845
FXHW60 PHFO 300158
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
358 PM HST WED APR 29 2026
SYNOPSIS
MODERATE TO LOCALLY BREEZY TRADES WILL PREVAIL FOR THE NEXT
SEVERAL DAYS, RESULTING IN PERIODS OF SHOWER ACTIVITY ACROSS
PRIMARILY WINDWARD AND MAUKA LOCATIONS. A NEARLY STATIONARY UPPER-
LEVEL LOW NORTHEAST OF THE ISLANDS WILL ENHANCE CLOUDS SHOWERS
THROUGH FRIDAY. BY THE WEEKEND, THE DISTURBANCE ALOFT IS FORECAST
TO FINALLY MEANDER FARTHER NORTHEAST AWAY FROM THE STATE.
HOWEVER, PERIODS OF WINDWARD AND MAUKA SHOWERS WILL CONTINUE.
DISCUSSION
THIS AFTERNOON, MODERATE TO LOCALLY BREEZY TRADE WINDS CONTINUE
TO PREVAIL ACROSS THE ISLAND CHAIN, STEERED BY TWO AREAS OF HIGH
PRESSURE CENTERED NORTH AND NORTHEAST OF THE ISLANDS THAT ARE
SEPARATED BY A FRONT THAT EXTENDS FROM SOUTHERN ALASKA TO NEAR
30N. MEANWHILE, WATER VAPOR IMAGERY SHOWS A DISTINCT LOW ALOFT
NORTHEAST OF THE MAIN HAWAIIAN ISLANDS. THIS UPPER-LEVEL
DISTURBANCE HAS INTRODUCED SOME INSTABILITY IN THE VICINITY OF THE
STATE, AS SEEN ON THE AFTERNOON UPPER AIR SOUNDINGS FROM LIHUE
AND HILO. THIS INSTABILITY IS RESULTING IN DEEPER CLOUDS AND SOME
ENHANCED SHOWER ACTIVITY THIS AFTERNOON, PARTICULARLY ACROSS
WINDWARD SECTIONS OF MAUI AND THE BIG ISLAND. A FEW SHOWERS HAVE
DRIFTED INTO LEEWARD AREAS AS WELL, AND AFTERNOON SEA BREEZE
CONVERGENCE HAS ALSO INCREASED CLOUDS AND SHOWERS ALONG SHELTERED
LEEWARD LOCATIONS, SUCH AS THE KONA SLOPES OF THE BIG ISLAND.
FORECAST GUIDANCE IS IN GOOD AGREEMENT THAT THE UPPER-LEVEL LOW
NORTHEAST OF THE ISLAND CHAIN WILL REMAIN NEARLY STATIONARY
THROUGH FRIDAY, WHICH WILL CONTINUE A SIMILAR WET TRADE WIND
PATTERN INTO THE NEXT COUPLE OF DAYS. SHOWERS WILL FAVOR WINDWARD
SLOPES OF ALL ISLANDS, WITH SOME POSSIBLE SHOWER ACTIVITY DRIFTING
INTO LEEWARD AREAS BRIEFLY. HOWEVER, BY THIS WEEKEND, THE UPPER-
LEVEL LOW WILL FINALLY EXIT THE REGION, THOUGH PERIODS OF SHOWERS
WILL CONTINUE TO FAVOR WINDWARD AREAS. ONLY SLIGHT VARIATIONS IN
DAY-TO-DAY TRADE WINDS ARE EXPECTED OVER THE NEXT SEVERAL DAYS,
WITH SLIGHT STENGHTENING FOLLOWED BY SLIGHT WEAKENING THIS
WEEKEND. BY EARLY NEXT WEEK, MODEL GUIDANCE SHOWS A SHALLOW COLD
FRONT AND ANOTHER UPPER-LEVEL TROUGH APPROACHING THE ISLANDS FROM
THE NORTHWEST EARLY NEXT WEEK, THOUGH IT REMAINS TO BE SEEN HOW
MUCH MOISTURE CAN BE EXPECTED WITH THIS SYSTEM.
AVIATION
MODERATE TO FRESH TRADES WILL STRENGTHEN SLIGHTLY TONIGHT. NO
AIRMETS IN EFFECT THIS AFTERNOON, WITH LIGHT LEEWARD TURBULENCE
EXPECTED AND BRIEF MOUNTAIN OBSCURATIONS DUE TO THE PRESENCE OF AN
UPPER LOW JUST NORTHEAST OF HAWAII. A BAND OF SHOWERS WILL MOVE IN
WITH THE TRADES TONIGHT, ALONG WITH THE BOOST IN WIND SPEEDS,
WILL LIKELY RESULT IN BOTH AIRMET SIERRA FOR WINDWARD TEMPO
MOUNTAIN OBSCURATIONS AND AIRMET TANGO FOR LEEWARD TEMPO MODERATE
TURBULENCE OVERNIGHT.
MARINE
HIGH PRESSURE STRENGTHENING TO OUR NORTH WILL STRENGTHEN THE
TRADE WINDS THURSDAY INTO FRIDAY WITH WIDESPREAD FRESH TO LOCALLY
STRONG TRADE WINDS EXPECTED BY THURSDAY AFTERNOON. CURRENTLY A
SMALL CRAFT ADVISORY (SCA) IS IN EFFECT FOR THE TYPICAL WINDY
AREAS OF MAUI COUNTY AND THE BIG ISLAND. THE SCA MAY NEED TO BE
EXTENDED TO OTHER AREA WATERS AS THE TRADE WINDS STRENGTHEN OVER
THE NEXT 24 TO 36 HOURS. OVER THE WEEKEND, A FRONT PASSING FAR
NORTH OF THE STATE WILL SHIFT THE HIGH FURTHER EAST AND WILL ALLOW
THE TRADE WINDS TO DECREASE BELOW SCA THRESHOLDS BY SUNDAY.
A NEW NORTHWEST TO NORTH-NORTHWEST (320-330 DEGREE) SWELL
CONTINUES TO FILL IN THIS AFTERNOON AND WILL LIKELY PEAK TONIGHT
INTO THURSDAY MORNING THEN SLOWLY DECLINE INTO FRIDAY. LOOKING
FURTHER AHEAD, A STORM-FORCE LOW CURRENTLY IN THE NORTH PACIFIC
WILL SEND A MODERATE, LONGER-PERIOD NORTHWEST SWELL TOWARD THE
ISLANDS FOR LATE FRIDAY INTO SATURDAY, WITH ABOVE AVERAGE SURF
EXPECTED ALONG NORTH AND WEST FACING SHORES. AVERAGE H1/10 HEIGHTS
FOR NORTH FACING SHORES IS 6 FEET FOR THE MONTH OF MAY (GODDARD-
CALDWELL DATABASE).
SURF ALONG SOUTH-FACING SHORES WILL REMAIN SMALL THROUGH MUCH OF
THE WEEK, WITH MAINLY BACKGROUND SOUTH TO SOUTHWEST SWELL
EXPECTED. A SMALL SOUTH-SOUTHWEST PULSE SHOULD ARRIVE THIS WEEKEND
FROM RECENT ACTIVITY EAST OF NEW ZEALAND, PROVIDING AN INCREASE IN
SURF ESPECIALLY BY SUNDAY.
SURF ALONG EAST-FACING SHORES WILL REMAIN SMALL AND CHOPPY
THROUGH MIDWEEK, WITH A SLIGHT RISE POSSIBLE THURSDAY AND FRIDAY
AS TRADES STRENGTHEN.
HFO WATCHES/WARNINGS/ADVISORIES
SMALL CRAFT ADVISORY UNTIL 6 PM HST FRIDAY FOR MAALAEA BAY-
PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND LEEWARD WATERS-BIG
ISLAND SOUTHEAST WATERS.
DISCUSSION...VAUGHAN
AVIATION...FOSTER
MARINE...KINO
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