142  
FXHW52 PHFO 190033  
SRDHFO  
 
COLLABORATIVE NEARSHORE SWELL AND WIND FORECAST FOR OAHU  
NWS/NCEI HONOLULU HI  
233 PM HST WED SEP 18 2019  
 
THIS COLLABORATIVE FORECAST WILL BE UPDATED MONDAY THROUGH FRIDAY AT  
300 PM WHEN PAT CALDWELL IS AVAILABLE.  
 
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 2 SSE 11 2 4 DOWN 11-16 E SAME  
09/18 1 SW 17 2 4 SAME  
 
THU 2 E 13 2 4 UP LOW 11-16 E SAME  
09/19 2 SW 15 3 4 SAME LOW  
 
FRI 2 E 13 2 4 SAME LOW 11-16 ENE UP  
09/20 2 SSW 18 3 5 UP LOW  
 
SAT 5 ENE 7 2 4 SAME LOW 11-16 ENE DOWN  
09/21 2 S 15 3 6 SAME LOW  
 
SUN 2 NW 14 3 4 UP LOW 4-6 VRB SAME  
09/22 5 ENE 7 2 4 SAME LOW  
2 S 15 3 5 UP LOW  
 
MON 2 NNW 11 2 4 DOWN LOW 9-13 E UP  
09/23 5 ENE 7 2 4 SAME LOW  
2 S 15 3 5 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 IN 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...  
SURF FROM AROUND THE COMPASS.  
 
DETAILED...  
MID WEDNESDAY ON NORTHERN SHORES HAS TINY TO SMALL BREAKERS FROM  
320-330 DEGREES. HEIGHTS ARE EXPECTED TO DROP ON THURSDAY.  
 
A COMPACT GALE SE OF KAMCHATKA 9/12-13 HAD TOO SMALL A FETCH AND  
WAS TOO FAR AWAY TO MAKE SIGNIFICANT SURF FOR HAWAII. THE  
PACIOOS/CDIP WAIMEA BUOY SHOWED IT PEAK OVER NIGHT TUESDAY 9/17  
WITH ONLY 1 FEET DEEP WATER SWELL LEFT ON 9/18.  
 
BETTER ODDS FROM A COMPACT GALE WITH FURTHER EASTWARD TRAVEL  
STARTING FROM SE OF KAMCHATKA 9/16. IT WAS STRONGEST 9/17 AND IS  
WEAKENING NEAR 48N, 170E 9/18. MODELS SHOW FURTHER WEAKENING AS IT  
CROSSES THE DATE LINE 9/19.  
 
SMALL SURF IS EXPECTED TO FILL IN OVERNIGHT SATURDAY NIGHT AND  
PEAK ON SUNDAY 9/22 FROM 315-325 DEGREES. IT SHOULD BE SHORT-  
LIVED, DROPPING TO TINY TO SMALL LEVELS BY MONDAY 9/23 FROM  
320-340 DEGREES.  
 
MID WEDNESDAY ON EASTERN SHORES HAS BREAKERS AT AN EAST SIDE  
MINIMUM. AN INCREASE IS PREDICTED FOR THURSDAY.  
 
ASCAT SATELLITE AND LOCAL WIND REPORTS SHOWED PEAK LOCAL WINDS  
INTO THE FRESH BRACKET 9/17-18 THOUGH THE UPSTREAM WINDS WERE  
GENTLE TO MODERATE. THE PACIOOS/CDIP MOKAPU BUOY HAS 5'@6S WHICH  
IS MOSTLY CHOP AND ONLY ENOUGH TO MAKE TINY BREAKERS FROM  
WINDSWELL.  
 
SURF FROM TROPICAL SYSTEM KIKO IN THE EASTERN NORTH PACIFIC  
9/12-16 IS EXPECTED TO FILL IN LOCALLY ON THURSDAY 9/19. HEIGHTS  
SHOULD STAY BELOW THE TRADE WINDSWELL AVERAGE. IT IS PREDICTED TO  
HOLD THROUGH FRIDAY.  
 
UPSTREAM TRADES ARE PREDICTED TO INCREASE 9/19-22 ENOUGH TO MAKE  
SMALL WINDSWELL FOR SATURDAY INTO MONDAY.  
 
SEE THE LATEST NWS STATE FORECAST DISCUSSION REGARDING THE LOCAL  
SKIES AND WINDS.  
 
MID WEDNESDAY ON SOUTHERN SHORES HAS BREAKERS FROM 150-220 DEGREES  
AT LEVELS WITHIN BACKGROUND TO NEAR AVERAGE. SIMILAR SURF IS  
PREDICTED FOR THURSDAY.  
 
SEVERE GALES TO STORM-FORCE WINDS SW TO SE OF TASMANIA 9/10-11 HAS  
SENT LOW, LONG-PERIOD SWELL TO HAWAII AS RECORDED BY THE  
PACIOOS/CDIP BARBERS POINT BUOY 9/18 IN THE 16-22S BAND. THIS LOW  
EVENT SHOULD HOLD INTO FRIDAY.  
 
WINDS OF SIMILAR STRENGTH TO THE SE OF NEW ZEALAND 9/12-13 GREW  
SEAS OVER 30 FEET FOR A WIDE AREA WITH HIGHEST AIM AT THE  
AMERICAS. THE SYSTEM HUGGED THE ANTARCTIC ICE SHEET, WITH THE  
HIGHEST SEAS SOUTH OF 50S. THE SYSTEM MOVED RAPIDLY EAST, OUT OF  
THE HAWAII SWELL WINDOW BY 9/14. THESE ASPECTS LOWER SURF  
POTENTIAL FOR HAWAII.  
 
THE ONSET STAGE FOR THE EVENT IS DUE LOCALLY ON FRIDAY, WITH  
INCONSISTENT SETS FROM 180-200 DEGREES. THE EVENT SHOULD BE FILLED  
IN AND PEAK ON SATURDAY NEAR THE AVERAGE.  
 
A SUB-TROPICAL LOW PRESSURE NEAR 30S, 155W 9/17 HAD ABOUT 24 HOURS  
OF GALES AIMED AT HAWAII WITH THE HEAD OF THE FETCH MUCH CLOSER  
THAN MOST MID LATITUDE SOUTHERN HEMISPHERE SOURCES. THIS GIVES  
BETTER ODDS FOR LOCAL SURF. THE SYSTEM WEAKENED MID 9/18. A  
SHORT-LIVED EVENT IS DUE LOCALLY FROM 175-185 DEGREES, BUILDING  
LATE SUNDAY, PEAKING SUNDAY NIGHT, AND DROPPING MONDAY.  
 
INTO THE LONG RANGE, A PAIR OF SEVERE-GALE SYSTEMS WITH PEAK WINDS  
TO STORM FORCE TRACKED EAST RAPIDLY WITHIN 50-60S TO THE SW TO SE  
OF NEW ZEALAND 9/15-18. THIS SHOULD GIVE OVERLAPPING EVENTS WITH  
A COMBINATION OF TASMAN (210) AND NEW ZEALAND (190) SWELL LOCALLY.  
THE ONSET STAGE FOR THE FIRST EVENT IS DUE MONDAY 9/23 AND SHOULD  
PEAK NEAR THE AVERAGE TUESDAY 9/24. THE SECOND EVENT IS EXPECTED  
TO BE A NOTCH LARGER, WITH ONSET 9/25 AND PEAKING 9/26.  
 
A FAST-MOVING GALE MOVING EAST FROM THE DATE LINE 9/21 HUGGING  
THE ALEUTIANS IS MODELLED TO GIVE A SMALL NNW EVENT LOCALLY FOR  
9/25.  
 
EAST SIDE IS EXPECTED TO BE AVERAGE OR LESS FROM 60-90 DEGREES.  
 
LONG RANGE FORECASTS ARE SUBJECT TO LOW CONFIDENCE.  
 
THIS COLLABORATIVE FORECAST WILL RESUME ON FRIDAY, SEPTEMBER 20.  
 
THIS FORECAST WAS PRODUCED THROUGH THE COLLABORATIVE EFFORTS OF  
NWS AND NCEI. PLEASE SEND SUGGESTIONS TO W-HFO.WEBMASTER@NOAA.GOV  
OR CALL THE WARNING COORDINATION METEOROLOGIST AT 808-973-5275.  
 
ADDITIONAL RESOURCES:  
SEE HTTPS://WWW.WEATHER.GOV/HFO/MARINE  
 

 
 
NWS FORECASTER AND NCEI PAT CALDWELL  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HI Page Main Text Page