863  
FXHW52 PHFO 230043  
SRDHFO  
 
COLLABORATIVE NEARSHORE SWELL AND WIND FORECAST FOR OAHU  
NWS/NCEI HONOLULU HI  
243 PM HST FRI FEB 22 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 NNW 11 1 3 SAME 4-6 VRB SAME  
02/22 6 E 9 4 6 DOWN  
 
SAT 2 NNW 11 1 3 SAME LOW 4-6 VRB SAME  
02/23 3 E 9 2 4 DOWN LOW  
 
SUN 2 NNW 11 1 3 SAME LOW 9-13 NE UP  
02/24  
 
MON 6 NNW 12 8 12 UP LOW 9-13 NE SAME  
02/25  
 
TUE 6 NNW 11 8 12 DOWN LOW 11-16 NNE UP  
02/26 4 NW 20 8 12 UP LOW  
 
WED 11 NW 17 24 30 UP LOW 17-21 NNW UP  
02/27 6 N 10 6 8 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... LOW SPELL OVER THE WEEKEND BUILDING LATE MONDAY.  
 
DETAILED...  
MID FRIDAY ON NORTHERN SHORES HAS SURF AT A SEASONAL MINIMUM. LOW  
SURF IS EXPECTED TO CONTINUE ON SATURDAY.  
 
THE BLOCKING JET STREAM PATTERN OVER THE ALEUTIANS IN THE CENTRAL  
PACIFIC HAS KEPT WAVE-GENERATING WEATHER PATTERNS TO A MINIMUM  
THIS WEEK IN THE NW TO N PACIFIC. BACKGROUND TINY TO SMALL SURF  
IS POSSIBLE FRIDAY THROUGH MONDAY 2/22-25 MORNING WITHIN OF  
300-360 DEGREES.  
 
A FRONT BACKED BY MOSTLY NEAR GALES IS PUSHING EAST FROM THE DATE  
LINE FRIDAY 2/22. MODELS SHOW THE ASSOCIATED LOW MOVING NNE AS THE  
FRONT WEAKENS EAST OF 170W NORTH OF 30N SATURDAY PM. SHORT- TO  
MODERATE-PERIOD SURF IS EXPECTED TO BUILD MONDAY AFTERNOON 2/25  
LOCALLY FROM 310-330 DEGREES. IT SHOULD PEAK BELOW THE WINTER  
AVERAGE MONDAY NIGHT THEN DROP TUESDAY 2/26 FROM 320-350 DEGREES.  
 
MODELS SHOW A SYSTEM GAINING HURRICANE-FORCE NEAR 40N, 165E MID  
SUNDAY 2/24. IT IS PREDICTED TO RACE NE TO NEAR 50N ON THE DATE  
LINE BY MID MONDAY 2/25, THEN MOVE N INTO THE BERING SEA TUESDAY  
2/26. THE FAST TRACK AND MOVEMENT OF THE TRACK PERPENDICULAR TO  
THE GREAT CIRCLE RAYS RELATIVE TO HAWAII LOWERS THE LOCAL SURF  
POTENTIAL.  
 
LONG-PERIOD FORERUNNERS FROM 300-315 DEGREES ARE EXPECTED TO FILL  
IN LOCALLY TUESDAY PM 2/26. IT SHOULD BE ABOVE THE WINTER AVERAGE  
BY WEDNESDAY MORNING 2/27 AS IT CONTINUES TO BUILD INTO WEDNESDAY  
AFTERNOON TO EXTRA-LARGE LEVELS, OR HIGH ENOUGH TO BREAK ON OUTER  
REEFS. IT SHOULD PEAK WEDNESDAY NIGHT FROM 310-330 DEGREES. IT  
SHOULD FALL BELOW EXTRA-LARGE TO NEAR THE WINTER AVERAGE BY  
THURSDAY MORNING 2/28.  
 
SEE THE LATEST NWS STATE FORECAST DISCUSSION REGARDING THE  
CHANGING LOCAL WIND PATTERN NEXT WEEK 2/26-27. ONSHORE WINDS  
LATE TUESDAY INTO WEDNESDAY ARE EXPECTED TO MAKE FOR ROUGH,  
CHOPPY CONDITIONS FOR NORTHERLY EXPOSURES.  
 
MID FRIDAY ON EASTERN SHORES HAS BREAKERS FROM 70-90 DEGREES AT  
LEVELS ABOVE THE TRADE WINDSWELL AVERAGE. HEIGHTS ARE PREDICTED TO  
DROP BELOW AVERAGE ON SATURDAY.  
 
STRONG SURFACE HIGH PRESSURE NEAR 40N, 150W EARLIER IN THE WEEK  
SHIFTED EAST AND WEAKENED 2/21-22. ON THE EAST SIDE OF THE LOW  
PRESSURE TROUGH JUST EAST OF THE BIG ISLAND THIS WEEK, ENHANCED  
TRADES TO NEAR GALES SET UP. THIS KEPT ELEVATED E SURF THROUGH  
THE WORK WEEK 2/19-22.  
 
ASCAT SATELLITE SHOWED A SHARP WEAKENING OF SURFACE WINDS EAST OF  
THE LOW PRESSURE TROUGH TO THE E TO ENE OF HAWAII OUT 1000 NM ON  
THURSDAY 2/21 AND STAYING LOW 2/22 EXCEPT FOR A SHORT FETCH OF  
FRESH TRADES EAST OF 145W. THUS THE LOCAL SURF FROM THIS REMOTE  
WINDSWELL IS PREDICTED TO FALL OFF STEADILY FRIDAY NIGHT INTO  
SATURDAY. HEIGHTS SHOULD REMAIN WELL BELOW AVERAGE SUNDAY INTO  
WEDNESDAY FROM 70-90 DEGREES.  
 
MORE NORTHERLY EXPOSURES OF THE EAST SIDE SHOULD SEE AN INCREASE  
TUESDAY INTO WEDNESDAY AFOREMENTIONED.  
 
MID FRIDAY ON SOUTHERN SHORES HAS SMALL BREAKERS FOR EASTERLY  
EXPOSURES. HEIGHTS SHOULD DROP ON SATURDAY.  
 
THE EASTERLY WINDSWELL HAS TOPPED THE HEIGHTS THIS WEEK 2/20-22  
FOR SELECT EXPOSURES ON THE SOUTH SHORE. THE LAST OF THE WAVE  
PACKETS ON THE CONVEYOR BELT OUT OF THE EAST ARE DUE TO ARRIVE  
LATE FRIDAY INTO SATURDAY, WITH A RETURN TO THE WINTER MINIMUM BY  
MID SATURDAY 2/23.  
 
INTO THE LONG RANGE, NO SURF BEYOND TINY TO SMALL IS EXPECTED ON  
SOUTHERN SHORES 2/28-3/2. TROPICAL CYCLONE OMA OFF EASTERN  
AUSTRALIA AND A MID LATITUDE LOW PRESSURE PREDICTED IN THE TASMAN  
SEA 2/23 GIVE LOW ODDS FOR BACKGROUND SURF LOCALLY WITHIN 3/3-4  
OUT OF 208-220 DEGREES.  
 
SHORTER-PERIOD N SWELL IS EXPECTED 3/1-2 AT LEVELS BELOW THE  
WINTER AVERAGE. SURF FROM THE TRADE WIND BELT OUT OF 50-90 DEGREES  
IS EXPECTED TO REMAIN NEAR NIL LATE NEXT WEEK.  
 
LONG RANGE FORECASTS ARE SUBJECT TO HIGH UNCERTAINTY.  
 
THIS COLLABORATIVE FORECAST WILL RESUME ON MONDAY, FEBRUARY 25.  
 
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 HTTP://WWW.PRH.NOAA.GOV/HNL/PAGES/MARINE.PHP  
 

 
 
NWS FORECASTER AND NCEI PAT CALDWELL  
 
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