552
FXHW60 PHFO 150148
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
348 PM HST MON APR 14 2025
SYNOPSIS
TRADE WINDS WILL EASE INTO TUESDAY, WITH PASSING CLOUDS AND
SHOWERS FAVORING WINDWARD AND MAUKA AREAS. LIGHTER WINDS ARE
EXPECTED BY THE MIDDLE OF THE WEEK WITH FEWER WINDWARD SHOWERS AND
A GREATER CHANCE FOR AFTERNOON INTERIOR SHOWERS THROUGH THE
WEEKEND. AN UPPER LEVEL TROUGH AND DEEP ATMOSPHERIC MOISTURE WILL
ENHANCE SHOWER ACTIVITY ON THURSDAY AND FRIDAY AND BRING THE
POTENTIAL FOR THUNDERSTORMS AND HEAVY RAINFALL.
DISCUSSION
HIGH PRESSURE CENTERED TO THE NORTHEAST OF THE STATE WILL
MAINTAIN BREEZY TRADE WINDS ACROSS THE REGION THROUGH TONIGHT,
CONTINUING TO FOCUS INCOMING CLOUDS AND SHOWERS OVER WINDWARD AND
MAUKA AREAS. WATER VAPOR IMAGERY SHOWS A WEAK UPPER-LEVEL LOW
SPINNING OVER THE STATE. MID-LEVEL RIDGING WILL BRIEFLY BUILD
OVERHEAD TUESDAY NIGHT INTO EARLY WEDNESDAY.
AT THE SURFACE, A STRONG LOW PRESSURE SYSTEM TO THE FAR NORTH
WILL DISPLACE THE RIDGE THAT'S BEEN ANCHORED TO OUR NORTHEAST TO
BRING IT CLOSER TO, OR OVER, THE ISLAND CHAIN. THE PROXIMITY OF
THIS RIDGE AXIS AND THE APPROACH OF A COLD FRONT FROM THE
NORTHWEST WILL BRING LIGHTER SOUTHEAST WINDS ACROSS THE AREA
BEGINNING TUESDAY AND FOR NIGHTTIME LAND AND DAYTIME SEA BREEZES
BY WEDNESDAY.
A SHORTWAVE TROUGH WILL DIVE SOUTHEASTWARD DOWN THE ISLAND CHAIN
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT BEFORE WEAKENING AND MOVING
OFF THE EAST FRIDAY. THE MOST FAVORABLE UPPER-LEVEL DYNAMICS
ASSOCIATED WITH THE ORIENTATION OF THE SHORTWAVE TROUGH, THE
COOLEST TEMPERATURES ALOFT (500 MB AROUND -12C), AND THE DEEPEST
ATMOSPHERIC MOISTURE (PRECIPITABLE WATER AROUND 1.6 INCHES) ALL
SEEM TO LINE UP BEST ON THURSDAY AND FRIDAY. AS SUCH, HEAVY
SHOWERS AND A SLIGHT CHANCE OF THUNDERSTORMS HAVE BEEN ADDED TO
THE FORECAST ACROSS THE STATE FOR THURSDAY AND FRIDAY (MORE OF THE
FOCUS WILL BE ON BIG ISLAND FRIDAY).
LIGHT WINDS WILL CONTINUE INTO THE WEEKEND AS THE MID-LEVEL
SHORTWAVE WEAKENS RESULTING IN EITHER A LAND/SEA BREEZE PATTERN
WITH MORE MUTED DIURNAL CONVECTION OR A HYBRID SEA BREEZE PATTERN
WHICH WILL TEND TO FOCUS SHOWERS OVER WESTERN SLOPES OF EACH
ISLAND. GENTLE TO MODERATE TRADES WILL MOVE IN AROUND SUNDAY OR
EARLY NEXT WEEK.
AVIATION
MODERATE TO BREEZY TRADE WINDS WILL GRADUALLY EASE TONIGHT AND
TUESDAY. AIRMET TANGO FOR TURBULENCE BELOW 8,000 FEET OVER AND
DOWNWIND OF TERRAIN REMAINS IN EFFECT. CONDITIONS ARE BORDERLINE,
AND THE AIRMET WILL LIKELY BE DROPPED OVERNIGHT. THE TRADES WILL
PRODUCE BRIEF PERIODS OF MVFR CONDITIONS OVER WINDWARD TERRAIN,
AND ASIDE FROM SPOTTY AFTERNOON AND EVENING SHOWERS ON LEEWARD
SLOPES OF THE BIG ISLAND, VFR WILL PREVAIL ACROSS LEEWARD AREAS.
A MID-LEVEL RIDGE WILL MAINTAIN OVERALL STABLE CONDITIONS, THOUGH
A LINGERING WEAK UPPER-LEVEL TROUGH MAY TRIGGER AN ISOLATED HEAVY
SHOWER ON BIG ISLAND SLOPES DURING THE AFTERNOON HOURS.
MARINE
HIGH PRESSURE CENTERED FAR NORTHEAST OF THE STATE WILL MAINTAIN
MODERATE TO LOCALLY STRONG EAST TO SOUTHEASTERLY WINDS THROUGH
TONIGHT. A SMALL CRAFT ADVISORY (SCA) REMAINS IN EFFECT THROUGH 6
AM TUESDAY FOR THE EASTERN HALF MARINE ZONES. THE SCA IS TO MAINLY
ACCOUNT FOR THE TYPICALLY WINDIER WATERS SURROUNDING MAUI COUNTY
AND BIG ISLAND WITHIN THIS EAST SOUTHEAST FLOW PATTERN. WINDS WILL
BEGIN TO WEAKEN TUESDAY. BREEZES WILL TRANSITION TO LIGHT AND
VARIABLE ACROSS MORE WESTERN WATERS LATER IN THE WEEK, WHILE
STAYING GENTLE TO MODERATE EAST SOUTHEAST ACROSS THE STATE'S
EASTERN WATERS. THIS WILL BE IN RESPONSE TO THE APPROACH AND
EVENTUAL STALLING OF A FRONT NORTHWEST OF THE ISLANDS LATER THIS
WEEK.
A SMALL TO MODERATE SIZE, MEDIUM PERIOD NORTHWEST SWELL IS FILLING
AROUND KAUAI AND OAHU TODAY. NEARSHORE BUOYS ARE OBSERVING A 4 TO
6 FOOT SWELL PEAKING IN THE 14 TO 16 SECOND BANDS THIS AFTERNOON.
THIS SWELL WILL RESULT IN SLIGHTLY OVER HEAD TO DOUBLE HEAD HIGH
SURF WITHIN THE HIGHEST SETS ALONG MANY NORTH AND WEST-FACING
SHORES THROUGH THE EARLY TUESDAY MORNING HOURS. THE SWELL WILL
DECLINE FROM TUESDAY MORNING INTO WEDNESDAY. A LARGER MODERATE
SIZE NORTH NORTHWEST SWELL WILL ARRIVE THURSDAY. IF THIS SWELL
COMES IN AS GUIDANCE IS CURRENTLY SUGGESTING, SURF WILL ACHIEVE
HIGH SURF ADVISORY HEIGHTS ALONG MANY OF THE NORTH AND WEST-FACING
SHORES OF THE SMALLER ISLANDS THURSDAY NIGHT AND FRIDAY.
EAST-FACING SHORE SURF WILL REMAIN SOMEWHAT ROUGH TONIGHT DUE TO
RECENT STRONG EAST TRADES OVER AND UPSTREAM OF THE ISLANDS. AS WINDS
FALL OFF IN THE COMING DAYS, RESPONDING EAST CHOP WILL SIGNIFICANTLY
DROP OFF.
SURF ALONG SOUTH-FACING SHORES WILL REMAIN SMALL AND MOSTLY AT
BACKGROUND LEVELS THROUGH THURSDAY. A SERIES OF SMALL OVERLAPPING
SOUTH SWELLS COULD INCREASE SURF UP TO SEASONAL LEVELS FROM FRIDAY
THROUGH THE WEEKEND.
HFO WATCHES/WARNINGS/ADVISORIES
SMALL CRAFT ADVISORY UNTIL 6 AM HST TUESDAY FOR KAIWI CHANNEL-
MAUI COUNTY WINDWARD WATERS-MAUI COUNTY LEEWARD WATERS-MAALAEA
BAY-PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND WINDWARD
WATERS-BIG ISLAND LEEWARD WATERS-BIG ISLAND SOUTHEAST WATERS.
DISCUSSION...FOSTER
AVIATION...WROE
MARINE...BLOOD
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page