310
FXHW60 PHFO 140139
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
339 PM HST WED MAY 13 2026
SYNOPSIS
BREEZY TRADE WINDS WILL PERSIST INTO THURSDAY, WITH SHOWERS
FAVORING WINDWARD AND MAUKA AREAS. FRIDAY INTO THE WEEKEND, TRADES
WILL EASE SLIGHTLY AND A PASSING UPPER-LEVEL DISTURBANCE, ALONG
WITH INCREASING MOISTURE, MAY BRING AN UPTICK IN TRADE WIND SHOWER
ACTIVITY, WITH POCKETS OF HEAVY RAIN POSSIBLE. THEN A MORE STABLE,
BREEZY TRADE WIND PATTERN SHOULD REDEVELOP BY MIDWEEK NEXT WEEK.
DISCUSSION
BROAD HIGH PRESSURE TO THE FAR NORTH OF THE STATE (CENTERED
AROUND 40 N) WILL MAINTAIN BREEZY TRADE WINDS ACROSS THE REGION
INTO THURSDAY, DELIVERING CLOUDS AND ISOLATED TO SCATTERED SHOWERS
TO WINDWARD AND MAUKA AREAS, PARTICULARLY DURING THE OVERNIGHT TO
EARLY MORNING HOURS.
DURING THIS TIME, A WEAKNESS WILL DEVELOP IN THE RIDGE ALOFT AND A
MID- TO UPPER-LEVEL LOW WILL BREAK AWAY FROM THE BASE OF A
LONGWAVE TROUGH AND MOVE DIRECTLY OVER THE MAIN HAWAIIAN ISLANDS
BY FRIDAY EVENING. THIS UPPER LEVEL DISTURBANCE WILL INDUCE A
BROAD SURFACE TROUGH OVER THE REGION, WEAKENING THE LOCAL PRESSURE
GRADIENT AND ALLOWING THE TRADE WINDS TO EASE AND VEER SLIGHTLY.
COOLER TEMPERATURES ALOFT AND THE POTENTIAL WEAKENING OF THE LOW-
LEVEL INVERSION WILL HELP TO CREATE A MORE UNSTABLE ENVIRONMENT
OVER THE STATE, LIKELY ENHANCING TRADE WIND SHOWERS. IN ADDITION,
DEEP TROPICAL MOISTURE WILL MOVE UP FROM THE SOUTH, WITH MODELS
SHOWING PRECIPITABLE WATER VALUES CLIMBING INTO THE 1.5 TO ALMOST
2 INCH RANGE OVER THE EASTERN END OF THE STATE. THIS SETUP WILL
LIKELY BRING ENHANCED SHOWERS TO THE WESTERN END OF THE STATE
BEGINNING ON FRIDAY WHERE THE GREATEST INSTABILITY WILL BE, THEN
TRANSITION OVER THE EASTERN END BY SUNDAY INTO MONDAY, WHERE THE
DEEPEST MOISTURE WILL BE. THE MAIN LIMITING FACTOR TO A MORE
ORGANIZED ENHANCED SHOWER SETUP IS THE LACK OF ANY STRONG LIFTING
MECHANISM AT THE SURFACE. AS SUCH, THE MOST LIKELY LOCATIONS TO
EXPERIENCE HEAVY RAIN ARE THE WINDWARD AND MAUKA AREAS THAT ARE
IMPACTED BY OROGRAPHIC LIFT IN A TRADE WIND PATTERN, THOUGH THE
HI-RES GUIDANCE IS JUST NOW REACHING FRIDAY AFTERNOON WHERE THEY
ALSO HIGHLIGHT INTERIOR AND LEEWARD OAHU AS THE UPPER-LEVEL LOW
MOVES OVERHEAD AND THE BACKGROUND WINDS BECOME LIGHT ENOUGH TO
SUPPORT SEA BREEZE DEVELOPMENT. IN ADDITION TO THE THE POTENTIAL
FOR POCKETS OF HEAVY RAIN THIS WEEKEND, DEW POINTS ARE EXPECTED TO
RISE INTO THE LOWER 70S, LEAVING THIS WEEKEND FEELING MUGGIER
WITH LIGHTER WINDS.
BEYOND MONDAY, DIFFERENCES BETWEEN THE GLOBAL MODELS BECOME MORE
APPARENT, BUT FOR NOW, EXPECTING A MORE STABLE, BREEZY TRADE WIND
PATTERN TO REDEVELOP BY MIDWEEK NEXT WEEK.
AVIATION
A BREEZY TRADE WIND PATTERN WILL CONTINUE THROUGH THURSDAY DUE TO
A HIGH PRESSURE SYSTEM FAR NORTH OF THE ISLANDS. SHOWERS WILL
CONTINUE TO BE CARRIED IN ON THE TRADE WIND FLOW, AT TIMES
BRINGING SOME MVFR CONDITIONS MAINLY TO WINDWARD AND MAUKA AREAS.
OTHERWISE VFR CONDITIONS ARE EXPECTED TO PREVAIL.
AIRMET TANGO REMAINS IN EFFECT FOR MECHANICAL TURBULENCE TO THE
LEE OF THE MOUNTAINS DUE TO THE BREEZY TRADE WINDS. EXPECT THIS TO
REMAIN IN PLACE AT LEAST THROUGH THURSDAY.
MARINE
HIGH PRESSURE ESTABLISHED NORTH OF THE ISLANDS MAINTAINS LOCALLY
STRONG TRADES UNTIL AN UPPER DISTURBANCE CAUSES WINDS TO WEAKEN
BY THIS WEEKEND. LATE MORNING ASCAT INDICATED SMALL CRAFT
ADVISORY (SCA) CONDITIONS CONTINUING WITHIN THE WINDIER WATERS OF
MAUI COUNTY AND THE BIG ISLAND. THE SCA THEREFORE REMAINS IN
EFFECT FOR THOSE ZONES.
SMALL, SHORT PERIOD NW SWELL FADES TODAY AND WILL BE REPLACED BY
A SMALL TO MODERATE, LONG PERIOD NW SWELL THAT WILL PEAK ON
THURSDAY BRINGING SMALL TO MODERATE SURF TO FAVORED EXPOSURES.
SMALL, MEDIUM TO LONG PERIOD S SWELL MAINTAINS SMALL SURF ALONG S
SHORES. MEANWHILE, LOCALLY STRONG TRADES MAINTAIN CHOPPY SHORT
PERIOD CONDITIONS ALONG E SHORES.
TIDES PEAK AROUND 2.5 FT MLLW THIS WEEKEND. COMBINED WITH ONGOING
TRADES AND A MODEST BOOST IN S SWELL, WATER LEVELS WILL PEAK
AROUND 3.0 FT LATE THIS WEEKEND INTO EARLY NEXT WEEK. MINOR
OVERWASH OF LOW LYING COASTAL AREAS WILL BE POSSIBLE AT HIGH TIDE
DURING THIS TIME.
HFO WATCHES/WARNINGS/ADVISORIES
SMALL CRAFT ADVISORY UNTIL 6 PM HST THURSDAY FOR ALENUIHAHA
CHANNEL-BIG ISLAND LEEWARD WATERS-BIG ISLAND SOUTHEAST WATERS-
MAALAEA BAY-PAILOLO CHANNEL.
DISCUSSION...FARRIS
AVIATION...M BALLARD
MARINE...JVC
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