIFFERENCES BETWEEN THE GLOBAL MODELS...MAINLY GFS AND ECMWF...ARE
MAKING THE FORECAST FOR MON AND MON NIGHT RATHER DIFFICULT. TIMING
WISE...BOTH ARE GRADUALLY BECOMING IN BETTER AGREEMENT IN TERMS OF
BRINGING THE BASE OF THE TROUGH INTO THE W HALF OF THE ISLAND CHAIN
LATE MON INTO TUE. THE SFC FRONT...HOWEVER...IS LOOKING WEAKER ON
GFS. 500 MB TEMPS ON GFS FOR THAT TIME PERIOD ARE AROUND -13C...
WHILE ECMWF SHOWS A LITTLE BETTER UPPER LVL SUPPORT WITH TEMPS
AROUND -17C.

REGARDLESS OF THE FINAL OUTCOME...THERE WILL BE AN INCREASE IN
SHOWER ACTIVITY ACROSS THE ALOHA STATE WITH THE FROPA STARTING MON
EVENING...AND POTENTIAL FOR LOCALIZED HEAVY RAIN. WILL LEAVE MENTION
OF THUNDERSTORMS OUT OF THE FORECAST ATTM...BUT UPCOMING GUIDANCE
WILL LIKELY SUPPORT MODIFYING THE FORECAST TO INCLUDE MENTION OF
SLIGHT CHANCES OF THUNDERSTORMS FOR MON NIGHT.

FOR THE LONG TERM FORECAST...THE MODELS REMAIN IN DISAGREEMENT
REGARDING THE SOLUTION FOR THE UPPER TROUGH. ECMWF KEEPS THE TROUGH
AXIS CLOSER OR OVER THE ISLANDS THROUGH LATE TUE WITH CHANCES OF
ENHANCED SHOWERS AND MAYBE SLIGHT CHANCES OF THUNDERSTORMS. GFS HAS
A FASTER SOLUTION...PUSHING THE TROUGH FURTHER TO THE NE OF THE
ISLANDS BY LATE TUE...SUGGESTING A DECREASE IN SHOWERS AND LITTLE
OR NO SUPPORT FOR DEEP CONVECTION BY THAT TIME. HOWEVER...BOTH
MODELS SHOW THE SFC FRONTAL BOUNDARY LINGERING ACROSS THE CENTRAL
PORTIONS OF THE STATE ON TUE...MAYBE REACHING MAUI COUNTY IN THE
AFTERNOON HOURS. THEREFORE...EXPECT AT LEAST A WETTER PATTERN
STARTING MON AFTERNOON AND EVENING...CONTINUING THROUGH TUE.

ONCE THE FRONTAL BOUNDARY AND THE TROUGH CLEAR THE AREA...MUCH
STRONGER N WINDS ARE ANTICIPATED...BRINGING PERIODS OF BREEZY TO
POSSIBLY WINDY CONDITIONS ACROSS THE ISLANDS FOR THE MIDDLE OF NEXT
WEEK. THE SITUATION WILL CONTINUE TO BE CLOSELY MONITORED AND
CHANGES TO THE FORECAST WILL CERTAINLY BE INCORPORATED AS NEW MODEL
GUIDANCE BECOMES AVAILABLE.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL OVER LEEWARD AREAS. WINDWARD AND
MAUKA...CLOUDS AND SHOWERS WILL MOVE IN WITH THE TRADE WINDS ARE
CAUSING ISOL MVFR CIGS AND MTN OBSC. COVERAGE MAY INCREASE TONIGHT
AND MAY REQUIRE AN AIRMET FOR MTN OBSC.

BREEZY TRADE WINDS ARE ALSO RESULTING IN LEEWARD MECHANICAL
TURBULENCE OVER ALL ISLANDS. AIRMET TANGO IS IN EFFECT FOR THIS...
AND WILL LIKELY CARRY ON THROUGH THE DAY FRIDAY.

&&

.MARINE...
THE SMALL CRAFT ADVISORY /SCA/ HAS BEEN EXPANDED TO INCLUDE
BASICALLY ALL COASTAL WATERS THROUGH FRIDAY 6 PM HST FOR A
COMBINATION OF INCREASING NORTHWEST SWELL AND STRONG WINDS
PERSISTING OVER THE SOUTHERN WATERS. CONDITIONS SHOULD THEN SUBSIDE
FRIDAY EVENING...THEN ANOTHER LARGE NORTHWEST SHOULD BRING BACK SCA
CONDITIONS BY SATURDAY NIGHT.

AN EVEN LARGER NW SWELL IS EXPECTED TO ARRIVE ON SUNDAY...LIKELY
PUSHING SURF HEIGHTS INTO WARNING LEVELS OVER BOTH NORTH AND WEST
FACING SHORES OF MOST ISLANDS. THE SOURCE OF THIS SWELL IS FROM A
RATHER BROAD STORM LOW CURRENTLY LOCATED OFF THE EAST COAST OF
JAPAN. IN ADDITION...A LOW PRESSURE SYSTEM FAR NORTH OF THE ALOHA
STATE MAY KEEP SURF ELEVATED OVER THE NORTH FACING SHORES...PROBABLY
AT ADVISORY LEVELS...THROUGH THE SECOND HALF OF NEXT WEEK.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 PM HST FRIDAY FOR NIIHAU-KAUAI
WINDWARD-KAUAI LEEWARD-WAIANAE COAST-OAHU NORTH SHORE-OAHU
KOOLAU-MOLOKAI-MAUI WINDWARD WEST-WINDWARD HALEAKALA.

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

&&

$$

DISCUSSION/MARINE...REYNES
AVIATION...FOSTER








000
FXHW60 PHFO 181932
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
932 AM HST THU DEC 18 2014

.SYNOPSIS...
HIGH PRESSURE CENTERED NORTH OF THE ISLANDS WILL MAINTAIN LOCALLY
BREEZY TRADE WINDS THROUGH FRIDAY. MOSTLY CLOUDY SKIES WITH FREQUENT
SHOWERS WILL CONTINUE OVER MOST WINDWARD AND MOUNTAIN AREAS THROUGH
THE REST OF THE MORNING HOURS...BECOMING SCATTERED IN THE AFTERNOON.
ISOLATED SHOWERS ARE POSSIBLE OVER LEEWARD AREAS TODAY. THE TRADES
ARE EXPECTED TO BECOME LIGHT OVER THE UPCOMING WEEKEND AS THE HIGH
LEAVES THE AREA AND A FRONT APPROACHES THE ISLANDS FROM THE
NORTHWEST. THE FRONT WILL MOVE DOWN THE ISLAND CHAIN BETWEEN SUNDAY
NIGHT AND TUESDAY NIGHT BRINGING WITH IT SOME SHOWERY AND WINDY
WEATHER.

&&

.DISCUSSION...
SATELLITE AND RADAR IMAGERY FROM EARLIER THIS MORNING SHOW A
PERSISTING ACTIVE SHOWER PATTERN ACROSS WINDWARD AREAS OF ALL THE
MAIN HAWAIIAN ISLANDS...WITH ADDITIONAL SHOWERS UPSTREAM HEADING
TOWARDS THE ALOHA STATE. THEREFORE...POPS HAVE BEEN INCREASED FOR
ALL WINDWARD AREAS FOR THE REST OF THE MORNING HOURS. POPS OVER
WINDWARD MAUI COUNTY HAVE ALSO BEEN INCREASED TO SCATTERED THIS
AFTERNOON AS THE TRADE WIND SHOWER PATTERN SHOULD REMAIN ACTIVE
TODAY.

DIFFERENCES REMAINS BETWEEN THE TWO GLOBAL MODELS...THE ECMWF
/EC/ AND GFS...REGARDING THE UPPER LEVEL SHORT WAVE TROUGH AND ITS
SUPPORT OF THE SURFACE FRONT EARLY NEXT WEEK.

THE MOST NOTABLE DIFFERENCE IS IN THE TIMING OF THE UPPER LEVEL
TROUGH WHERE THE EC HAS THE TROUGH JUST WEST OF KAUAI MONDAY EVENING
WHILE THE GFS HAS IT OVER KAUAI AND OAHU.

THE EC REMAINS THE STRONGER OF THE TWO WITH A COLD 500 MB TEMP OF
MINUS 17 C. THE GFS HAS A MINUS 14 C. NOT MUCH OF A DIFFERENCE HERE
WHERE BOTH TEMPS ARE COLD ENOUGH TO SUPPORT AT LEAST A SLIGHT CHANCE
OF A THUNDERSTORM AND ALMOST CERTAIN...SPOTTY HEAVY SHOWERS.

THE MODELS DIFFER THEREAFTER. THE EC KEEPS THE UPPER TROUGH OVER
THE ISLANDS TUESDAY...THUS MAINTAINING A CHANCE OF ENHANCED SHOWERS
AND A SLIGHT CHANCE OF A THUNDERSTORMS. ON THE OTHER HAND...THE GFS
HAS THE UPPER TROUGH FAR NE OF THE ISLANDS...SUGGESTING MORE LIGHT
TO MODERATE SHOWERS WITH THE FRONT. THE TWO MODELS DO AGREE ON THE
LOCATION OF THE FRONT...OVER MAUI TUESDAY AFTERNOON. SHOULD WE
PURSUE THE EC SOLUTION...IMPROVEMENT IN THE WEATHER WILL COME
TUESDAY NIGHT AS THE UPPER TROUGH FINALLY LIFTS OUT.

THIS IS STILL A GOOD FEW DAYS AWAY SO WE WILL WAIT AND SEE IF THE
MODELS MAINTAINS A SHOWERY OUTLOOK FOR MONDAY AND MONDAY NIGHT.

THE WEATHER PATTERN MAY TURN SLIGHTLY CONVECTIVE WITH LOCAL DAYTIME
SEA BREEZES AS THE TRADES EASES TO LIGHT TO LOCALLY MODERATE DURING
THE WEEKEND. A STRONG AND STABLE AIR MASS WILL PUT A LID ON THESE
CONVECTIVE CLOUDS. THERE WILL BE ENOUGH OF AN EASTERLY WIND FLOW TO
CARRY A FEW SHOWER BEARING CLOUDS TO THE WINDWARD AREAS OF ALL THE
ISLANDS.


&&

.AVIATION...
CLOUDS AND SHOWERS CARRYING IN WITH THE TRADE WINDS ARE CAUSING MVFR
CIGS AND TEMPO MTN OBSC THIS MORNING. THEREFORE...AIRMET SIERRA HAS
BEEN ISSUED FOR MTN OBSC ON THE WINDWARD SIDES OF OAHU...MOLOKAI AND
MAUI THROUGH 22Z. THE CLOUDS AND SHOWERS ARE EXPECTED TO DECREASE BY
AFTERNOON AS THE CLOUD TOPS WARM AND MIXING INCREASES.
ELSEWHERE...VFR CONDITIONS WILL PREVAIL.

BREEZY TRADE WINDS ARE ALSO RESULTING IN LEEWARD MECHANICAL
TURBULENCE OVER ALL ISLANDS. AIRMET TANGO IS IN EFFECT FOR THIS...
AND WILL LIKELY CARRY ON UNTIL FRIDAY.

&&

.MARINE...
A SMALL CRAFT ADVISORY /SCA/ REMAINS IN EFFECT FOR THE WINDWARD
WATERS OF KAUAI AND OAHU...DUE MAINLY TO A LARGE NW SWELL...AND FOR
MAALAEA BAY...THE WATERS SOUTH OF THE BIG ISLAND...AND THE PAILOLO
AND ALENUIHAHA CHANNELS DUE TO STRONG GUSTY WINDS. THE SCA IS VALID
THROUGH 6 PM HST FRIDAY.

WE DO LOOK FORWARD TO THE SCA BEING LOWER LATE FRIDAY AFTERNOON.
THIS WILL BE SHORT LIVE HOWEVER. SCA CONDITIONS ARE AGAIN EXPECTED
SATURDAY NIGHT FOR THE ANTICIPATED LARGE NW SWELL.

SURF HEIGHTS ARE EXPECTED TO RISE TO ADVISORY LEVELS FOR THE NORTH
AND WEST SHORES OF MOST OF THE SMALLER ISLANDS TONIGHT. SO...A SURF
ADVISORY WILL BE IN EFFECT FROM 4 PM HST THIS AFTERNOON THROUGH
FRIDAY. THIS SWELL WILL PEAK TONIGHT AND GRADUALLY LOWER FRIDAY.

AN UPCOMING LARGE NW SWELL ON SUNDAY WILL LIKELY NEED A HIGH SURF
WARNING INVOLVING BOTH NORTH AND WEST FACING SHORES OF MOST ISLANDS.
THE SOURCE OF THIS SWELL IS FROM A RATHER BROAD STORM LOW CURRENTLY
LOCATED OFF THE EAST COAST OF JAPAN. ANOTHER STORM LOW IS PREDICTED
BY THE MODELS TO FORM NORTH OF THE ISLANDS THE MIDDLE OF NEXT WEEK
WHICH MAY KEEP SURF ELEVATED IN AT LEAST THE ADVISORY RANGE THROUGH
CHRISTMAS.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 600 PM HST FRIDAY FOR WINDWARD WATERS OF
KAUAI AND OAHU...MAALAEA BAY...THE WATERS SOUTH OF THE BIG ISLAND...
AND THE PAILOLO AND ALENUIHAHA CHANNELS.

HIGH SURF ADVISORY FROM 4 PM THIS AFTERNOON TO 6 PM HST FRIDAY
FOR NIIHAU-KAUAI WINDWARD-KAUAI LEEWARD-WAIANAE COAST-OAHU NORTH
SHORE-OAHU KOOLAU-MOLOKAI-MAUI WINDWARD WEST-WINDWARD HALEAKALA.

&&

$$

DISCUSSION/MARINE...REYNES/LAU
AVIATION...FOSTER








000
FXHW60 PHFO 181415
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
340 AM HST THU DEC 18 2014

.SYNOPSIS...
HIGH PRESSURE CENTERED NORTH OF THE ISLANDS WILL MAINTAIN LOCALLY
BREEZY TRADE WINDS THROUGH FRIDAY. THE TRADES WILL FOCUS SHOWERS
OVER WINDWARD AND MOUNTAIN AREAS. THE WINDS WILL BECOME LIGHT OVER
THE WEEKEND AS THE HIGH LEAVES THE AREA AND A FRONT APPROACHES THE
ISLANDS FROM THE NORTHWEST. THE FRONT WILL MOVE DOWN THE ISLAND
CHAIN BETWEEN SUNDAY NIGHT AND TUESDAY NIGHT BRINGING WITH IT SOME
SHOWERY AND WINDY WEATHER.

&&

.DISCUSSION...
DIFFERENCES REMAINS BETWEEN THE TWO GLOBAL MODELS...THE ECMWF
/EC/ AND GFS...REGARDING THE UPPER LEVEL SHORT WAVE TROUGH AND ITS
SUPPORT OF THE SURFACE FRONT EARLY NEXT WEEK.

THE MOST NOTABLE DIFFERENCE IS IN THE TIMING OF THE UPPER LEVEL
TROUGH WHERE THE EC HAS THE TROUGH JUST WEST OF KAUAI MONDAY EVENING
WHILE THE GFS HAS THE TROUGH OVER KAUAI AND OAHU.

THE EC REMAINS THE STRONGER OF THE TWO WITH A COLD 500 MB TEMP OF
MINUS 17 C. THE GFS HAS A MINUS 14 C. NOT MUCH OF A DIFFERENCE HERE
WHERE BOTH TEMPS ARE COLD ENOUGH TO SUPPORT AT LEAST A SLIGHT CHANCE
OF A THUNDERSTORM AND ALMOST CERTAIN...SPOTTY HEAVY SHOWERS.

THE MODELS DIFFER THEREAFTER. THE EC KEEPS THE UPPER TROUGH OVER
THE ISLANDS TUESDAY...THUS MAINTAINING A CHANCE OF ENHANCED SHOWERS
AND A SLIGHT CHANCE OF A THUNDERSTORM. ON THE OTHER HAND...THE GFS
HAS THE UPPER TROUGH FAR NE OF THE ISLANDS...SUGGESTING MORE LIGHT
TO MODERATE SHOWERS WITH THE FRONT. THE TWO MODEL DO AGREE ON THE
LOCATION OF THE FRONT...OVER MAUI TUESDAY AFTERNOON. SHOULD WE
PURSUE THE EC SOLUTION...IMPROVEMENT IN THE WEATHER WILL COME
TUESDAY NIGHT AS THE UPPER TROUGH FINALLY LIFTS OUT.

THIS IS STILL A GOOD FEW DAYS AWAY SO WE WILL WAIT AND SEE IF THE
MODELS MAINTAINS A SHOWERY OUTLOOK FOR MONDAY AND MONDAY NIGHT.

THE MODELS DO ALSO AGREE ON A QUIET WEEKEND. THE WEATHER PATTERN
MAY TURN SLIGHTLY CONVECTIVE WITH LOCAL DAYTIME SEA BREEZES AS THE
TRADES EASES TO LIGHT TO LOCALLY MODERATE. A STRONG AND STABLE AIR
MASS WILL PUT A LID ON THESE CONVECTIVE CLOUDS. THERE WILL BE ENOUGH
OF AN EASTERLY WIND FLOW TO CARRY A FEW SHOWER BEARING CLOUDS TO THE
WINDWARD AREAS OF ALL THE ISLANDS.

THE POPS AND SKY COVER HAVE BEEN TRIMMED DOWN FOR THE WINDWARD AND
MOUNTAIN AREAS OF MOLOKAI MAUI AND THE BIG ISLAND THIS MORNING. IT
LOOKS LIKE IT WON/T BE THAT SHOWERY IN THESE PLACES THIS MORNING.


&&

.AVIATION...
HIGH PRESSURE TO THE NORTH OF THE ISLANDS MAINTAINING TRADE WIND
FLOW...WITH CLOUDS AND SHOWERS MOVING OVER MOSTLY WINDWARD AND MAUKA
AREAS. SOME MVFR CONDITIONS ARE EXPECTED WITH THE CLOUDS AND SHOWERS
IN THOSE AREAS. OTHERWISE VFR CONDITIONS ARE EXPECTED TO PREVAIL.

HIGH PRESSURE BUILDING TO THE NORTH WILL STRENGTHEN TRADE WINDS
TODAY WHICH MAY REQUIRE AN AIRMET FOR MECHANICAL TURBULENCE TO
THE LEE OF THE MOUNTAINS.

&&

.MARINE...
A COUPLE OF ZONES HAVE BEEN ADDED TO THE EXISTING SMALL CRAFT
ADVISORY /SCA/. THESE TWO ZONES ARE THE WINDWARD WATERS OF KAUAI
AND OAHU AND IS DUE MAINLY TO THE BUILDING NW SWELL. THE SCA FOR THE
AFFECTED ZONES IS GOOD TILL 6 PM HST FRIDAY.

WE DO LOOK FORWARD TO THE SCA BEING LOWER LATE FRIDAY AFTERNOON.
THIS WILL BE SHORT LIVE HOWEVER. THE SCA WILL LIKELY BE HOISTED
SATURDAY NIGHT FOR THE ANTICIPATED LARGE NW SWELL.

WE WILL BE KEEPING A CLOSE WATCH TO THIS NEW NW SWELL. SURF HEIGHTS
ARE EXPECTED TO RISE TO NEAR OR AT ADVISORY LEVELS FOR THE NORTH AND
WEST SHORES OF SOME ISLANDS TONIGHT. SO...AN ADVISORY MAY BE NEEDED
LATER THIS MORNING. THIS SWELL JUST HIT BUOY 51001 A COUPLE OF HOURS
AGO. IT WILL PEAK TONIGHT AND GRADUALLY LOWER FRIDAY.

THE UPCOMING LARGE NW SWELL WILL LIKELY NEED A HIGH SURF WARNING
INVOLVING BOTH NORTH AND WEST FACING SHORES OF MOST ISLANDS. THE
SOURCE OF THIS SWELL IS FROM A RATHER BROAD STORM LOW CURRENTLY
LOCATED OFF THE EAST COAST OF JAPAN. ANOTHER STORM LOW IS PREDICTED
BY THE MODELS TO FORM NORTH OF THE ISLANDS THE MIDDLE OF NEXT WEEK
WHICH MAY KEEP SURF ELEVATED IN AT LEAST THE ADVISORY RANGE THROUGH
CHRISTMAS.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 600 PM HST FRIDAY FOR WINDWARD WATERS OF
KAUAI AND OAHU...MAALAEA BAY...THE WATERS SOUTH OF THE BIG ISLAND...
AND THE PAILOLO AND ALENUIHAHA CHANNELS.

&&

$$
PUBLIC/MARINE...LAU
AVIATION...M BALLARD










000
FXHW60 PHFO 181415
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
340 AM HST THU DEC 18 2014

.SYNOPSIS...
HIGH PRESSURE CENTERED NORTH OF THE ISLANDS WILL MAINTAIN LOCALLY
BREEZY TRADE WINDS THROUGH FRIDAY. THE TRADES WILL FOCUS SHOWERS
OVER WINDWARD AND MOUNTAIN AREAS. THE WINDS WILL BECOME LIGHT OVER
THE WEEKEND AS THE HIGH LEAVES THE AREA AND A FRONT APPROACHES THE
ISLANDS FROM THE NORTHWEST. THE FRONT WILL MOVE DOWN THE ISLAND
CHAIN BETWEEN SUNDAY NIGHT AND TUESDAY NIGHT BRINGING WITH IT SOME
SHOWERY AND WINDY WEATHER.

&&

.DISCUSSION...
DIFFERENCES REMAINS BETWEEN THE TWO GLOBAL MODELS...THE ECMWF
/EC/ AND GFS...REGARDING THE UPPER LEVEL SHORT WAVE TROUGH AND ITS
SUPPORT OF THE SURFACE FRONT EARLY NEXT WEEK.

THE MOST NOTABLE DIFFERENCE IS IN THE TIMING OF THE UPPER LEVEL
TROUGH WHERE THE EC HAS THE TROUGH JUST WEST OF KAUAI MONDAY EVENING
WHILE THE GFS HAS THE TROUGH OVER KAUAI AND OAHU.

THE EC REMAINS THE STRONGER OF THE TWO WITH A COLD 500 MB TEMP OF
MINUS 17 C. THE GFS HAS A MINUS 14 C. NOT MUCH OF A DIFFERENCE HERE
WHERE BOTH TEMPS ARE COLD ENOUGH TO SUPPORT AT LEAST A SLIGHT CHANCE
OF A THUNDERSTORM AND ALMOST CERTAIN...SPOTTY HEAVY SHOWERS.

THE MODELS DIFFER THEREAFTER. THE EC KEEPS THE UPPER TROUGH OVER
THE ISLANDS TUESDAY...THUS MAINTAINING A CHANCE OF ENHANCED SHOWERS
AND A SLIGHT CHANCE OF A THUNDERSTORM. ON THE OTHER HAND...THE GFS
HAS THE UPPER TROUGH FAR NE OF THE ISLANDS...SUGGESTING MORE LIGHT
TO MODERATE SHOWERS WITH THE FRONT. THE TWO MODEL DO AGREE ON THE
LOCATION OF THE FRONT...OVER MAUI TUESDAY AFTERNOON. SHOULD WE
PURSUE THE EC SOLUTION...IMPROVEMENT IN THE WEATHER WILL COME
TUESDAY NIGHT AS THE UPPER TROUGH FINALLY LIFTS OUT.

THIS IS STILL A GOOD FEW DAYS AWAY SO WE WILL WAIT AND SEE IF THE
MODELS MAINTAINS A SHOWERY OUTLOOK FOR MONDAY AND MONDAY NIGHT.

THE MODELS DO ALSO AGREE ON A QUIET WEEKEND. THE WEATHER PATTERN
MAY TURN SLIGHTLY CONVECTIVE WITH LOCAL DAYTIME SEA BREEZES AS THE
TRADES EASES TO LIGHT TO LOCALLY MODERATE. A STRONG AND STABLE AIR
MASS WILL PUT A LID ON THESE CONVECTIVE CLOUDS. THERE WILL BE ENOUGH
OF AN EASTERLY WIND FLOW TO CARRY A FEW SHOWER BEARING CLOUDS TO THE
WINDWARD AREAS OF ALL THE ISLANDS.

THE POPS AND SKY COVER HAVE BEEN TRIMMED DOWN FOR THE WINDWARD AND
MOUNTAIN AREAS OF MOLOKAI MAUI AND THE BIG ISLAND THIS MORNING. IT
LOOKS LIKE IT WON/T BE THAT SHOWERY IN THESE PLACES THIS MORNING.


&&

.AVIATION...
HIGH PRESSURE TO THE NORTH OF THE ISLANDS MAINTAINING TRADE WIND
FLOW...WITH CLOUDS AND SHOWERS MOVING OVER MOSTLY WINDWARD AND MAUKA
AREAS. SOME MVFR CONDITIONS ARE EXPECTED WITH THE CLOUDS AND SHOWERS
IN THOSE AREAS. OTHERWISE VFR CONDITIONS ARE EXPECTED TO PREVAIL.

HIGH PRESSURE BUILDING TO THE NORTH WILL STRENGTHEN TRADE WINDS
TODAY WHICH MAY REQUIRE AN AIRMET FOR MECHANICAL TURBULENCE TO
THE LEE OF THE MOUNTAINS.

&&

.MARINE...
A COUPLE OF ZONES HAVE BEEN ADDED TO THE EXISTING SMALL CRAFT
ADVISORY /SCA/. THESE TWO ZONES ARE THE WINDWARD WATERS OF KAUAI
AND OAHU AND IS DUE MAINLY TO THE BUILDING NW SWELL. THE SCA FOR THE
AFFECTED ZONES IS GOOD TILL 6 PM HST FRIDAY.

WE DO LOOK FORWARD TO THE SCA BEING LOWER LATE FRIDAY AFTERNOON.
THIS WILL BE SHORT LIVE HOWEVER. THE SCA WILL LIKELY BE HOISTED
SATURDAY NIGHT FOR THE ANTICIPATED LARGE NW SWELL.

WE WILL BE KEEPING A CLOSE WATCH TO THIS NEW NW SWELL. SURF HEIGHTS
ARE EXPECTED TO RISE TO NEAR OR AT ADVISORY LEVELS FOR THE NORTH AND
WEST SHORES OF SOME ISLANDS TONIGHT. SO...AN ADVISORY MAY BE NEEDED
LATER THIS MORNING. THIS SWELL JUST HIT BUOY 51001 A COUPLE OF HOURS
AGO. IT WILL PEAK TONIGHT AND GRADUALLY LOWER FRIDAY.

THE UPCOMING LARGE NW SWELL WILL LIKELY NEED A HIGH SURF WARNING
INVOLVING BOTH NORTH AND WEST FACING SHORES OF MOST ISLANDS. THE
SOURCE OF THIS SWELL IS FROM A RATHER BROAD STORM LOW CURRENTLY
LOCATED OFF THE EAST COAST OF JAPAN. ANOTHER STORM LOW IS PREDICTED
BY THE MODELS TO FORM NORTH OF THE ISLANDS THE MIDDLE OF NEXT WEEK
WHICH MAY KEEP SURF ELEVATED IN AT LEAST THE ADVISORY RANGE THROUGH
CHRISTMAS.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 600 PM HST FRIDAY FOR WINDWARD WATERS OF
KAUAI AND OAHU...MAALAEA BAY...THE WATERS SOUTH OF THE BIG ISLAND...
AND THE PAILOLO AND ALENUIHAHA CHANNELS.

&&

$$
PUBLIC/MARINE...LAU
AVIATION...M BALLARD









000
FXHW60 PHFO 180620
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
800 PM HST WED DEC 17 2014

.SYNOPSIS...
HIGH PRESSURE CENTERED NORTH OF THE ISLANDS WILL MAINTAIN LOCALLY
BREEZY TRADE WINDS THROUGH FRIDAY. THE TRADES WILL FOCUS SHOWERS
OVER WINDWARD AND MOUNTAIN AREAS. THE WINDS WILL BECOME LIGHT OVER
THE WEEKEND AS THE HIGH LEAVES THE AREA AND A FRONT APPROACHES THE
ISLANDS FROM THE NORTHWEST. THE FRONT WILL MOVE DOWN THE ISLAND
CHAIN BETWEEN SUNDAY NIGHT AND TUESDAY NIGHT BRINGING WITH IT SOME
SHOWERY AND WINDY WEATHER.

&&

.DISCUSSION...
BOTH THE ECMWF /EC/ AND GFS ARE IN GOOD AGREEMENT WITH THE TIMING OF
THE NEXT WEATHER SYSTEM TO AFFECT THE ISLANDS...THAT IS A COLD
FRONT. THE MODELS CONCUR THE FRONT WILL REACH KAUAI SUNDAY NIGHT AND
EXIT THE BIG ISLAND LATE TUESDAY NIGHT...EARLY WEDNESDAY MORNING.

THE FRONT WILL BE ACCOMPANIED BY SOME SHOWERY WEATHER ALONG WITH
STRONG AND GUSTY NORTH AND NORTHEAST WINDS. THE FRONT WILL HAVE
SOME UPPER LEVEL...DYNAMIC SUPPORT...BY WAYS OF A SHORT WAVE TROUGH
ACCOMPANIED BY A POOL OF COLD AIR OF MINUS 14 C BY THE GFS TO MINUS
17 C BY THE EC.  THIS WILL MOST LIKELY RESULT IN ENHANCED
SHOWERS...LOCALLY HEAVY RAINS AND EVEN A SLIGHT CHANCE OF A
THUNDERSTORM.

THIS ASSESSMENT WILL NOT BE REFLECTED IN THE GRIDS YET...WE WILL
CONFIRM THIS WITH SEVERAL MORE MODELS RUNS TO SEE IF THIS TREND
CONTINUES OR THE MODELS BACKS OFF. WE SHOULD HAVE A BETTER IDEA BY
FRIDAY.

IN THE MEAN TIME...IT WILL BE A MODERATE TO LOCALLY STRONG TRADE
WIND PATTERN WITH SHOWERS MAINLY NIGHTS AND MORNINGS AND FAVORING
THE WINDWARD AND MOUNTAIN AREAS. THE HIGH CENTERED 700 MILES N OF
THE ISLANDS WITH AT 1027 MB VALUE IS FORECAST TO MOVE EASTWARD
DURING THE NEXT 72 HOURS. BY ABOUT THE 60TH HOUR...OR SATURDAY
MORNING...THE HIGH WILL BE OUT OF RANGE WHERE WE CAN FINALLY LOWER
THE SMALL CRAFT ADVISORY.

THE MODELS ARE MAINTAINING A FEW WINDWARD SHOWERS BUT OTHERWISE
RATHER DRY CONDITIONS OVER THE WEEKEND WHILE THE WINDS BRIEFLY TURN
SOUTHEAST SATURDAY. ON SUNDAY...THE WINDS WILL BECOME LIGHT AND
VARIABLE AHEAD OF THE APPROACHING FRONT.

&&

.AVIATION...
CLOUDS AND SHOWERS MOVING OVER MAINLY WINDWARD AND MAUKA AREAS WILL
AT TIMES BRING MVFR CONDITIONS TO THOSE AREAS. OTHERWISE VFR
CONDITIONS ARE EXPECTED TO PREVAIL.

HIGH PRESSURE BUILDING TO THE NORTH WILL STRENGTHEN TRADE WINDS
THURSDAY WHICH MAY REQUIRE AN AIRMET FOR MECHANICAL TURBULENCE TO
THE LEE OF THE MOUNTAINS.

&&

.MARINE...
THE TRADE WINDS WILL BE WINDING DOWN DURING THE NEXT COUPLE OF DAYS
WHERE THE SMALL CRAFT ADVISORY /SCA/ CAN FINALLY BE LOWERED BY
FRIDAY NIGHT.

AS FOR THE SWELLS...A BUMP FROM THE NW IS EXPECTED THURSDAY EVENING
WHERE SURF HEIGHTS WILL COME CLOSE TO OR REACH ADVISORY LEVELS FOR
THE N AND W FACING SHORES OF AT LEAST KAUAI AND OAHU. THIS SWELL
WILL BE SUBSIDING STARTING FRIDAY. THEN A VERY LARGE NW SWELL WILL
BE ARRIVING SUNDAY BOOSTING THE SURF INTO THE WARNING CATEGORY FOR
THE N AND W FACING SHORES OF MOST ISLANDS. THE SOURCE OF THIS SWELL
IS FROM A RATHER BROAD AREA OF STRONG LOW PRESSURE SITUATED OFF THE
EAST COAST OF JAPAN TONIGHT. A STORM LOW PREDICTED BY THE MODELS TO
FORM NORTH OF THE ISLANDS THE MIDDLE OF NEXT WEEK MAY KEEP SURF
ELEVATED IN AT LEAST THE ADVISORY RANGE THROUGH CHRISTMAS.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 600 PM HST FRIDAY FOR MAALAEA BAY...THE
WATERS SOUTH OF THE BIG ISLAND...AND THE PAILOLO AND ALENUIHAHA
CHANNELS.

&&

$$
PUBLIC/MARINE...LAU
AVIATION...M BALLARD








000
FXHW60 PHFO 180620
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
800 PM HST WED DEC 17 2014

.SYNOPSIS...
HIGH PRESSURE CENTERED NORTH OF THE ISLANDS WILL MAINTAIN LOCALLY
BREEZY TRADE WINDS THROUGH FRIDAY. THE TRADES WILL FOCUS SHOWERS
OVER WINDWARD AND MOUNTAIN AREAS. THE WINDS WILL BECOME LIGHT OVER
THE WEEKEND AS THE HIGH LEAVES THE AREA AND A FRONT APPROACHES THE
ISLANDS FROM THE NORTHWEST. THE FRONT WILL MOVE DOWN THE ISLAND
CHAIN BETWEEN SUNDAY NIGHT AND TUESDAY NIGHT BRINGING WITH IT SOME
SHOWERY AND WINDY WEATHER.

&&

.DISCUSSION...
BOTH THE ECMWF /EC/ AND GFS ARE IN GOOD AGREEMENT WITH THE TIMING OF
THE NEXT WEATHER SYSTEM TO AFFECT THE ISLANDS...THAT IS A COLD
FRONT. THE MODELS CONCUR THE FRONT WILL REACH KAUAI SUNDAY NIGHT AND
EXIT THE BIG ISLAND LATE TUESDAY NIGHT...EARLY WEDNESDAY MORNING.

THE FRONT WILL BE ACCOMPANIED BY SOME SHOWERY WEATHER ALONG WITH
STRONG AND GUSTY NORTH AND NORTHEAST WINDS. THE FRONT WILL HAVE
SOME UPPER LEVEL...DYNAMIC SUPPORT...BY WAYS OF A SHORT WAVE TROUGH
ACCOMPANIED BY A POOL OF COLD AIR OF MINUS 14 C BY THE GFS TO MINUS
17 C BY THE EC.  THIS WILL MOST LIKELY RESULT IN ENHANCED
SHOWERS...LOCALLY HEAVY RAINS AND EVEN A SLIGHT CHANCE OF A
THUNDERSTORM.

THIS ASSESSMENT WILL NOT BE REFLECTED IN THE GRIDS YET...WE WILL
CONFIRM THIS WITH SEVERAL MORE MODELS RUNS TO SEE IF THIS TREND
CONTINUES OR THE MODELS BACKS OFF. WE SHOULD HAVE A BETTER IDEA BY
FRIDAY.

IN THE MEAN TIME...IT WILL BE A MODERATE TO LOCALLY STRONG TRADE
WIND PATTERN WITH SHOWERS MAINLY NIGHTS AND MORNINGS AND FAVORING
THE WINDWARD AND MOUNTAIN AREAS. THE HIGH CENTERED 700 MILES N OF
THE ISLANDS WITH AT 1027 MB VALUE IS FORECAST TO MOVE EASTWARD
DURING THE NEXT 72 HOURS. BY ABOUT THE 60TH HOUR...OR SATURDAY
MORNING...THE HIGH WILL BE OUT OF RANGE WHERE WE CAN FINALLY LOWER
THE SMALL CRAFT ADVISORY.

THE MODELS ARE MAINTAINING A FEW WINDWARD SHOWERS BUT OTHERWISE
RATHER DRY CONDITIONS OVER THE WEEKEND WHILE THE WINDS BRIEFLY TURN
SOUTHEAST SATURDAY. ON SUNDAY...THE WINDS WILL BECOME LIGHT AND
VARIABLE AHEAD OF THE APPROACHING FRONT.

&&

.AVIATION...
CLOUDS AND SHOWERS MOVING OVER MAINLY WINDWARD AND MAUKA AREAS WILL
AT TIMES BRING MVFR CONDITIONS TO THOSE AREAS. OTHERWISE VFR
CONDITIONS ARE EXPECTED TO PREVAIL.

HIGH PRESSURE BUILDING TO THE NORTH WILL STRENGTHEN TRADE WINDS
THURSDAY WHICH MAY REQUIRE AN AIRMET FOR MECHANICAL TURBULENCE TO
THE LEE OF THE MOUNTAINS.

&&

.MARINE...
THE TRADE WINDS WILL BE WINDING DOWN DURING THE NEXT COUPLE OF DAYS
WHERE THE SMALL CRAFT ADVISORY /SCA/ CAN FINALLY BE LOWERED BY
FRIDAY NIGHT.

AS FOR THE SWELLS...A BUMP FROM THE NW IS EXPECTED THURSDAY EVENING
WHERE SURF HEIGHTS WILL COME CLOSE TO OR REACH ADVISORY LEVELS FOR
THE N AND W FACING SHORES OF AT LEAST KAUAI AND OAHU. THIS SWELL
WILL BE SUBSIDING STARTING FRIDAY. THEN A VERY LARGE NW SWELL WILL
BE ARRIVING SUNDAY BOOSTING THE SURF INTO THE WARNING CATEGORY FOR
THE N AND W FACING SHORES OF MOST ISLANDS. THE SOURCE OF THIS SWELL
IS FROM A RATHER BROAD AREA OF STRONG LOW PRESSURE SITUATED OFF THE
EAST COAST OF JAPAN TONIGHT. A STORM LOW PREDICTED BY THE MODELS TO
FORM NORTH OF THE ISLANDS THE MIDDLE OF NEXT WEEK MAY KEEP SURF
ELEVATED IN AT LEAST THE ADVISORY RANGE THROUGH CHRISTMAS.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 600 PM HST FRIDAY FOR MAALAEA BAY...THE
WATERS SOUTH OF THE BIG ISLAND...AND THE PAILOLO AND ALENUIHAHA
CHANNELS.

&&

$$
PUBLIC/MARINE...LAU
AVIATION...M BALLARD









000
FXHW60 PHFO 180142
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 PM HST WED DEC 17 2014

.SYNOPSIS...
A RIDGE NORTH OF THE ISLANDS WILL MAINTAIN LOCALLY BREEZY TRADE
WINDS THROUGH FRIDAY. THE TRADES WILL FOCUS SHOWERS OVER WINDWARD
AREAS. WINDS WILL SUBSIDE AND RAINFALL WILL BECOME LIGHT OVER THE
WEEKEND AS A SHEAR LINE APPROACHES FROM THE NORTHWEST. SHOWERS ALONG
THE SHEAR LINE WILL REACH KAUAI SUNDAY NIGHT AND PUSH PAST THE BIG
ISLAND BY TUESDAY NIGHT. STRONG NORTH WINDS WILL MOVE IN BEHIND THE
SHEAR LINE.

&&

.DISCUSSION...
THE GLOBAL MODELS ARE NOW IN PRETTY GOOD AGREEMENT THROUGH EARLY
NEXT WEEK.

A 1026 MB HIGH NORTHEAST OF THE BIG ISLAND WILL MOVE SOUTHEAST AND
DISSIPATE OVER THE NEXT 12 HOURS. THE TRADE WINDS WILL WEAKEN
BRIEFLY...THEN STRENGTHEN AGAIN STARTING TONIGHT AS A NEW 1027 MB
HIGH MOVES BY TO THE NORTH OF THE ISLANDS. THE TRADES WILL PUSH
SHOWERY LOW CLOUDS OVER THE ISLANDS TONIGHT AND THURSDAY MORNING.
SOME OF THESE SHOWERS MAY SPREAD LEEWARD ON OAHU AND MOLOKAI.

SHOWERS WILL DECREASE THURSDAY NIGHT AS DRIER AIR MOVES OVER THE
ISLANDS FROM THE EAST. WINDS WILL WEAKEN AGAIN STARTING FRIDAY AS A
FRONT APPROACHES FROM THE NORTHWEST AND THE SUBTROPICAL RIDGE
WEAKENS AND MOVES CLOSER TO THE ISLANDS. RAINFALL WILL BECOME QUITE
SPARSE THROUGH THE DAY ON SUNDAY.

THE FRONT WILL WEAKEN TO A SHEAR LINE AND MOVE OVER KAUAI FROM THE
NORTHWEST SUNDAY NIGHT AND PUSH DOWN PAST THE BIG ISLAND TUESDAY
NIGHT. GENTLE EAST WINDS WILL SHIFT OUT OF THE NORTH AND BECOME MUCH
STRONGER BEHIND THE SHEAR LINE. A BAND OF SHOWERS ALONG THE SHEAR
LINE WILL PRODUCE WIDESPREAD SHOWERS BUT SINCE THE BAND WILL BE
RELATIVELY SHALLOW AND FAST-MOVING EXCESSIVE RAINFALL IS NOT
EXPECTED.

TRADE WIND WEATHER WILL PROBABLY PREVAIL ONCE THE SHEAR LINE HAS
PASSED...BUT THE GLOBAL MODELS ARE STILL INCONSISTENT THAT FAR OUT.
THE ECMWF AND GFS BOTH SHOW A LOW FORMING NORTH OF THE ISLANDS EARLY
NEXT WEEK BUT THE ECMWF HAS THE LOW DEEPER AND CLOSER TO THE ISLANDS
AND MOVES IT OFF TO THE NORTHEAST SLOWER THAN THE GFS. WE WILL HAVE
TO WAIT TO SEE WHICH MODEL HANDLES THE SYSTEM BETTER.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL THIS EVENING...BUT THE CHANCE OF MVFR
CEILINGS AND VSBY OVER WINDWARD AREAS WILL INCREASE OVERNIGHT AND
AIRMETS FOR MT OBSC COULD BE NEEDED LATER TONIGHT.

&&

.MARINE...
A NEW 1027 MB HIGH WILL MOVE INTO POSITION NORTH OF THE AREA TONIGHT
AND MAINTAIN SMALL CRAFT ADVISORY WINDS OVER THE WINDY AREAS AROUND
THE BIG ISLAND AND MAUI COUNTY THROUGH FRIDAY EVENING. WINDS WILL
WEAKEN AND VEER OUT OF THE SOUTHEAST OVER THE WEEKEND. STRONG NORTH
TO NORTHEAST WINDS WILL SPREAD OVER THE ISLANDS STARTING MONDAY AS A
SHEAR LINE MOVES SOUTHEAST OVER THE ISLANDS.

NORTHWEST SWELL IN THE AREA WILL BE SMALLER THAN IT HAS BEEN FOR A
WHILE AND SURF WILL LIKELY REMAIN BELOW ADVISORY LEVELS ALONG ALL
SHORES THROUGH TOMORROW. HOWEVER...A NEW SWELL ARRIVING TOMORROW
WILL BOOST SURF BACK ABOVE THE ADVISORY LEVEL TOMORROW NIGHT. THE
NEXT NORTHWEST SWELL ARRIVING SATURDAY NIGHT IS LIKELY TO REQUIRE
HIGH SURF WARNINGS EARLY NEXT WEEK. THE STORM PRODUCING THIS SWELL
WILL BE QUITE LARGE WITH STRONG WINDS EXTENDING TO LOW LATITUDES.
THE SWELL WILL HAVE ENOUGH OF A WEST COMPONENT TO BRING HIGH SURF
TO WEST FACING SHORES OF THE BIG ISLAND. THIS SWELL WILL ALSO BE
LONG-LASTING...WITH SURF POSSIBLY REMAINING ABOVE THE ADVISORY LEVEL
THROUGH CHRISTMAS EVE.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 600 PM FRIDAY FOR MAALAEA BAY...THE
WATERS SOUTH OF THE BIG ISLAND...AND THE PAILOLO AND ALENUIHAHA
CHANNELS.

&&

$$
DONALDSON






000
FXHW60 PHFO 180142
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 PM HST WED DEC 17 2014

.SYNOPSIS...
A RIDGE NORTH OF THE ISLANDS WILL MAINTAIN LOCALLY BREEZY TRADE
WINDS THROUGH FRIDAY. THE TRADES WILL FOCUS SHOWERS OVER WINDWARD
AREAS. WINDS WILL SUBSIDE AND RAINFALL WILL BECOME LIGHT OVER THE
WEEKEND AS A SHEAR LINE APPROACHES FROM THE NORTHWEST. SHOWERS ALONG
THE SHEAR LINE WILL REACH KAUAI SUNDAY NIGHT AND PUSH PAST THE BIG
ISLAND BY TUESDAY NIGHT. STRONG NORTH WINDS WILL MOVE IN BEHIND THE
SHEAR LINE.

&&

.DISCUSSION...
THE GLOBAL MODELS ARE NOW IN PRETTY GOOD AGREEMENT THROUGH EARLY
NEXT WEEK.

A 1026 MB HIGH NORTHEAST OF THE BIG ISLAND WILL MOVE SOUTHEAST AND
DISSIPATE OVER THE NEXT 12 HOURS. THE TRADE WINDS WILL WEAKEN
BRIEFLY...THEN STRENGTHEN AGAIN STARTING TONIGHT AS A NEW 1027 MB
HIGH MOVES BY TO THE NORTH OF THE ISLANDS. THE TRADES WILL PUSH
SHOWERY LOW CLOUDS OVER THE ISLANDS TONIGHT AND THURSDAY MORNING.
SOME OF THESE SHOWERS MAY SPREAD LEEWARD ON OAHU AND MOLOKAI.

SHOWERS WILL DECREASE THURSDAY NIGHT AS DRIER AIR MOVES OVER THE
ISLANDS FROM THE EAST. WINDS WILL WEAKEN AGAIN STARTING FRIDAY AS A
FRONT APPROACHES FROM THE NORTHWEST AND THE SUBTROPICAL RIDGE
WEAKENS AND MOVES CLOSER TO THE ISLANDS. RAINFALL WILL BECOME QUITE
SPARSE THROUGH THE DAY ON SUNDAY.

THE FRONT WILL WEAKEN TO A SHEAR LINE AND MOVE OVER KAUAI FROM THE
NORTHWEST SUNDAY NIGHT AND PUSH DOWN PAST THE BIG ISLAND TUESDAY
NIGHT. GENTLE EAST WINDS WILL SHIFT OUT OF THE NORTH AND BECOME MUCH
STRONGER BEHIND THE SHEAR LINE. A BAND OF SHOWERS ALONG THE SHEAR
LINE WILL PRODUCE WIDESPREAD SHOWERS BUT SINCE THE BAND WILL BE
RELATIVELY SHALLOW AND FAST-MOVING EXCESSIVE RAINFALL IS NOT
EXPECTED.

TRADE WIND WEATHER WILL PROBABLY PREVAIL ONCE THE SHEAR LINE HAS
PASSED...BUT THE GLOBAL MODELS ARE STILL INCONSISTENT THAT FAR OUT.
THE ECMWF AND GFS BOTH SHOW A LOW FORMING NORTH OF THE ISLANDS EARLY
NEXT WEEK BUT THE ECMWF HAS THE LOW DEEPER AND CLOSER TO THE ISLANDS
AND MOVES IT OFF TO THE NORTHEAST SLOWER THAN THE GFS. WE WILL HAVE
TO WAIT TO SEE WHICH MODEL HANDLES THE SYSTEM BETTER.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL THIS EVENING...BUT THE CHANCE OF MVFR
CEILINGS AND VSBY OVER WINDWARD AREAS WILL INCREASE OVERNIGHT AND
AIRMETS FOR MT OBSC COULD BE NEEDED LATER TONIGHT.

&&

.MARINE...
A NEW 1027 MB HIGH WILL MOVE INTO POSITION NORTH OF THE AREA TONIGHT
AND MAINTAIN SMALL CRAFT ADVISORY WINDS OVER THE WINDY AREAS AROUND
THE BIG ISLAND AND MAUI COUNTY THROUGH FRIDAY EVENING. WINDS WILL
WEAKEN AND VEER OUT OF THE SOUTHEAST OVER THE WEEKEND. STRONG NORTH
TO NORTHEAST WINDS WILL SPREAD OVER THE ISLANDS STARTING MONDAY AS A
SHEAR LINE MOVES SOUTHEAST OVER THE ISLANDS.

NORTHWEST SWELL IN THE AREA WILL BE SMALLER THAN IT HAS BEEN FOR A
WHILE AND SURF WILL LIKELY REMAIN BELOW ADVISORY LEVELS ALONG ALL
SHORES THROUGH TOMORROW. HOWEVER...A NEW SWELL ARRIVING TOMORROW
WILL BOOST SURF BACK ABOVE THE ADVISORY LEVEL TOMORROW NIGHT. THE
NEXT NORTHWEST SWELL ARRIVING SATURDAY NIGHT IS LIKELY TO REQUIRE
HIGH SURF WARNINGS EARLY NEXT WEEK. THE STORM PRODUCING THIS SWELL
WILL BE QUITE LARGE WITH STRONG WINDS EXTENDING TO LOW LATITUDES.
THE SWELL WILL HAVE ENOUGH OF A WEST COMPONENT TO BRING HIGH SURF
TO WEST FACING SHORES OF THE BIG ISLAND. THIS SWELL WILL ALSO BE
LONG-LASTING...WITH SURF POSSIBLY REMAINING ABOVE THE ADVISORY LEVEL
THROUGH CHRISTMAS EVE.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 600 PM FRIDAY FOR MAALAEA BAY...THE
WATERS SOUTH OF THE BIG ISLAND...AND THE PAILOLO AND ALENUIHAHA
CHANNELS.

&&

$$
DONALDSON







000
FXHW60 PHFO 180142
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 PM HST WED DEC 17 2014

.SYNOPSIS...
A RIDGE NORTH OF THE ISLANDS WILL MAINTAIN LOCALLY BREEZY TRADE
WINDS THROUGH FRIDAY. THE TRADES WILL FOCUS SHOWERS OVER WINDWARD
AREAS. WINDS WILL SUBSIDE AND RAINFALL WILL BECOME LIGHT OVER THE
WEEKEND AS A SHEAR LINE APPROACHES FROM THE NORTHWEST. SHOWERS ALONG
THE SHEAR LINE WILL REACH KAUAI SUNDAY NIGHT AND PUSH PAST THE BIG
ISLAND BY TUESDAY NIGHT. STRONG NORTH WINDS WILL MOVE IN BEHIND THE
SHEAR LINE.

&&

.DISCUSSION...
THE GLOBAL MODELS ARE NOW IN PRETTY GOOD AGREEMENT THROUGH EARLY
NEXT WEEK.

A 1026 MB HIGH NORTHEAST OF THE BIG ISLAND WILL MOVE SOUTHEAST AND
DISSIPATE OVER THE NEXT 12 HOURS. THE TRADE WINDS WILL WEAKEN
BRIEFLY...THEN STRENGTHEN AGAIN STARTING TONIGHT AS A NEW 1027 MB
HIGH MOVES BY TO THE NORTH OF THE ISLANDS. THE TRADES WILL PUSH
SHOWERY LOW CLOUDS OVER THE ISLANDS TONIGHT AND THURSDAY MORNING.
SOME OF THESE SHOWERS MAY SPREAD LEEWARD ON OAHU AND MOLOKAI.

SHOWERS WILL DECREASE THURSDAY NIGHT AS DRIER AIR MOVES OVER THE
ISLANDS FROM THE EAST. WINDS WILL WEAKEN AGAIN STARTING FRIDAY AS A
FRONT APPROACHES FROM THE NORTHWEST AND THE SUBTROPICAL RIDGE
WEAKENS AND MOVES CLOSER TO THE ISLANDS. RAINFALL WILL BECOME QUITE
SPARSE THROUGH THE DAY ON SUNDAY.

THE FRONT WILL WEAKEN TO A SHEAR LINE AND MOVE OVER KAUAI FROM THE
NORTHWEST SUNDAY NIGHT AND PUSH DOWN PAST THE BIG ISLAND TUESDAY
NIGHT. GENTLE EAST WINDS WILL SHIFT OUT OF THE NORTH AND BECOME MUCH
STRONGER BEHIND THE SHEAR LINE. A BAND OF SHOWERS ALONG THE SHEAR
LINE WILL PRODUCE WIDESPREAD SHOWERS BUT SINCE THE BAND WILL BE
RELATIVELY SHALLOW AND FAST-MOVING EXCESSIVE RAINFALL IS NOT
EXPECTED.

TRADE WIND WEATHER WILL PROBABLY PREVAIL ONCE THE SHEAR LINE HAS
PASSED...BUT THE GLOBAL MODELS ARE STILL INCONSISTENT THAT FAR OUT.
THE ECMWF AND GFS BOTH SHOW A LOW FORMING NORTH OF THE ISLANDS EARLY
NEXT WEEK BUT THE ECMWF HAS THE LOW DEEPER AND CLOSER TO THE ISLANDS
AND MOVES IT OFF TO THE NORTHEAST SLOWER THAN THE GFS. WE WILL HAVE
TO WAIT TO SEE WHICH MODEL HANDLES THE SYSTEM BETTER.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL THIS EVENING...BUT THE CHANCE OF MVFR
CEILINGS AND VSBY OVER WINDWARD AREAS WILL INCREASE OVERNIGHT AND
AIRMETS FOR MT OBSC COULD BE NEEDED LATER TONIGHT.

&&

.MARINE...
A NEW 1027 MB HIGH WILL MOVE INTO POSITION NORTH OF THE AREA TONIGHT
AND MAINTAIN SMALL CRAFT ADVISORY WINDS OVER THE WINDY AREAS AROUND
THE BIG ISLAND AND MAUI COUNTY THROUGH FRIDAY EVENING. WINDS WILL
WEAKEN AND VEER OUT OF THE SOUTHEAST OVER THE WEEKEND. STRONG NORTH
TO NORTHEAST WINDS WILL SPREAD OVER THE ISLANDS STARTING MONDAY AS A
SHEAR LINE MOVES SOUTHEAST OVER THE ISLANDS.

NORTHWEST SWELL IN THE AREA WILL BE SMALLER THAN IT HAS BEEN FOR A
WHILE AND SURF WILL LIKELY REMAIN BELOW ADVISORY LEVELS ALONG ALL
SHORES THROUGH TOMORROW. HOWEVER...A NEW SWELL ARRIVING TOMORROW
WILL BOOST SURF BACK ABOVE THE ADVISORY LEVEL TOMORROW NIGHT. THE
NEXT NORTHWEST SWELL ARRIVING SATURDAY NIGHT IS LIKELY TO REQUIRE
HIGH SURF WARNINGS EARLY NEXT WEEK. THE STORM PRODUCING THIS SWELL
WILL BE QUITE LARGE WITH STRONG WINDS EXTENDING TO LOW LATITUDES.
THE SWELL WILL HAVE ENOUGH OF A WEST COMPONENT TO BRING HIGH SURF
TO WEST FACING SHORES OF THE BIG ISLAND. THIS SWELL WILL ALSO BE
LONG-LASTING...WITH SURF POSSIBLY REMAINING ABOVE THE ADVISORY LEVEL
THROUGH CHRISTMAS EVE.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 600 PM FRIDAY FOR MAALAEA BAY...THE
WATERS SOUTH OF THE BIG ISLAND...AND THE PAILOLO AND ALENUIHAHA
CHANNELS.

&&

$$
DONALDSON






000
FXHW60 PHFO 180142
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 PM HST WED DEC 17 2014

.SYNOPSIS...
A RIDGE NORTH OF THE ISLANDS WILL MAINTAIN LOCALLY BREEZY TRADE
WINDS THROUGH FRIDAY. THE TRADES WILL FOCUS SHOWERS OVER WINDWARD
AREAS. WINDS WILL SUBSIDE AND RAINFALL WILL BECOME LIGHT OVER THE
WEEKEND AS A SHEAR LINE APPROACHES FROM THE NORTHWEST. SHOWERS ALONG
THE SHEAR LINE WILL REACH KAUAI SUNDAY NIGHT AND PUSH PAST THE BIG
ISLAND BY TUESDAY NIGHT. STRONG NORTH WINDS WILL MOVE IN BEHIND THE
SHEAR LINE.

&&

.DISCUSSION...
THE GLOBAL MODELS ARE NOW IN PRETTY GOOD AGREEMENT THROUGH EARLY
NEXT WEEK.

A 1026 MB HIGH NORTHEAST OF THE BIG ISLAND WILL MOVE SOUTHEAST AND
DISSIPATE OVER THE NEXT 12 HOURS. THE TRADE WINDS WILL WEAKEN
BRIEFLY...THEN STRENGTHEN AGAIN STARTING TONIGHT AS A NEW 1027 MB
HIGH MOVES BY TO THE NORTH OF THE ISLANDS. THE TRADES WILL PUSH
SHOWERY LOW CLOUDS OVER THE ISLANDS TONIGHT AND THURSDAY MORNING.
SOME OF THESE SHOWERS MAY SPREAD LEEWARD ON OAHU AND MOLOKAI.

SHOWERS WILL DECREASE THURSDAY NIGHT AS DRIER AIR MOVES OVER THE
ISLANDS FROM THE EAST. WINDS WILL WEAKEN AGAIN STARTING FRIDAY AS A
FRONT APPROACHES FROM THE NORTHWEST AND THE SUBTROPICAL RIDGE
WEAKENS AND MOVES CLOSER TO THE ISLANDS. RAINFALL WILL BECOME QUITE
SPARSE THROUGH THE DAY ON SUNDAY.

THE FRONT WILL WEAKEN TO A SHEAR LINE AND MOVE OVER KAUAI FROM THE
NORTHWEST SUNDAY NIGHT AND PUSH DOWN PAST THE BIG ISLAND TUESDAY
NIGHT. GENTLE EAST WINDS WILL SHIFT OUT OF THE NORTH AND BECOME MUCH
STRONGER BEHIND THE SHEAR LINE. A BAND OF SHOWERS ALONG THE SHEAR
LINE WILL PRODUCE WIDESPREAD SHOWERS BUT SINCE THE BAND WILL BE
RELATIVELY SHALLOW AND FAST-MOVING EXCESSIVE RAINFALL IS NOT
EXPECTED.

TRADE WIND WEATHER WILL PROBABLY PREVAIL ONCE THE SHEAR LINE HAS
PASSED...BUT THE GLOBAL MODELS ARE STILL INCONSISTENT THAT FAR OUT.
THE ECMWF AND GFS BOTH SHOW A LOW FORMING NORTH OF THE ISLANDS EARLY
NEXT WEEK BUT THE ECMWF HAS THE LOW DEEPER AND CLOSER TO THE ISLANDS
AND MOVES IT OFF TO THE NORTHEAST SLOWER THAN THE GFS. WE WILL HAVE
TO WAIT TO SEE WHICH MODEL HANDLES THE SYSTEM BETTER.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL THIS EVENING...BUT THE CHANCE OF MVFR
CEILINGS AND VSBY OVER WINDWARD AREAS WILL INCREASE OVERNIGHT AND
AIRMETS FOR MT OBSC COULD BE NEEDED LATER TONIGHT.

&&

.MARINE...
A NEW 1027 MB HIGH WILL MOVE INTO POSITION NORTH OF THE AREA TONIGHT
AND MAINTAIN SMALL CRAFT ADVISORY WINDS OVER THE WINDY AREAS AROUND
THE BIG ISLAND AND MAUI COUNTY THROUGH FRIDAY EVENING. WINDS WILL
WEAKEN AND VEER OUT OF THE SOUTHEAST OVER THE WEEKEND. STRONG NORTH
TO NORTHEAST WINDS WILL SPREAD OVER THE ISLANDS STARTING MONDAY AS A
SHEAR LINE MOVES SOUTHEAST OVER THE ISLANDS.

NORTHWEST SWELL IN THE AREA WILL BE SMALLER THAN IT HAS BEEN FOR A
WHILE AND SURF WILL LIKELY REMAIN BELOW ADVISORY LEVELS ALONG ALL
SHORES THROUGH TOMORROW. HOWEVER...A NEW SWELL ARRIVING TOMORROW
WILL BOOST SURF BACK ABOVE THE ADVISORY LEVEL TOMORROW NIGHT. THE
NEXT NORTHWEST SWELL ARRIVING SATURDAY NIGHT IS LIKELY TO REQUIRE
HIGH SURF WARNINGS EARLY NEXT WEEK. THE STORM PRODUCING THIS SWELL
WILL BE QUITE LARGE WITH STRONG WINDS EXTENDING TO LOW LATITUDES.
THE SWELL WILL HAVE ENOUGH OF A WEST COMPONENT TO BRING HIGH SURF
TO WEST FACING SHORES OF THE BIG ISLAND. THIS SWELL WILL ALSO BE
LONG-LASTING...WITH SURF POSSIBLY REMAINING ABOVE THE ADVISORY LEVEL
THROUGH CHRISTMAS EVE.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 600 PM FRIDAY FOR MAALAEA BAY...THE
WATERS SOUTH OF THE BIG ISLAND...AND THE PAILOLO AND ALENUIHAHA
CHANNELS.

&&

$$
DONALDSON







000
FXHW60 PHFO 172235 AAA
AFDHFO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HONOLULU HI
1230 PM HST WED DEC 17 2014

.SYNOPSIS...
A HIGH NORTHEAST OF THE ISLANDS WILL MOVE SOUTHEAST AND DISSIPATE. A
NEW HIGH WILL MOVE INTO POSITION NORTHEAST OF THE ISLANDS TONIGHT
AND MAINTAIN MODERATE TRADE WINDS THROUGH FRIDAY EVENING. THE TRADES
WILL FOCUS SHOWERS OVER WINDWARD AREAS. WINDS WILL WEAKEN OVER THE
WEEKEND AS A SHEAR LINE APPROACHES FROM THE NORTHWEST AND RAINFALL
WILL BECOME SPARSE. SHOWERS ALONG THE SHEAR LINE WILL REACH KAUAI
SUNDAY NIGHT AND PUSH PAST THE BIG ISLAND BY TUESDAY NIGHT. BREEZY
NORTH WINDS WILL SPREAD OVER THE ISLANDS BEHIND THE SHEAR LINE.

&&

.DISCUSSION...
THE GLOBAL MODELS ARE NOW IN PRETTY GOOD AGREEMENT THROUGH EARLY
NEXT WEEK.

A 1027 MB HIGH NORTHEAST OF THE MAIN HAWAIIAN ISLANDS WILL MOVE
SOUTHEAST AND DISSIPATE OVER THE NEXT 12 HOURS. THE TRADE WINDS WILL
WEAKEN BRIEFLY...THEN STRENGTHEN AGAIN STARTING TONIGHT AS A NEW
1027 MB HIGH MOVES BY TO THE NORTH OF THE ISLANDS. THE TRADES WILL
PUSH A BAND OF SHOWERY LOW CLOUDS OVER THE ISLANDS TONIGHT AND
THURSDAY MORNING. SOME OF THESE SHOWERS MAY SPREAD LEEWARD ON OAHU
AND MOLOKAI.

IT WILL TURN DRIER THURSDAY NIGHT AS DRIER AIR MOVES OVER THE
ISLANDS FROM THE EAST. WINDS WILL WEAKEN AGAIN STARTING FRIDAY AS A
FRONT APPROACHES FROM THE NORTHWEST AND THE SUBTROPICAL RIDGE
WEAKENS AND MOVES CLOSER TO THE ISLANDS. RAINFALL WILL BECOME QUITE
SPARSE THROUGH THE DAY ON SUNDAY.

THE FRONT WILL WEAKEN TO A SHEAR LINE AND MOVE OVER KAUAI FROM THE
NORTHWEST SUNDAY NIGHT AND PUSH DOWN PAST THE BIG ISLAND TUESDAY
NIGHT. GENTLE EAST WINDS WILL SHIFT OUT OF THE NORTH AND BECOME MUCH
STRONGER BEHIND THE SHEAR LINE. A BAND OF SHOWERS ALONG THE SHEAR
LINE WILL PRODUCE WIDESPREAD SHOWERS BUT SINCE THE BAND WILL BE
RELATIVELY SHALLOW AND FAST-MOVING EXCESSIVE RAINFALL IS NOT
EXPECTED.

&&

.AVIATION...
NO AIRMETS ARE ANTICIPATED TODAY AND VFR CONDITIONS WILL PREVAIL.
THERE MAY BE SMALL AREAS OF MVFR CEILINGS OVER WINDWARD AREAS AND
OVER CENTRAL LANAI FROM MID-MORNING THROUGH EARLY EVENING.

&&

.MARINE...
A SMALL CRAFT ADVISORY...SCA...REMAINS UP FOR THE WINDY AREAS AROUND
THE BIG ISLAND AND MAUI. WINDS MAY BRIEFLY DROP BELOW THE 25 KT
LEVEL TODAY AS A SURFACE HIGH MOVES EAST SOUTHEAST AND WEAKENS.
HOWEVER... A NEW 1027 MB HIGH WILL MOVE INTO POSITION NORTH OF THE
AREA TONIGHT AND MAINTAIN SCA WINDS THROUGH FRIDAY EVENING. WINDS
WILL WEAKEN AND VEER OUT OF THE SOUTHEAST OVER THE WEEKEND. STRONG
NORTH TO NORTHEAST WINDS WILL SPREAD OVER THE ISLANDS STARTING
MONDAY AS A SHEAR LINE MOVES SOUTHEAST OVER THE ISLANDS.

NORTHWEST SWELL IN THE AREA WILL BE SMALLER THAN IT HAS BEEN FOR A
WHILE AND SURF WILL LIKELY REMAIN BELOW ADVISORY LEVELS ALONG ALL
SHORES THROUGH TOMORROW. HOWEVER...A NEW SWELL ARRIVING TOMORROW
WILL BOOST SURF BACK ABOVE THE ADVISORY LEVEL TOMORROW NIGHT. THE
NEXT NORTHWEST SWELL ARRIVING SATURDAY NIGHT IS LIKELY TO REQUIRE
HIGH SURF WARNINGS EARLY NEXT WEEK. THE STORM PRODUCING THIS SWELL
WILL BE QUITE LARGE WITH STRONG WINDS EXTENDING TO LOW LATITUDES.
THE SWELL WILL HAVE ENOUGH OF A WEST COMPONENT TO BRING HIGH SURF
TO WEST FACING SHORES OF THE BIG ISLAND. THIS SWELL WILL ALSO BE
LONG-LASTING...WITH SURF POSSIBLY REMAINING ABOVE THE ADVISORY LEVEL
THROUGH CHRISTMAS.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 600 PM FRIDAY FOR MAALAEA BAY...THE
WATERS SOUTH OF THE BIG ISLAND...AND THE PAILOLO AND ALENUIHAHA
CHANNELS.

&&

$$
DONALDSON







000
FXHW60 PHFO 172000
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1000 AM HST WED DEC 17 2014

.SYNOPSIS...
A HIGH NORTHEAST OF THE ISLANDS WILL MOVE SOUTHEAST AND DISSIPATE. A
NEW HIGH WILL MOVE INTO POSITION NORTHEAST OF THE ISLANDS TONIGHT
AND MAINTAIN MODERATE TRADE WINDS THROUGH FRIDAY EVENING. THE TRADES
WILL FOCUS SHOWERS OVER WINDWARD AREAS. WINDS WILL WEAKEN OVER THE
WEEKEND AS A SHEAR LINE APPROACHES FROM THE NORTHWEST AND RAINFALL
WILL BECOME SPARSE. SHOWER BAND ALONG THE SHEAR LINE WILL REACH
KAUAI SUNDAY NIGHT AND MOVE DOWN PAST THE BIG ISLAND BY TUESDAY
NIGHT. BREEZY NORTH WINDS WILL SPREAD OVER THE ISLANDS BEHIND THE
SHEAR LINE.

&&

.DISCUSSION...
THE GLOBAL MODELS ARE NOW IN PRETTY GOOD AGREEMENT THROUGH EARLY
NEXT WEEK.

A 1027 MB HIGH NORTHEAST OF THE MAIN HAWAIIAN ISLANDS WILL MOVE
SOUTHEAST AND DISSIPATE OVER THE NEXT 12 HOURS. THE TRADE WINDS WILL
WEAKEN BRIEFLY...THEN STRENGTHEN AGAIN STARTING TONIGHT AS A NEW
1027 MB HIGH MOVES BY TO THE NORTH OF THE ISLANDS. THE TRADES WILL
PRODUCE SCATTERED WINDWARD SHOWERS BUT LEEWARD AREAS WILL REMAIN
MOSTLY DRY.

WINDS WILL WEAKEN AGAIN OVER THE WEEKEND AS A FRONT APPROACHES FROM
THE NORTHWEST AND THE SUBTROPICAL RIDGE WEAKENS AND MOVES CLOSER TO
THE ISLANDS. RAINFALL WILL BECOME SPARSE THROUGH THE WEEKEND.

THE FRONT WILL WEAKEN TO A SHEAR LINE AND MOVE OVER KAUAI FROM THE
NORTHWEST SUNDAY NIGHT AND PUSH DOWN PAST THE BIG ISLAND TUESDAY
NIGHT. GENTLE EAST WINDS WILL SHIFT OUT OF THE NORTH AND BECOME MUCH
STRONGER BEHIND THE SHEAR LINE. A BAND OF SHOWERS ALONG THE SHEAR
LINE WILL PRODUCE WIDESPREAD SHOWERS BUT SINCE THE BAND WILL BE
RELATIVELY SHALLOW AND FAST-MOVING EXCESSIVE RAINFALL IS NOT
EXPECTED.

&&

.AVIATION...
NO AIRMETS ARE ANTICIPATED TODAY AND VFR CONDITIONS WILL PREVAIL.
THERE MAY BE SMALL AREAS OF MVFR CEILINGS OVER WINDWARD AREAS AND
OVER CENTRAL LANAI FROM MID-MORNING THROUGH EARLY EVENING.

&&

.MARINE...
A SMALL CRAFT ADVISORY...SCA...REMAINS UP FOR THE WINDY AREAS AROUND
THE BIG ISLAND AND MAUI. WINDS MAY BRIEFLY DROP BELOW THE 25 KT
LEVEL TODAY AS A SURFACE HIGH MOVES EAST SOUTHEAST AND WEAKENS.
HOWEVER... A NEW 1027 MB HIGH WILL MOVE INTO POSITION NORTH OF THE
AREA TONIGHT AND MAINTAIN SCA WINDS THROUGH FRIDAY EVENING. WINDS
WILL WEAKEN AND VEER OUT OF THE SOUTHEAST OVER THE WEEKEND. STRONG
NORTH TO NORTHEAST WINDS WILL SPREAD OVER THE ISLANDS STARTING
MONDAY AS A SHEAR LINE MOVES SOUTHEAST OVER THE ISLANDS.

NORTHWEST SWELL IN THE AREA WILL BE SMALLER THAN IT HAS BEEN FOR A
WHILE AND SURF WILL LIKELY REMAIN BELOW ADVISORY LEVELS ALONG ALL
SHORES THROUGH TOMORROW. HOWEVER...A NEW SWELL ARRIVING TOMORROW
WILL BOOST SURF BACK ABOVE THE ADVISORY LEVEL TOMORROW NIGHT. THE
NEXT NORTHWEST SWELL ARRIVING SATURDAY NIGHT IS LIKELY TO REQUIRE
HIGH SURF WARNINGS EARLY NEXT WEEK. THE STORM PRODUCING THIS SWELL
WILL BE QUITE LARGE WITH STRONG WINDS EXTENDING TO LOW LATITUDES.
THE SWELL WILL HAVE ENOUGH OF A WEST COMPONENT TO BRING HIGH SURF
TO WEST FACING SHORES OF THE BIG ISLAND. THIS SWELL WILL ALSO BE
LONG-LASTING...WITH SURF POSSIBLY REMAINING ABOVE THE ADVISORY LEVEL
THROUGH CHRISTMAS.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 600 PM FRIDAY FOR MAALAEA BAY...THE
WATERS SOUTH OF THE BIG ISLAND...AND THE PAILOLO AND ALENUIHAHA
CHANNELS.

&&

$$
DONALDSON






000
FXHW60 PHFO 172000
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1000 AM HST WED DEC 17 2014

.SYNOPSIS...
A HIGH NORTHEAST OF THE ISLANDS WILL MOVE SOUTHEAST AND DISSIPATE. A
NEW HIGH WILL MOVE INTO POSITION NORTHEAST OF THE ISLANDS TONIGHT
AND MAINTAIN MODERATE TRADE WINDS THROUGH FRIDAY EVENING. THE TRADES
WILL FOCUS SHOWERS OVER WINDWARD AREAS. WINDS WILL WEAKEN OVER THE
WEEKEND AS A SHEAR LINE APPROACHES FROM THE NORTHWEST AND RAINFALL
WILL BECOME SPARSE. SHOWER BAND ALONG THE SHEAR LINE WILL REACH
KAUAI SUNDAY NIGHT AND MOVE DOWN PAST THE BIG ISLAND BY TUESDAY
NIGHT. BREEZY NORTH WINDS WILL SPREAD OVER THE ISLANDS BEHIND THE
SHEAR LINE.

&&

.DISCUSSION...
THE GLOBAL MODELS ARE NOW IN PRETTY GOOD AGREEMENT THROUGH EARLY
NEXT WEEK.

A 1027 MB HIGH NORTHEAST OF THE MAIN HAWAIIAN ISLANDS WILL MOVE
SOUTHEAST AND DISSIPATE OVER THE NEXT 12 HOURS. THE TRADE WINDS WILL
WEAKEN BRIEFLY...THEN STRENGTHEN AGAIN STARTING TONIGHT AS A NEW
1027 MB HIGH MOVES BY TO THE NORTH OF THE ISLANDS. THE TRADES WILL
PRODUCE SCATTERED WINDWARD SHOWERS BUT LEEWARD AREAS WILL REMAIN
MOSTLY DRY.

WINDS WILL WEAKEN AGAIN OVER THE WEEKEND AS A FRONT APPROACHES FROM
THE NORTHWEST AND THE SUBTROPICAL RIDGE WEAKENS AND MOVES CLOSER TO
THE ISLANDS. RAINFALL WILL BECOME SPARSE THROUGH THE WEEKEND.

THE FRONT WILL WEAKEN TO A SHEAR LINE AND MOVE OVER KAUAI FROM THE
NORTHWEST SUNDAY NIGHT AND PUSH DOWN PAST THE BIG ISLAND TUESDAY
NIGHT. GENTLE EAST WINDS WILL SHIFT OUT OF THE NORTH AND BECOME MUCH
STRONGER BEHIND THE SHEAR LINE. A BAND OF SHOWERS ALONG THE SHEAR
LINE WILL PRODUCE WIDESPREAD SHOWERS BUT SINCE THE BAND WILL BE
RELATIVELY SHALLOW AND FAST-MOVING EXCESSIVE RAINFALL IS NOT
EXPECTED.

&&

.AVIATION...
NO AIRMETS ARE ANTICIPATED TODAY AND VFR CONDITIONS WILL PREVAIL.
THERE MAY BE SMALL AREAS OF MVFR CEILINGS OVER WINDWARD AREAS AND
OVER CENTRAL LANAI FROM MID-MORNING THROUGH EARLY EVENING.

&&

.MARINE...
A SMALL CRAFT ADVISORY...SCA...REMAINS UP FOR THE WINDY AREAS AROUND
THE BIG ISLAND AND MAUI. WINDS MAY BRIEFLY DROP BELOW THE 25 KT
LEVEL TODAY AS A SURFACE HIGH MOVES EAST SOUTHEAST AND WEAKENS.
HOWEVER... A NEW 1027 MB HIGH WILL MOVE INTO POSITION NORTH OF THE
AREA TONIGHT AND MAINTAIN SCA WINDS THROUGH FRIDAY EVENING. WINDS
WILL WEAKEN AND VEER OUT OF THE SOUTHEAST OVER THE WEEKEND. STRONG
NORTH TO NORTHEAST WINDS WILL SPREAD OVER THE ISLANDS STARTING
MONDAY AS A SHEAR LINE MOVES SOUTHEAST OVER THE ISLANDS.

NORTHWEST SWELL IN THE AREA WILL BE SMALLER THAN IT HAS BEEN FOR A
WHILE AND SURF WILL LIKELY REMAIN BELOW ADVISORY LEVELS ALONG ALL
SHORES THROUGH TOMORROW. HOWEVER...A NEW SWELL ARRIVING TOMORROW
WILL BOOST SURF BACK ABOVE THE ADVISORY LEVEL TOMORROW NIGHT. THE
NEXT NORTHWEST SWELL ARRIVING SATURDAY NIGHT IS LIKELY TO REQUIRE
HIGH SURF WARNINGS EARLY NEXT WEEK. THE STORM PRODUCING THIS SWELL
WILL BE QUITE LARGE WITH STRONG WINDS EXTENDING TO LOW LATITUDES.
THE SWELL WILL HAVE ENOUGH OF A WEST COMPONENT TO BRING HIGH SURF
TO WEST FACING SHORES OF THE BIG ISLAND. THIS SWELL WILL ALSO BE
LONG-LASTING...WITH SURF POSSIBLY REMAINING ABOVE THE ADVISORY LEVEL
THROUGH CHRISTMAS.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 600 PM FRIDAY FOR MAALAEA BAY...THE
WATERS SOUTH OF THE BIG ISLAND...AND THE PAILOLO AND ALENUIHAHA
CHANNELS.

&&

$$
DONALDSON







000
FXHW60 PHFO 171404
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST WED DEC 17 2014

.SYNOPSIS...
A SURFACE HIGH NORTHEAST OF THE MAIN HAWAIIAN ISLANDS WILL CONTINUE
MOVING SLOWLY EASTWARD...WHICH WILL ALLOW TRADE WIND SPEEDS TO
WEAKEN SLIGHTLY LATER TODAY AND TONIGHT. THE TRADES WILL STRENGTHEN
AGAIN STARTING THURSDAY AS A NEW SURFACE HIGH PASSES NORTH OF THE
STATE. MOISTURE RIDING IN ON THE TRADES WILL BRING SHOWERS MOSTLY TO
WINDWARD AND MAUKA SECTIONS. TRADE WINDS ARE EXPECTED TO WEAKEN AND
SHIFT TO A SOUTHEASTERLY DIRECTION THIS WEEKEND AHEAD OF AN
APPROACHING FRONT.

&&

.DISCUSSION...
THE RELATIVELY TIGHT PRESSURE GRADIENT SOUTH AND SOUTHWEST OF A 1026
MB SURFACE HIGH CENTERED NEAR 29N 152W...OR ABOUT 650 MILES
NORTHEAST OF HONOLULU...IS MAINTAINING MODERATE TRADES ACROSS THE
MAIN HAWAIIAN ISLANDS EARLY THIS MORNING. ALOFT...MID- TO
UPPER-LEVEL RIDGING IS MAINTAINING STABLE ATMOSPHERIC CONDITIONS
ACROSS MOST OF THE REGION. AS A RESULT...THE LOW-LEVEL TRADE WIND
FLOW IS TRANSPORTING SCATTERED TO BROKEN LOW CLOUDS WITH BRIEF LIGHT
SHOWERS MAINLY INTO WINDWARD AND MAUKA SECTIONS OF THE STATE BASED
ON LOOPS OF SATELLITE IMAGERY AND RADAR REFLECTIVITY DATA. THE
TRADES ARE ALSO CARRYING A FEW LIGHT SHOWERS OVER TO LEEWARD
SECTIONS OF SOME OF THE SMALLER ISLANDS.

THE SURFACE HIGH IS MOVING SLOWLY EASTWARD...SO EXPECT THE GRADIENT
TO GRADUALLY RELAX LATER TODAY. THIS WILL CAUSE A SLIGHT DROP IN
TRADE WIND SPEEDS. AT THE SAME TIME...A SURFACE FRONT...WHICH IS
ABOUT 700 MILES NORTHWEST OF KAUAI...WILL SHIFT EASTWARD TO A
POSITION FAR NORTH OF THE ISLANDS. AS THIS FRONT WEAKENS TONIGHT...
A NEW SURFACE HIGH WILL PUSH EASTWARD TO A POSITION ABOUT 700 MILES
NORTH OF HONOLULU THURSDAY MORNING. THIS WILL REESTABLISH THE
PRESSURE GRADIENT ACROSS THE REGION...SO EXPECT A SLIGHT INCREASE IN
TRADE WIND SPEEDS FROM THURSDAY INTO FRIDAY.

A RATHER TYPICAL COVERAGE OF LOW CLOUDS AND SHOWERS CARRIED BY THE
LOW-LEVEL TRADE WIND FLOW IS EXPECTED TO CONTINUE THROUGH TONIGHT.
THIS SHOULD RESULT IN A RATHER TYPICAL WEATHER PATTERN OF MAINLY
NIGHT AND MORNING SHOWERS FALLING OVER WINDWARD AND MAUKA SECTIONS
OF THE ALOHA STATE. WITH THE STABLE ATMOSPHERIC CONDITIONS
CONTINUING DUE TO MID- AND UPPER-LEVEL RIDGING OVER THE AREA...
EXPECT OVERALL RAINFALL TOTALS AND RATES TO REMAIN RELATIVELY LOW.
THE FORECAST MODELS INDICATE A DRIER AIR MASS WILL MOVE ACROSS THE
STATE LATE THURSDAY...WHICH WILL LIKELY CONTINUE INTO THE WEEKEND.

BY THIS WEEKEND...THE HIGH NORTH OF THE STATE IS EXPECTED TO SHIFT
EASTWARD...WHICH WILL WEAKEN THE PRESSURE GRADIENT OVER THE AREA. AS
THE HIGH CONTINUES MOVING EASTWARD...THE TRADE WINDS WILL NOT ONLY
WEAKEN...BUT VEER OUT OF THE EAST SOUTHEAST OR SOUTHEAST. NOTE THAT
THE SOUTHEASTERLY FLOW MAY ALLOW SOME VOLCANIC HAZE FROM SOURCES ON
THE BIG ISLAND TO BE CARRIED UP OVER PORTIONS OF THE SMALLER ISLANDS
THIS WEEKEND. THE LIGHT WINDS AND RELATIVELY DRY AIR MASS WILL
LIKELY PRODUCE AN INACTIVE DIURNAL CONVECTIVE PATTERN THIS WEEKEND.
THIS WEATHER PATTERN WILL FEATURE SOME AFTERNOON CLOUDS MAINLY OVER
LEEWARD AND INTERIOR SECTIONS OF THE SMALLER ISLANDS...BUT MINIMAL
SHOWER COVERAGE IS FORECAST THIS WEEKEND.

IN THE LONGER RANGE...THE FORECAST MODELS ARE SHOWING SOME BIG
CHANGES IN THE LOCAL WEATHER PATTERN. CURRENTLY...THE GUIDANCE
SHOWS A STRONG COLD FRONT WILL PUSH IN FROM THE WEST NORTHWEST FROM
LATE SUNDAY INTO MONDAY OVER THE WESTERN END OF THE MAIN HAWAIIAN
ISLAND CHAIN. BEYOND THAT TIME PERIOD THERE WERE SOME SIGNIFICANT
DISAGREEMENTS IN MODEL OUTPUT. THE MOST RECENT RUN OF THE ECMWF
MODEL NO LONGER STALLS THE FRONT OVER THE ISLANDS. IT IS NOW MUCH
CLOSER TO THE GFS SOLUTION...WHICH CONTINUES TO SHOW THE COLD FRONT
WILL PUSH DOWN THE ENTIRE ISLAND CHAIN EARLY NEXT WEEK. WE WILL
CONTINUE TO MONITOR THE MODEL OUTPUT OVER THE NEXT COUPLE OF DAYS TO
SEE IF THIS CONVERGENCE TOWARD A CONSENSUS HAS TAKEN PLACE YET OR
NOT. IN THE MEANTIME...THERE REMAINS SOME UNCERTAINLY IN THE
LONG-RANGE FORECAST AS WE HEAD INTO THE HOLIDAYS NEXT WEEK.

&&

.AVIATION...
HIGH PRESSURE TO THE NORTHEAST OF THE ISLANDS WILL MAINTAIN MODERATE
TRADES. CLOUDS AND SHOWERS WILL CONTINUE TO RIDE IN ON THE TRADES...
MAINLY AFFECTING WINDWARD AND MAUKA AREAS...AND WILL AT TIMES BRING
MVFR CONDITIONS TO THOSE AREAS. OTHERWISE VFR CONDITIONS ARE
EXPECTED TO PREVAIL.

&&

.MARINE...
A SMALL CRAFT ADVISORY /SCA/ REMAINS IN EFFECT FOR THE TYPICALLY
WINDY WATERS ADJACENT TO THE ISLANDS OF MAUI AND HAWAII COUNTIES
TODAY. TRADE WIND SPEEDS ARE FORECAST TO BRIEFLY DROP BELOW THE SCA
CRITERIA THIS EVENING. A SCA WILL LIKELY BE NEEDED AGAIN FOR THE
NORMALLY WINDY MARINE ZONES FROM THURSDAY INTO FRIDAY.

THE CIRCULATIONS ASSOCIATED WITH A SERIES OF LOWS MOVING ACROSS THE
NORTH PACIFIC OCEAN WILL PRODUCE NORTHWEST SWELLS AIMED AT THE MAIN
HAWAIIAN ISLANDS INTO EARLY NEXT WEEK. A SURFACE LOW DEVELOPING NEAR
THE INTERNATIONAL DATELINE AROUND LATITUDE 40N IS EXPECTED TO SEND A
LONG-PERIOD NORTHWEST SWELL TOWARD THE ISLANDS ON THURSDAY. THIS
SWELL IS FORECAST TO PRODUCE SURF NEAR THE HIGH SURF ADVISORY
CRITERIA ALONG MOST NORTH AND WEST FACING SHORES OF THE SMALLER
ISLANDS FROM LATE THURSDAY INTO EARLY FRIDAY. A MORE POWERFUL LOW
EAST OF JAPAN WILL SEND AN EVEN LARGER LONG-PERIOD SWELL TOWARD THE
ISLANDS. SURF PRODUCED BY THIS SWELL WILL PROBABLY REACH THE HIGH
SURF WARNING THRESHOLDS ALONG MOST NORTH AND WEST FACING SHORES OF
THE ISLANDS ON SUNDAY. NOTE THAT THE SOUTHERN EXTENT OF THE FETCH
AREA MAY PUSH LARGE BREAKERS INTO THE LEEWARD COAST OF THE BIG
ISLAND. AS A RESULT...THERE MAY BE MORE IMPACTS ON THE WEST SIDE OF
THE BIG ISLAND COMPARED WITH RECENT SWELLS. THIS SWELL WILL ALSO
LIKELY INCREASE SEAS TO NEAR THE SCA CRITERIA ACROSS MOST OF THE
COASTAL WATERS STARTING SUNDAY.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 6 PM HST THIS EVENING FOR MAALAEA
BAY...THE WATERS SOUTH OF THE BIG ISLAND...AND THE PAILOLO AND
ALENUIHAHA CHANNELS.

&&

$$

DISCUSSION/MARINE...HOUSTON
AVIATION...MBALLARD







000
FXHW60 PHFO 171404
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST WED DEC 17 2014

.SYNOPSIS...
A SURFACE HIGH NORTHEAST OF THE MAIN HAWAIIAN ISLANDS WILL CONTINUE
MOVING SLOWLY EASTWARD...WHICH WILL ALLOW TRADE WIND SPEEDS TO
WEAKEN SLIGHTLY LATER TODAY AND TONIGHT. THE TRADES WILL STRENGTHEN
AGAIN STARTING THURSDAY AS A NEW SURFACE HIGH PASSES NORTH OF THE
STATE. MOISTURE RIDING IN ON THE TRADES WILL BRING SHOWERS MOSTLY TO
WINDWARD AND MAUKA SECTIONS. TRADE WINDS ARE EXPECTED TO WEAKEN AND
SHIFT TO A SOUTHEASTERLY DIRECTION THIS WEEKEND AHEAD OF AN
APPROACHING FRONT.

&&

.DISCUSSION...
THE RELATIVELY TIGHT PRESSURE GRADIENT SOUTH AND SOUTHWEST OF A 1026
MB SURFACE HIGH CENTERED NEAR 29N 152W...OR ABOUT 650 MILES
NORTHEAST OF HONOLULU...IS MAINTAINING MODERATE TRADES ACROSS THE
MAIN HAWAIIAN ISLANDS EARLY THIS MORNING. ALOFT...MID- TO
UPPER-LEVEL RIDGING IS MAINTAINING STABLE ATMOSPHERIC CONDITIONS
ACROSS MOST OF THE REGION. AS A RESULT...THE LOW-LEVEL TRADE WIND
FLOW IS TRANSPORTING SCATTERED TO BROKEN LOW CLOUDS WITH BRIEF LIGHT
SHOWERS MAINLY INTO WINDWARD AND MAUKA SECTIONS OF THE STATE BASED
ON LOOPS OF SATELLITE IMAGERY AND RADAR REFLECTIVITY DATA. THE
TRADES ARE ALSO CARRYING A FEW LIGHT SHOWERS OVER TO LEEWARD
SECTIONS OF SOME OF THE SMALLER ISLANDS.

THE SURFACE HIGH IS MOVING SLOWLY EASTWARD...SO EXPECT THE GRADIENT
TO GRADUALLY RELAX LATER TODAY. THIS WILL CAUSE A SLIGHT DROP IN
TRADE WIND SPEEDS. AT THE SAME TIME...A SURFACE FRONT...WHICH IS
ABOUT 700 MILES NORTHWEST OF KAUAI...WILL SHIFT EASTWARD TO A
POSITION FAR NORTH OF THE ISLANDS. AS THIS FRONT WEAKENS TONIGHT...
A NEW SURFACE HIGH WILL PUSH EASTWARD TO A POSITION ABOUT 700 MILES
NORTH OF HONOLULU THURSDAY MORNING. THIS WILL REESTABLISH THE
PRESSURE GRADIENT ACROSS THE REGION...SO EXPECT A SLIGHT INCREASE IN
TRADE WIND SPEEDS FROM THURSDAY INTO FRIDAY.

A RATHER TYPICAL COVERAGE OF LOW CLOUDS AND SHOWERS CARRIED BY THE
LOW-LEVEL TRADE WIND FLOW IS EXPECTED TO CONTINUE THROUGH TONIGHT.
THIS SHOULD RESULT IN A RATHER TYPICAL WEATHER PATTERN OF MAINLY
NIGHT AND MORNING SHOWERS FALLING OVER WINDWARD AND MAUKA SECTIONS
OF THE ALOHA STATE. WITH THE STABLE ATMOSPHERIC CONDITIONS
CONTINUING DUE TO MID- AND UPPER-LEVEL RIDGING OVER THE AREA...
EXPECT OVERALL RAINFALL TOTALS AND RATES TO REMAIN RELATIVELY LOW.
THE FORECAST MODELS INDICATE A DRIER AIR MASS WILL MOVE ACROSS THE
STATE LATE THURSDAY...WHICH WILL LIKELY CONTINUE INTO THE WEEKEND.

BY THIS WEEKEND...THE HIGH NORTH OF THE STATE IS EXPECTED TO SHIFT
EASTWARD...WHICH WILL WEAKEN THE PRESSURE GRADIENT OVER THE AREA. AS
THE HIGH CONTINUES MOVING EASTWARD...THE TRADE WINDS WILL NOT ONLY
WEAKEN...BUT VEER OUT OF THE EAST SOUTHEAST OR SOUTHEAST. NOTE THAT
THE SOUTHEASTERLY FLOW MAY ALLOW SOME VOLCANIC HAZE FROM SOURCES ON
THE BIG ISLAND TO BE CARRIED UP OVER PORTIONS OF THE SMALLER ISLANDS
THIS WEEKEND. THE LIGHT WINDS AND RELATIVELY DRY AIR MASS WILL
LIKELY PRODUCE AN INACTIVE DIURNAL CONVECTIVE PATTERN THIS WEEKEND.
THIS WEATHER PATTERN WILL FEATURE SOME AFTERNOON CLOUDS MAINLY OVER
LEEWARD AND INTERIOR SECTIONS OF THE SMALLER ISLANDS...BUT MINIMAL
SHOWER COVERAGE IS FORECAST THIS WEEKEND.

IN THE LONGER RANGE...THE FORECAST MODELS ARE SHOWING SOME BIG
CHANGES IN THE LOCAL WEATHER PATTERN. CURRENTLY...THE GUIDANCE
SHOWS A STRONG COLD FRONT WILL PUSH IN FROM THE WEST NORTHWEST FROM
LATE SUNDAY INTO MONDAY OVER THE WESTERN END OF THE MAIN HAWAIIAN
ISLAND CHAIN. BEYOND THAT TIME PERIOD THERE WERE SOME SIGNIFICANT
DISAGREEMENTS IN MODEL OUTPUT. THE MOST RECENT RUN OF THE ECMWF
MODEL NO LONGER STALLS THE FRONT OVER THE ISLANDS. IT IS NOW MUCH
CLOSER TO THE GFS SOLUTION...WHICH CONTINUES TO SHOW THE COLD FRONT
WILL PUSH DOWN THE ENTIRE ISLAND CHAIN EARLY NEXT WEEK. WE WILL
CONTINUE TO MONITOR THE MODEL OUTPUT OVER THE NEXT COUPLE OF DAYS TO
SEE IF THIS CONVERGENCE TOWARD A CONSENSUS HAS TAKEN PLACE YET OR
NOT. IN THE MEANTIME...THERE REMAINS SOME UNCERTAINLY IN THE
LONG-RANGE FORECAST AS WE HEAD INTO THE HOLIDAYS NEXT WEEK.

&&

.AVIATION...
HIGH PRESSURE TO THE NORTHEAST OF THE ISLANDS WILL MAINTAIN MODERATE
TRADES. CLOUDS AND SHOWERS WILL CONTINUE TO RIDE IN ON THE TRADES...
MAINLY AFFECTING WINDWARD AND MAUKA AREAS...AND WILL AT TIMES BRING
MVFR CONDITIONS TO THOSE AREAS. OTHERWISE VFR CONDITIONS ARE
EXPECTED TO PREVAIL.

&&

.MARINE...
A SMALL CRAFT ADVISORY /SCA/ REMAINS IN EFFECT FOR THE TYPICALLY
WINDY WATERS ADJACENT TO THE ISLANDS OF MAUI AND HAWAII COUNTIES
TODAY. TRADE WIND SPEEDS ARE FORECAST TO BRIEFLY DROP BELOW THE SCA
CRITERIA THIS EVENING. A SCA WILL LIKELY BE NEEDED AGAIN FOR THE
NORMALLY WINDY MARINE ZONES FROM THURSDAY INTO FRIDAY.

THE CIRCULATIONS ASSOCIATED WITH A SERIES OF LOWS MOVING ACROSS THE
NORTH PACIFIC OCEAN WILL PRODUCE NORTHWEST SWELLS AIMED AT THE MAIN
HAWAIIAN ISLANDS INTO EARLY NEXT WEEK. A SURFACE LOW DEVELOPING NEAR
THE INTERNATIONAL DATELINE AROUND LATITUDE 40N IS EXPECTED TO SEND A
LONG-PERIOD NORTHWEST SWELL TOWARD THE ISLANDS ON THURSDAY. THIS
SWELL IS FORECAST TO PRODUCE SURF NEAR THE HIGH SURF ADVISORY
CRITERIA ALONG MOST NORTH AND WEST FACING SHORES OF THE SMALLER
ISLANDS FROM LATE THURSDAY INTO EARLY FRIDAY. A MORE POWERFUL LOW
EAST OF JAPAN WILL SEND AN EVEN LARGER LONG-PERIOD SWELL TOWARD THE
ISLANDS. SURF PRODUCED BY THIS SWELL WILL PROBABLY REACH THE HIGH
SURF WARNING THRESHOLDS ALONG MOST NORTH AND WEST FACING SHORES OF
THE ISLANDS ON SUNDAY. NOTE THAT THE SOUTHERN EXTENT OF THE FETCH
AREA MAY PUSH LARGE BREAKERS INTO THE LEEWARD COAST OF THE BIG
ISLAND. AS A RESULT...THERE MAY BE MORE IMPACTS ON THE WEST SIDE OF
THE BIG ISLAND COMPARED WITH RECENT SWELLS. THIS SWELL WILL ALSO
LIKELY INCREASE SEAS TO NEAR THE SCA CRITERIA ACROSS MOST OF THE
COASTAL WATERS STARTING SUNDAY.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 6 PM HST THIS EVENING FOR MAALAEA
BAY...THE WATERS SOUTH OF THE BIG ISLAND...AND THE PAILOLO AND
ALENUIHAHA CHANNELS.

&&

$$

DISCUSSION/MARINE...HOUSTON
AVIATION...MBALLARD








000
FXHW60 PHFO 170635
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
830 PM HST TUE DEC 16 2014

.SYNOPSIS...
A SURFACE HIGH NORTH NORTHEAST OF THE MAIN HAWAIIAN ISLANDS WILL
CONTINUE MOVING SLOWLY EASTWARD DURING THE NEXT COUPLE OF DAYS. AS
THIS HIGH MOVES TO A POSITION NORTHEAST OF THE ISLANDS...TRADE WIND
SPEEDS WILL WEAKEN SLIGHTLY WEDNESDAY...THEN INCREASE AGAIN STARTING
THURSDAY AS A NEW SURFACE HIGH PASSES NORTH OF THE STATE. MOISTURE
RIDING IN ON THE TRADES WILL BRING SHOWERS MOSTLY TO WINDWARD AND
MAUKA SECTIONS. TRADE WINDS ARE EXPECTED TO WEAKEN AND SHIFT TO A
SOUTHEASTERLY DIRECTION THIS WEEKEND AHEAD OF AN APPROACHING FRONT.

&&

.DISCUSSION...
THE RELATIVELY TIGHT PRESSURE GRADIENT SOUTH OF A 1026 MB SURFACE
HIGH CENTERED NEAR 29N 153W...OR ABOUT 650 MILES NORTH NORTHEAST OF
HONOLULU...IS MAINTAINING MODERATE TRADES ACROSS THE MAIN HAWAIIAN
ISLANDS EARLY THIS EVENING. ALOFT...MID- TO UPPER-LEVEL RIDGING IS
MAINTAINING STABLE ATMOSPHERIC CONDITIONS ACROSS MOST OF THE REGION.
AS A RESULT...THE LOW-LEVEL TRADE WIND FLOW IS TRANSPORTING BROKEN
LOW CLOUDS WITH BRIEF LIGHT SHOWERS MAINLY INTO WINDWARD AND MAUKA
SECTIONS OF THE STATE BASED ON LOOPS OF SATELLITE IMAGERY AND RADAR
REFLECTIVITY DATA.

THE SURFACE HIGH IS MOVING SLOWLY EASTWARD...SO EXPECT LITTLE CHANGE
IN WIND SPEEDS OVERNIGHT. HOWEVER...BY WEDNESDAY THE GRADIENT WILL
CONTINUE TO RELAX AS THE HIGH MOVES TO A POSITION NORTHEAST OF THE
ISLANDS. THIS WILL CAUSE A SLIGHT DROP IN TRADE WIND SPEEDS. AT THE
SAME TIME...A SURFACE FRONT...WHICH IS NOW MORE THAN 800 MILES
NORTHWEST OF KAUAI...WILL SHIFT EASTWARD FAR NORTH OF THE ISLANDS.
AS THIS FRONT WEAKENS WEDNESDAY NIGHT...A NEW SURFACE HIGH WILL PUSH
EASTWARD TO A POSITION ABOUT 700 MILES NORTH OF HONOLULU THURSDAY
MORNING. THIS WILL REESTABLISH THE PRESSURE GRADIENT ACROSS THE
REGION...SO EXPECT A SLIGHT INCREASE IN TRADE WIND SPEEDS FROM
THURSDAY INTO FRIDAY.

A RATHER TYPICAL COVERAGE OF LOW CLOUDS AND SHOWERS CARRIED BY THE
LOW-LEVEL TRADE WIND FLOW IS EXPECTED TO CONTINUE FOR THE NEXT
COUPLE OF DAYS. THIS SHOULD RESULT IN A RATHER TYPICAL WEATHER
PATTERN OF MAINLY NIGHT AND MORNING SHOWERS FALLING OVER WINDWARD
AND MAUKA SECTIONS OF THE ALOHA STATE. WITH THE STABLE ATMOSPHERIC
CONDITIONS CONTINUING DUE TO MID- AND UPPER-LEVEL RIDGING OVER THE
STATE...EXPECT OVERALL RAINFALL TOTALS AND RATES TO REMAIN
RELATIVELY LOW. THE FORECAST MODELS INDICATE A DRIER AIR MASS WILL
MOVE ACROSS THE STATE ON THURSDAY...WHICH WILL LIKELY CONTINUE INTO
THE WEEKEND.

BY THIS WEEKEND...THE HIGH NORTH OF THE STATE IS EXPECTED TO SHIFT
EASTWARD...WHICH WILL WEAKEN THE PRESSURE GRADIENT OVER THE AREA. AS
THE HIGH CONTINUES MOVING EASTWARD...THE TRADE WINDS WILL NOT ONLY
WEAKEN...BUT VEER OUT OF THE EAST SOUTHEAST OR SOUTHEAST. NOTE THAT
THE SOUTHEASTERLY FLOW MAY ALLOW SOME VOLCANIC HAZE FROM SOURCES ON
THE BIG ISLAND TO BE CARRIED UP OVER PORTIONS OF THE SMALLER ISLANDS
THIS WEEKEND. THE LIGHT WINDS AND RELATIVELY DRY AIR MASS WILL
LIKELY PRODUCE AN INACTIVE DIURNAL CONVECTIVE PATTERN THIS WEEKEND.
THIS WEATHER PATTERN WILL FEATURE SOME AFTERNOON CLOUDS OVER LEEWARD
AND INTERIOR SECTIONS OF THE SMALLER ISLANDS...BUT MINIMAL SHOWER
COVERAGE IS FORECAST THIS WEEKEND.

IN THE LONGER RANGE...THE FORECAST MODELS ARE TRENDING TOWARD SOME
FAIRLY BIG CHANGES IN THE LOCAL WEATHER PATTERN. CURRENTLY...THE
GUIDANCE SHOWS A STRONG COLD FRONT WILL PUSH IN FROM THE WEST
NORTHWEST FROM LATE SUNDAY INTO MONDAY OVER THE WESTERN END OF THE
MAIN HAWAIIAN ISLAND CHAIN. BEYOND THAT TIME PERIOD THE MODELS
DIVERGE IN THE MOVEMENT OF THE FRONT. THE ECMWF MODEL HAS BEEN
PERSISTENTLY STALLING THE FRONT OVER THE ISLANDS...EVENTUALLY
LEADING TO CYCLOGENESIS AND STORMY WEATHER ACROSS MOST OF THE STATE
TOWARD THE MIDDLE OF NEXT WEEK. THE GFS SOLUTION CONTINUES TO SHOW
THE COLD FRONT WILL PUSH DOWN THE ENTIRE ISLAND CHAIN EARLY NEXT
WEEK. EACH OF THESE FORECAST SOLUTIONS WOULD PRODUCE DRASTICALLY
DIFFERENT WEATHER CONDITIONS OVER THE ISLANDS. WE WILL CONTINUE TO
MONITOR THE MODEL OUTPUT OVER THE NEXT COUPLE OF DAYS TO SEE IF
THERE IS CONVERGENCE TOWARD A CONSENSUS. IN THE MEANTIME...THERE
REMAINS A GREAT DEAL OF UNCERTAINLY IN THE FORECAST AS WE HEAD INTO
THE HOLIDAYS NEXT WEEK.

&&

.AVIATION...
MODERATE TRADES ARE EXPECTED TO EASE SLIGHTLY TONIGHT AS THE SURFACE
HIGH TO THE NORTH OF THE ISLANDS SLIDES TO THE EAST. AIRMET TANGO
FOR MECHANICAL TURBULENCE TO THE LEE OF THE MOUNTAINS CONTINUES...
BUT WILL LIKELY BE DROPPED LATER TONIGHT.

CLOUDS AND SHOWERS WILL CONTINUE TO MAINLY AFFECT WINDWARD AND MAUKA
AREAS...AND WILL AT TIMES BRING MVFR CONDITIONS TO THOSE AREA.
OTHERWISE...VFR CONDITIONS ARE EXPECTED TO PREVAIL.

&&

.MARINE...
A SMALL CRAFT ADVISORY /SCA/ REMAINS IN EFFECT FOR THE TYPICALLY
WINDY WATERS ADJACENT TO THE ISLANDS OF MAUI AND HAWAII COUNTIES
THROUGH EARLY WEDNESDAY MORNING. TRADE WIND SPEEDS ARE FORECAST TO
DROP BELOW THE SCA CRITERIA DURING THE DAY ON WEDNESDAY. A SCA WILL
LIKELY BE NEEDED AGAIN FOR THE WINDIER MARINE ZONES FROM THURSDAY
INTO FRIDAY.

THE CIRCULATIONS ASSOCIATED WITH A SERIES OF LOWS MOVING ACROSS THE
NORTH PACIFIC OCEAN WILL PRODUCE NORTHWEST SWELLS AIMED AT THE
HAWAIIAN ISLANDS THROUGH THE WEEKEND. A SURFACE LOW DEVELOPING NEAR
THE INTERNATIONAL DATELINE AROUND LATITUDE 40N IS EXPECTED TO SEND A
LONG-PERIOD NORTHWEST SWELL TOWARD THE ISLANDS ON THURSDAY. THIS
SWELL IS FORECAST TO PRODUCE SURF NEAR THE HIGH SURF ADVISORY
CRITERIA ALONG MOST NORTH AND WEST FACING SHORES OF THE SMALLER
ISLANDS FROM LATE THURSDAY INTO EARLY FRIDAY. A MORE POWERFUL LOW
DEVELOPING OFF THE COAST OF JAPAN WILL SEND AN EVEN LARGER SWELL
TOWARD THE ISLANDS. SURF PRODUCED BY THIS SWELL WILL PROBABLY REACH
THE HIGH SURF WARNING THRESHOLDS ALONG MOST NORTH AND WEST FACING
SHORES OF THE ISLANDS ON SUNDAY. NOTE THAT THE SOUTHERN EXTENT OF
THE FETCH AREA MAY PUSH LARGE BREAKERS INTO THE LEEWARD COAST OF THE
BIG ISLAND...SO THERE MAY BE MORE IMPACTS ON THE WEST SIDE OF THE
BIG ISLAND THAN OTHER RECENT SWELLS HAVE HAD. THIS SWELL WILL ALSO
LIKELY INCREASE SEAS TO NEAR THE SCA CRITERIA ACROSS MOST OF THE
COASTAL WATERS STARTING SUNDAY.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 6 AM HST WEDNESDAY FOR MAALAEA BAY...THE
WATERS SOUTH OF THE BIG ISLAND...AND THE PAILOLO AND ALENUIHAHA
CHANNELS.

&&

$$

DISCUSSION/MARINE...HOUSTON
AVIATION...MBALLARD







000
FXHW60 PHFO 170635
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
830 PM HST TUE DEC 16 2014

.SYNOPSIS...
A SURFACE HIGH NORTH NORTHEAST OF THE MAIN HAWAIIAN ISLANDS WILL
CONTINUE MOVING SLOWLY EASTWARD DURING THE NEXT COUPLE OF DAYS. AS
THIS HIGH MOVES TO A POSITION NORTHEAST OF THE ISLANDS...TRADE WIND
SPEEDS WILL WEAKEN SLIGHTLY WEDNESDAY...THEN INCREASE AGAIN STARTING
THURSDAY AS A NEW SURFACE HIGH PASSES NORTH OF THE STATE. MOISTURE
RIDING IN ON THE TRADES WILL BRING SHOWERS MOSTLY TO WINDWARD AND
MAUKA SECTIONS. TRADE WINDS ARE EXPECTED TO WEAKEN AND SHIFT TO A
SOUTHEASTERLY DIRECTION THIS WEEKEND AHEAD OF AN APPROACHING FRONT.

&&

.DISCUSSION...
THE RELATIVELY TIGHT PRESSURE GRADIENT SOUTH OF A 1026 MB SURFACE
HIGH CENTERED NEAR 29N 153W...OR ABOUT 650 MILES NORTH NORTHEAST OF
HONOLULU...IS MAINTAINING MODERATE TRADES ACROSS THE MAIN HAWAIIAN
ISLANDS EARLY THIS EVENING. ALOFT...MID- TO UPPER-LEVEL RIDGING IS
MAINTAINING STABLE ATMOSPHERIC CONDITIONS ACROSS MOST OF THE REGION.
AS A RESULT...THE LOW-LEVEL TRADE WIND FLOW IS TRANSPORTING BROKEN
LOW CLOUDS WITH BRIEF LIGHT SHOWERS MAINLY INTO WINDWARD AND MAUKA
SECTIONS OF THE STATE BASED ON LOOPS OF SATELLITE IMAGERY AND RADAR
REFLECTIVITY DATA.

THE SURFACE HIGH IS MOVING SLOWLY EASTWARD...SO EXPECT LITTLE CHANGE
IN WIND SPEEDS OVERNIGHT. HOWEVER...BY WEDNESDAY THE GRADIENT WILL
CONTINUE TO RELAX AS THE HIGH MOVES TO A POSITION NORTHEAST OF THE
ISLANDS. THIS WILL CAUSE A SLIGHT DROP IN TRADE WIND SPEEDS. AT THE
SAME TIME...A SURFACE FRONT...WHICH IS NOW MORE THAN 800 MILES
NORTHWEST OF KAUAI...WILL SHIFT EASTWARD FAR NORTH OF THE ISLANDS.
AS THIS FRONT WEAKENS WEDNESDAY NIGHT...A NEW SURFACE HIGH WILL PUSH
EASTWARD TO A POSITION ABOUT 700 MILES NORTH OF HONOLULU THURSDAY
MORNING. THIS WILL REESTABLISH THE PRESSURE GRADIENT ACROSS THE
REGION...SO EXPECT A SLIGHT INCREASE IN TRADE WIND SPEEDS FROM
THURSDAY INTO FRIDAY.

A RATHER TYPICAL COVERAGE OF LOW CLOUDS AND SHOWERS CARRIED BY THE
LOW-LEVEL TRADE WIND FLOW IS EXPECTED TO CONTINUE FOR THE NEXT
COUPLE OF DAYS. THIS SHOULD RESULT IN A RATHER TYPICAL WEATHER
PATTERN OF MAINLY NIGHT AND MORNING SHOWERS FALLING OVER WINDWARD
AND MAUKA SECTIONS OF THE ALOHA STATE. WITH THE STABLE ATMOSPHERIC
CONDITIONS CONTINUING DUE TO MID- AND UPPER-LEVEL RIDGING OVER THE
STATE...EXPECT OVERALL RAINFALL TOTALS AND RATES TO REMAIN
RELATIVELY LOW. THE FORECAST MODELS INDICATE A DRIER AIR MASS WILL
MOVE ACROSS THE STATE ON THURSDAY...WHICH WILL LIKELY CONTINUE INTO
THE WEEKEND.

BY THIS WEEKEND...THE HIGH NORTH OF THE STATE IS EXPECTED TO SHIFT
EASTWARD...WHICH WILL WEAKEN THE PRESSURE GRADIENT OVER THE AREA. AS
THE HIGH CONTINUES MOVING EASTWARD...THE TRADE WINDS WILL NOT ONLY
WEAKEN...BUT VEER OUT OF THE EAST SOUTHEAST OR SOUTHEAST. NOTE THAT
THE SOUTHEASTERLY FLOW MAY ALLOW SOME VOLCANIC HAZE FROM SOURCES ON
THE BIG ISLAND TO BE CARRIED UP OVER PORTIONS OF THE SMALLER ISLANDS
THIS WEEKEND. THE LIGHT WINDS AND RELATIVELY DRY AIR MASS WILL
LIKELY PRODUCE AN INACTIVE DIURNAL CONVECTIVE PATTERN THIS WEEKEND.
THIS WEATHER PATTERN WILL FEATURE SOME AFTERNOON CLOUDS OVER LEEWARD
AND INTERIOR SECTIONS OF THE SMALLER ISLANDS...BUT MINIMAL SHOWER
COVERAGE IS FORECAST THIS WEEKEND.

IN THE LONGER RANGE...THE FORECAST MODELS ARE TRENDING TOWARD SOME
FAIRLY BIG CHANGES IN THE LOCAL WEATHER PATTERN. CURRENTLY...THE
GUIDANCE SHOWS A STRONG COLD FRONT WILL PUSH IN FROM THE WEST
NORTHWEST FROM LATE SUNDAY INTO MONDAY OVER THE WESTERN END OF THE
MAIN HAWAIIAN ISLAND CHAIN. BEYOND THAT TIME PERIOD THE MODELS
DIVERGE IN THE MOVEMENT OF THE FRONT. THE ECMWF MODEL HAS BEEN
PERSISTENTLY STALLING THE FRONT OVER THE ISLANDS...EVENTUALLY
LEADING TO CYCLOGENESIS AND STORMY WEATHER ACROSS MOST OF THE STATE
TOWARD THE MIDDLE OF NEXT WEEK. THE GFS SOLUTION CONTINUES TO SHOW
THE COLD FRONT WILL PUSH DOWN THE ENTIRE ISLAND CHAIN EARLY NEXT
WEEK. EACH OF THESE FORECAST SOLUTIONS WOULD PRODUCE DRASTICALLY
DIFFERENT WEATHER CONDITIONS OVER THE ISLANDS. WE WILL CONTINUE TO
MONITOR THE MODEL OUTPUT OVER THE NEXT COUPLE OF DAYS TO SEE IF
THERE IS CONVERGENCE TOWARD A CONSENSUS. IN THE MEANTIME...THERE
REMAINS A GREAT DEAL OF UNCERTAINLY IN THE FORECAST AS WE HEAD INTO
THE HOLIDAYS NEXT WEEK.

&&

.AVIATION...
MODERATE TRADES ARE EXPECTED TO EASE SLIGHTLY TONIGHT AS THE SURFACE
HIGH TO THE NORTH OF THE ISLANDS SLIDES TO THE EAST. AIRMET TANGO
FOR MECHANICAL TURBULENCE TO THE LEE OF THE MOUNTAINS CONTINUES...
BUT WILL LIKELY BE DROPPED LATER TONIGHT.

CLOUDS AND SHOWERS WILL CONTINUE TO MAINLY AFFECT WINDWARD AND MAUKA
AREAS...AND WILL AT TIMES BRING MVFR CONDITIONS TO THOSE AREA.
OTHERWISE...VFR CONDITIONS ARE EXPECTED TO PREVAIL.

&&

.MARINE...
A SMALL CRAFT ADVISORY /SCA/ REMAINS IN EFFECT FOR THE TYPICALLY
WINDY WATERS ADJACENT TO THE ISLANDS OF MAUI AND HAWAII COUNTIES
THROUGH EARLY WEDNESDAY MORNING. TRADE WIND SPEEDS ARE FORECAST TO
DROP BELOW THE SCA CRITERIA DURING THE DAY ON WEDNESDAY. A SCA WILL
LIKELY BE NEEDED AGAIN FOR THE WINDIER MARINE ZONES FROM THURSDAY
INTO FRIDAY.

THE CIRCULATIONS ASSOCIATED WITH A SERIES OF LOWS MOVING ACROSS THE
NORTH PACIFIC OCEAN WILL PRODUCE NORTHWEST SWELLS AIMED AT THE
HAWAIIAN ISLANDS THROUGH THE WEEKEND. A SURFACE LOW DEVELOPING NEAR
THE INTERNATIONAL DATELINE AROUND LATITUDE 40N IS EXPECTED TO SEND A
LONG-PERIOD NORTHWEST SWELL TOWARD THE ISLANDS ON THURSDAY. THIS
SWELL IS FORECAST TO PRODUCE SURF NEAR THE HIGH SURF ADVISORY
CRITERIA ALONG MOST NORTH AND WEST FACING SHORES OF THE SMALLER
ISLANDS FROM LATE THURSDAY INTO EARLY FRIDAY. A MORE POWERFUL LOW
DEVELOPING OFF THE COAST OF JAPAN WILL SEND AN EVEN LARGER SWELL
TOWARD THE ISLANDS. SURF PRODUCED BY THIS SWELL WILL PROBABLY REACH
THE HIGH SURF WARNING THRESHOLDS ALONG MOST NORTH AND WEST FACING
SHORES OF THE ISLANDS ON SUNDAY. NOTE THAT THE SOUTHERN EXTENT OF
THE FETCH AREA MAY PUSH LARGE BREAKERS INTO THE LEEWARD COAST OF THE
BIG ISLAND...SO THERE MAY BE MORE IMPACTS ON THE WEST SIDE OF THE
BIG ISLAND THAN OTHER RECENT SWELLS HAVE HAD. THIS SWELL WILL ALSO
LIKELY INCREASE SEAS TO NEAR THE SCA CRITERIA ACROSS MOST OF THE
COASTAL WATERS STARTING SUNDAY.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 6 AM HST WEDNESDAY FOR MAALAEA BAY...THE
WATERS SOUTH OF THE BIG ISLAND...AND THE PAILOLO AND ALENUIHAHA
CHANNELS.

&&

$$

DISCUSSION/MARINE...HOUSTON
AVIATION...MBALLARD








000
FXHW60 PHFO 170131
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
331 PM HST TUE DEC 16 2014

.SYNOPSIS...
HIGH PRESSURE NORTH OF THE ISLANDS WILL MOVE AWAY TO THE EAST THE
NEXT COUPLE OF DAYS. THE TRADE WINDS WILL WEAKEN A BIT THROUGH
MIDWEEK...THEN INCREASE AGAIN LATER IN THE WORK WEEK AS A NEW HIGH
PASSES NORTH OF THE STATE. MOISTURE RIDING IN ON THE TRADES WILL
BRING SHOWERS MOSTLY TO WINDWARD AND MAUKA SECTIONS. TRADE WINDS
WILL WEAKEN AND TURN SOUTHEAST THIS WEEKEND AHEAD OF AN APPROACHING
FRONT.

&&

.DISCUSSION...
THE HIGH PRESSURE AREA THAT BROUGHT THE STRONG TRADES A COUPLE OF
DAYS AGO WILL MOVE A LITTLE FARTHER AWAY FROM THE ISLANDS TONIGHT
AND WEDNESDAY. TRADES WILL DROP BACK TO MODERATE LEVELS DURING
THAT TIME. A NEW HIGH WILL BUILD N OF THE ISLANDS BY THU RETURNING
TRADES TO MODERATE TO FRESH LEVELS FOR A COUPLE OF DAYS. AS WE
HEAD INTO THE WEEKEND...THE HIGH WILL RESUME SLIDING E WHICH WILL
CAUSE LOCAL WINDS TO VEER TO THE ESE OR SE AND WEAKEN. THE SE FLOW
APPEARS TO LAST LONG ENOUGH TO ALLOW THE VOG PLUME FROM KILAUEA
VOLCANO TO BE DRAWN NORTH OVER THE SMALLER ISLANDS THIS WEEKEND.

PATCHY MOISTURE IS EXPECTED TO CONTINUE TO RIDE IN ON THE TRADES...
BRINGING THE TYPICAL MAINLY NIGHT AND MORNING SHOWERS TO WINDWARD
AND MAUKA AREAS. GUIDANCE MAINTAINS A RELATIVELY LOW INVERSION
THROUGH THIS TIME SO OVERALL RAINFALL AMOUNTS AND INTENSITY SHOULD
BE RATHER LIGHT. THE MODELS ARE IN GOOD AGREEMENT ABOUT A SURGE OF
DRIER AIR PUSHING IN ON THE TRADES ON THU...AND LASTING INTO THE
WEEKEND. THE LIGHT WINDS AND RELATIVELY DRY AIR WILL LEAD TO AN
INACTIVE CONVECTIVE PATTERN THAT WILL FEATURE SOME AFTERNOON
CLOUDS...BUT VERY FEW SHOWERS THIS WEEKEND. THE LACK OF RAIN AND
SE FLOW IS EXPECTED TO BRING THE VOG PLUME NEAR OR OVER THE
SMALLER ISLANDS FOR A TIME THIS WEEKEND.

THE MODELS CONTINUE TO ADVERTISE SOME FAIRLY BIG CHANGES IN THE
LONGER RANGE. THEY AGREE THAT A STRONG COLD FRONT WILL PUSH IN
FROM THE WNW LATE SUNDAY INTO MONDAY OVER THE WESTERN MAIN
ISLANDS...BUT AFTER THAT...ALL BETS ARE OFF. THE ECMWF HAS BEEN
PERSISTENTLY STALLING THE FRONT OVER THE ISLANDS...EVENTUALLY
LEADING TO CYCLOGENESIS AND STORMY WEATHER OVER AND NEAR THE
ISLANDS TOWARD THE MIDDLE OF NEXT WEEK. ON THE OTHER HAND...THE
GFS HAS BEEN STANDING FIRM BY IT/S OWN SOLUTION FEATURING A MORE
PROGRESSIVE COLD FRONT THAT MAKES IT ALL THE WAY DOWN THE CHAIN
EARLY NEXT WEEK...WITH CYCLOGENESIS INSTEAD WELL TO THE N OF THE
ISLANDS. EACH OF THESE TWO SOLUTIONS WOULD PRODUCE DRASTICALLY
DIFFERENT SENSIBLE WEATHER OVER THE ISLANDS. GIVEN THAT THIS IS
STILL 7 DAYS AND BEYOND...CONFIDENCE IN ANY GIVEN SOLUTION IS
EXTREMELY LOW...BUT WE WILL NEED TO KEEP AN EYE ON THIS.

&&

.AVIATION...
MODERATE TRADE WINDS WILL EASE UP SLIGHTLY TONIGHT AS THE SURFACE
HIGH SLIDES EAST. AIRMET TANGO FOR LOW LEVEL TURBULENCE REMAINS
POSTED AS OF NOW. THIS WILL LIKELY BE RE-EVALUATED AS TRADE WINDS
WEAKEN.

ISOLATED SHOWERS WILL MAINLY AFFECT WINDWARD AND MAUKA ARES...AT
TIMES CARRYING MVFR CIGS/VIS. OTHERWISE...VFR CONDITIONS WILL
PREVAIL.

&&

.MARINE...
LOCAL WINDS ARE EXPECTED TO DROP BELOW THE SMALL CRAFT ADVISORY
CRITERIA FOR AWHILE ON WED...BUT AN SCA MAY BE NEEDED AGAIN FOR
THE WINDIER MARINE ZONES AGAIN THU AND FRI.

A SERIES OF LOWS IN THE NORTH PACIFIC WILL KEEP PULSES OF NW
SWELL GOING THE NEXT FEW DAYS. LOW PRESSURE DEVELOPING NEAR THE
DATELINE AT 40N WILL SEND THE NEXT LONGER PERIOD NW SWELL OUR WAY
THU WITH ADVISORY LEVEL SURF LIKELY TO WRAP UP THE WORK WEEK. A
MORE POWERFUL LOW DEVELOPING OFF THE COAST OF JAPAN WILL SEND AN
EVEN LARGER SWELL OUR WAY THAT WILL PROBABLY REACH HIGH SURF WARNING
LEVELS ON SUNDAY. THE FETCH AREA IS FAR ENOUGH S THAT IT SHOULD
HAVE MORE IMPACTS ON THE WEST SIDE OF THE BIG ISLAND THAN OTHER
RECENT SWELLS HAVE HAD. THIS SWELL WILL ALSO BRING SCA-CRITERIA
SEAS AS WELL.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 6 AM HST WEDNESDAY FOR MAALAEA BAY-
PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND LEEWARD WATERS-BIG
ISLAND SOUTHEAST WATERS.


&&

$$

DISCUSSION/MARINE...R BALLARD
AVIATION...EATON








000
FXHW60 PHFO 170131
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
331 PM HST TUE DEC 16 2014

.SYNOPSIS...
HIGH PRESSURE NORTH OF THE ISLANDS WILL MOVE AWAY TO THE EAST THE
NEXT COUPLE OF DAYS. THE TRADE WINDS WILL WEAKEN A BIT THROUGH
MIDWEEK...THEN INCREASE AGAIN LATER IN THE WORK WEEK AS A NEW HIGH
PASSES NORTH OF THE STATE. MOISTURE RIDING IN ON THE TRADES WILL
BRING SHOWERS MOSTLY TO WINDWARD AND MAUKA SECTIONS. TRADE WINDS
WILL WEAKEN AND TURN SOUTHEAST THIS WEEKEND AHEAD OF AN APPROACHING
FRONT.

&&

.DISCUSSION...
THE HIGH PRESSURE AREA THAT BROUGHT THE STRONG TRADES A COUPLE OF
DAYS AGO WILL MOVE A LITTLE FARTHER AWAY FROM THE ISLANDS TONIGHT
AND WEDNESDAY. TRADES WILL DROP BACK TO MODERATE LEVELS DURING
THAT TIME. A NEW HIGH WILL BUILD N OF THE ISLANDS BY THU RETURNING
TRADES TO MODERATE TO FRESH LEVELS FOR A COUPLE OF DAYS. AS WE
HEAD INTO THE WEEKEND...THE HIGH WILL RESUME SLIDING E WHICH WILL
CAUSE LOCAL WINDS TO VEER TO THE ESE OR SE AND WEAKEN. THE SE FLOW
APPEARS TO LAST LONG ENOUGH TO ALLOW THE VOG PLUME FROM KILAUEA
VOLCANO TO BE DRAWN NORTH OVER THE SMALLER ISLANDS THIS WEEKEND.

PATCHY MOISTURE IS EXPECTED TO CONTINUE TO RIDE IN ON THE TRADES...
BRINGING THE TYPICAL MAINLY NIGHT AND MORNING SHOWERS TO WINDWARD
AND MAUKA AREAS. GUIDANCE MAINTAINS A RELATIVELY LOW INVERSION
THROUGH THIS TIME SO OVERALL RAINFALL AMOUNTS AND INTENSITY SHOULD
BE RATHER LIGHT. THE MODELS ARE IN GOOD AGREEMENT ABOUT A SURGE OF
DRIER AIR PUSHING IN ON THE TRADES ON THU...AND LASTING INTO THE
WEEKEND. THE LIGHT WINDS AND RELATIVELY DRY AIR WILL LEAD TO AN
INACTIVE CONVECTIVE PATTERN THAT WILL FEATURE SOME AFTERNOON
CLOUDS...BUT VERY FEW SHOWERS THIS WEEKEND. THE LACK OF RAIN AND
SE FLOW IS EXPECTED TO BRING THE VOG PLUME NEAR OR OVER THE
SMALLER ISLANDS FOR A TIME THIS WEEKEND.

THE MODELS CONTINUE TO ADVERTISE SOME FAIRLY BIG CHANGES IN THE
LONGER RANGE. THEY AGREE THAT A STRONG COLD FRONT WILL PUSH IN
FROM THE WNW LATE SUNDAY INTO MONDAY OVER THE WESTERN MAIN
ISLANDS...BUT AFTER THAT...ALL BETS ARE OFF. THE ECMWF HAS BEEN
PERSISTENTLY STALLING THE FRONT OVER THE ISLANDS...EVENTUALLY
LEADING TO CYCLOGENESIS AND STORMY WEATHER OVER AND NEAR THE
ISLANDS TOWARD THE MIDDLE OF NEXT WEEK. ON THE OTHER HAND...THE
GFS HAS BEEN STANDING FIRM BY IT/S OWN SOLUTION FEATURING A MORE
PROGRESSIVE COLD FRONT THAT MAKES IT ALL THE WAY DOWN THE CHAIN
EARLY NEXT WEEK...WITH CYCLOGENESIS INSTEAD WELL TO THE N OF THE
ISLANDS. EACH OF THESE TWO SOLUTIONS WOULD PRODUCE DRASTICALLY
DIFFERENT SENSIBLE WEATHER OVER THE ISLANDS. GIVEN THAT THIS IS
STILL 7 DAYS AND BEYOND...CONFIDENCE IN ANY GIVEN SOLUTION IS
EXTREMELY LOW...BUT WE WILL NEED TO KEEP AN EYE ON THIS.

&&

.AVIATION...
MODERATE TRADE WINDS WILL EASE UP SLIGHTLY TONIGHT AS THE SURFACE
HIGH SLIDES EAST. AIRMET TANGO FOR LOW LEVEL TURBULENCE REMAINS
POSTED AS OF NOW. THIS WILL LIKELY BE RE-EVALUATED AS TRADE WINDS
WEAKEN.

ISOLATED SHOWERS WILL MAINLY AFFECT WINDWARD AND MAUKA ARES...AT
TIMES CARRYING MVFR CIGS/VIS. OTHERWISE...VFR CONDITIONS WILL
PREVAIL.

&&

.MARINE...
LOCAL WINDS ARE EXPECTED TO DROP BELOW THE SMALL CRAFT ADVISORY
CRITERIA FOR AWHILE ON WED...BUT AN SCA MAY BE NEEDED AGAIN FOR
THE WINDIER MARINE ZONES AGAIN THU AND FRI.

A SERIES OF LOWS IN THE NORTH PACIFIC WILL KEEP PULSES OF NW
SWELL GOING THE NEXT FEW DAYS. LOW PRESSURE DEVELOPING NEAR THE
DATELINE AT 40N WILL SEND THE NEXT LONGER PERIOD NW SWELL OUR WAY
THU WITH ADVISORY LEVEL SURF LIKELY TO WRAP UP THE WORK WEEK. A
MORE POWERFUL LOW DEVELOPING OFF THE COAST OF JAPAN WILL SEND AN
EVEN LARGER SWELL OUR WAY THAT WILL PROBABLY REACH HIGH SURF WARNING
LEVELS ON SUNDAY. THE FETCH AREA IS FAR ENOUGH S THAT IT SHOULD
HAVE MORE IMPACTS ON THE WEST SIDE OF THE BIG ISLAND THAN OTHER
RECENT SWELLS HAVE HAD. THIS SWELL WILL ALSO BRING SCA-CRITERIA
SEAS AS WELL.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 6 AM HST WEDNESDAY FOR MAALAEA BAY-
PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND LEEWARD WATERS-BIG
ISLAND SOUTHEAST WATERS.


&&

$$

DISCUSSION/MARINE...R BALLARD
AVIATION...EATON









000
FXHW60 PHFO 170131 CCA
AFDHFO

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE HONOLULU HI
331 PM HST TUE DEC 16 2014

.SYNOPSIS...
HIGH PRESSURE NORTH OF THE ISLANDS WILL MOVE AWAY TO THE EAST THE
NEXT COUPLE OF DAYS. THE TRADE WINDS WILL WEAKEN A BIT THROUGH
MIDWEEK...THEN INCREASE AGAIN LATER IN THE WORK WEEK AS A NEW HIGH
PASSES NORTH OF THE STATE. MOISTURE RIDING IN ON THE TRADES WILL
BRING SHOWERS MOSTLY TO WINDWARD AND MAUKA SECTIONS. TRADE WINDS
WILL WEAKEN AND TURN SOUTHEAST THIS WEEKEND AHEAD OF AN APPROACHING
FRONT.

&&

.DISCUSSION...
THE HIGH PRESSURE AREA THAT BROUGHT THE STRONG TRADES A COUPLE OF
DAYS AGO WILL MOVE A LITTLE FARTHER AWAY FROM THE ISLANDS TONIGHT
AND WEDNESDAY. TRADES WILL DROP BACK TO MODERATE LEVELS DURING
THAT TIME. A NEW HIGH WILL BUILD N OF THE ISLANDS BY THU RETURNING
TRADES TO MODERATE TO FRESH LEVELS FOR A COUPLE OF DAYS. AS WE
HEAD INTO THE WEEKEND...THE HIGH WILL RESUME SLIDING E WHICH WILL
CAUSE LOCAL WINDS TO VEER TO THE ESE OR SE AND WEAKEN. THE SE FLOW
APPEARS TO LAST LONG ENOUGH TO ALLOW THE VOG PLUME FROM KILAUEA
VOLCANO TO BE DRAWN NORTH OVER THE SMALLER ISLANDS THIS WEEKEND.

PATCHY MOISTURE IS EXPECTED TO CONTINUE TO RIDE IN ON THE TRADES...
BRINGING THE TYPICAL MAINLY NIGHT AND MORNING SHOWERS TO WINDWARD
AND MAUKA AREAS. GUIDANCE MAINTAINS A RELATIVELY LOW INVERSION
THROUGH THIS TIME SO OVERALL RAINFALL AMOUNTS AND INTENSITY SHOULD
BE RATHER LIGHT. THE MODELS ARE IN GOOD AGREEMENT ABOUT A SURGE OF
DRIER AIR PUSHING IN ON THE TRADES ON THU...AND LASTING INTO THE
WEEKEND. THE LIGHT WINDS AND RELATIVELY DRY AIR WILL LEAD TO AN
INACTIVE CONVECTIVE PATTERN THAT WILL FEATURE SOME AFTERNOON
CLOUDS...BUT VERY FEW SHOWERS THIS WEEKEND.

THE MODELS CONTINUE TO ADVERTISE SOME FAIRLY BIG CHANGES IN THE
LONGER RANGE. THEY AGREE THAT A STRONG COLD FRONT WILL PUSH IN
FROM THE WNW LATE SUNDAY INTO MONDAY OVER THE WESTERN MAIN
ISLANDS...BUT AFTER THAT...ALL BETS ARE OFF. THE ECMWF HAS BEEN
PERSISTENTLY STALLING THE FRONT OVER THE ISLANDS...EVENTUALLY
LEADING TO CYCLOGENESIS AND STORMY WEATHER OVER AND NEAR THE
ISLANDS TOWARD THE MIDDLE OF NEXT WEEK. ON THE OTHER HAND...THE
GFS HAS BEEN STANDING FIRM BY IT/S OWN SOLUTION FEATURING A MORE
PROGRESSIVE COLD FRONT THAT MAKES IT ALL THE WAY DOWN THE CHAIN
EARLY NEXT WEEK...WITH CYCLOGENESIS INSTEAD WELL TO THE N OF THE
ISLANDS. EACH OF THESE TWO SOLUTIONS WOULD PRODUCE DRASTICALLY
DIFFERENT SENSIBLE WEATHER OVER THE ISLANDS. GIVEN THAT THIS IS
STILL 7 DAYS AND BEYOND...CONFIDENCE IN ANY GIVEN SOLUTION IS
EXTREMELY LOW...BUT WE WILL NEED TO KEEP AN EYE ON THIS.

&&

.AVIATION...
MODERATE TRADE WINDS WILL EASE UP SLIGHTLY TONIGHT AS THE SURFACE
HIGH SLIDES EAST. AIRMET TANGO FOR LOW LEVEL TURBULENCE REMAINS
POSTED AS OF NOW. THIS WILL LIKELY BE RE-EVALUATED AS TRADE WINDS
WEAKEN.

ISOLATED SHOWERS WILL MAINLY AFFECT WINDWARD AND MAUKA ARES...AT
TIMES CARRYING MVFR CIGS/VIS. OTHERWISE...VFR CONDITIONS WILL
PREVAIL.

&&

.MARINE...
LOCAL WINDS ARE EXPECTED TO DROP BELOW THE SMALL CRAFT ADVISORY
CRITERIA FOR AWHILE ON WED...BUT AN SCA MAY BE NEEDED AGAIN FOR
THE WINDIER MARINE ZONES AGAIN THU AND FRI.

A SERIES OF LOWS IN THE NORTH PACIFIC WILL KEEP PULSES OF NW
SWELL GOING THE NEXT FEW DAYS. LOW PRESSURE DEVELOPING NEAR THE
DATELINE AT 40N WILL SEND THE NEXT LONGER PERIOD NW SWELL OUR WAY
THU WITH ADVISORY LEVEL SURF LIKELY TO WRAP UP THE WORK WEEK. A
MORE POWERFUL LOW DEVELOPING OFF THE COAST OF JAPAN WILL SEND AN
EVEN LARGER SWELL OUR WAY THAT WILL PROBABLY REACH HIGH SURF WARNING
LEVELS ON SUNDAY. THE FETCH AREA IS FAR ENOUGH S THAT IT SHOULD
HAVE MORE IMPACTS ON THE WEST SIDE OF THE BIG ISLAND THAN OTHER
RECENT SWELLS HAVE HAD. THIS SWELL WILL ALSO BRING SCA-CRITERIA
SEAS AS WELL.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 6 AM HST WEDNESDAY FOR MAALAEA BAY-
PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND LEEWARD WATERS-BIG
ISLAND SOUTHEAST WATERS.


&&

$$

DISCUSSION/MARINE...R BALLARD
AVIATION...EATON











000
FXHW60 PHFO 170131 CCA
AFDHFO

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE HONOLULU HI
331 PM HST TUE DEC 16 2014

.SYNOPSIS...
HIGH PRESSURE NORTH OF THE ISLANDS WILL MOVE AWAY TO THE EAST THE
NEXT COUPLE OF DAYS. THE TRADE WINDS WILL WEAKEN A BIT THROUGH
MIDWEEK...THEN INCREASE AGAIN LATER IN THE WORK WEEK AS A NEW HIGH
PASSES NORTH OF THE STATE. MOISTURE RIDING IN ON THE TRADES WILL
BRING SHOWERS MOSTLY TO WINDWARD AND MAUKA SECTIONS. TRADE WINDS
WILL WEAKEN AND TURN SOUTHEAST THIS WEEKEND AHEAD OF AN APPROACHING
FRONT.

&&

.DISCUSSION...
THE HIGH PRESSURE AREA THAT BROUGHT THE STRONG TRADES A COUPLE OF
DAYS AGO WILL MOVE A LITTLE FARTHER AWAY FROM THE ISLANDS TONIGHT
AND WEDNESDAY. TRADES WILL DROP BACK TO MODERATE LEVELS DURING
THAT TIME. A NEW HIGH WILL BUILD N OF THE ISLANDS BY THU RETURNING
TRADES TO MODERATE TO FRESH LEVELS FOR A COUPLE OF DAYS. AS WE
HEAD INTO THE WEEKEND...THE HIGH WILL RESUME SLIDING E WHICH WILL
CAUSE LOCAL WINDS TO VEER TO THE ESE OR SE AND WEAKEN. THE SE FLOW
APPEARS TO LAST LONG ENOUGH TO ALLOW THE VOG PLUME FROM KILAUEA
VOLCANO TO BE DRAWN NORTH OVER THE SMALLER ISLANDS THIS WEEKEND.

PATCHY MOISTURE IS EXPECTED TO CONTINUE TO RIDE IN ON THE TRADES...
BRINGING THE TYPICAL MAINLY NIGHT AND MORNING SHOWERS TO WINDWARD
AND MAUKA AREAS. GUIDANCE MAINTAINS A RELATIVELY LOW INVERSION
THROUGH THIS TIME SO OVERALL RAINFALL AMOUNTS AND INTENSITY SHOULD
BE RATHER LIGHT. THE MODELS ARE IN GOOD AGREEMENT ABOUT A SURGE OF
DRIER AIR PUSHING IN ON THE TRADES ON THU...AND LASTING INTO THE
WEEKEND. THE LIGHT WINDS AND RELATIVELY DRY AIR WILL LEAD TO AN
INACTIVE CONVECTIVE PATTERN THAT WILL FEATURE SOME AFTERNOON
CLOUDS...BUT VERY FEW SHOWERS THIS WEEKEND.

THE MODELS CONTINUE TO ADVERTISE SOME FAIRLY BIG CHANGES IN THE
LONGER RANGE. THEY AGREE THAT A STRONG COLD FRONT WILL PUSH IN
FROM THE WNW LATE SUNDAY INTO MONDAY OVER THE WESTERN MAIN
ISLANDS...BUT AFTER THAT...ALL BETS ARE OFF. THE ECMWF HAS BEEN
PERSISTENTLY STALLING THE FRONT OVER THE ISLANDS...EVENTUALLY
LEADING TO CYCLOGENESIS AND STORMY WEATHER OVER AND NEAR THE
ISLANDS TOWARD THE MIDDLE OF NEXT WEEK. ON THE OTHER HAND...THE
GFS HAS BEEN STANDING FIRM BY IT/S OWN SOLUTION FEATURING A MORE
PROGRESSIVE COLD FRONT THAT MAKES IT ALL THE WAY DOWN THE CHAIN
EARLY NEXT WEEK...WITH CYCLOGENESIS INSTEAD WELL TO THE N OF THE
ISLANDS. EACH OF THESE TWO SOLUTIONS WOULD PRODUCE DRASTICALLY
DIFFERENT SENSIBLE WEATHER OVER THE ISLANDS. GIVEN THAT THIS IS
STILL 7 DAYS AND BEYOND...CONFIDENCE IN ANY GIVEN SOLUTION IS
EXTREMELY LOW...BUT WE WILL NEED TO KEEP AN EYE ON THIS.

&&

.AVIATION...
MODERATE TRADE WINDS WILL EASE UP SLIGHTLY TONIGHT AS THE SURFACE
HIGH SLIDES EAST. AIRMET TANGO FOR LOW LEVEL TURBULENCE REMAINS
POSTED AS OF NOW. THIS WILL LIKELY BE RE-EVALUATED AS TRADE WINDS
WEAKEN.

ISOLATED SHOWERS WILL MAINLY AFFECT WINDWARD AND MAUKA ARES...AT
TIMES CARRYING MVFR CIGS/VIS. OTHERWISE...VFR CONDITIONS WILL
PREVAIL.

&&

.MARINE...
LOCAL WINDS ARE EXPECTED TO DROP BELOW THE SMALL CRAFT ADVISORY
CRITERIA FOR AWHILE ON WED...BUT AN SCA MAY BE NEEDED AGAIN FOR
THE WINDIER MARINE ZONES AGAIN THU AND FRI.

A SERIES OF LOWS IN THE NORTH PACIFIC WILL KEEP PULSES OF NW
SWELL GOING THE NEXT FEW DAYS. LOW PRESSURE DEVELOPING NEAR THE
DATELINE AT 40N WILL SEND THE NEXT LONGER PERIOD NW SWELL OUR WAY
THU WITH ADVISORY LEVEL SURF LIKELY TO WRAP UP THE WORK WEEK. A
MORE POWERFUL LOW DEVELOPING OFF THE COAST OF JAPAN WILL SEND AN
EVEN LARGER SWELL OUR WAY THAT WILL PROBABLY REACH HIGH SURF WARNING
LEVELS ON SUNDAY. THE FETCH AREA IS FAR ENOUGH S THAT IT SHOULD
HAVE MORE IMPACTS ON THE WEST SIDE OF THE BIG ISLAND THAN OTHER
RECENT SWELLS HAVE HAD. THIS SWELL WILL ALSO BRING SCA-CRITERIA
SEAS AS WELL.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 6 AM HST WEDNESDAY FOR MAALAEA BAY-
PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND LEEWARD WATERS-BIG
ISLAND SOUTHEAST WATERS.


&&

$$

DISCUSSION/MARINE...R BALLARD
AVIATION...EATON












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