136
FXHW60 PHFO 011955
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
955 AM HST TUE SEP 1 2026
SYNOPSIS
BREEZY TRADE WINDS TODAY WILL BECOME STRONG AND GUSTY AS EARLY AS
TOMORROW AFTERNOON. SHOWERS WILL GENERALLY FAVOR WINDWARD AND
MAUKA AREAS, PARTICULARLY DURING THE OVERNIGHT THROUGH EARLY
MORNING HOURS EACH DAY. TROPICAL STORM LOWELL IS ABOUT 500 MILES
SOUTHEAST OF THE BIG ISLAND EARLY THIS MORNING, AND IS FORECAST
TO PASS SOUTH OF THE BIG ISLAND LATE WEDNESDAY INTO THURSDAY.
WINDS ARE EXPECTED TO REMAIN STRONG AND GUSTY THROUGH FRIDAY AS
LOWELL PASSES SOUTH OF THE ISLANDS. THE FORECAST REMAINS UNCERTAIN
FOR LABOR DAY WEEKEND, WITH THE POTENTIAL FOR LOWELL AND KARINA
IN THE THE VICINITY OF THE STATE.
SHORT TERM UPDATE
TRADE WIND SHOWERS WERE MOVING WEST ACROSS WINDWARD AND MAUKA
AREAS OF MOST ISLANDS THIS MORNING, WITH RAINFALL AMOUNTS FROM A
FEW HUNDREDTHS TO A FEW TENTHS OF AN INCH. TRADES ARE EXPECTED TO
GRADUALLY INCREASE IN SPEED. THEY MAY REACH ADVISORY LEVEL
WEDNESDAY AFTERNOON IN THE TYPICAL WINDY SPOTS, BUT WE WILL AWAIT
FURTHER MODEL RUNS BEFORE DECIDING WHETHER TO ISSUE.
OTHERWISE, ALL EYES REMAIN GLUED TO THE HURRICANES IN THE AREA.
LOWELL AND KARINA'S CURRENT FORECAST TRACKS FROM THE NHC KEEP THEM
AWAY FROM THE STATE FOR THE NEXT 5 DAYS, BUT THERE IS SIGNIFICANT
UNCERTAINTY IN THE FORECAST AFTER THAT. MODELS CONTINUE TO DEPICT
LOWELL TURNING NORTH AFTER IT MOVES WEST OF THE STATE. THE TIMING OF
THAT TURN IS A HUGE QUESTION MARK AT THIS TIME. THE MAJORITY OF THE
RUNS SHOW IT MOVING BY TO THE WEST OF THE MAIN HAWAIIAN ISLANDS. IF
IT ENDS UP HEADING FOR THE MAIN PART OF THE STATE (LOW PROBABILITY
SOLUTION FOR NOW), THE TIMING WOULD INDICATE PASSAGE ON THE 7TH OR
8TH. SEE THE PREVIOUS DISCUSSION FOR ADDITIONAL DETAILS.
PREV DISCUSSION
ISSUED AT 342 AM HST TUE SEP 1 2026
NO SIGNIFICANT CHANGES TO THE FORECAST THIS MORNING. ALTHOUGH THE
POP GRID WAS ADJUSTED, LITTLE CHANGE THROUGH THURSDAY NIGHT. FOR
FRIDAY THERE IS A MARKED DECREASE IN SHOWER ACTIVITY OVER THE
ISLANDS AS LOWELL WILL HAVE MOVED FURTHER FROM THE ISLANDS.
CLOUDS AND SHOWERS CONTINUE TO BE CARRIED IN ON THE TRADE WIND
FLOW, AND AS A RESULT ARE FOCUSED OVER THE WINDWARD AND MAUKA
AREAS. A SURFACE TROUGH ABOUT 350 MILES EAST OF THE ISLANDS WILL
CONTINUE TO MOVE TOWARDS THE ISLANDS TODAY AND WEAKEN. MOISTURE
FROM THAT TROUGH WILL REACH THE ISLANDS TONIGHT, HELPING TO BOOST
SHOWER ACTIVITY TONIGHT.
TROPICAL STORM LOWELL IS ABOUT 550 MILES SOUTHEAST OF THE BIG
ISLAND EARLY THIS MORNING, AND THE LATEST FORECAST FROM THE
NATIONAL HURRICANE CENTER (NHC) HAS LOWELL STRENGTHENING TO A
HURRICANE WITHIN THE NEXT 12 HOURS. THE LATEST TRACK AND CONE FOR
LOWELL HAS THE SYSTEM PASSING SOUTH OF THE ISLANDS WEDNESDAY
NIGHT THROUGH FRIDAY. OUTER RAINBANDS AND MOISTURE FROM LOWELL
COULD BEGIN TO SPREAD ACROSS THE ISLANDS TODAY, INCREASING
CHANCES OF PASSING TRADE WIND SHOWERS, HOWEVER THE BULK OF
MOISTURE WILL LIKELY PASS SOUTH OF THE STATE. ADDITIONALLY
DEWPOINT TEMPERATURES ARE EXPECTED TO EXCEED 70 DEGREES, WHICH
WILL MAKE THE ATMOSPHERE MUGGIER THAN NORMAL. TRADE WINDS WILL
STAY BREEZY DUE TO A STRONG SURFACE HIGH REMAINING FAR NORTH OF
THE AREA.
OVERALL EXPECT AN UPTICK IN PASSING SHOWERS OVER THE NEXT FEW
DAYS, DUE TO THE MOISTURE FROM THE TROUGH MENTIONED ABOVE TONIGHT,
AND MOISTURE LOOSELY ASSOCIATED WITH LOWELL PASSING THROUGH THE
STATE.
THE LATEST FORECAST FROM THE NHC HAS LOWELL PASSING A LITTLE OVER
300 MILES SOUTH OF THE BIG ISLAND WEDNESDAY NIGHT INTO THURSDAY
AS A CATEGORY 3 MAJOR HURRICANE. WHILE PROBABILITIES FOR TROPICAL
STORM FORCE WINDS REMAIN LOW OVER THE STATE, THE TIGHTENING OF
THE PRESSURE GRADIENT OVER THE ISLANDS WILL LIKELY PRODUCE VERY
WINDY AND GUSTY TRADE WINDS AS EARLY AS WEDNESDAY AFTERNOON
THROUGH FRIDAY. WINDS COULD REACH ADVISORY THRESHOLDS WITH WIND
GUSTS OVER 50 MPH POSSIBLE DURING THIS TIME.
AS WE HEAD INTO THE WEEKEND, AS LOWELL EXITS, OUR FOCUS WILL SHIFT
MORE TO HURRICANE KARINA WHICH IS CURRENTLY ABOUT 1500 MILES EAST
OF THE BIG ISLAND. THE LATEST FORECAST FROM NHC FOR KARINA BRINGS
IT ABOUT 600 MILES EAST OF THE BIG ISLAND ON SATURDAY. WE WILL
CONTINUE TO MONITOR KARINA OVER THE COMING DAYS TO DISCERN ITS
POTENTIAL IMPACTS ON THE STATE.
THE FORECAST SPREAD DRASTICALLY INCREASES OVER THE LABOR DAY
WEEKEND INTO EARLY NEXT WEEK AS AN UPPER LEVEL TROUGH/LOW DEVELOPS
NORTH OF THE STATE. SEVERAL MODELS SHOW LOWELL TAKING A SHARP
NORTHWARD TURN OVER THE WEEKEND. WHILE CONFIDENCE HAS INCREASED ON
LOWELL PASSING SOUTH OF THE STATE DURING THE WEEK, THE FORECAST
STILL REMAINS VERY UNCERTAIN OVER LABOR DAY WEEKEND DUE TO THE
NORTHWARD TURN IN THE VARIOUS MODELS. ALSO DURING THIS TIME, WE
COULD SEE KARINA WITHIN THE VICINITY OF THE ISLANDS LATE THIS
WEEKEND. PLEASE KEEP AN EYE OUT ON THE HURRICANES.GOV PAGE FOR THE
OFFICIAL NHC FORECAST FOR LOWELL AND KARINA.
AVIATION
18Z TAFS - ACTIVE SHOWERS THIS MORNING IMPACTING MAUI AND BIG
ISLAND BRINGING MVFR CONDITIONS AND LOCALLY IFR IN HEAVIEST
SHOWERS. OTHERWISE, MODERATE TRADE WINDS WILL PERSIST THROUGH THIS
PERIOD. DIURNAL TRENDS OF MVFR CONDITIONS AND BRIEF SHOWERS
THROUGH THE TRADES WILL GENERALLY FAVOR WINDWARD EXPOSURES, MAUKA
AND HIGHER TERRAIN. OTHERWISE, VFR CONDITIONS WILL PREVAIL.
TROPICAL CYCLONE LOWELL IS FORECAST TO PASS FAR SOUTH OF THE
ISLAND CHAIN THE NEXT FEW DAYS. ON THIS TRACK, LATE WEEK TRADE
WINDS WILL STRENGTHEN AS THE PRESSURE GRADIENT TIGHTENS BETWEEN
TROPICAL CYCLONE LOWELL AND HIGH PRESSURE TO THE FAR NORTH.
AIRMET SIERRA IS IN EFFECT FOR MOUNTAIN OBSCURATION FOR THE NORTH
THROUGH EAST DISTRICTS OF BIG ISLAND DUE TO PERSISTENT LOW CLOUDS
AND SHOWER COVERAGE. AIRMET SIERRA WILL REMAIN IN EFFECT FOR BIG
ISLAND THROUGH THIS MORNING.
AIRMET TANGO REMAINS IN EFFECT FOR MODERATE LOW LEVEL TURBULENCE
SOUTH THROUGH WEST DOWNSTREAM OF HIGH TERRAIN. AIRMET TANGO WILL
LIKELY BE IN EFFECT FOR THE FORESEEABLE FUTURE.
MARINE
A STRONG SURFACE HIGH WILL REMAIN NEARLY STATIONARY FAR NORTH OF
THE HAWAIIAN ISLANDS THIS WEEK, KEEPING FRESH TO LOCALLY STRONG
TRADE WINDS IN PLACE. A SMALL CRAFT ADVISORY (SCA) REMAINS IN
EFFECT FOR THE TYPICALLY WINDY WATERS AS A RESULT OF THE LOCALLY
STRONG TRADES. THE SCA WILL LIKELY NEED TO BE EXPANDED AS TRADE
WINDS GRADUALLY STRENGTHEN ACROSS THE STATE TO STRONG TO POSSIBLE
LOCALLY GALE FORCE LATE WEDNESDAY THROUGH THURSDAY AS LOWELL
PASSES FAR SOUTH. THE OFFSHORE WATERS WILL LIKELY SEE TROPICAL
STORM CONDITIONS OVER THE SOUTH WATERS AS THE CORE OF HURRICANE
FORCE WINDS REMAINS JUST OUTSIDE THE AREA WEDNESDAY INTO THURSDAY.
THERE IS STILL SOME UNCERTAINTY WITH THE FORECAST TRACK OF
LOWELL, ESPECIALLY THIS WEEKEND AND EARLY NEXT WEEK AS THE CYCLONE
BEGINS TO GAIN LATITUDE, WHICH WILL HAVE SIGNIFICANT IMPACTS ON
THE WIND, WAVE, AND SURF FORECAST FOR THE REGION. ADDING TO THE
EXTENDED FORECAST UNCERTAINTY WILL BE THE APPROACH OF HURRICANE
KARINA FROM THE EAST.
A MODERATE, LONG-PERIOD SOUTH SWELL ARRIVES TODAY. THIS SWELL WILL
BUILD THROUGH THE DAY AND OVERNIGHT BEFORE PEAKING ON WEDNESDAY,
BRINGING SURF HEIGHTS TO JUST BELOW ADVISORY THRESHOLDS. THIS SWELL
WILL THEN GRADUALLY DECLINE THROUGH THE REST OF THE WEEK. A
SMALL, MEDIUM-PERIOD SOUTH SOUTHEAST SWELL ENERGY FROM LOWELL
COULD START FILLING IN ACROSS SOUTH AND SOUTHEAST SHORES. SOUTH
SHORE SURF WILL LIKELY REMAIN ELEVATED NEAR TO JUST ADVISORY
LEVELS THROUGH AT LEAST FRIDAY. BEYOND THAT POINT, THE SURF
FORECAST IS HIGHLY DEPENDENT ON THE EVENTUAL TRACK AND INTENSITY
OF LOWELL, WHICH HAS THE POTENTIAL TO BE A SIGNIFICANT SOURCE OF
SOUTH TO SOUTHWESTERLY SWELL THROUGH THIS WEEKEND AND INTO NEXT
WEEK DEPENDING ON HOW SHARPLY AND QUICKLY THE CYCLONE TURNS TO THE
NORTH.
TRADE WIND SWELL ENERGY WILL KEEP ROUGH, CHOPPY SURF ALONG ALL
EAST-FACING SHORES THROUGH THE COMING WEEK. TONIGHT, A SMALL,
MEDIUM- PERIOD EAST SWELL ARRIVES FROM HURRICANE KARINA THAT WILL
BUILD THROUGH THE WEEK AND COULD PUSH EAST SHORE SURF TO ADVISORY
THRESHOLDS BY THIS WEEKEND AND INTO NEXT WEEK.
FIRE WEATHER
ISSUED AT 342 AM HST TUE SEP 1 2026
BREEZY TRADES TODAY ARE EXPECTED TO STRENGTHEN FURTHER AS EARLY
AS WEDNESDAY AFTERNOON THROUGH FRIDAY AS TROPICAL STORM LOWELL
PASSES SOUTH OF THE ISLANDS AS A HURRICANE. STRONG GUSTY WINDS
OVER 50 MPH WILL BE POSSIBLE ACROSS SELECT AREAS DURING THIS TIME.
WHILE FUEL CONDITIONS ARE NOT AT CRITICAL LEVELS DUE TO ABUNDANT
RAINFALL WE HAVE RECEIVED OVER THE PAST SEVERAL WEEKS, MODERATE
FIRE DANGER WILL BE POSSIBLE FOR AREAS MAINLY DUE TO VERY WINDY
CONDITIONS. DEWPOINTS ARE EXPECTED TO INCREASE IN THE UPPER 60S
AND LOW 70S BY TUESDAY AFTERNOON AND HOLD THROUGH THE WEEK,
KEEPING MINIMUM HUMIDITIES IN THE 50S FOR THE MOST PART. A FEW
LEEWARD AREAS COULD STILL SEE HUMIDITIES DOWN INTO THE MID 40S
ESPECIALLY ON THURSDAY AS A POCKET OF DRY AIR MOVES IN. THE EXACT
TRACK OF LOWELL REMAINS UNCERTAIN AND THUS POTENTIAL FOR
MEANINGFUL RAINFALL REMAINS UNCERTAIN AT THIS TIME. THE INVERSION
WILL HOVER BETWEEN 5500 FT AND 6500 FT OVER THE NEXT COUPLE OF
DAYS.
HFO WATCHES/WARNINGS/ADVISORIES
SMALL CRAFT ADVISORY UNTIL 6 PM HST WEDNESDAY FOR ALENUIHAHA
CHANNEL-BIG ISLAND LEEWARD WATERS-BIG ISLAND SOUTHEAST WATERS-
MAALAEA BAY-PAILOLO CHANNEL.
SHORT TERM UPDATE...PARKER
DISCUSSION...M BALLARD
AVIATION...MEHLE
MARINE...ALMANZA
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