348
FXHW60 PHFO 281847
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
847 AM HST FRI AUG 28 2026
SYNOPSIS
BREEZY TRADES CONTINUE WELL INTO NEXT WEEK WITH LIMITED SHOWERS
DIRECTED WINDWARD AND MAUKA DURING THIS TIME.
SHORT TERM UPDATE
BENIGN TRADE WIND PATTERN THROUGH THE FORECAST PERIOD AS STRONG
LONGWAVE RIDGING APPROACHING 598DM AT 500MB REMAINS ANCHORED ALONG
170W LONGITUDE. THIS IN TURN FAVORS EXPANSIVE SURFACE HIGH PRESSURE
IN MAINTENANCE OF BREEZY TRADES THROUGH THE MIDDLE OF NEXT WEEK. AN
UPTICK IN SHOWERS FOR WINDWARD AND MAUKA ZONES IS POSSIBLE NEXT WEEK
AS MOISTURE OFF THE CALIFORNIA COAST BECOMES ENTRAINED IN THE
TRADES, REACHING THE ISLANDS AROUND WEDNESDAY.
THE TROPICS REMAIN REMAIN ACTIVE WITH THE PRIMARY FOCUS AT THE
MOMENT BEING TROPICAL STORM LOWELL. THIS SYSTEM IS FORECAST BY NHC
TO BECOME A HURRICANE THIS WEEKEND. EVEN THOUGH IT IS ALREADY AROUND
135W, OR ABOUT 1500 MILES SE OF HILO, WEAK STEERING WINDS DELAY ANY
POTENTIAL ARRIVAL TO/AROUND THE HAWAIIAN ISLANDS TO BEYOND THE 7
DAY FORECAST PERIOD.
PREV DISCUSSION
ISSUED AT 425 AM HST FRI AUG 28 2026
UPPER AND MID LEVEL RIDGING HAS ASSERTED ENOUGH INFLUENCE ACROSS
THE CENTRAL PACIFIC TO STILL PROVIDE THE NEEDED SUBSIDENCE TO
RESULT IN CONTINUED WARM AND DRY WEATHER, WITH ONLY ISOLATED
EARLY DAY WINDWARD SHOWERS. A LARGE AREA OF 1034 MB SURFACE HIGH
PRESSURE LOCATED FAR NORTH OF THE STATE IS CREATING A TIGHT ENOUGH
PRESSURE GRADIENT, IN RELATION TO LOWER EQUATORIAL PRESSURE, TO
RESULT IN PERSISTENT MODERATE TO LOCALLY BREEZY TRADE WINDS. THE
NEXT FEW DAYS WILL FEEL LESS HUMID AND GENERALLY MORE PLEASANT
UNDER THIS MODERATE TRADE FLOW.
THE LOWER LEVELS REMAIN VOID OF ANY SIGNIFICANT FEATURES THAT
WOULD INDICATE ANY SHORT TERM DEVIATION FROM THE RECENT PATTERN.
MORNING SOUNDINGS INDICATE A 6-7K FT INVERSION LAYER DEPTH THAT
IS DEEP ENOUGH TO SUPPORT MAINLY ISOLATED SHOWERS. LOCALLY
STRONGER WINDS GUSTING TO NEAR 25 TO 30 MPH WILL OCCUR ATOP
HIGHER TERRAIN RIDGETOPS AND THROUGH LEE VALLEYS AND/OR SLOPES.
THESE AMPED UP TRADES WILL HANG WITH US THROUGH EARLY NEXT WEEK
WITH A POTENTIAL APPROACHING TROPICAL CYCLONE BEING A DISRUPTER
TO WHAT WILL BE SEVERAL DAYS OF BREEZY TRADES. MOST DIURNAL RAIN
ACCUMULATION WILL MEASURE IN THE HUNDREDTHS OF AN INCH. GREATER
RAINFALL WILL LIKELY FOCUS ACROSS WINDWARD UPSLOPE AREAS. RECENT
REGIONAL SOUNDING PROFILES INDICATE THAT MID TO UPPER RIDGING
WILL REMAIN IN CONTROL HELPING TO MAINTAIN DRY MID-LEVELS (20-40%
%RHS BETWEEN 8-15K FT). THIS SCENARIO WILL RESULT IN LESS FREQUENT
WINDWARD EXPOSURE SHOWERS. QUICK-HITTING LIGHT SHOWERS TRAPPED
WITHIN THE TRADE BELT WILL LIKELY BE MORE RECURRENT DURING THE
NOCTURNAL HOURS THAN DURING THE DAY. THE RAPID NATURE OF THESE
CELLS PASSING OVER HIGH TERRAIN WILL HAVE BETTER ORGANIZED SHOWERS
WETTING LEESIDE COMMUNITIES. THE WEATHER PATTERN WILL TURN MORE
WET GOING INTO THE MIDDLE OF NEXT WEEK AS HIGHER MOISTURE REACHES
GREATER DEPTHS AS WEAK RIDGING SLIDES WESTWARD.
THE NATIONAL HURRICANE CENTER IS ISSUING FORECAST ADVISORIES FOR
TROPICAL STORM LOWELL. LONG-RANGE MODELS SHOW LOWELL WILL ADVANCE
TOWARD THE STATE NEXT WEEK. AS NO DISTINCT CENTER OF CIRCULATION
HAS APPEARED WITH LOWELL AND IT HAS BEEN DRIFTING, DETERMINISTIC
MODEL GUIDANCE HAVE STRUGGLED WITH GRABBING ONTO THIS SYSTEM AND
THEREFORE HAVE LACKED ANY RUN-TO-RUN CONSISTENCY. ENSEMBLE
MEMBERS THAT MOVE LOWELL IN CLOSE VICINITY OF THE ISLAND CHAIN IN
A LITTLE OVER A WEEK STILL REMAIN IN THE MINORITY. GOOGLE
DEEPMIND'S ENSEMBLE TAKES THE STORM DUE WEST THEN NORTHWEST INTO
A LESS SHEARED ENVIRONMENT SOUTH OF HAWAII OVER THE LABOR DAY
WEEKEND.
AVIATION
FOR 18Z - MODERATE TRADES REGIME CONTINUES. MOSTLY VFR THROUGH THE
TAF PERIOD WITH SOME MVFR CONDITIONS WITH PASSING HEAVIER SHOWERS/LOWER
CIGS. EXPECT LOW CIGS AND SHRA OVER WINDWARD AND MAUKA SLOPES
MOST AREAS AND REFLECTED AS VCSH MOST TAFS.
AIRMET TANGO IS IN EFFECT FOR MOD LOW-LEVEL TURB LEE OF TERRAIN
AND MAY BE NEEDED FOR A FEW DAYS.
MARINE
HIGH PRESSURE LOCATED FAR NORTH OF THE WATERS WILL REMAIN NEARLY
STATIONARY THROUGH THE FORECAST PERIOD MAINTAINING MODERATE TO
LOCALLY STRONG TRADE WINDS. A SMALL CRAFT ADVISORY (SCA) IS IN
EFFECT FOR THE WINDIER WATERS AND CHANNELS AROUND MAUI COUNTY AND
THE BIG ISLAND THROUGH SATURDAY. THE SCA WILL LIKELY BE EXTENDED
THROUGH THE WEEKEND AND COULD BE EXPANDED TO OTHER ZONES AROUND
KAUAI AND OAHU WATERS EARLY NEXT WEEK.
SURF ALONG SOUTH FACING SHORES WILL HOLD JUST BELOW ADVISORY
LEVELS TODAY AS THE MODERATE MEDIUM TO LONG PERIOD SOUTH SWELL
FILLED IN OVER NIGHT. THE SWELL WILL SLOWLY FADE THROUGH THE
WEEKEND. ANOTHER SOUTH SWELL SIMILAR IN SIZE IS EXPECTED DURING
THE MIDDLE OF NEXT WEEK.
SURF ALONG EAST FACING SHORES WILL REMAIN CHOPPY IN RESPONSE TO
THE LOCALLY STRONG TRADE WINDS OVER AND UPSTREAM OF THE ISLANDS. A
SMALL MEDIUM PERIOD EAST SWELL FROM TROPICAL STORM ISELLE WILL
FILL IN LATER TODAY AND HOLD THROUGH SATURDAY. ANOTHER ROUND OF
EAST TO SOUTHEAST SWELLS ARE POSSIBLE NEXT WEEK BUT REMAINS AT
HIGH UNCERTAINTY DUE TO THE POTENTIAL TRACK AND INTENSITY OF THE
STORMS.
FIRE WEATHER
ISSUED AT 425 AM HST FRI AUG 28 2026
RELATIVELY DRY REGIONAL AIR AND MODERATE TO LOCALLY BREEZY TRADE
WINDS WILL MAINTAIN MODERATE FIRE WEATHER CONCERNS INTO EARLY
NEXT WEEK. A SLIGHT INCREASE IN MOISTURE NEXT WEEK WILL MARGINALLY
IMPROVE CONDITIONS.
HFO WATCHES/WARNINGS/ADVISORIES
SMALL CRAFT ADVISORY UNTIL 6 PM HST SATURDAY FOR ALENUIHAHA
CHANNEL-BIG ISLAND LEEWARD WATERS-BIG ISLAND SOUTHEAST WATERS-
MAALAEA BAY-PAILOLO CHANNEL.
SHORT TERM UPDATE...JVC
DISCUSSION...BLOOD
AVIATION...AR
MARINE...SHIGESATO
FIRE WEATHER...BLOOD
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