FZHW50 PHFO 201850
SRFHFO

SURF ZONE FORECAST
NATIONAL WEATHER SERVICE HONOLULU HI
900 AM HST TUE MAY 20 2008
 
HIZ005>011-210100-
OAHU-
900 AM HST TUE MAY 20 2008

SURF ALONG NORTH FACING SHORES WILL BE 2 TO 4 FEET THROUGH WEDNESDAY.

SURF ALONG WEST FACING SHORES WILL BE 1 TO 3 FEET THROUGH WEDNESDAY.

SURF ALONG SOUTH FACING SHORES WILL BE 2 TO 4 FEET THROUGH WEDNESDAY.

SURF ALONG EAST FACING SHORES WILL BE 2 TO 4 FEET THROUGH WEDNESDAY.

OUTLOOK THROUGH MONDAY MAY 26:
A SMALL SOUTHEAST SWELL IS EXPECTED TO CONTINUE THROUGH THE WEEK.  
A SMALL SOUTH TO SOUTHWEST SWELL IS EXPECTED TO ARRIVE FRIDAY.

SURF HEIGHTS ARE FORECAST HEIGHTS OF THE FACE OR FRONT OF WAVES. THE
SURF FORECAST IS BASED ON THE SIGNIFICANT WAVE HEIGHT IN THE ZONE OF
MAXIMUM REFRACTION. SOME WAVES MAY BE MORE THAN TWICE AS HIGH AS THE
SIGNIFICANT WAVE HEIGHT. EXPECT TO ENCOUNTER RIP CURRENTS IN OR NEAR
ANY SURF ZONE.

&&

COLLABORATIVE NEARSHORE SWELL AND WIND FORECAST FOR OAHU
NWS/NCDDC HONOLULU HI
300 PM HST MON MAY 19 2008

THIS COLLABORATIVE FORECAST WILL BE UPDATED MONDAY THROUGH FRIDAY AT
300 PM WHEN PAT CALDWELL IS AVAILABLE. WHEN PAT CALDWELL IS NOT
AVAILABLE...THE LATEST COLLABORATIVE FORECAST WILL REMAIN POSTED FOR 
4 DAYS. 

FORECAST  SWL  DMNT DMNT  H    H     HGT          WIND   WIND   SPD
DATE      HGT  DIR  PD    1/3  1/10  TEND   PROB  SPD    DIR    TEND

1 PM        3  NNW   10     4     6  DOWN          7-10   NE    SAME
05/19       2  W     14     2     4  SAME
            2  S     14     2     4  SAME

TUE         2  NNW    9     2     4  DOWN   LOW    7-10   ENE   SAME
05/20       2  W     13     2     4  DOWN   LOW 
            2  SE    17     2     4  UP     LOW 

WED         2  NW    10     2     4  SAME   LOW    7-10   ESE   DOWN
05/21       2  SE    17     2     4  SAME   LOW 

THU         2  NNW    9     2     4  SAME   LOW    7-10   SE    SAME
05/22       2  SE    15     2     4  SAME   LOW 

FRI         2  NNW    9     2     4  SAME   LOW    7-10   E     UP  
05/23       2  SE    14     2     4  SAME   LOW 
            2  SSW   15     2     4  UP     LOW 

SAT         2  NNW    9     2     4  SAME   LOW    7-10   E     SAME
05/24       2  S     14     2     4  SAME   LOW 

LEGEND:
SWL HGT    OPEN OCEAN SWELL HEIGHT MEASURED FROM TROUGH TO CREST
           IN FEET LOCATED 20 NAUTICAL MILES OFFSHORE
DMNT DIR   DOMINANT DIRECTION TYPICALLY +/-10 DEGREES IN 16 COMPASS
           POINTS
DMNT PD    DOMINANT PERIOD IN SECONDS
H1/3       SIGNIFICANT WAVE HEIGHT IN THE SURF ZONE
H1/10      AVERAGE HEIGHT OF THE HIGHEST ONE-TENTH WAVES IN THE SURF
           ZONE
HGT TEND   HEIGHT TENDENCY OF SWELL (VALID VALUES: UP/DOWN/SAME)
PROB       PROBABILITY OF OCCURRENCE (VALID VALUES: HIGH/MED/LOW)
WIND SPD   OPEN WATER WIND SPEED MEASURED IN KNOTS LOCATED
           20 NAUTICAL MILES OFFSHORE
WIND DIR   WIND DIRECTION IN 16 COMPASS POINTS
SPD TEND   WIND SPEED TENDENCY (VALID VALUES: UP/DOWN/SAME)

SURF HEIGHTS WILL VARY BETWEEN DIFFERENT BEACHES AND AT THE SAME 
BEACH AT DIFFERENT BREAK AREAS.

DISCUSSION:
SUMMARY...
SOUTHERN SHORES TOPPING THE HEIGHTS MID WEEK.

DETAILED...
MID MONDAY ON NORTHERN SHORES HAS SMALL SURF FROM 330-350 DEGREES 
WITH 8-11 SECOND PERIODS AND FROM 250-290 DEGREES WITH 12-15 
SECONDS. THE FORMER WAS GENERATED A NEAR GALES BEYOND 1500 NM AWAY 
LAST THURSDAY. THIS EPISODE SHOULD FADE TOWARD TINY LEVELS 
OVERNIGHT. THE LATTER WAS GENERATED BY TYPHOON RAMMASUN LAST WEEK SE 
OF JAPAN. THIS EPISODE SHOULD ALSO DROP ON TUESDAY.

THE JET STREAM HAS A BROAD TROUGH...OR EQUATORWARD LOOP...IN THE 
NORTH CENTRAL PACIFIC. MODELS SUGGEST WEAK...BROAD AREAS OF LOW 
PRESSURE TO DOMINATE THIS AREA THROUGH THE WEEK. PEAK WINDS ARE 
SUB-GALE...25 KNOTS...OR LESS...THUS SURF POTENTIAL IS LOW. TINY TO 
SMALL SURF FROM 310-350 DEGREES COULD LINGER THROUGH THE WEEK INTO 
EARLY NEXT WEEK.

MID MONDAY ON EASTERN SHORES HAS FLAT TO TINY CONDITIONS FROM 40-100 
DEGREES. LOCAL AND UPSTREAM TRADES REMAIN LIGHT WITH SIMILAR SURF 
THROUGH THE WEEK.

LAND AND SEABREEZES SHOULD DOMINATE THE COASTAL ZONES THROUGH THE 
PERIOD. SEE THE LATEST NWS STATE WEATHER FORECAST DISCUSSION FOR THE 
DETAILS.

MID MONDAY ON SOUTHERN SHORES HAS SMALL SURF...UP RELATIVE TO LAST 
WEEK. THIS IS THE HIGH SURF SEASON BACKGROUND PATTERN. THE 13-15 
SECOND ENERGY SEEN AT BUOYS 51002...51003...AND THE KILO NALU SENSOR 
IS LIKELY A MIX OF THE RAMMASUN SWELL AND SOUTHERN HEMISPHERE SWELL. 
THE LATTER COULD BE THE START OF A SE EPISODE. WAVE WATCH III 
SUGGESTS THIS SE SWELL IS IN THE ISLANDS ALREADY.

THIS EPISODE WAS GENERATED ABOUT 4500 NM SE OF HAWAII...WELL SE OF 
FRENCH POLYNESIA NEAR 100-110W LONGITUDE...LAST TUESDAY THROUGH 
THURSDAY...WHERE SEVERE GALES TO HURRICANE-FORCE WINDS BLEW OVER A 
LONG...NARROW FETCH IN THE 130-145 DEGREE BAND RELATIVE TO HAWAII. 
THIS DIRECTION IS SHADOWED ON OAHU BY THE BIG ISLAND...ALTHOUGH 
REFRACTION SHOULD ALLOW AT LEAST SMALL SURF LOCALLY. THIS EPISODE 
SHOULD BUILD ON TUESDAY...PEAK ON WEDNESDAY...AND SLOWLY DROP INTO 
SATURDAY. GIVE BIG ERROR BARS DUE TO THE UNCERTAINTY ASSOCIATED WITH 
THE SHADOWING.

GALES TO SEVERE GALES IN THE 185-200 DEGREE BAND BEYOND 5000 NM AWAY 
WERE ASSOCIATED WITH AN EXTRA-TROPICAL CYCLONE SE OF NEW ZEALAND 
LAST THURSDAY. THE SYSTEM TRACKED NORTH AS THE WINDS WEAKENED. THE 
LOW PRESSURE AREA OCCLUDED OVER THE WEEKEND...AS WINDS INCREASE 
AGAIN TO GALES. THE SYSTEM MOVED SLOWLY WEST WITH A FETCH IN THE 
180-190 DEGREE BAND WITH THE HEAD ABOUT 3000 NM AWAY FOR ABOUT 48 
HOURS. THIS SHOULD LEAD TO A LONG-LIVED...SMALL TO MODERATE EPISODE. 
IT SHOULD BUILD ON FRIDAY FROM 185-200 DEGREES...PEAK ON SATURDAY 
INTO SUNDAY FROM 180-195 DEGREES...AND SLOWLY DROP OFF INTO NEXT 
TUESDAY.

INTO THE LONG RANGE...THE PATTERN IS UNFAVORABLE IN THE SOUTHERN 
HEMISPHERE THIS WEEK...MEANING LOW SURF NEXT WEEK. HINTS OF A MORE 
FAVORABLE PATTERN DOWNUNDER EARLY NEXT WEEK...GIVING WAY TO AN 
INCREASE IN LOCAL SURF FOR THE FIRST WEEK OF JUNE.

IN THE NORTHERN HEMISPHERE...A STRING OF LOW PRESSURES FROM JAPAN TO 
THE LONGITUDES OF HAWAII GIVE POTENTIAL FOR SHORT-LIVED...SMALL 
EPISODES FROM NW TO N FOR THE LAST WEEK OF MAY AND INTO EARLY JUNE. 
ODDS ARE LOW FOR MORE SURF THIS SEASON AS HIGH AS THE RECENT 
EPISODE. TRADES BELOW AVERAGE SPEEDS MOST DAYS INTO THE END OF 
MAY...WITH MORE NORMAL CONDITIONS SUGGESTED FOR THE FIRST WEEK OF 
JUNE. LONG RANGE ESTIMATES ARE SUBJECT TO GENEROUS JUGGLING. THE 
NEXT COLLABORATIVE FORECAST WILL BE ISSUED ON WEDNESDAY...MAY 21.

THIS FORECAST WAS PRODUCED THROUGH THE COLLABORATIVE EFFORTS OF
NWS AND NCDDC. PLEASE SEND SUGGESTIONS TO W-HFO.WEBMASTER@NOAA.GOV
OR CALL THE WARNING COORDINATION METEOROLOGIST AT 808-973-5275.

ADDITIONAL RESOURCES:
SEE /IN LOWERCASE/  HTTP://WWW.PRH.NOAA.GOV/HNL/PAGES/MARINE.PHP

$$

NWS FORECASTER CRAIG AND NCDDC PAT CALDWELL