922
FXHW60 PHFO 160114
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
314 PM HST TUE JUL 15 2025
SYNOPSIS
A HIGH PRESSURE SYSTEM WILL REMAIN FAR NORTHEAST OF THE STATE
THROUGH THE WEEK BEFORE SHIFTING WESTWARD OVER THE WEEKEND INTO
EARLY NEXT WEEK. MODERATE TO LOCALLY BREEZY TRADE WINDS WILL
PERSIST THROUGH THE FORECAST PERIOD. STABLE CONDITIONS WILL BUILD
OVER THE STATE WITH BEST CHANCES OF RAINFALL ALONG WINDWARD AND
MAUKA AREAS, ESPECIALLY DURING THE OVERNIGHT HOURS. THERE MAY BE
A SLIGHT INCREASE IN SHOWER ACTIVITY AS EARLY AS THURSDAY NIGHT
INTO THE WEEKEND AS A UPPER LEVEL DISTURBANCE MOVES OVER THE
ISLANDS.
DISCUSSION
A SURFACE HIGH PRESSURE ROUGHLY 1750 MILES NORTHEAST OF THE STATE
IS GENERATING MODERATE TO LOCALLY BREEZY TRADE WINDS. SATELLITE
AND RADAR IMAGERY SHOWS CLOUDS AND SHOWERS FOCUSING ALONG
WINDWARD AND MAUKA AREAS. THE PAST 3 HOUR RAINFALL TOTALS RANGE
FROM .01 TO .33 INCHES WITH THE HIGHEST TOTALS GENERALLY OVER THE
WETTER AREAS OF KAUAI WHERE A SLIGHTLY ENHANCE MOISTURE PLUME
CONTINUES TO EXIT WESTWARD. THERE ARE ALSO SOME CLOUDS AND
SHOWERS BUILDING OVER AND ALONG THE KONA SLOPES OF THE BIG ISLAND
THIS AFTERNOON AS SEA BREEZES DEVELOPED. AS THE EVENING
PROGRESSES EXPECT CLOUDS AND SHOWERS TO DIMINISH ALONG THE KONA
SLOPES AND TO INCREASE OVER THE WINDWARD AND MAUKA AREAS. THIS
TYPICAL DIURNAL TRADEWIND PATTERN IS EXPECTED TO REPEAT EACH DAY
THROUGH THE FORECAST PERIOD AS THE HIGH PRESSURE SYSTEM REMAINS
ANCHORED FAR NORTHEAST OF THE STATE.
AS EARLY AS LATE THURSDAY INTO THE WEEKEND WINDWARD CLOUDS AND
SHOWER ACTIVITY MAY SEE A SLIGHT UPTICK AS AN UPPER LEVEL LOW
DEVELOPS NORTHWEST OF KAUAI AND LOW LEVEL MOISTURE IS ADVECTED
IN. IN ADDITION, A FEW SHOWERS MAY MOVE OVER TO LEEWARD AREAS AT
TIME ALONG THE SMALLER ISLANDS AS INVERSION HEIGHTS INCREASE,
ESPECIALLY DURING THE OVERNIGHT AND EARLY MORNING HOURS.
CONFIDENCE IN THESE SHOWER TRENDS REMAIN MODERATE AT THIS TIME, AS
THE STRENGTH OF THE UPPER LOW IS CURRENTLY PROJECTED TO BE ON THE
WEAKER SIDE OF THE EQUATION. MORE DETAILS WILL BECOME CLEARER
LATER THIS WEEK, AS THE TIME PERIOD GROWS CLOSER, AND OUR
CONFIDENCE ON ISLAND BY ISLAND SHOWER TRENDS IMPROVE.
AVIATION
LOCALLY BREEZY TRADE WINDS WILL PERSIST THROUGH MUCH OF THE WEEK
AS HIGH PRESSURE HOLDS FAR NORTH OF HAWAII, AND STABLE CONDITIONS
WILL PREVAIL DURING THE NEXT SEVERAL DAYS. PERIODS OF MVFR
CEILINGS AND VISIBILITY ARE EXPECTED OVER WINDWARD SLOPES, WHERE
AIRMET SIERRA FOR MOUNTAIN OBSCURATION MAY BE NEEDED DURING SOME
OVERNIGHT AND MORNING HOURS. VFR WILL DOMINATE ACROSS LEEWARD
AREAS. UNDER THE BREEZY AND STABLE TRADE WIND FLOW, SOME LOW LEVEL
TURBULENCE IS EXPECTED OVER AND DOWNWIND OF TERRAIN, AND SOME
STRENGTHENING OF LOW LEVEL WINDS IN THE GUIDANCE SUGGESTS THAT
AIRMET TANGO WILL BE NEEDED ON WEDNESDAY.
MARINE
HIGH PRESSURE WILL REMAIN FAR NORTHEAST OF THE STATE THROUGHOUT
THE WEEK. FRESH TO LOCALLY STRONG TRADES WILL LIKELY PERSIST
THROUGH MOST OF THE WEEK, ALTHOUGH WE COULD SEE WIND SPEEDS DROP
SLIGHTLY AS A WEAK TROUGH DEVELOPS NEAR THE WESTERN END OF THE
STATE INTO THE WEEKEND. A SMALL CRAFT ADVISORY (SCA) IS NOW IN
EFFECT FOR THE TYPICAL WINDY AREAS AROUND MAUI COUNTY AND THE BIG
ISLAND THROUGH WEDNESDAY NIGHT.
A LONG-PERIOD SOUTH SWELL CAUSED SURF ALONG SOUTH FACING SHORES
TO PEAK NEAR THE SUMMER AVERAGE EARLIER TODAY. AS THIS SWELL
DECLINES, A REINFORCING SHORT-PERIOD SOUTH-SOUTHEAST SWELL WILL
CONTINUE TO FILL IN THIS EVENING INTO WEDNESDAY, SLOWING THE
DECLINE OF SURF HEIGHTS THROUGH FRIDAY. ANOTHER SMALL INCREASE IS
EXPECTED HEADING INTO THE WEEKEND AS A NEW LONG-PERIOD SOUTHWEST
SWELL ARRIVES FROM THE TASMAN SEA.
SURF ALONG EAST FACING SHORES WILL CONTINUE TO REMAIN ROUGH AND CHOPPY
WITH A SLIGHT BOOST IN SURF HEIGHTS EXPECTED THROUGH MID WEEK AS
THE TRADES STRENGTHEN AND AGAIN LATE THIS WEEK INTO THE WEEKEND
AS A SHORT-PERIOD NORTHEAST SWELL FILLS IN. SURF ALONG NORTH
FACING SHORES WILL CONTINUE TO DECLINE THROUGH WEDNESDAY AND
REMAIN NEARLY FLAT THROUGH THE WEEKEND.
FIRE WEATHER
TRADE WINDS WILL REMAIN IN THE MODERATE TO LOCALLY BREEZY RANGE
THROUGH THE FORECAST PERIOD. WEATHER CONDITIONS WILL BECOME MORE
DRY AND STABLE OVER THE NEXT COUPLE OF DAYS. SHOWER TRENDS MAY
INCREASE AS EARLY AS THURSDAY NIGHT INTO THE WEEKEND AS AN UPPER
LEVEL DISTURBANCE MOVES OVER THE ISLAND CHAIN AND LOW LEVEL
MOISTURE INCREASES.
HFO WATCHES/WARNINGS/ADVISORIES
SMALL CRAFT ADVISORY UNTIL 6 AM HST THURSDAY FOR MAALAEA BAY-
PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND LEEWARD WATERS-BIG
ISLAND SOUTHEAST WATERS.
DISCUSSION...ALMANZA
AVIATION...WROE
MARINE...FARRIS/VAUGHAN
FIRE WEATHER...ALMANZA
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