High Surf in Hawaii, November 17 to 18, 2014

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
359 AM HST MON NOV 17 2014

.SYNOPSIS...
SURFACE HIGH PRESSURE WILL BUILD NORTH OF THE STATE TODAY...THEN
PERSIST THROUGH MOST OF THE WEEK...GENERATING MODERATE TO BREEZY
TRADE WINDS WITH LIMITED RAINFALL. AN INCREASINGLY WET PATTERN IS
FORECAST LATE THIS WEEK INTO THE WEEKEND AS ENHANCED MOISTURE
MOVES UP ACROSS THE STATE FROM THE SOUTHEAST.

&&

.DISCUSSION...
SHOWERS HAVE DIMINISHED ON RADAR ACROSS THE WINDWARD BIG ISLAND
DURING THE NIGHT...BUT SOME RAIN GAUGES IN THAT AREA CONTINUE TO
MEASURE LIGHT RAINFALL AMOUNTS. DRY CONDITIONS HAVE PREVAILED
ACROSS THE REMAINDER OF THE STATE...WITH A FEW LIGHT SHOWERS JUST
REACHING WINDWARD HALEAKALA DURING THE PAST HOUR. AT THE SURFACE...
A 1021 MB HIGH IS CENTERED ABOUT 450 MILES NORTHWEST OF KAUAI...
WITH A RIDGE BUILDING NORTH OF THE STATE. ALOFT...A DEEP MID/UPPER
TROUGH IS CENTERED BETWEEN NEAR 140W...WHILE A DEEP LAYERED RIDGE
CENTERED NEAR 22N170W IS BUILDING EASTWARD INTO THE STATE. THE
12Z LIHUE SOUNDING REFLECTED A DRY AND STABLE PROFILE WITH PWAT OF
ONLY 1.02 INCHES....AND A LOW INVERSION BASED NEAR 4000 FEET. THE
12Z HILO SOUNDING HAS ALSO DRIED OUT AND STABILIZED DURING THE
PAST 12 HOURS... WITH A WELL DEFINED INVERSION DEVELOPING NEAR
7000 FEET AND PWAT DOWN TO 1.16 INCHES.

MOSTLY CLEAR AND DRY CONDITIONS WILL PREVAIL ACROSS THE STATE
TODAY...WITH THE BEST RAIN CHANCES OCCURRING ACROSS THE WINDWARD
BIG ISLAND WHERE A BIT MORE RESIDUAL LOW LEVEL MOISTURE REMAINS.
THE SMALLER ISLANDS WILL SEE LITTLE RAINFALL EVEN ACROSS WINDWARD
AREAS...DUE TO THE LOWER THAN NORMAL INVERSION AND LACK OF
AVAILABLE MOISTURE.

SURFACE HIGH PRESSURE NORTH OF THE STATE AND A MID LEVEL RIDGE
OVERHEAD WILL COMBINE TO PRODUCE A RATHER DRY MODERATE TO LOCALLY
BREEZY TRADE WIND PATTERN FROM TONIGHT THROUGH WEDNESDAY NIGHT.
SHOWERS DURING THIS TIME WILL BE MAINLY LIGHT AND LIMITED TO
WINDWARD/MAUKA AREAS DURING THE NIGHT AND EARLY MORNING HOURS.
LEEWARD AREAS WILL SEE MOSTLY CLEAR AND DRY CONDITIONS...WHILE THE
KONA COAST OF THE BIG ISLAND WILL SEE THE USUAL CLOUDS BUT ONLY
ISOLATED SHOWERS AT MOST EACH AFTERNOON.

A DEVELOPING NEARBY MID/UPPER LEVEL TROUGH AND A LARGE AREA
OF DEEPER TROPICAL MOISTURE MOVING INTO THE STATE FROM THE
SOUTHEAST SHOULD YIELD A SIGNIFICANTLY WETTER PATTERN ACROSS THE
STATE LATE THIS WEEK AND INTO THE WEEKEND. MODEL CONSENSUS SPREADS
THE AREA OF HIGHER MOISTURE INTO THE BIG ISLAND ON THURSDAY...MAUI
COUNTY THURSDAY NIGHT INTO FRIDAY...AND ACROSS OAHU/KAUAI BY
FRIDAY OR FRIDAY NIGHT. MODELS CONTINUE TO VARY REGARDING THE
POSITION OF THE NEXT FRONTAL BOUNDARY TO OUR NORTHWEST DURING THE
WEEKEND... BUT IN GENERAL IT APPEARS THAT A MOIST AND SOMEWHAT
UNSTABLE ATMOSPHERE WILL BE IN PLACE OVER THE STATE...ALONG WITH
MODERATE EAST OR EAST/SOUTHEAST LOW LEVEL FLOW. THIS WOULD FAVOR
HIGH RAIN CHANCES ACROSS WINDWARD AREAS...WITH SCATTERED SHOWERS
AFFECTING MANY LEEWARD AREAS AS WELL. THE ENHANCED MOISTURE IN
PLACE ALONG WITH INSTABILITY ALOFT DUE TO THE EXPECTED PROXIMITY
OF THE MID/UPPER LEVEL TROUGH MAY ALLOW FOR SOME LOCALLY HEAVY
RAINS AND POSSIBLY EVEN ISOLATED THUNDERSTORMS AS WELL FROM FRIDAY
INTO THE WEEKEND. THIS PORTION OF THE FORECAST IS STILL SEVERAL
DAYS AWAY WITH CONSIDERABLE UNCERTAINTY AT THIS POINT...SO WILL
CONTINUE TO MONITOR LATER MODEL RUNS AND MAKE ADJUSTMENTS AS
NEEDED DURING THE WEEK.

&&

.AVIATION...
VFR WILL PREVAIL OVER MOST AREAS THROUGH THE DAY...THOUGH REMNANT
MOISTURE FROM AN OLD FRONT WILL PERSIST AS LOW CLOUDS AND SHOWERS...
TEMPO MVFR CONDITIONS...OVER THE NORTHEAST QUADRANT OF THE BIG
ISLAND THROUGH MUCH OF THE MORNING.

AIRMET SIERRA FOR MOUNTAIN OBSCURATION IS IN EFFECT FOR THE BIG
ISLAND FROM UPOLU POINT TO HILO. WITH TRADE WINDS ON THE INCREASE...
AN AIRMET FOR LOW LEVEL TURBULENCE SOUTH THROUGH WEST OF THE
MOUNTAINS ON ALL THE ISLANDS WILL BE POSTED THIS MORNING AS OF 0600
HST.

&&

.MARINE...
THE NEW NNW SWELL HAS ARRIVED AT BUOY 51101 DURING THE PAST SEVERAL
HOURS PRETTY MUCH AS EXPECTED...AND IF ANYTHING MAY BE RUNNING
SLIGHTLY ABOVE WAVE WATCH GUIDANCE. THIS SWELL IS STILL EXPECTED
TO REACH THE NEARSHORE WATERS BEFORE SUNRISE TODAY...THEN PEAK
DURING THE DAY WITH ADVISORY LEVEL SURF EXPECTED ON NORTH FACING
SHORES. WITH INCREASED CONFIDENCE IN THE OCCURRENCE OF HIGH
SURF TODAY AND THE LATEST WAVEWATCH GUIDANCE...THE HIGH SURF
ADVISORY HAS BEEN EXTENDED THROUGH MIDNIGHT TONIGHT. THE NNW
SWELL IS THEN FORECAST TO GRADUALLY SUBSIDE LATE TONIGHT THROUGH
WEDNESDAY. A SMALLER NW SWELL IS EXPECTED TO ARRIVE WEDNESDAY
AFTERNOON...PEAK WEDNESDAY NIGHT AND THURSDAY...THEN SUBSIDE
THURSDAY NIGHT AND FRIDAY. RESULTING SURF SHOULD REMAIN BELOW
ADVISORY LEVELS ON NORTH AND WEST FACING SHORES.

THE SUNDAY EVENING ASCAT PASS MISSED THE COASTAL WATERS...BUT
AVAILABLE LAND-BASED OBSERVATIONS INDICATE THAT SMALL CRAFT
ADVISORY /SCA/ WINDS ARE LIKELY OCCURRING IN THE CHANNELS AROUND
THE BIG ISLAND AND MAUI COUNTY. WINDS SHOULD INCREASE FURTHER
ACROSS THE AREA TODAY...AND THE ARRIVING NNW SWELL COMBINED WITH
THE FRESH WINDS WILL PUSH COMBINED SEAS ABOVE 10 FEET IN OTHER
AREAS EXPOSED TO THE SWELL. MODERATE TO FRESH TRADE WINDS ARE
FORECAST TO PERSIST THROUGH MOST OF THIS WEEK...SO EXPECT SCA
CONDITIONS TO CONTINUE IN THE TYPICALLY WINDY WATERS THROUGH
AT LEAST THURSDAY.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL MIDNIGHT HST TONIGHT FOR NORTH FACING
SHORES OF NIIHAU KAUAI OAHU MAUI MOLOKAI AND THE BIG ISLAND.

SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 PM HST
WEDNESDAY FOR BIG ISLAND LEEWARD WATERS.

SMALL CRAFT ADVISORY UNTIL MIDNIGHT HST TONIGHT FOR KAUAI
NORTHWEST WATERS-KAUAI WINDWARD WATERS-KAUAI LEEWARD WATERS-
KAUAI CHANNEL-OAHU WINDWARD WATERS-KAIWI CHANNEL-MAUI COUNTY
WINDWARD WATERS-BIG ISLAND WINDWARD WATERS.

SMALL CRAFT ADVISORY UNTIL 6 PM HST WEDNESDAY FOR MAALAEA BAY-
PAILOLO CHANNEL-ALENUIHAHA CHANNEL.

SMALL CRAFT ADVISORY UNTIL 6 PM HST WEDNESDAY FOR BIG ISLAND
SOUTHEAST WATERS.

&&

DISCUSSION/MARINE...JACOBSON
AVIATION...KINEL