984
FXHW60 PHFO 180116
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
316 PM HST THU JUL 17 2025
SYNOPSIS
SEASONAL HIGH PRESSURE TO THE NORTH WILL MAINTAIN MODERATE TO
BREEZY NORTHEAST TO EASTERLY TRADE WINDS THROUGH NEXT WEEK. AN
AREA OF ENHANCED MOISTURE ALONG WITH WEAK MID LEVEL TROUGHING
WILL INCREASE TRADE WIND SHOWERS TOMORROW AND SATURDAY. SHOWERS
SHOULD THEN DECREASE BACK TO TYPICAL SUMMERTIME AMOUNTS NEXT WEEK
AS DRIER AIR MOVES BACK IN ON THE TRADE WIND FLOW.
DISCUSSION
A STABLE PATTERN IS FIRMLY ESTABLISHED AS A 1034 MB HIGH PRESSURE
FAR NORTH OF THE REGION REMAINS IN PLACE. A MINOR DECREASE IN
STABILITY TOMORROW INTO THIS WEEKEND IS POSSIBLE AS A WEAK MID TO
UPPER LEVEL LOW EDGES IN JUST NORTH OF THE AREA AND A MID LEVEL
TROUGH MOVES IN FROM THE EAST. THIS WEAK UPPER LOW AND MID LEVEL
TROUGH COULD PROVIDE A SMALL BOOST IN LIFT FOR THE ISLANDS FRIDAY
AND SATURDAY BEFORE WEAKENING SUNDAY AND A MORE STABLE PATTERN
RETURNS FOR NEXT WEEK.
OBSERVATIONAL DATA TODAY FROM RADAR AND SATELLITE SHOW A TYPICAL
TRADE WIND CLOUD AND SHOWER DISTRIBUTION AND THE BALLOON LAUNCH
FROM THIS AFTERNOON SHOWS INVERSION HEIGHTS AROUND 6,000 FT. THE
INVERSION HEIGHTS ARE EXPECTED TO BE RAISED ACROSS THE REGION
THROUGH THE WEEKEND AS THE INSTABILITY FROM THE MID LEVEL TROUGH
AND UPPER LOW CREEPS IN. CURRENT MODEL GUIDANCE SHOWS TRADE WIND
SHOWERS INCREASING EARLY TOMORROW MORNING FOR KAUAI AND OAHU AS
LOW AND MID LEVEL MOISTURE MOVES THROUGH THE AREA UNDER THE WEAK
UPPER LEVEL LOW AND TROUGH. ANY SHOWERS THAT DO DEVELOP STATEWIDE
WILL LIKELY BE A BIT MORE HEAVY. THIS FEATURE ALONG WITH ITS
ASSOCIATED MOISTURE SHOULD WEAKEN SUNDAY AND A MORE DRY AND STABLE
TRADE WIND PATTERN WILL RETURN MONDAY THROUGH NEXT WEEK.
AVIATION
LOCALLY BREEZY TRADE WINDS WILL PREVAIL ACROSS THE
ISLANDS WITH OCCASIONAL PASSING SHOWERS FAVORING THE TYPICAL
WINDWARD AND MOUNTAIN LOCATIONS. A SLIGHT UPTICK IN SHOWER
ACTIVITY IS POSSIBLE DURING THE OVERNIGHT HOURS ACROSS WINDWARD
AREAS, PRIMARILY ACROSS THE WESTERN ISLANDS. OTHERWISE, VFR
CONDITIONS ARE EXPECTED FRIDAY.
DUE TO THE LOCALLY BREEZY TRADES, AIRMET TANGO FOR LOW LEVEL
TURBULENCE BELOW 7,000 FEET WILL CONTINUE THROUGH EARLY FRIDAY.
WINDS ARE EXPECTED TO EASE BY FRIDAY NIGHT.
MARINE
HIGH PRESSURE WILL REMAIN FAR NORTHEAST OF THE STATE THROUGH THE
REST OF THE WEEK. FRESH TO LOCALLY STRONG TRADES WILL PERSIST
THROUGH FRIDAY, THEN DROP SLIGHTLY AS A WEAK LOW-LEVEL TROUGH
MOVES THROUGH THE STATE FROM THE EAST THROUGH THE WEEKEND. THE
SMALL CRAFT ADVISORY (SCA) HAS BEEN EXTENDED THROUGH FRIDAY
AFTERNOON FOR THE TYPICAL WINDY AREAS AROUND MAUI COUNTY AND THE
BIG ISLAND.
FADING SOUTH AND SOUTH-SOUTHEAST SWELLS WILL MAINTAIN BELOW
AVERAGE SURF ON SOUTH FACING SHORES THROUGH FRIDAY. A SLIGHT BUMP
IN SURF IS EXPECTED THIS WEEKEND AS A NEW LONG-PERIOD SOUTHWEST
SWELL ARRIVES FROM THE TASMAN SEA, ALONG WITH A SMALL SHORT-PERIOD
SOUTH-SOUTHEAST SWELL. THE TASMAN SWELL IS EXPECTED TO PEAK
SATURDAY, WITH SURF HEIGHTS TOPPING NEAR THE SUMMER AVERAGE,
BEFORE GRADUALLY DECLINING INTO EARLY NEXT WEEK.
SURF ALONG EAST FACING SHORES WILL CONTINUE TO REMAIN ROUGH AND
CHOPPY DUE TO THE FRESH TO LOCALLY STRONG TRADE WINDS. SURF ALONG
NORTH FACING SHORES WILL REMAIN NEARLY FLAT THROUGH THE WEEKEND.
MINOR COASTAL FLOODING ALONG THE SHORELINE AND IN LOW-LYING COASTAL
AREAS WILL BE POSSIBLE AROUND THE DAILY HIGH TIDE STARTING MONDAY
OF NEXT WEEK DUE TO PEAK MONTHLY TIDES AND HIGHER THAN PREDICTED
WATER LEVELS AT SELECT LOCATIONS.
FIRE WEATHER
FIRE WEATHER CONCERNS WILL LOWER TOMORROW INTO THIS WEEKEND AS A
WETTER PATTERN DEVELOPS ACROSS THE STATE. TRADE WINDS WILL REMAIN
LIGHT TO LOCALLY BREEZY THROUGH THE DAY BEFORE SLIGHTLY WEAKENING
THIS WEEKEND. A HIGHER FREQUENCY OF SHOWERS IS EXPECTED TOMORROW
MORNING THROUGH SUNDAY MORNING. DRIER, MORE STABLE WEATHER IS
EXPECTED TO RETURN SUNDAY AFTERNOON THROUGH NEXT WEEK. THIS MAY
INCREASE THE FIRE WEATHER THREAT OVER MORE LEEWARD AREAS THAT DO
NOT RECEIVE THE BENEFIT OF WEEKEND RAIN.
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...TSAMOUS/FARRIS
AVIATION...VAUGHAN/PECHACEK
MARINE...TS
FIRE WEATHER...TSAMOUS
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