732
FXHW60 PHFO 170232
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
432 PM HST MON MAR 16 2026
SYNOPSIS
AN OVERALL WET WEATHER PATTERN WILL PERSIST THIS WEEK WITH BANDS
OF TRANSIENT SHOWERS, SOME OF WHICH COULD BE HEAVY AT TIMES,
MOVING OVER THE ISLANDS. WINDS WILL BE MUCH LIGHTER THAN THOSE
EXPERIENCED WITHIN RECENT DAYS, AND WILL BECOME VARIABLE THROUGH
MID-WEEK BEFORE SOUTHERLY FLOW RETURNS LATE THIS WEEK. AN
ADDITIONAL PERIOD OF HEAVY RAINFALL WILL BE POSSIBLE DURING THE
LATTER PORTION OF THIS WEEK AS A NEW, BUT MUCH WEAKER, KONA LOW
DEVELOPS NEAR THE ISLANDS.
DISCUSSION
THIS AFTERNOON, DEEP MOISTURE EMBEDDED WITHIN LIGHT TO MODERATE
SOUTHERLY BACKGROUND FLOW ACROSS THE EASTERN END OF THE STATE
CONTINUES TO STREAM OVER THE BIG ISLAND AND ITS SURROUNDING
WATERS, WITH FEWER SHOWERS OBSERVED NEAR EAST MAUI. POCKETS OF
HEAVY RAINFALL HAVE FALLEN OVER PORTIONS OF THE BIG ISLAND
THROUGHOUT THE DAY, INCLUDING THE KA'U AND PUNA DISTRICTS LATE
MORNING INTO EARLY AFTERNOON, FOLLOWED BY THE NORTH AND SOUTH
KOHALA AND KONA DISTRICTS AS OF MID-AFTERNOON. FOR THE REMAINDER
OF THE ISLANDS, MUCH LIGHTER AND MORE ISOLATED TO SCATTERED
SHOWERS HAVE OCCURRED THUS FAR TODAY. HOWEVER, ADDITIONAL
CONVECTION CAN BE SEEN DEVELOPING ON REGIONAL SATELLITE AND RADAR
IMAGERY AT THE WESTERN END OF THE STATE NEAR KAUAI AS OF PRESS
TIME, WHICH HAS THE POTENTIAL TO BRING SOME LOCALIZED HEAVY RAIN
TO THE GARDEN ISLE OVER THE NEXT FEW HOURS AS WELL. ALL OF THESE
SCENARIOS WERE DECENTLY WELL-SUPPORTED IN THE HI-RES GUIDANCE AND
HREF PROBABILITIES TODAY. FOR THIS EVENING AND TONIGHT, BANDS OF
SHOWERS, SOME OF WHICH COULD BE HEAVY AT TIMES, WILL CONTINUE TO
MOVE ACROSS PORTIONS OF THE STATE, THOUGH THE MAIN ONE LOOKS TO BE
THE WESTERNMOST BAND THAT WILL MOVE SOUTHEASTWARD THROUGHOUT THE
NIGHT. OF NOTE, WE ARE NOT EXPECTING ANYWHERE NEAR THE
SIGNIFICANT IMPACTS THAT WERE ASSOCIATED WITH THE KONA STORM LATE
LAST WEEK WITH THIS ACTIVITY.
THE HIGH WIND WARNING THAT WAS PREVIOUSLY IN EFFECT FOR THE BIG
ISLAND SUMMITS AND HALEAKALA HAS BEEN DOWNGRADED TO A WIND
ADVISORY WITH THIS AFTERNOON'S UPDATES. BASED ON THE LATEST
TRENDS, IT IS POSSIBLE THAT THIS ADVISORY WILL BE CANCELLED EARLY,
AS WIND SPEEDS HAVE QUICKLY DROPPED WITHIN THE PAST HOUR OR SO.
CURRENT MODEL SOLUTIONS FOR TUESDAY THROUGH MID-WEEK MAINTAIN AN
UPPER-LEVEL TROUGH ACROSS THE REGION, SUPPORTING A PATTERN OF
LIGHT AND VARIABLE WINDS WITH PERIODS OF OCCASIONAL SHOWERS.
DURING THE LATTER PART OF THE WEEK, CONFIDENCE IS INCREASING THAT
ANOTHER KONA LOW WILL DEVELOP WEST OF THE ISLANDS. IMPORTANTLY,
HOWEVER, THIS LOW IS EXPECTED TO BE CONSIDERABLY WEAKER THAN THE
MOST RECENT ONE, BUT COULD STILL BE CAPABLE OF DELIVERING PERIODS
OF HEAVY RAIN AND FLASH FLOODING. GUIDANCE INDICATES THAT WINDS
WILL ALSO NOT BE AS STRONG AS THE MOST RECENT STORM, AND ARE IN
FACT EXPECTED BE BE UNUSUALLY WEAK FOR A KONA LOW. IT REMAINS TOO
EARLY TO DETERMINE WHICH ISLANDS WILL BE THE MOST IMPACTED AT
THIS TIME, AND IS ALSO UNCERTAIN WHEN THE INITIAL FLOODING THREAT
MAY DEVELOP. WITH THAT SAID, THE FORECAST FOR THE EXTENDED PERIOD
HAS UNDERGONE SIGNIFICANT UPDATES WITH THIS AFTERNOON'S FORECAST
PACKAGE, MAINLY TO INCLUDE ADJUSTMENTS TO THE LOCATION, TIMING,
AND MAGNITUDE OF RAIN CHANCES FROM THURSDAY INTO THE WEEKEND.
GIVEN THE UNCERTAINTY AT THIS RANGE, THE FORECAST WILL CONTINUE TO
BE REFINED IN SUBSEQUENT UPDATES.
AVIATION
SHOWERS CONTINUE TO BRING INTERMITTENT MVFR AND IFR TO PHKO ON
THE BIG ISLAND THIS AFTERNOON AND TONIGHT. A SEPARATE BAND OF
SHOWERS MOVING IN FROM THE WEST WILL BEGIN TO IMPACT PHLI LATER
THIS AFTERNOON AND INTO TONIGHT AS A SURFACE TROUGH MOVES INTO THE
STATE. THIS BAND OF SHOWERS WILL MOVE THROUGH KAUAI, OAHU, AND
MAUI BEFORE REINFORCING THE SHOWERS ON THE BIG ISLAND TUESDAY.
OCCASIONAL MVFR IS FORECAST, AND ISOLATED IFR WILL CONTINUE TO
OCCUR.
AIRMET SIERRA REMAINS IN EFFECT FOR MOUNTAIN OBSCURATION FOR
MAUI, LANAI, AND THE BIG ISLAND. CONDITIONS HAVE NOT BEEN
IMPROVING AS MUCH AS PREVIOUSLY EXPECTED, AND THIS AIRMET MAY NEED
TO BE EXTENDED.
MARINE
THE GRADIENT WILL REMAIN RATHER WEAK THROUGH WEDNESDAY, WITH
LIGHT AND VARIABLE WINDS PREVAILING OVER THE WATERS. A BRIEF
PERIOD OF LIGHT TO MODERATE TRADES WILL BE POSSIBLE THURSDAY AS A
WEAK RIDGE BUILDS NORTH OF THE STATE, FOLLOWED BY LIGHT TO
MODERATE S WINDS ON FRIDAY AS A NEW SYSTEM APPROACHES FROM THE
WEST.
SURF ALONG S SHORES IS TRENDING DOWN AS S TO SW WINDS EASE. A NEW
LONG PERIOD SOUTH SWELL WILL THEN ARRIVE LATE TONIGHT AND
TUESDAY GIVING AN EXTENDED BOOST TO S SHORE SURF THROUGH LATE
THIS WEEK.
A MODERATE SHORT-PERIOD W SWELL ASSOCIATED WITH THE RECENT KONA
STORM IS AFFECTING N AND W FACING SHORES TODAY, BUT SURF REMAINS
BELOW THE ADVISORY THRESHOLD. THE SHORT-PERIOD W SWELL WILL LOWER
TONIGHT AND TUESDAY WHILE A NEW MEDIUM-PERIOD NNW SWELL FILLS IN.
THIS NNW SWELL COULD ELEVATE SURF TO NEAR THE ADVISORY THRESHOLD
TUESDAY NIGHT AND WEDNESDAY. THE SWELL THEN SHIFTS MORE N AND
LOWERS THURSDAY INTO THE WEEKEND.
SURF ALONG E FACING SHORES WILL REMAIN WELL BELOW NORMAL THROUGH
LATE WEEK AS TRADES OVER AND UPSTREAM OF THE ISLANDS REMAIN DISRUPTED.
HFO WATCHES/WARNINGS/ADVISORIES
WIND ADVISORY UNTIL 6 PM HST WEDNESDAY FOR HALEAKALA SUMMIT-BIG
ISLAND SUMMITS.
DISCUSSION...VAUGHAN
AVIATION...PARKER
MARINE...JVC
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