High Surf in Hawaii, February 17, 2011

AREA FORECAST DISCUSSION COR
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST THU FEB 17 2011

.SYNOPSIS...A FRONT IS EXPECTED TO BRING MOISTURE TO A PORTION OF
THE 50TH STATE DURING THE NEXT DAY OR TWO. THE UNSETTLE WEATHER
WILL AFFECT PRIMARILY KAUAI DURING THIS STRETCH. VOG WILL MAKE A
RETURN VISIT TO OAHU AND MAUI COUNTIES AS WELL AS THE WIND FLOW
TURNS SOUTHERLY AHEAD OF THE FRONT. LIGHT TO MODERATE EASTERLY WINDS
ARE SLATED TO RETURN SATURDAY NIGHT AND LINGER THROUGH THE FIRST
HALF OF NEXT WEEK.

&&

.DISCUSSION...
SO FAR EVERYTHING IS GOING TO PLAN. SHOWERS WILL BE INCREASING
ACROSS KAUAI TODAY WITH SOME HEAVY SHOWERS FOR THE OVERNIGHT HOURS
TONIGHT AND FRIDAY. A FLASH FLOOD WATCH HAS BEEN POSTED THAT WILL
GO INTO EFFECT AT 4 PM THIS AFTERNOON.

BASED ON THE GFS SOLUTION...THE FRONT...CURRENTLY 380 MILES WEST OF
KAUAI...IS FORECAST TO TEMPORARILY STALL OVER KAUAI SATURDAY
MORNING. THIS IS A LATER ARRIVAL TIME OF 12 HOURS THAN THE PREVIOUS
PREDICTION. I SHOULD POINT OUT THAT BOTH THE NAM AND NOGAPS HAVE
SIMILAR SOLUTION OF THE FRONT NOT COMING CLOSE TO KAUAI...WHILE THE
ECMWF /EC/ SHOW SIGNS OF SIDING WITH THE GFS WITH THE FRONT BRUSHING
KAUAI SATURDAY NIGHT. THE GFS HAS THE HEAVY SHOWERS ABATING ONCE THE
FRONT REACHES KAUAI. SOME OF THE MOISTURE FROM THE FRONT WILL SPREAD
TO MOLOKAI.

THIS FORECAST PACKAGE USES THE GFS SOLUTION WITH POPS FROM THE EC
BLENDED IN. THE EC POPS ARE DRIER.

THE FRONT WILL RETREAT FAR TO THE WEST OF KAUAI SATURDAY NIGHT AND
SUNDAY...THUS ALLOWING LIGHT TO MODERATE EASTERLY WINDS TO MOVE BACK
IN...AND HENCE SHOWERS FOR THE WINDWARD AND MOUNTAIN AREAS.

&&

.MARINE...
THE WINDS ARE STILL STRONG FOR THE WINDWARD WATERS OF THE BIG
ISLAND. THUS THE SMALL CRAFT ADVISORY HAS BEEN EXTENDED TO 6 PM HST
TODAY.

THE HIGH SURF ADVISORY REMAINS IN EFFECT FOR THE EAST FACING SHORES
AS THE NEW NORTH SWELL EASES IN. THE NORTH FACING SHORES WILL STAY
BELOW ADVISORY LEVELS.

ADDITIONALLY...THIS NORTH SWELL...ALTHOUGH NOT VERY LARGE...CONTAIN
LONG PERIODS OF 14 T0 17 SECONDS. THIS IS GOOD ENOUGH TO WARRANT
A MESSAGE TO VESSEL OPERATORS AND HARBOR MASTERS OF KAHULUI AND HILO
HARBORS OF THE POTENTIAL OF HARBOR SURGES TODAY AND TONIGHT.

&&

.AVIATION...
A SLOW MOVING FRONTAL BOUNDARY CONTINUES TO ADVANCE SLOWLY TOWARD
THE FA FROM THE W. S-SE FLOW AND SCT RA ALSO PERSIST ACROSS THE
AREA. THE SRLY FLOW MAY BRING UP PATCHY VOG AND ISOL AREAS OF MVFR
VIS TO THE SMALLER ISLANDS THROUGH THE FORECAST PERIOD. MAINLY VFR
EXP FOR THE TERMINALS WITH PHLI SEEING A FEW MVFR CIGS FROM TIME TO
TIME. AS THE FRONT NEARS...MVFR WILL BECOME THE RULE SOMETIME AFT
00Z WHICH IS REFLECTED IN THE TAF AND FA.

AIRMET SIERRA REMAINS UNCHANGED FOR THE BIG ISLAND AND WILL CONTINUE
BEYOND SUNRISE. KAUAI HAS BEEN ADDED TO AIRMET SIERRA DUE TO THE
CONSISTENT INFLUX OF SHRA FROM THE S. AIRMET TANGO WAS SCALED BACK
TO KAUAI/OAHU WHERE THE VAD WINDS INDICATE SERLY FLOW REMAINS STRONG
ENOUGH TO PRODUCE LEE TURB. 12Z SOUNDINGS AND VAD DATA SUGGEST ICING
COULD REQUIRE AN AIRMET IN THE NEAR FUTURE AS THE HIGHER LEVEL
MOISTURE GRADUALLY DEEPENS AND DEWPOINT DEPRESSIONS SHRINK THROUGH
THE MID LEVELS OVER THE FAR WRN PORTION OF THE STATE.

ELSEWHERE ACROSS THE HFO AOR THINGS LOOK GENERALLY QUIET WITH ISOL
CONVECTION ALONG THE ITCZ WELL S OF THE STATE. TSTORMS REMAIN ISOL
WITH TOPS TO FL510 AND MAY REQUIRE A SIGMET IF COVERAGE INCREASES
OVER THE NEXT FEW HOURS AS IT MAY BEGIN TO IMPACT SOUTHBOUND TRAFFIC.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FOR KAUAI AND NIIHAU STARTING AT 4 PM HST THIS
AFTERNOON.

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

SMALL CRAFT ADVISORY UNTIL 6 PM HST TODAY FOR WINDWARD BIG ISLAND
WINDWARD WATERS.

PUBLIC/MARINE...LAU
AVIATION...DE JESUS