722
FXHW60 PHFO 230149
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
349 PM HST THU OCT 22 2026
SYNOPSIS
LIGHT TO MODERATE TRADE WINDS WILL PRODUCE A HYBRID TRADE WIND
AND SEA BREEZE WIND FLOW EACH DAY LASTING INTO EARLY NEXT WEEK.
BRIEF PASSING SHOWERS WILL DRIFT INTO THE ISLANDS ON THE EASTERLY
TRADE WINDS, FAVORING WINDWARD MOUNTAIN AREAS DURING THE OVERNIGHT
TO EARLY MORNING HOURS. A MORE SIGNIFICANT CHANGE TO OUR WEATHER
PATTERN CONTINUES TO EVOLVE FOR EARLY NEXT WEEK BEGINNING SOMETIME
MONDAY NIGHT OR TUESDAY. DEEPLY UNSTABLE TROPICAL MOISTURE MOVING
ACROSS THE STATE WILL BRING THE POTENTIAL FOR HEAVY RAIN AND
THUNDERSTORMS AFFECTING ALL ISLANDS.
DISCUSSION
SATELLITE AND RADAR IMAGERY SHOW ISOLATED TO SCATTERED SHOWERS
MOVING INTO WINDWARD AND MAUKA AREAS ON THE LIGHT TO MODERATE
TRADE WIND FLOW THIS AFTERNOON, WITH THE BEST COVERAGE OVER THE
CENTRAL PART OF THE STATE. IN ADDITION, SHOWERS HAVE ALSO
DEVELOPED OVER SOME LEEWARD AREAS DUE TO SEA BREEZE ACTIVITY IN
THE LIGHTER TRADE WIND FLOW, PARTICULARLY ACROSS OAHU.
THE TRADE WINDS HAVE EASED TO BECOME LIGHT TO MODERATE IN
RESPONSE TO THE WEAKENING PRESSURE GRADIENT AS THE SURFACE HIGH
GETS PUSHED FARTHER NORTHEAST OF THE STATE WHILE A LOW PRESSURE
SYSTEM SETS UP TO THE NORTH. THESE LIGHT TO MODERATE TRADE WINDS
WILL MORE OR LESS PERSIST THROUGH THE WEEKEND, ALLOWING FOR A
HYBRID TRADE WIND AND LAND/SEA BREEZE PATTERN TO COMMENCE.
HOWEVER, WITH HIGH CLOUDS EXPECTED TO MOVE IN FROM THE WEST-
SOUTHWEST FRIDAY THROUGH MOST OF THE WEEKEND, SEA BREEZE ACTIVITY
MIGHT BE SOMEWHAT SUPPRESSED. WITH THE WEAKENING MID TO UPPER
LEVEL LOW OVER THE STATE TODAY, THE INSTABILITY ASSOCIATED WITH
THIS FEATURE HAS HELPED TO SUPPORT THE DEVELOPMENT OF AFTERNOON
SHOWERS OVER SOME LEEWARD AND INTERIOR AREAS AS SEA BREEZES FORM.
HOWEVER, LIMITED AVAILABLE MOISTURE AND WEAK LIFTING MECHANISMS AT
THE SURFACE WILL CONTINUE TO KEEP THE SHOWER ACTIVITY RATHER
LIMITED. THIS MID TO UPPER LEVEL LOW WILL LIFT NORTHEASTWARD
TONIGHT INTO FRIDAY AND RIDGING WILL TRY TO NUDGE IN FROM THE
SOUTH, LIMITING SHOWER ACTIVITY EVEN FURTHER. HOWEVER, DEEPER
MOISTURE WILL MOVE OVER THE BIG ISLAND AND MAYBE MAUI FROM THE
SOUTHEAST, INCREASING THE POTENTIAL FOR SHOWERS ALONG THE LOWER
SOUTH- AND EAST-FACING SLOPES.
REMNANTS OF A DISSIPATING FRONTAL BOUNDARY EXTENDING FROM THE LOW
TO THE NORTH MAY MOVE IN SATURDAY THROUGH SATURDAY NIGHT AS THE
LOW DIPS SOUTH-SOUTHEAST, BRINGING A SLIGHT BOOST IN THE EAST-
NORTHEAST TRADE WIND SPEEDS AND TRADE WIND SHOWERS OVER THE
WESTERN END OF THE STATE AS RIDGING TRIES TO BUILD IN FROM THE
NORTH. THE UPPER LEVEL TROUGH SUPPORTING THE SURFACE LOW WILL FORM
A CUTOFF LOW TO THE NORTHEAST OF THE STATE OVER THE WEEKEND,
DRIVING THE SURFACE LOW OVER THE SAME AREA.
MEANWHILE, TO THE WEST OF THE STATE, A LOW WILL TRY TO DEVELOP
SOMEWHERE NEAR 16N AND THE DATELINE THIS WEEKEND, WITH THE
NATIONAL HURRICANE CENTER GIVING THIS FEATURE A LOW (30 PERCENT)
CHANCE OF DEVELOPING INTO A TROPICAL CYCLONE OVER THE NEXT 7 DAYS.
REGARDLESS OF THE POTENTIAL TROPICAL DEVELOPMENT, THE MAIN THREAT
FOR HAWAII IS THE POTENTIAL FOR HEAVY RAIN AND POSSIBLY ISOLATED
THUNDERSTORMS NEXT WEEK AS THIS POTENTIAL LOW AND A LARGE
CONVERGENT BAND OF DEEP TROPICAL MOISTURE TO ITS EAST GET SWEPT
EASTWARD BY A PASSING SHORTWAVE TROUGH AND DRAWN ACROSS HAWAII
BEGINNING SOMETIME MONDAY NIGHT OR TUESDAY. THE THREAT FOR HEAVY
RAIN MAY PERSIST THROUGH MUCH OF THE WEEK AS THIS BAND OF DEEP
TROPICAL MOISTURE LINGERS OVER THE AREA. HOWEVER, IT’S IMPORTANT
TO NOTE THAT FORECAST UNCERTAINTY REMAINS MODERATE TO HIGH AS
THERE CONTINUES TO BE A FAIRLY WIDE SPREAD AMONG THE GLOBAL MODEL
SOLUTIONS.
AVIATION
SCATTERED -SHRA CHANCES CONTINUE THROUGH THIS AFTERNOON WITH
TRADES AOB 15KTS. WINDS DROP TO 5-10KTS OVERNIGHT. VFR CIGS/VIS
PREVAIL THROUGH THE PERIOD WITH BRIEF WINDOWS OF MVFR WITH THE
AFOREMENTIONED -SHRA.
AIRMET SIERRA IS IN EFFECT FOR MOUNTAIN OBSCURATION FOR NORTH
THROUGH EAST SECTIONS OF MAUI.
MARINE
EASTERLY TRADE WINDS WILL BE AT GENTLE TO MODERATE STRENGTH
THROUGH FRIDAY AS SURFACE LOW PRESSURE FAR NORTH OF HAWAII AND A
NEARBY SURFACE TROUGH WEAKEN THE LOCAL PRESSURE GRADIENT. TRADES
ARE EXPECTED TO HOLD AT CURRENT STRENGTH AND SHIFT OUT OF THE
NORTHEAST THIS WEEKEND AS HIGH PRESSURE FAR NORTHWEST OF HAWAII
PUSHES TO LOW EASTWARD. THE WEAKER TRADE WINDS SHOULD PERSIST
MONDAY, BUT UNCERTAINTY INCREASES ON TUESDAY, HINGING ON THE
POTENTIAL DEVELOPMENT OF A LOW SOUTHWEST OF THE ISLANDS.
A SMALL, MEDIUM-PERIOD NORTHWEST SWELL WILL ARRIVE OVERNIGHT AND
PROVIDE A SMALL BOOST TO SURF ALONG NORTH-FACING SHORES ON FRIDAY.
A MODERATE, MEDIUM-PERIOD NORTH-NORTHWEST SWELL WILL BUILD LATE
SATURDAY AND PEAK AROUND SEASONAL AVERAGE ON SUNDAY. AS THIS SWELL
DECLINES ON MONDAY, A LONG-PERIOD WEST-NORTHWEST SWELL WILL
ARRIVE, MAINTAINING SMALL TO MODERATE SURF INTO THE MIDDLE OF NEXT
WEEK.
SMALL BACKGROUND LEVEL SURF WILL PREVAIL ALONG SOUTH-FACING
SHORES THROUGH FRIDAY. A SMALL TO MODERATE SOUTH-SOUTHWEST SWELL
IS EXPECTED TO BOOST SURF TO AROUND SEASONAL AVERAGE THIS WEEKEND
INTO EARLY NEXT WEEK.
ALONG EAST-FACING SHORES, TRADE-WIND SWELL WILL CONTINUE TO
DECREASE THROUGH FRIDAY, THOUGH A SMALL, MEDIUM-PERIOD NORTHEAST
SWELL MAY MAINTAIN SMALL SURF THROUGH SATURDAY. ASIDE FROM
WRAPPING NORTH-NORTHWEST SWELL IN EXPOSED AREAS, EAST SHORE SURF
SHOULD REMAIN BELOW SEASONAL AVERAGE MUCH OF NEXT WEEK.
FIRE WEATHER
TRADE WIND SPEEDS WILL CONTINUE TO BE SUPPRESSED THROUGH MONDAY
AS THE HIGH IS PUSHED FARTHER NORTHEAST WHILE A LOW SETS UP NORTH
OF THE STATE. PASSING SHOWERS WILL MOVE INTO MAINLY WINDWARD AND
MAUKA AREAS ON THE TRADE WIND FLOW AND SOME SHOWERS MAY ALSO BE
EXPECTED OVER LEEWARD AREAS AS SEAS BREEZES DEVELOP IN THE MOST
WIND-PROTECTED AREAS. THEN AMPLE TROPICAL MOISTURE AND WILL MOVE
IN FROM THE WEST SOMETIME BEGINNING MONDAY NIGHT OR TUESDAY,
BRINING A THREAT FOR HEAVY RAIN THROUGH THURSDAY. AS A RESULT,
FIRE WEATHER CONCERNS WILL BE LOW THROUGH THE NEXT SEVERAL DAYS.
INVERSION HEIGHTS WILL RANGE FROM 6,000 TO 8,000 FEET OVERNIGHT
INTO FRIDAY.
HFO WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...FARRIS
AVIATION...DYE
MARINE...WROE
FIRE WEATHER...FARRIS
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