372
FXHW60 PHFO 151301
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
301 AM HST FRI MAY 15 2026
SYNOPSIS
MODERATE TO LOCALLY BREEZY TRADE WINDS WILL CONTINUE TONIGHT,
WITH PERIODS OF SHOWERS FAVORING WINDWARD MOUNTAIN AREAS. AN UPPER
LEVEL LOW WILL BRIEFLY MOVE OVER THE REGION TODAY AND TONIGHT,
ENHANCING THREATS FOR LOCALLY HEAVY RAINFALL AND ISOLATED
THUNDERSTORMS. EXPECT PERIODS OF HEAVY SHOWERS ALONG WITH ISOLATED
TO SCATTERED THUNDERSTORMS TODAY ACROSS THE ISLANDS IN KAUAI
COUNTY, OAHU, AND MAUI COUNTY. A WET TRADE WIND WEATHER PATTERN
HOWEVER WILL LIKELY CONTINUE THROUGH SUNDAY MORNING FOR MOST
AREAS. MORE TYPICAL TRADE WIND WEATHER WILL RETURN FROM LATE
SUNDAY INTO THE END OF NEXT WEEK WITH BRIEF PASSING SHOWERS IN THE
FORECAST AS MODERATE TO LOCALLY BREEZY TRADE WINDS CONTINUE TO
BLOW ACROSS THE REGION.
DISCUSSION
AN UNSTABLE UPPER LEVEL LOW CONTINUES TO DROP INTO THE ISLANDS
FROM THE NORTH THIS MORNING WITH THUNDERSTORMS FORMING LESS THAN
100 MILES NORTH OF NIIHAU, KAUAI, AND OAHU. EXPECT PERIODS OF
HEAVY SHOWERS ALONG WITH ISOLATED TO SCATTERED THUNDERSTORMS TODAY
ACROSS THE ISLANDS IN KAUAI COUNTY, OAHU, AND MAUI COUNTY. A
FLOOD WATCH WAS ISSUED THROUGH THIS AFTERNOON FOR THESE ISLANDS
DUE TO THE HEAVY RAIN AND FLOODING THREATS ACROSS MOST OF THE
STATE. THIS WATCH MAY NEED TO BE EXTENDED INTO THE OVERNIGHT HOURS
FOR SOME AREAS AS THIS UPPER LOW PIVOTS OVER KAUAI, THEN WEAKENS
AND DRIFTS EASTWARD ACROSS THE STATE.
UNSTABLE COLD AIR ALOFT WITHIN THIS UPPER LEVEL LOW WILL ENHANCE
SHOWER ACTIVITY STATEWIDE, SHOWERS WILL BECOME HEAVY AT TIMES
WITH ISOLATED TO SCATTERED THUNDERSTORMS. SMALL SCALE LOW LEVEL
WIND CONVERGENCE BANDS AND THUNDERSTORM OUTFLOWS WILL LIKELY DRIVE
THE HEAVIEST SHOWER ACTIVITY TODAY. HIGHER RAINFALL RATES WILL
LIKELY LEAD TO FLASH FLOODING IN SOME AREAS THROUGH AT LEAST THE
AFTERNOON HOURS AND POSSIBLY INTO THE OVERNIGHT TIME PERIOD. THIS
LOW WILL SLOWLY WEAKEN AS IT DRIFTS EASTWARD ON SATURDAY,
DECREASING THE THREAT FOR HEAVY RAINFALL, ESPECIALLY AS THE LOW
DEPARTS THE HAWAII REGION ON SUNDAY. A WET TRADE WIND WEATHER
PATTERN HOWEVER WILL LIKELY CONTINUE THROUGH SUNDAY MORNING FOR
MOST AREAS.
A BROAD HIGH PRESSURE RIDGE REMAINS IN PLACE NORTH OF THE ISLANDS
THROUGH MUCH OF NEXT WEEK. EXPECT A MORE TYPICAL MODERATE TO
LOCALLY BREEZY TRADE WIND WEATHER BLOWING ACROSS THE HAWAIIAN
ISLANDS FROM LATE SUNDAY INTO THE END OF NEXT WEEK. BRIEF PASSING
SHOWERS WILL OCCUR FAVORING THE WINDWARD MOUNTAIN AREAS IN THE
OVERNIGHT TO EARLY MORNING HOURS.
AVIATION
MODERATE TO LOCALLY BREEZY TRADES. LOW CIGS AND SHRA POSSIBLE
ALONG WINDWARD AND MAUKA LOCATIONS WITH SOME SPILLOVER POSSIBLE
INTO LEEWARD AREAS. MVFR CONDS IN ANY HEAVIER SHRA BUT VFR SHOULD
PREVAIL. AN UPPER LOW NEAR THE STATE MAY PROVIDE THE POTENTIAL FOR
PERIODS OF +RA AND ISOL TSTMS, ESPECIALLY OVER WESTERN SIDE OF
THE STATE. CONDS MAY DETERIORATE TO IFR/MVFR IN THOSE LOCATIONS.
AIRMET SIERRA IS IN EFFECT FOR MTN OBSC FOR WINDWARD LOCATIONS OF
ALL ISLANDS DUE TO CLDS AND SHRA.
AIRMET TANGO IS IN EFFECT FOR LOW-LEVEL TURB LEE OF TERRAIN DUE
TO THE BREEZY TRADES.
MARINE
AN UPPER LEVEL LOW AND ITS SURFACE REFLECTION TROUGH NORTH OF
KAUAI WILL TURN WEAKENING WINDS MORE EAST SOUTHEAST TODAY AND
THIS WEEKEND. THE SMALL CRAFT ADVISORY (SCA) HAS BEEN EXTENDED TO
COVER THOSE WATERS SURROUNDING MAUI COUNTY AND BIG ISLAND THROUGH
6 AM HST SATURDAY. THE CLOSE PROXIMITY OF THE UPPER LOW, ALONG
WITH DISTURBANCES COMING UP AROUND THE LOW FROM THE SOUTH
SOUTHWEST, WILL PRODUCE WIDESPREAD RAIN WITH PERIODS OF LOCALLY
HEAVY RAINFALL AND SCATTERED THUNDERSTORMS, ACROSS THE NEARSHORE
WATERS.
A SMALL, MODERATE PERIOD NORTH NORTHWEST (320-330 DEGREE) SWELL
THAT PEAKED LAST NIGHT IS COMING DOWN THIS MORNING AND WILL
PRODUCE NEAR TO SLIGHTLY ABOVE HEAD HIGH SURF ALONG MANY NORTH-
FACING SHORES TODAY. THIS SWELL WILL GRADUALLY DECLINE INTO THE
WEEKEND.
A MIX OF SMALL, MEDIUM TO LONG PERIOD SOUTH SWELLS WILL MAINTAIN
SMALL SURF ALONG SOUTH-FACING SHORES INTO THE WEEKEND. A SERIES
OF GALE LOWS PASSING SOUTH OF NEW ZEALAND SHOULD SEND SMALL SOUTH
SWELL INTO THE SOUTHERN WATERS THROUGH NEXT WEEK. SURF SHOULD
LIFT TO SUMMER AVERAGES AROUND SUNDAY AND THIS WILL HOLD THROUGH
WEDNESDAY OF NEXT WEEK. LOCALLY MODERATE TO FRESH TRADES WILL
MAINTAIN ROUGH AND CHOPPY SURF ALONG EAST-FACING SHORES.
TIDES WILL PEAK AROUND 2.5 FT MLLW THIS WEEKEND. COMBINED WITH
ONGOING TRADES AND A SMALL SOUTH SWELL BUMP, WATER LEVELS WILL
PEAK NEAR 3.0 FT AS EARLY AS TOMORROW. MINOR OVERWASH OF LOW
LYING COASTAL AREAS WILL BE POSSIBLE DURING TIMES OF HIGH TIDE.
HFO WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH THROUGH THIS AFTERNOON FOR NIIHAU, KAUAI, OAHU,
MOLOKAI, LANAI, KAHOOLAWE, AND MAUI.
SMALL CRAFT ADVISORY UNTIL 6 AM HST SATURDAY FOR MOST WATERS
SURROUNDING MAUI COUNTY AND THE BIG ISLAND.
DISCUSSION...BOHLIN
AVIATION...WALSH
MARINE...BLOOD
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