582
FXHW60 PHFO 030658
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
858 PM HST MON DEC 2 2024
SYNOPSIS
RELATIVELY DRY AND STABLE CONDITIONS WILL PERSIST THROUGH MID
WEEK WITH LIGHT WINDS THAT WILL ALLOW FOR SEA BREEZES EACH DAY AND
LAND BREEZES OVERNIGHT. A FRONT WILL MOVE THROUGH KAUAI ON
THURSDAY THEN DISSIPATE OVER THE CENTRAL PORTION OF THE STATE ON
FRIDAY. CHANCES OF RAIN WILL INCREASE AHEAD OF AND ALONG THE
FRONTAL BOUNDARY WITH MODERATE TO LOCALLY BREEZY NORTHEAST WINDS
FILLING IN BEHIND IT.
DISCUSSION
A DRY AND STABLE AIR MASS WILL REMAIN IN PLACE THROUGH TUESDAY
DUE TO A RIDGE OF HIGH PRESSURE OVER THE STATE. WINDS WILL BE
LIGHT AND VARIABLE WITH A BACKGROUND SOUTHERLY FLOW. WINDS SHOULD
BE LIGHT ENOUGH FOR DAY TIME SEA BREEZES AND NIGHT TIME LAND
BREEZES. DAY TIME SEA BREEZES WILL LEAD TO AFTERNOON CLOUDS OVER
INTERIOR AND MOUNTAIN AREAS WITH A FEW LIGHT SHOWERS POSSIBLE.
OVER ON THE BIG ISLAND, THERE IS A POCKET OF MOISTURE MOVING IN
FROM THE SOUTH. PAHALA RAIN GAUGE HAS PICKED UP 0.69 INCHES IN
THE PAST HOUR. RAINFALL IS EXPECTED TO TREND DOWN THROUGH THE
NIGHT AS LAND BREEZES DEVELOP, PUSHING THE AREA OF CONVERGENCE
OFFSHORE. HOWEVER, A SLIGHTLY STRONGER SOUTHEAST FLOW IS EXPECTED
IN THE MORNING WHICH SHOULD CONTINUE TO PRODUCE SOME SHOWERS OVER
SOUTHEAST BIG ISLAND DURING THE NEXT FEW DAYS ESPECIALLY DURING
THE AFTERNOON AND EVENING HOURS.
STARTING WEDNESDAY, A FRONT WILL BEGIN TO APPROACH THE STATE FROM
THE NORTHWEST AND WILL STRENGTHEN THE SOUTHERLY WIND FLOW
ESPECIALLY AROUND KAUAI. CHANCES OF SHOWERS WILL GRADUALLY
INCREASE ON WEDNESDAY MAINLY FOR THE WESTERN END OF THE STATE AS
THE FRONT APPROACHES KAUAI. BY THURSDAY, THE FRONT IS EXPECTED TO
BE OVER OR THROUGH KAUAI WITH SOME PREFRONTAL SHOWERS INCREASING
OVER OAHU AND POSSIBLY PARTS OF MAUI COUNTY. THE FRONT IS EXPECTED
TO EVENTUALLY STALL OUT AND DISSIPATE NEAR THE CENTRAL PORTION OF
THE STATE FRIDAY. OVERALL THE FRONT DOES NOT LOOK VERY
IMPRESSIVE, BUT IT COULD BRING SOME LIGHT TO MODERATE RAINFALL TO
SOME MUCH NEEDED LOCATIONS ON THE LEEWARD SIDE. SOME LOCALLY HEAVY
RAINFALL WILL BE POSSIBLE LATE THURSDAY INTO FRIDAY, IN THE AREA
WHERE THE FRONTAL BOUNDARY STALLS.
MODERATE TO LOCALLY BREEZY TRADES SHOULD BRIEFLY RETURN OVER THE
WESTERN HALF OF THE STATE ON FRIDAY AS A WEAK HIGH DEVELOPS
NORTHWEST OF THE STATE. TRADES WILL BE SHORT- LIVED AS THE HIGH
QUICKLY SHIFTS EAST AS ANOTHER FRONT PASSES NORTH OF THE STATE.
THIS WILL PUT THE WESTERN END OF THE STATE IN A LIGHT WIND FLOW
PATTER WHILE GENTLE EASTERLY WINDS LINGER OVER THE EASTERN END.
CONFIDENCE IN THE WEATHER FORECAST OVER THE WEEKEND REMAINS LOW
WITH MOST OF THE ENSEMBLE MEMBERS SHOWING SOME TYPE OF UPPER LEVEL
TROUGH PUSHING THROUGH THE STATE. STAY TUNED FOR MORE DETAILS.
AVIATION
A DEEP RIDGE OVER THE STATE WILL MAINTAIN A STABLE AND RATHER DRY
LAND/SEA BREEZE PATTERN AND PREVAILING VFR FOR THE NEXT COUPLE OF
DAYS. ANY CIGS WILL MAINLY BE VFR, AND LITTLE RAINFALL IS
EXPECTED. OVERNIGHT LAND BREEZES WILL LEAD TO CLEARING OVER MOST
AREAS.
NO AIRMETS ANTICIPATED.
MARINE
AN E-W ORIENTED RIDGE OF HIGH PRESSURE EXTENDING OVER THE ISLANDS
FROM THE E IS SUPPORTING GENTLE WINDS STATEWIDE THAT ARE OUT OF
THE E-SE OVER BIG ISLAND WATERS, AND FROM THE S-SW OVER KAUAI AND
OAHU WATERS. LITTLE OVERALL CHANGE IN THE RIDGE'S POSITION IS
EXPECTED THROUGH WEDNESDAY.
A LOW PASSING N OF THE ISLANDS LATE WEDNESDAY AND THURSDAY WILL
FORCE THE RIDGE EASTWARD, WITH A TIGHTENING LOW-LEVEL GRADIENT
SUPPORTING FRESH TO LOCALLY STRONG S TO SW WINDS STATEWIDE AS AN
ASSOCIATED FRONT APPROACHES FROM THE NW. FAIRLY HIGH CONFIDENCE IN
THE FRONT MOVING OVER PORTIONS OF THE ISLANDS FROM LATE THURSDAY
INTO FRIDAY, LIKELY STALLING ON FRIDAY OVER THE CENTRAL PORTION OF
THE ISLAND CHAIN. WINDS AND SEAS WILL LIKELY REACH SMALL CRAFT
ADVISORY CRITERIA IN AT LEAST SOME OF THE WATERS THURSDAY AND
FRIDAY.
FAIRLY DYNAMIC CHANGES TO THE WIND SPEED AND DIRECTION ARE
EXPECTED THEREAFTER, WITH LOCALLY FRESH POST-FRONTAL N WINDS
WEAKENING AND VEERING TO THE NE THURSDAY NIGHT INTO FRIDAY, THEN
QUICKLY WEAKENING INTO SATURDAY, WHEN A PERIOD OF LIGHT AND
VARIABLE WINDS IS EXPECTED. INCREASING TRADE WIND FLOW IS EXPECTED
IN THE LONGER TERM.
FAST-MOVING LOW PRESSURE SYSTEMS PASSING EASTWARD WELL N OF THE
ISLANDS WILL SEND NW SWELL OF VARYING SIZES AND PERIODS TOWARD THE
ISLANDS THIS WEEK. ALTHOUGH MOST OF THE SWELL ENERGY WILL REMAIN
IN THE SHORTER-PERIOD BANDS OF 12-14 SECONDS, RESULTANT SURF WILL
BE NEAR OR ABOVE HIGH SURF ADVISORY (HSA) LEVELS ALONG EXPOSED N
AND W FACING SHORES.
IN THE SHORT TERM, INCREASING WAVE HEIGHTS AT NDBC BUOYS
51001/51101 NW OF KAUAI ARE PRIMARILY ASSOCIATED WITH RELATIVELY
SHORT-PERIOD NW SWELL ENERGY, WITH SOME LONGER PERIOD ENERGY
INTERTWINED. SIGNIFICANT WAVE HEIGHTS ARE NEAR 10 FEET, BUT
VALUES ARE NOT SUFFICIENTLY HIGH TO WARRANT THE ISSUANCE OF A HSA
AT THIS TIME. SOME INCREASE IN LONGER-PERIOD ENERGY IS ANTICIPATED
OVERNIGHT, AND IF IT DEVELOPS, SURF COULD REACH HSA HEIGHTS
TUESDAY AFTERNOON INTO WEDNESDAY. ANOTHER SWELL THURSDAY INTO
FRIDAY WILL LIKELY PRODUCE HSA-LEVEL SURF BEFORE A GENERAL
DIMINISHING TREND IN NW SWELL DEVELOPS NEXT WEEKEND.
A LONG-PERIOD S SWELL WILL PEAK THROUGH TUESDAY, PRODUCING
SURF NEAR SUMMERTIME AVERAGES ALONG S FACING SHORES, BEFORE
GRADUALLY DIMINISHING THROUGH THURSDAY. ANOTHER SIMILARLY-SIZED
LONG-PERIOD S SWELL IS EXPECTED BY NEXT WEEKEND.
FIRE WEATHER
CRITICAL FIRE WEATHER CONDITIONS ARE NOT EXPECTED THROUGH THE
WEEK AND INTO THE WEEKEND. DAYTIME RELATIVE HUMIDITY VALUES MAY
BRIEFLY APPROACH CRITICAL LEVELS TUESDAY AFTERNOON BUT WINDS WILL
REMAIN LIGHT AND PRECLUDE ANY FIRE WEATHER CONCERNS. FROM WEDNESDAY
INTO THE WEEKEND, MINIMUM RELATIVE HUMIDITY VALUES ARE EXPECTED
TO TREND ABOVE CRITICAL LEVELS DUE TO INCREASING MOISTURE AND
SHOWERS AS A FRONT APPROACHES AND DISSIPATES NEAR THE CENTRAL
PORTION OF THE STATE.
HFO WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...ALMANZA
AVIATION...WALSH
MARINE...BIRCHARD
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